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Proxy records of climate change in subtropical and tropical karst environments

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Title:
Proxy records of climate change in subtropical and tropical karst environments
Physical Description:
Book
Language:
English
Creator:
Polk, Jason Samuel
Publisher:
University of South Florida
Place of Publication:
Tampa, Fla
Publication Date:

Subjects

Subjects / Keywords:
Paleoclimate
Caves
Florida
Stable isotopes
Holocene
Dissertations, Academic -- Geography/Environmental Science and Policy -- Doctoral -- USF   ( lcsh )
Genre:
non-fiction   ( marcgt )

Notes

Summary:
ABSTRACT: Understanding the paleoclimate of a region is important, especially when trying to determine the extent of natural climate variability within the context of anthropogenic impacts. Recent anomalous periods of climate change in the Late Holocene, including the Little Ice Age and Medieval Warm Period, could possibly repeat in the future, having significant worldwide consequences. This holds especially true for tropical and subtropical karst environments, where limited paleoclimate proxies provide minimal data regarding past climate change. An investigation into past climate change in Belize using fulvic acids from cave sediments shows periods of drought during the collapse of the Maya society around 1400 years ago. Comparison of changes in the carbon isotope data from the fulvic acids agree with speleothem records, but more closely reflect changes in the vegetation above the cave, showing Maya population decline through waning agriculture.Further investigation of using fulvic and other organics acids are examined from cave sediments in Florida. The data show fulvic acid carbon isotopes are the most robust recorders of climate change, agreeing with several nearby speleothem δ¹⁸O and δ¹³C records from west-central Florida. A more detailed record of climate change in Florida through a calibration study of precipitation and cave dripwater oxygen and hydrogen isotopes revealed that the amount effect dominates rainfall in west-central Florida. Homogenization of epikarst dripwater gives average δ¹⁸O values representative of the annual amount-weighted average of precipitation δ¹⁸O for the area, suggesting speleothem isotope records reflect changes in rainfall amount. Examination of two speleothems from west-central Florida show complex teleconnection and solar forcing mechanisms responsible for past climate changes.A high-resolution stable isotope, trace element, and time series analysis study for the last 1500 years shows variability during the LIA and MWP, pointing to a combined influence of Pacific and Atlantic teleconnection mechanisms, especially the ITCZ, NAO and PDO, being responsible for precipitation variability. Long-term reconstruction of the mid-Holocene and Late Pleistocene from another speleothem reveals differences in temperature and precipitation between glacial and interglacial conditions in Florida. Climate proxies from the tropics and subtropics provide additional clues to global climate change crucial to understanding future water availability.
Thesis:
Dissertation (Ph.D.)--University of South Florida, 2009.
Bibliography:
Includes bibliographical references.
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Mode of access: World Wide Web.
System Details:
System requirements: World Wide Web browser and PDF reader.
Statement of Responsibility:
by Jason Samuel Polk.
General Note:
Title from PDF of title page.
General Note:
Document formatted into pages; contains 629 pages.
General Note:
Includes vita.

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Source Institution:
University of South Florida Library
Holding Location:
University of South Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 002046180
oclc - 495699102
usfldc doi - E14-SFE0003058
usfldc handle - e14.3058
System ID:
SFS0027375:00001


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Proxy Records of Climate Change in Subtropical and Tropical Karst Environments by Jason Samuel Polk A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Geography College of Arts and Sciences University of South Florida Major Professor: Philip van Beynen, Ph.D. Robert Brinkmann, Ph.D. Bogdan Onac, Ph.D. Philip Reeder, Ph.D. Jonathan Wynn, Ph.D. Date of Approval: April 30, 2009 Keywords: paleoclimate, caves, Fl orida, stable isotopes, Holocene, teleconnections, speleothems Copyright 2009, Jason Samuel Polk

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h d c I ded ere at the d edicate thi s ompletion o i cate this t o d estination s to my fa m o f this doc u o those wh o I will rem e m ily, friends u ment and m Dedicati o o were with e mber you a and Lesli e m y succes s o n me during a lways, re s e all of wh o s in life thu s the journe y s t in peace. o m were in t s fa r y but are n I further t egral in m y n ot y

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i Table of Contents List of Figures ....................................................................................................... vii List of T ables ........................................................................................................ xi List of E quations ................................................................................................... xii Abstract ............................................................................................................... xiii Preface ................................................................................................................ xv Chapter 1: Introduction, Context and Pu rpose....................................................... 1 1.1 Introdu ction ........................................................................................... 1 1.2 Climate Change .................................................................................... 2 1.3 Teleco nnections ................................................................................... 3 1.4 Proxy Records ...................................................................................... 5 1.5 Karst Proxies ........................................................................................ 6 1.6 Social and Ph ysical Cont ext ................................................................. 7 1.7 Research Purpos e .............................................................................. 13 1.8 Broader Impacts .................................................................................. 13 1.9 Dissertation Organization .................................................................... 14 1.10 Chapter Re ferences .......................................................................... 17 Chapter 2: Background and Literature Review .................................................... 21 2.1 Chapter Prefac e .................................................................................. 21 2.2 Introdu ction ......................................................................................... 21 2.3 Karst Environments ............................................................................. 22 2.4 Cave Deposits as Proxy Re cord ......................................................... 23 2.5 Speleothem Formation ........................................................................ 23 2.6 Stable Isotopes ................................................................................... 25 2.6.1 Stable Is otope Geochem istry ................................................ 25 2.6.2 Oxy gen Isotopes ................................................................... 27 2.6.3 Car bon Isotopes .................................................................... 30 2.7 Speleothem Oxygen Isotopes ( 18O) .................................................. 31 2.8 Speleothem Carbon Isotopes ( 13C) ................................................... 33 2.9 Speleothem Equilib rium Deposi tion .................................................... 35 2.10 Speleot hem Dati ng ........................................................................... 37

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ii 2.11 Atmospheric-Oceani c Teleconnec tions ............................................ 38 2.11.1 Atmospheric-O ceanic Influ ences ......................................... 38 2.11.2 North Atlantic Oscillation (NAO) .......................................... 40 2.11.3 Atlantic Multi decadal Oscillati on (AMO ) .............................. 41 2.11.4 El-Nio-Southe rn Oscillation (ENSO) .................................. 42 2.11.5 Intertropical Convergence Zone (ITCZ) ............................... 43 2.11.6 Pacific Decadal Oscillation (PDO ) ....................................... 43 2.12 Belize Pal eoclimate .......................................................................... 44 2.13 Florida Climat e Influenc es ................................................................ 46 2.14 Florida Pa leoclima te ......................................................................... 47 2.15 Chapter Re ferences .......................................................................... 49 Chapter 3: Late Holocene En vironmental Reconstructi on using Cave Sediments from Be lize ........................................................................................................... 60 3.1 Chapter Preface ................................................................................ 60 3.2 Abst ract .............................................................................................. 61 3.3 Introdu ction ......................................................................................... 61 3.3.1 Cave Sedim ents .................................................................... 67 3.3.2 Car bon Isotopes .................................................................... 69 3.4 Study Area ......................................................................................... 69 3.4.1 V egetatio n ............................................................................. 71 3.4.2 Climate .................................................................................. 72 3.4.3 Refl ection Ca ve ..................................................................... 72 3.5 Met hodology ...................................................................................... 74 3.5.1 Field Sa mple Colle ction ......................................................... 74 3.5.2 Radiocarbon Dating ............................................................... 74 3.5.3 Stable Carbon Isot opes ......................................................... 74 3.6 Results ................................................................................................ 76 3.6.1 Ch ronology ............................................................................ 76 3.6.2 Interpretation of FA Carbon Isotopes .................................... 78 3.7 Discu ssion .......................................................................................... 81 3.7.1 Interpretation of Cave Sediment Record ............................... 81 3.7.2 Proxy Climate Record Com parisons ..................................... 84 3.7.3 Climatic C auses of Ar idity ..................................................... 88 3.8 Conclu sions ........................................................................................ 89 3.9 Chapter A cknowledgem ents ............................................................... 91 3.10 Chapter References .......................................................................... 92 Chapter 4: Investigatin g a Multi-proxy Approach to Paleoenvironmental Reconstruction in Florida using Cave S ediment s ................................................ 99 4.1 Chapter Prefac e ................................................................................. 99 4.2 Abstra ct ............................................................................................ 100 4.3 Introdu ction ....................................................................................... 101 4.4 Research Purpose ............................................................................ 103 4.4.1 Research Questions ............................................................ 104

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iii 4.5 Backgr ound ...................................................................................... 104 4.5.1 Cave Sediment s .................................................................. 104 4.5.2 Car bon Isotopes .................................................................. 107 4.5.3 Orga nic Acid s ...................................................................... 108 4.5.4 Florida Ca ve Sedim ents ...................................................... 111 4.6 Study Areas ...................................................................................... 114 4.6.1 Vandal Cave ........................................................................ 118 4.6.2 Geologi c Setting .................................................................. 120 4.6.3 Climate ................................................................................ 120 4.6.4 Soil a nd Vegetati on ............................................................. 121 4.7 Methodol ogy ..................................................................................... 124 4.7.1 Jennings Cave ..................................................................... 124 4.7.2 Radiocarbon Dating ............................................................. 126 4.7.3 Bulk sediment, HA, and FA, 13C Analysis .......................... 126 4.7.4 Pollen Analysis ................................................................... 128 4.7.5 Vandal Ca ve Analysis ......................................................... 129 4.7.6 Lead-210 (210Pb) Dating ...................................................... 131 4.7.7 FA 13C Analysis ................................................................. 131 4.8 Results .............................................................................................. 131 4.8.1 Cave S ediment Co res ......................................................... 131 4.8.2 Jennings Ca ve Sedim ents ................................................... 132 4.8.3 Physica l Descripti on ............................................................ 132 4.8.4 Radiocarbon Dating ............................................................. 133 4.8.5 Cave Sediment Carbon Isotope Data .................................. 134 4.8.6 Humic Acid 13C .................................................................. 135 4.8.7 Fulvic Acid 13C ................................................................... 136 4.8.8 Bulk Sediment 13C ............................................................. 138 4.8.9 Polle n Data .......................................................................... 140 4.9 Jennings Cave S ediment Discu ssion ............................................... 142 4.9.1 Interpretation of 13C Isotopes ............................................. 142 4.9.2 Fulvic Acid Carbon Isot opes ................................................ 143 4.9.3 Discounting Humic Acid and Bulk Carbon Isotopes ............ 144 4.9.4 Interpretation of Cave Sediment FAs 13C Data .................. 145 4.9.5 Polle n Data .......................................................................... 147 4.9.6 Comparison of J1-07 13C to Speleothem Records ............. 149 4.9.7 Precipitation Proxy Compar isons ........................................ 152 4.9.8 Climate Implicat ions from the J1-07 FA 13C Record .......... 158 4.9.9 Sediment Layering and Nature of D eposition ...................... 158 4.10 Vandal Cave Sedi ment Resu lts ...................................................... 160 4.10.1 Vandal Ca ve Sedim ents .................................................... 160 4.10.2 Vandal Cave Sediment Physical Charac teristics ............... 160 4.10.3 Pb210 Dating ..................................................................... 161 4.10.4 V1-08 Fulvic Acid 13CResults ........................................... 164 4.11 Vandal Cave Sedi ments Discussi on ............................................... 165 4.11.1 Depositi on Rates and Age ................................................. 165

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iv 4.11.2 Vandal Cave S ediment Laye ring ....................................... 167 4.11.3 V1-08 Car bon Isotope Da ta ............................................... 170 4.11.4 Vandal Cave Ca libration Pot ential ..................................... 172 4.12 Conclu sions .................................................................................... 174 4.13 Chapter Ack nowledgement s ........................................................... 175 4.14 Chapter References ........................................................................ 176 Chapter 5: An Isotopic Calibration Study of Precipitation, Cave Dripwater, and Climate in West-central Florida .......................................................................... 186 5.1 Chapter Preface ............................................................................... 186 5.2 Abstra ct ............................................................................................ 186 5.3 Introdu ction ....................................................................................... 187 5.3.1 Research Objectives ........................................................... 191 5.4 Study Area ........................................................................................ 191 5.4.1 Geologic and Hydrologic Se tting ......................................... 194 5.4.2 Climate and Vegetati on ....................................................... 195 5.5 Methodol ogy ..................................................................................... 196 5.5.1 Cave Dripwa ter Collecti on ................................................... 197 5.5.2 Precipitat ion Collecti on ........................................................ 199 5.5.3 Stable Is otope Analysi s ....................................................... 201 5.5.4 Synoptic and Meso scale Climate Data ................................ 202 5.5.5 Data Analysis ...................................................................... 203 5.6 Results and Discussion .................................................................... 203 5.6.1 Precipitati on Isotopic Da ta ................................................... 205 5.6.2 Controls on Isotopic Comp osition of Precip itation ............... 207 5.6.3 Deuter ium Exce ss ............................................................... 212 5.6.4 Cave Dripwa ter Isotopic Data .............................................. 213 5.6.5 Synoptic Weather Data and Climate Change ...................... 216 5.6.6 Teleconnec tion Influenc es ................................................... 221 5.6.7 Applicability to Speleothem Cali bration ............................... 222 5.7 Conclu sions ...................................................................................... 223 5.8 Chapter Ack nowledgement s ............................................................. 224 5.9 Chapter References .......................................................................... 225 Chapter 6: High-Resolution Late Holoc ene Paleoclimate in Florida ................. 230 6.1 Chapter Preface ................................................................................ 230 6.2 Abstract ............................................................................................. 230 6.3 Introdu ction ....................................................................................... 231 6.4 Study Area ........................................................................................ 234 6.4.1 Brooksvill e Ridge Cave ....................................................... 234 6.4.2 Geologic and Hydrologic Se tting ......................................... 234 6.4.3 Climate and Vegetati on ....................................................... 236 6.5 Methodol ogy ..................................................................................... 237 6.5.1 234U-230Th Chronol ogy ......................................................... 237 6.5.2 Stable Is otope Analysi s ....................................................... 238

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v 6.5.3 Trace El ement Anal ysis ....................................................... 239 6.5.4 Petrogr aphic Analysi s .......................................................... 240 6.5.5 Time Se ries Anal ysis ........................................................... 240 6.6 Results and Discussion .................................................................... 243 6.6.1 Petr ography ......................................................................... 243 6.6.2 Chronology a nd Stable Isot opes ......................................... 245 6.6.3 Local Proxy Influences & Isotope Interp retation .................. 249 6.6.4 Trac e Element s ................................................................... 250 6.6.5 Time Se ries Anal ysis ........................................................... 253 6.6.6 Local Clim ate Influenc es ..................................................... 259 6.6.7 Regional Tele connections Infl uences .................................. 264 6.6.8 Large-scale Tele connection Infl uences ............................... 266 6.6.9 Complexity of Telecon nections............................................ 274 6.7 Conclu sions ...................................................................................... 276 6.8 Chapter Ack nowledgement s ............................................................. 278 6.9 Chapter References .......................................................................... 279 Chapter 7: Late Pleistocene and mid-Ho locene Climate Change from a Florida Speleothe m ....................................................................................................... 286 7.1 Chapter Preface ................................................................................ 286 7.2 Abstract ............................................................................................. 286 7.3 Introdu ction ....................................................................................... 288 7.4 Study Area ........................................................................................ 291 7.4.1 Brooksvill e Ridge Cave ....................................................... 291 7.4.2 Geologic and Hydrologic Se tting ......................................... 291 7.4.3 Climate and Vegetati on ....................................................... 292 7.5 Methodol ogy ..................................................................................... 294 7.5.1 234U-230Th Chronol ogy ......................................................... 294 7.5.2 Stable Is otope Analysi s ....................................................... 295 7.6 Results .............................................................................................. 296 7.6.1 U/Th Dating .......................................................................... 296 7.6.2 Stable Is otope Result s ........................................................ 299 7.7 Discuss ion ........................................................................................ 301 7.7.1 Oxygen Isot ope Interpreta tion ............................................. 302 7.7.2 Carbon Isot ope Interpreta tion .............................................. 305 7.7.3 Grow th Rate s ...................................................................... 306 7.7.4 Heinri ch Event 2 .................................................................. 306 7.7.5 Proxy Comparison s ............................................................. 308 7.8 Conclu sions ...................................................................................... 311 7.9 Chapter Ack nowledgement s ............................................................. 313 7.10 Chapter Re ferences ........................................................................ 313 Chapter 8: Conclusions and Implicati ons .......................................................... 318 8.1. Conclu sions ..................................................................................... 318 8.2. Implic ations ...................................................................................... 324

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vi 8.3. Chapter Re ferences ......................................................................... 326 Appendix A. Jennings Cave Sedi ment Core Descr iption ................................... 328 Appendix B. Jennings Cave S ediment Core Data ............................................ 336 Appendix C. Vandal Cave Sedim ent Core Descr iption ...................................... 340 Appendix D. Vandal Cave Se diment Core Data ................................................ 344 Appendix E. Legend Cave Prec ipitation Da ta .................................................... 346 Appendix F. Legend Cave Surface and Temperature Data ............................... 357 Appendix G. Legend Cave Isotope Data ........................................................... 368 Appendix H. Legend Cave Surf ace Weather Data ............................................ 371 Appendix I. Legend Cave Rain Gauge CR10 Pr ogram ..................................... 577 Appendix J. Legend Water Co llector Pr ogram................................................... 581 Appendix K. BRC03-02 St able Isotope Da ta ..................................................... 590 Appendix L. BRC03-02 Tr ace Element Data ..................................................... 619 Appendix M. BRC03-03 St able Isotope Da ta .................................................... 623 About the Author ...................................................................................... End Page

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vii List of Figures Figure 1.1 Map of Florida and Belize ................................................................. 2 Figure 1.2 Future climat e change predi ctions ................................................... 9 Figure 1.3 Water shortage al ert ....................................................................... 10 Figure 1.4 Map of the Floridan Aq uifer ............................................................ 12 Figure 2.1 Conceptual model of speleothem formati on ................................... 25 Figure 2.2 Oxygen isotope effe cts ................................................................... 28 Figure 2.3 The am ount effe ct .......................................................................... 29 Figure 2.4 Carbon isot ope discrimi nation ........................................................ 31 Figure 2.5 Carbon is otope effe cts ................................................................... 34 Figure 2.6 Crevice Cave record ....................................................................... 35 Figure 2.7 Major teleconnecti ons .................................................................... 39 Figure 3.1 Study area m ap .............................................................................. 64 Figure 3.2 Map of Ix Chel ................................................................................ 70 Figure 3.3 Map of Reflection Cave .................................................................. 73 Figure 3.4 Depth to age model fo r Reflection Cave sediments ....................... 78 Figure 3.5 Reflection Cave sediment 13C record ........................................... 80 Figure 4.1 Cave sediment model ................................................................... 110 Figure 4.2 Study area m ap ............................................................................ 115

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viii Figure 4.3 Map of Jennings Cave .................................................................. 117 Figure 4.4 Map of Vandal Cave ..................................................................... 119 Figure 4.5 Veget ation m ap ............................................................................ 123 Figure 4.6 J1-07 co re and trenc h .................................................................. 125 Figure 4.7 V1-08 co re and trenc h .................................................................. 130 Figure 4.8 J107 age model .......................................................................... 134 Figure 4.9 J1-07 isotope dat a ........................................................................ 135 Figure 4.10 J107 HA dat a .............................................................................. 136 Figure 4.11 J107 FA dat a ............................................................................... 138 Figure 4.12 J1-07 bul k sediment data ............................................................. 139 Figure 4.13 J107 pollen dat a .......................................................................... 141 Figure 4.14 J107 LIA and MW P ..................................................................... 147 Figure 4.15 J1-07 vs BRIARS04 -02 ................................................................ 150 Figure 4.16 J1-07 pr oxy comparis ons ............................................................. 153 Figure 4.17 Proxy location m ap ....................................................................... 155 Figure 4.18 Proxy compar ison to BRC0 3-02 ................................................... 157 Figure 4.19 V108 age model .......................................................................... 163 Figure 4.20 V1-08 isotope dat a ....................................................................... 164 Figure 4.21 GTOPO60 DEM map of Vandal Cave .......................................... 166 Figure 5.1 Teleconnection in fluences in Florida ............................................ 190 Figure 5.2 Study area m ap ............................................................................ 192 Figure 5.3 Legend Ca ve map ........................................................................ 193 Figure 5.4 Calibration conceptual m odel ....................................................... 196

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ix Figure 5.5 Water collection setup in Legend Cave ........................................ 198 Figure 5.6 Precipitatio n collection setup ........................................................ 200 Figure 5.7 Temperature data from Legend Cave .......................................... 204 Figure 5.8 Legend Cave precipitation 18O and 2H values .......................... 206 Figure 5.9 Legend Ca ve LMWL..................................................................... 207 Figure 5.10 Legend Cave rain fall vs temper ature............................................ 208 Figure 5.11 Legend Cave ra infall vs am ount ................................................... 209 Figure 5.12 Conceptual model of amount effect .............................................. 211 Figure 5.13 Deuteriu m excess pl ot .................................................................. 213 Figure 5.14 Legend Cave 18O and 2H values ............................................... 215 Figure 5.15 Radar for 12/3/ 07 ......................................................................... 218 Figure 5.16 Radar for 12/21/ 07 ....................................................................... 219 Figure 5.17 TS Fay radar ................................................................................ 220 Figure 6.1 Location of BRC in Hernando County, Florida ............................. 235 Figure 6.2 Map of BRC .................................................................................. 237 Figure 6.3 Monte Carol simu lation of B RC03-02 ........................................... 242 Figure 6.4 BRC0302 speleothe m ................................................................. 244 Figure 6.5 The BRC03-02 isotope reco rd ...................................................... 248 Figure 6.6 Photo of the area near BRC in 1940 ............................................ 248 Figure 6.7 BRC03-02 tr ace element data ...................................................... 251 Figure 6.8 Lomb-Sc argle plot ........................................................................ 254 Figure 6.9 Multitaper spectrum ..................................................................... 255

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x Figure 6.10 BRC03-02 wavelet anal ysis ......................................................... 257 Figure 6.11 Proxy record m ap ......................................................................... 258 Figure 6.12 Local prox y record map ................................................................ 260 Figure 6.13 Proxy reco rd comparis ons ............................................................ 262 Figure 6.14 SE prec ipitation proxy comparis on ............................................... 264 Figure 6.15 Regional pr oxy comparis ons ........................................................ 267 Figure 6.16 NAO and AMO pr oxy comparis ons .............................................. 269 Figure 6.17 ENSO and PDO proxy compar isons ............................................ 271 Figure 6.18 Solar irradianc e proxy com parison ............................................... 273 Figure 7.1 Location of BRC in Hernando County, Florida ............................. 292 Figure 7.2 Map of BRC .................................................................................. 293 Figure 7.3 BRC03-03 with dat ed layers indi cated ......................................... 298 Figure 7.4 BRC03-03 mid-Holocene 18O and 13C data .............................. 300 Figure 7.5 BRC03-03 Late Pleistocene (glacial) 18O and 13C data ............. 301 Figure 7.6 BRC03-03 oxyg en isotope comp arison ........................................ 303 Figure 7.7 Evidenc e of H2 ............................................................................. 307 Figure 7.8 BRC03-03 proxy re cord compar isons .......................................... 310

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xi List of Tables Table 2.1 Stabl e isotopes ............................................................................... 26 Table 3.1 AMS r adiocarbon dat es .................................................................. 77 Table 4.1 Radiocarbon ages for core J1-07 from Jenni ngs Cave ................ 133 Table 4.2 P b210 dating ................................................................................ 162 Table 6.1 U/Th dates from BRC0302 .......................................................... 245 Table 6.2 Trace element model .................................................................... 252 Table 7.1 U-series date s for BRC0303 ....................................................... 297

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xii List of Equations Eq. 2.1 Calcium car bonate dissol ution ....................................................... 24 Eq. 2.2 Isotopic abundance calc ulation (per mil) ....................................... 26 Eq. 2.3 Oxygen isotope ra tios (per mil) ...................................................... 31 Eq. 2.4 Speleothem te mperature dependence ........................................... 32 Eq. 5.1 Amount-weighted isotopic mean for precip itation ......................... 202 Eq. 5.2 D-exce ss equatio n........................................................................ 202 Eq. 5.3 Local meteoric water line .............................................................. 205

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xiii Proxy Records of Climate Change in Subtropical and Tropical Karst Environments Jason Samuel Polk ABSTRACT Understanding the paleoclimate of a region is important, especially when trying to determine the extent of natural climate variability within the context of anthropogenic impacts. Recent anomalous peri ods of climate change in the Late Holocene, including the Little Ice Age and Medieval Warm Period, could possibly repeat in the future, having significant worldwide consequences. This holds especially true for tropical and subtropi cal karst environments, where limited paleoclimate proxies provide minimal dat a regarding past climate change. An investigation into past climate c hange in Belize using fulvic acids from cave sediments shows periods of drought during the collapse of the Maya society around 1400 years ago. Compar ison of changes in the carbon isotope data from the fulvic acids agree with speleothem records, but more closely reflect changes in the vegetation above the cave, s howing Maya population decline through waning agriculture. Further investigation of using fulvic and other organics acids are examined from cave sediments in Flor ida. The data show fulvic acid carbon

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xiv isotopes are the most robust recorders of climate change, agreeing with several nearby speleothem 18O and 13C records from west-central Florida. A more detailed record of climat e change in Florida through a calibration study of precipitation and cave dripwa ter oxygen and hydrogen isotopes revealed that the amount effect dominates rainfa ll in west-central Fl orida. Homogenization of epikarst dripwater gives average 18O values representative of the annual amount-weighted average of precipitation 18O for the area, suggesting speleothem isotope records reflect changes in rainfall amount. Examination of two speleothems from west-central Florida show complex teleconnection and solar forcing mechanisms responsible for past climate changes. A high-resolution stable isotope, trace element, and time series analysis study for the last 1500 years s hows variability during the LIA and MWP, pointing to a combined influence of Pacific and Atlantic teleconnection mechanisms, especially the ITCZ, NAO and PDO, being responsible for precipitation variability. Long-term rec onstruction of the mid-Holocene and Late Pleistocene from another speleothem re veals differences in temperature and precipitation between glacial and intergla cial conditions in Florida. Climate proxies from the tropics and subtropics provide additional clues to global climate change crucial to understanding future water availability.

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xv Preface “Today I shed my old skin which hath, too long, suffered the bruises of failure and the wounds of mediocrity. Today I am born anew and my birthplace is a vineyard where there is fruit for all. Today I will pluck grapes of wisdom from the tallest and fullest vines in the vineyard, for these were planted by the wisest of my profession who have come before me, generation upon generation. Today I will savor the taste of grapes from these vines and verily I will swallow the seed of success buried in each and new life will sprout within me. The career I have chosen is laden with opportunity yet it is fraught with heartbreak and despair and the bodies of those who have failed, were they piled one atop another, would cast a shadow down upon all the pyramids of the earth. Yet I will not fail, as the others, for in my hands I now hold the charts which will guide through perilous waters to shores which only yesterday seemed but a dream. …I will persist until I succeed.” ~The Greatest Salesman in the World (Og Mandino) When I began this journey into my graduate school education, I never anticipated the myriad twists, turn, ups, and downs I would encounter. Nor did I anticipate the amount of s upport, assistance, and friendship that would make this crazy ride worthwhile. The life experiences and people I met dur ing my time at USF have shaped who I am today. Despite its appearance as an individual effort, no dissertation is completed without an im mense collaborative effort, which holds especially true for this one. A picture may be worth a thousand words, but a dissertation is worth a thousand experienc es and equally as many thank you's; hence a preface rather than a short acknowledgements page, because this

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xvi dissertation culminates the most transfo rmative and rewarding period of my life thus far, signifying much more than just a degree. So, where do I begin? I will start with Leslie North, my futu re wife, who has been my guiding “North Star” throughout this ordeal since we met as undergrads in chemistry class (and will happily point out the irony of how I now work in geochemistry, despite my extreme loathing and ignorance of it during my undergraduate years). We have traveled this path together since the beginning, all over the world, and whenever I was lost or unsure, I only had to turn and look to you to guide me through. Thank you for always being there. Without your unc onditional support, assistance, love, and organization, there is no way I would be writing this right now. I sincerely thank you for maintain ing the balance and holding down the fort during the jungle expeditions, all-night ca ving trips, and long, long hours in the lab. You are the voice of reason and the dr iving force behind all that I do. I look forward to this next part of the j ourney with you and hope it is even more adventurous and fulfilling than the first leg. No amount of words could express my indebtedness or gratitude to you, so simply, I love you! Next, and equally import ant, are my Mom and Dad (Marsha and Sid) who have endured everything imaginable as I have navigated through the seemingly endless years (and cost and stress) of coll ege and soul searching, all the way up to coffee runs and moral support at 4 am in the last few nights of writing this dissertation. I don’t even know how to begin thanking you for everything, for believing in me always, and for trusting me. Through all the ups and downs, you have always been there, even going so far as helping me with fieldwork and

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xvii going into caveswhat more could I possi bly ask for in the way of unconditional love, support, and encouragement? You have in stilled in me a work ethic that is unmatched and taught me the import ance of always giving 110%, no matter what. My accomplishments thus far are only a shadow of what you have achieved, as my successes started wit h your love and support the day I was born. And yes, Mom and Dad, there is mo re to it than just going in caves! Jenny, my sole sibling, we share par ents, initials, and the drive to do our best. You probably don't even know it, but you are inspirational to me in so many ways, as you never give up, always look to help others, and most importantly provide me the 'big brother' position of being a good role model. I hope I have done it justice and given you someone to be proud of. Thank you for believing in me and don't ever give up on your dreams! To my future parent-in-laws, Patti, Ranger, and Ernest, I want you to know that it has been a blessing hav ing you in my life and thank you for raising such a wonderful daughter. I appreciate all of your support, from delivered home-cooked meals to usage of your vehicle for “short” road trips, you have been graciously selfless. Thank you for everything and we can all celebrate again when Leslie finally finishes! “Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime.” ~ Chinese proverb

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xviii In academics, the majority of commi ttees usually are only around for the few important events requir ed of their job as a commi ttee member. However, the lucky minority of graduate students have committee members who become deeply involved and truly garner an interest in his or her success and growth. I was lucky enough to be in the minority. First and foremost, I want to thank my major advisor, mentor, and friend, Dr. Philip van Beynen. Your guidance, tutelage, patience, and support through the years helped me become a proficient researcher, scientist, and teacher. You introduced me to karst and took me under y our wing, instilling in me a passion for knowledge and science. Most importantly, y ou calmly stood by as I ambitiously attacked every project and idea that presented itself and reigned in my enthusiasm to focus on what was important. I am grateful for the opportunity to have studied under you, and that you gav e me the freedom and trusted me to take on seemingly insurmountable projec ts. I could not (and would not) have completed this dissertation without you, so thank you for long discussions, quick reviews, and encouraging words. I wish you the most success in the future! Dr. Robert Brinkmann is the most or ganized, efficient, and enthusiastic person I know and one of the most infl uential people in my life. Sometimes you get lucky enough to meet those peoplethe ones who make you want to do more and do it betterand Bob, you are one of them. Your wisdom and advice were crucial in helping me discover who I am an d learning to follow my passions in life. You enlightened me to the wonders of Florida (not just a flat, featureless plain) and have always supported my ideas and aspi rations, as well as helping to keep

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xix karst alive at USF. From hosting gatherings to coming out in the field, you have always been there to guide me along and I appreciate everything. I hope I have made you proud. Thank you for being you, and most of all, for keepin' it real! Next, I want to extend my sincere thanks to Dr. Philip Reeder, who much like a good coach has a way of motivating you through consistency and leadership, and driving home the importance of the fundamentals. You were there in the beginning, and as I’ve grow n as a researcher, teacher, and caver, I credit you for helping me get started and teaching me the ways of the jungle (academic and Belizean!). And most impor tantly, thanks for sharing your wisdom on cave sediments at the last minute! I will try to do my bes t by your alma mater! Dr. Bogdan Onac is one of the hardest working individuals I know, but he also knows how to have funa true exam ple of work hard, play hard. Bogdan, we have had many adventures together both at home and abroad, and I learned a great deal from you about many different things. Your enthusiasm is contagious and I appreciate your patience as I finished this dissertation, and your insights on the various components of my res earch. Mult'umesc foarte mult! Last, and definitely not least, thanks to Dr. Jonathan Wynn, who is like an isotope ninja: silent, skillful, and always there to assist. I appreciate how you embraced karst when you arrived at US F and have become a solid foundation for so many of us in the field, in the l ab, and in the classroom. You always have a new idea to share and never let the details go unnoticed, which I admire greatly. It has been very rewarding having you involved with my dissertation and I hope you continue your caving adventures!

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xx A special thanks to Dr. Peter Harries for being there through the years to review my research and critique my ar ticles, always providing sound advice and great comments. It is mo st fitting you are my def ense chairperson and I thank you for doing me the honor. "Truly great friends are hard to find, diffi cult to leave, and impossible to forget." ~Unknown. Grant Harley, we have had more adventures together than I can remember and you have been he re through it all. From the jungles of Belize (Vebstah!) to cross-country hobo life (Lak e Tahoe...?) to every rotten hole in Florida we barely made it out of (to a P ublix honey-pressed reward!) it has been memorable, and I know there are many mo re adventures to come. I am grateful for your help in the field, enthusiasm for adventure, and most of all your friendship (and for having a wife who under standsthanks Mandi!). We made it through without arrest records, permanent injuries, or broken cameras, so obviously we need to rise to the occa sion and do it better from here on out. Lastly, thanks for your astounding insight s on the natural processes forming the Brooksville Ridge! None of this research would have been possible without the expert advice and assistance of Tom Turner and Robert Brooks, two of the most knowledgeable, enthusiastic, and dedicat ed individuals I have the privilege of calling friends. Their abilities as cavers researchers, and stewards of karst are

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xxi unmatched, as is their intimate familia rity with Florida's underground. Tom (aka Sir William, GoogleMaster), thanks for "c'm on man, don't rape the features!" and being a dedicated thinker. Robert, I onl y have one question for you after all these years: Got any gossip brother? You are t he glue holding it a ll together and thanks for bringing me into the circle and teaching me to think outside the cave. Between the two of you, my caving world is richer and more fulfilled, and I look forward to our future adventures! Thank you for entrusting me with the secrets of the underground. Long live the FKM! Spencer, brutha, you are like a calm wind gently helping to guide things with sound advice and a friendly smile. Than ks for helping me to keep grounded and for comic relief in multiple states and countries (so great!). I love your pessimistic optimism, ability to take it all in stride, and for making me a karst movie star (at least on YouTube)! Most importantly, you introduced me to Mr. Carbonic Acid, who is now iconic here at USF. And I can’t forget your wonderful wife for helping keep Leslie sane while I was writing and stressing! Now, do you want to go in some of those cruddy Florida caves or what? Josh Birky, my fellow baller (until the ankle sprain that is), I have to thank you the most for moral support and getting the ‘old man’ out there to run the courts and push the limits. I am a be tter man for having been around your midWestern wholesomeness, and your wife makes some awesome cookies! You can believe I’ll be meeting you in IL somewhere for a cookie swap and some bball in August!

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xxii Special thanks to Jon Sumrall, the incredible shrinking man, who braved Legend Cave despite all odds and taught me to push caving to my limits by doing just that himself. You are a gentleman and a caver, which is hard to have in one person! I also have to thank you for the encouragement to get back out on the ballcourt and remember my passion for it. We both suffered sprained ankles, yours caving, mine basketball, yours running from trouble, mine running into it! Lastly, I appreciate the discussions about Florida caves and also for your friendship. Your better half, Christina, is pretty good at listening and helping with advice as well! You better keep her around to keep you straight. My enduring gratitude goes out to the other two legs of the lonely tripod, Jonathan Bloch and Naimish Upadhyay, who stuck it out with me in their own thesis torture the last fe w weeks, sleeping and eating when possible (rarely) and always there for support. Next time we dec ide to have a ‘slumber party’ at 8am on the floor of the grad office after se veral all-nighters, we will be smart enough to put up a sign on the door to keep fr om scaring off other students and their parents! Seriously, you two are gentlem an and scholars, and I couldn’t have made it through without t he occasional ranting or unnecessary screaming and throwing of objects. I want to acknowledge Lee Florea, w ho paved the way for the growth of the Karst Research Group and helping us all to understand karst in west-central Florida and is a top-notch caver and res earcher. Your advice and guidance have been much appreciated through the years and I look forward to being your colleague at WKU!

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xxiii “I can no other answer make, but, thanks, and thanks.” ~William Shakespeare Although I wish I had the space to mention every single person individually, for the sake of saving trees, I will try to be brief from here out, as pages are filling up (and this dissertati on is long enough!). I’ll start with thanking all the graduate students who have made this adventure so much fun. Especially, Jeanne Lambert (I’ll just say Salt Lake Cit y?), who is the most fun and outgoing person I know and made grad school seem like the place to be. Thanks to John Merrill for reintroducing me to frolf and fo r being a gracious friend and super nice guy. Kirk, you know I can still eat that bu rrito and beat you, right ? Mark, let’s play poker! Big Josh Wolf, wherever you are, I know you are having fun! Cindy, I am glad we stayed connected throughout the years and thanks for all the support during those last monthsnow we are free! To Josh, Lori, Erin S., Dave, Geoff, Damian, Rich, Erin H., Heather, and about 50 more grad students who have all been there in some way along this journey to make it bearable and enrich my life in some waythank you. Karen Sc hrader, our department den mother and candyprovider, thank you so much for everyt hing over the years, your friendship, support, and your belief in meyou are amazing! Dr. Graham Tobin (aka the White Wizard), your advice and counsel have been invaluable, and I thank you! Everyone at USF, students, professo rs, and staff, have made this entire experience rewarding and I thank you all. I want to thank all the members of USF Karst Research Group for being so active and supportive and putting USF Karst on the map, especially Beth

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xxiv Fratesi and Dorien McGee, who always step up and rock it! I also want to thank Dr. Len Vacher, who behind the scenes has done more for USF Karst than anyone knowsyou are the epitome of a tr ue academic and I admire greatly your intellect and calm demeanor. Thank you for everything! My gratitude goes out to Lance Elder Mike Stonehocker, Justin Marks, Dan Straley, Walter and Lindsey Pickel, and all the other cavers who I have had the privilege to share darkness with. You are the nicest folks I have ever known and I admire you all for your passion regarding karst. Colleen Werner of the Withlaco ochee State Forest is the most hardworking state employee I know and t he one person I can say who believes in what she does and takes protecting t he environment seriously. You have been instrumental in my success with this di ssertation, always willing to lend a hand and trust me to do my res earch, and generous with permi ts and flexibility. You are like a Mom to all of us cavers and students and we appreciate all that you do more than you will ever know. Thanks! To Drs. Yemane Asmerom and Victor Polyak, thank you for opening your lab up to me and always being there to get dating done quickly and accurately. I also have to acknowledge the wizardry of Ethan Goddard with a mass spec, not only are you quick, but you redefine effici encythanks for all the last-last-last minute help! Deb Willard and Dan Doctor of the USGS, I could not have completed my sediments work with your helpDeb is a pollen master and Dan, thanks to you for opening up your home to me and for being so supportive

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xxv through it all. Zac Atlas is the laser guruthanks to you for helping me get things going with the laser and for getting my data to me during the chaotic rush of it all. Someone who deserves a thousand thank you’s is Kristine DeLong of the USGS for her help (and by that I mean la st minute, frantic phone call help) with my time series analysisyou are truly an expert and have a gift for it. I cannot thank you enough for everything and I look forward to future collaborations with once you arrive at LSU! Another thousand thank you’s to J oanne Sullivan for her expertise in electronics, mechanics, and now water collect ors. Thank you for dedicating time you didn’t have to spare to help me get th ings goingI appreciate that you cared enough about the project to make the wate r collector finally sing and dance! To Dr. Jennifer Collins and Sara Giunta, I owe you much appreciation for your hard work on the NEXR AD radar data and compili ng surface weather data for the calibration study. Thank you for your countless hours and assistance. To Derek Ford, Henry Schwarcz, Ch ris Groves, Art and Peggy Palmer, Alexander Klimchouk, George Veni, and J ohn and Joan Mylroie, thanks for being our Best of Karst guests and special t hanks for pondering Florida cave and cave sediments with me during my research You are all amazing researchers and wonderful people! Most importantly, I want to a cknowledge Farmer John’s for hearty breakfasts that you can go all day long on in the field, Diet Coke and Earl Grey tea for much needed caffeine boo sts, the faithful pups (C hocolat, Belle, Kinzie, Tiki, and Nelly) for keeping Les company wh ile I was away, and my computer for

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xxvi hanging in there despite sounding like a je t plane in the last days. To anyone I have missed, you know who you are and I th ank you profuselyif I forgot you here, I blame it on burnout and lost sleep! Lastly, I just want to say how much I have learned to appreciate natural Florida and its unique karst landscape. It truly is much more than a flat, featureless plain, and deserves the utmo st attention towards understanding, preserving, and protecting such a frag ile and unrivaled resource. Thanks to everyone whose efforts work toward these goals. Take nothing but pictures, leave nothing but footprints, kill nothing but time. Caver's motto (NSS) This dissertation is as much a prog ression of my own academic interests and passions as it is a collective body of re search in its own right. I started where my interests first began, questioning how climate change impacts societies and the environment, with the past example of the Maya in Belize being one of the most forthright examples of thes e interactions. Using new geochemical techniques to investigate the collapse of the Maya in Chapter 3 I was able to elucidate how the environment was im pacted by both climate change and anthropogenic disturbance, as recorded in cave sedime nts. From there, my interest in delving further into the sci entific method and new techniques by which climate change can be determined leads to Chapter 4 Therein, an exhaustive testing of the utility of cave sediment s in Florida, another climatically and environmentally sensitive landscape, is pr esented in an effort to expand the tools useful for paleoclimate research as I tried new ventures.

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xxvii The complexities of the modern record of climate seen in the Florida cave sediments justify the rationale for Chapter 5 which closely examines the role of precipitation and cave dripwater in Flor ida through a modern one year calibration study. This study provides insight on how the modern climate of Florida works and the processes by which it is affected, which I began to question as soon as I went in my first Florida cave. In Chapter 6 I attempt to use all the tools and knowledge I accumulated and apply them to a longer-term, high-resolution study of Florida’s paleoclimate using speleothem stable isotopes and trace elements to look at geologically-abrupt periods of c limate change that affected the area over the last 1,500 years. This more in-dept h approach allowed me to better constrain the parameters controlling climate dynamics in subtr opical Florida, which is complex and unique, to determine what fu ture climate changes may occur based on teleconnection cyclicity. Finally, in Chapter 7 I extend these climate interpretations back into the Late Plei stocene to examine the evolution of Florida’s climate during its glacia l and interglacial end-members. Collectively, the data amassed herein provide a reference to how climate change affected a past society in a sensitive landscape in Belize, then comes full circle to establishing the vulnerability and sensitivity of Florida to climate change since the last ice age. This is my a ttempt to shed light on the importance of understanding how natural climate change may affect water resources and those societies dependent upon its availability. Enjoy! Jason S. Polk

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1 Chapter 1 Introduction, Context and Purpose 1.1. Introduction In the 21st century, climate change is a common platform topic for politicians, an inspiring concept for author s and filmmakers, and part of everyday conversations between people throughout the world. Thus, the need to understand the dynamic character of Earth’ s climate system is a global priority for scientists and policymakers. D ebate persists regar ding the anthropogenic contribution to climate change, with a fo cus on the controversial topic of global warming caused by enhanced gre enhouse gas emissions. Increasing amounts of data are str ongly supporting the argument for anthropogenic forcing over natural vari ability as the reas on for this phenomenon (IPCC 2007; Li et al 2007; Lean and Rind 2008). However, the causal mechanisms of natural climate change on a long-term, global scale are still somewhat unresolved, despite a plethor a of recent climate change research attempting to address these uncertainties. This dissertation a ttempts to provide additional insight regarding mechanisms of climate change and water resource availability in the relatively understudied ar eas of Florida and Be lize (Figure 1.1).

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2 Figure 1 1 Map of Florida and Belize. They are situated near the Gulf of Mexico, Caribbean Sea, and North Atlantic Ocean (created by author). 1.2 Climate Change By definition, climate c hange is the long-term global variation in patterns of temperature and precipitation at differ ent spatial and temporal scales (IPCC 2007). Climate changes occur on interannual to millennial scales, including abrupt centennial cooling and warming events, and long-term 100,000-year

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3 glacial-interglacial cycles that occu rred repeatedly over the last few hundred thousand years (Petit et al. 1999; Alley et al. 2003). These global-scale climatic phenomena occur because of complex intera ctions between long-term variations in solar insolation and ice sheet-ocean interactions, and shorter-term volcanic activity and atmospheric-oceanic teleconnections. 1.3 Teleconnections Teleconnections are defined as "...re curring and persistent, large-scale pattern(s) of pressure and circulation anom alies that span vast geographical areas." (NOAA 2009). These teleconnections arise from interaction between oceanic and atmospheric systems on regi onal and global scales, affecting convection, precipitation, storm tra cks, and temperature. To better understand climate systems, investigations into the timing, magnitude, thresholds, and interrelationships of atmospheric-oceani c teleconnection influences triggering climate change are necessary. Descriptions of some of the major teleconnections and their respective influences are provided in Chapter 2. Recently, attention has focused on under standing the role of low-latitude (tropical and subtropical) geographic regions (Sirocko 2003; Lachniet et al. 2004) in global climate change. This especially holds true in the Atlantic Ocean, where high-latitude climate mechanisms were pr eviously conjectured to dominate the climate system from evidence in Greenland ice core records (Alley et al. 2003; Lynch-Stieglitz 2004). However, resear ch now shows the atmospheric-oceanic climate system to be more co mplex, with Antarctic temper ature shifts leading the

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4 North Atlantic response during previous glacial cycles (Sirocko 2003; LynchStieglitz 2004), and modern evidence of annual to decadal connections between high-latitude climate mechanisms and thei r effect on tropical climate regimes (Enfield et al. 2001; van Be ynen et al. 2007a, 2007b, 2008). Reasons for these phenomena are attributed to solar forcing and changes in ocean and atmospheric dynamics (Rut er et al. 2004; Mann 2007). Atlantic Ocean current systems and decadal to centennial atmospheric circulation patterns play major roles in transferring in tense solar radiation from the tropics to the cooler polar regions, and thus ma intaining the global climatic balance (Visbeck 2002). Therefore, t he subtropical region of the Atlantic Ocean serves as a transition point between the tropicaland highlatitude climat ic end-members. Understanding the timing and phasi ng of mechanisms that govern atmospheric-oceanic processes is crucia l to more comprehensively addressing climate variability. The response of tropi cal and subtropical areas to climate change events is important because the majo rity of precipitation driving the global hydrological cycle or iginates in these areas (Mickler et al. 2004). The effects of global warming and climatic changes could severely disrupt this cycle, especially in the low latitudes, having relatively unknown consequences. Thus, the overarching question remaining is how have perturbations in climate affected tropical and subtropical regions in the past? The answer is explored within the various chapters of this dissertation us ing proxy paleoclimate records from the tropical and subtropical karst environments of Belize and Florida, respectively.

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5 1.4 Proxy Records The broad temporal and spatial influenc es of the aforementioned global climate forcing mechanisms present the challenge of acquiring data suitable for studying natural climate variability on the appropriate scale, which is often beyond the established instrumental reco rd spanning the last few hundred years. Since instrumental records of climat e change lack the temporal resolution to understand the long-term natural variability of atmospheric-oceanic teleconnections, paleoclimate "proxies," or indirect substitutes usually consisting of geologic or hydrologic deposits sens itive to, and preserving of, climate variability are used to reconstruct past climate conditions and provide insight regarding possible future climate scenarios. However, an understanding of the context from which a paleoenvironmental proxy is obtained is nec essary to deconvolve the different factors affecting the way the proxy re cords climate and environmental change. For example, to use an ice core fo r paleoclimate reconstruction, one must account for melting, compaction, and differences in ice age versus gas age (Bradley 1999). By considering and calib rating for these factors, the data are more reliable and useful from an ice core record. In the last few decades, paleoclimate studies from proxies broadened in their spatial extent, record reliabilit y, and temporal length (Bradley 1999; Jones et al. 2009). Proxy data from lake and marine records, tree rings, corals, foraminifera, sediments, and ice cores pr ovide accurate, high-resolution records of past precipitation, tem perature, and vegetation changes (e.g. Curtis et al.

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6 1999; deMenocal et al. 2001; Bond et al. 2001; Mayewski et al. 2004; Lachniet et al. 2004; Otvos 2005; Sutton and Hodson 20 05; Rohling and Palike 2005; Richey et al. 2007). These proxy records provi de useful information regarding climate variability; however, obtaining suitable pal eoclimate proxies can be challenging in certain environments where the geological hydrological, or geomorphological setting is not conducive to their existence or preservation (Ruther ford et al. 2005; Jones et al. 2009). To undertake studies that examine lar ge-scale climate processes, it is necessary to find locations that ensure a climate signal repres entative of regional or broad-scale influences. It is also crucial to understand the way controlling factors, such as temperature, seasonality, precipitation, or humidity, affect how the proxy responds to climate change to deconvolve the record (Bradley 1999; Jones et al. 2009). Proxies from karst env ironments, specifical ly caves, provide the opportunity for detailed pal eoclimate reconstructions. 1.5 Karst Proxies Some of the most preserving envir onments are karst landscapes, wherein caves provide protection from weather ing and destruction and often safely preserve climate-recording proxies in the form of cave deposits (Collcutt 1979; Ellwood et al. 1997; Palmer 2007). Calcit e speleothems, with the possibility of producing interannual resolution for up to half a million years of deposition, offer the best potential terrestrial compliment to long-term, high-resolution ice core and marine sediment records of climate va riability. Speleothems capture climate

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7 change over long-term scales, being sens itive to local, regional, and global climatically-driven processes (McDermott et al. 1999; Frappier et al. 2002; Fairchild et al. 2006; van Beynen et al. 2007b; Lachniet 2009). Cave sediment deposits also show promise as paleoenvir onmental proxies for both shortand long-term climate change research (Pol k et al. 2007; Ford and Williams 2007). 1.6 Social and Ph ysical Context In 1988, the world saw the convening of the Intergovernmental Panel of Climate Change (IPCC), set up by the World Meteorological Organization (WMO) and the United Nations Environment Program (UNEP) to addre ss global climate change issues (IPCC 2001). In the last decade, several reports were generated by the IPCC leading to a worldwi de focus on climate change analysis and mitigation, with the United States play ing a leading role. The most recent technical report from the IPCC in 2 007, “Climate Change and Water,” directs attention to the profound problem of wa ter resource availability and its future scarcity due to anthropogenic overuse and climate change (Bates et al. 2008). A main source of water is groundwat er in karst aquifers, which according to estimates supplies over 25% of t he world’s population with drinking water (Fleury 2009). According to the IPCC 2001 report, Groundwater flow in shallow aquifers is part of the hydrological cycle and is affected by climate variability and change through recharge processes (Chen et al., 2002), as well as by human interventions in many locations (Petheram et al., 2001). Groundwater levels of many aquifers around the world show a decreasing trend over the last few decades, but this is generally due to groundwater pumping surpassing groundwater recharge

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8 rates, and not to a climate related decrease in groundwater recharge. (IPCC 2001). In a general sense this observation may be true, but in areas like Florida and Belize, recent periods of drought hinder groundwater recharge and serve to enhance anthropogenic overuse, thereby compounding the problem of groundwater scarcity. The IPCC 2007 report predicts these areas of North and Central America will see a decrease in precipitation and increase in evapotranspiration (Figure 1.2), thereby creating further strain on the groundwater resources in t he subtropics and tropics.

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9 Figure 1.2 Future climate change predictions. Modeled mean change in precipitation, runoff, soil moisture, and evaporation from the IPCC 2007 repo rt (Figure 10.12). Note the areas of Belize and Florida will be impacted negatively by these future predictions. In Florida, rapid population growth and increased environmental awareness in recent decades contribut ed to a heightened fo cus on groundwater issues. In 1984, former Florida governor Robert Graham recognized this in the Water Resources Atlas of Florida : “…water is Florida’s most critical resource…Florida’s matchless climate, our ability to accommodate population growth, and our capacity to balance the water needs of agriculture all depend on knowing everything we can about our water supply.” (Fernald and Patton 1984, p.iii). Today, Florida still faces the challenge of understanding the complexities of water resources and their management in the state, and depends on local water

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10 management districts to address this i ssue. The Southwest Florida Water Management District (SWFWMD) oversees groundwater and surface water resources for the region of Florida focused on in this dissertation. As recently as March 2009, SWFWMD issued a critical drou ght warning for multiple counties in its district due to low rainfall amounts (SWFWMD 2009) (Figure 1.3). Figure 1.3Water shortage alert. In March 2009, SWFWMD issued a series of water shortage alerts due to drought conditions from low rain fall in preceding months. This set historical p recedent in the district's hist ory by issuing the first warning of this magnitude for a water shortage (from SWFWMD 2009).

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11 This warning is unprecedented in t he history of SWFWMD, and points to the increasing importance of understanding potential c limate change impacts on Florida’s groundwater (SWFWMD 2009). At the convening of Florida’s 2007 legislative session, Governor Charlie Crist forewarned this by stating: “I am persuaded that global climate change is one of the most important issues that we will face this century. With almost 1,200 miles of coastline and the majority of our citizens living near that coastline, Florida is more vulnerable to rising ocean levels and violent weather patterns than any other state.” (FDEP 2008). While the vulnerabilities he mentioned are po ssible in the long-term, it seems the short-term consequences of climate change may be manifesting more quickly through recent drought impacts on the Stat e’s groundwater resources. In terms of groundwater abundance, the Floridan Aquife r System (FAS) is one of the most productive in the world (Figure 1.4), providing water to over 90% of the population of Florida (FDEP 2008). The FAS extends northward into Georgia, North Carolina, and Alabama (Fernald and Patton 1984). However, recharge to the FAS depends upon precipitati on and runoff, which compete with evapotranspiration, and both vary with c limate change over time. As withdrawal continues from the FAS, combined with low recharge, groundwater resources will decline and possibly cause detrimental impacts for both the residents and environment in the future. Part of the motivation for conducting th is research stems from a need to address social and physical issues related to climate change, especially future water resource availability. In Florida, entities like SWFWMD are interested in

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12 better understanding possible future scenarios of climate change t hat could affect precipitation and subsequent recharge to the FAS. SWFWMD benefits from data that provide insight to the paleoclimatic history of their region because it is conducive to understanding concepts lik e drought cycles and storm frequency, which can affect grou ndwater resources. Figure 1.4 Map of the Floridan Aquifer. It extends into Georgia, North Carolina, and Alabama (from Johnson and Bush 1988).

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13 1.7 Research Purpose The impetus for this research is to help address the dearth of paleoclimate information in subtropical and tropical karst environments. This dissertation provides a multi-proxy approach to paleoc limate reconstruction in tropical and subtropical karst environments, explor ing Florida, USA and Belize, Central America, in an attempt to elucidate the timing, magnitude, and spatial extent of atmospheric-oceanic teleconnections and their effects on climate change in these areas. Additionally, it introduces a new technique using cave sediments tested in tropical and subtropical karst l andscapes to produce paleoclimatological records in locations that lack other more commonly available proxies. 1.8 Broader Impacts In this document, I comb ine several unique research projects into a collective body of work that addresses mu ltiple knowledge gaps in the field of paleoclimatology in tropical and subtropi cal karst settings. These research projects involve the introduction of a new method for using cave sediments as a proxy for climate change, and the developm ent of new proxy climate data for Belize and Florida. More specifically, this body of research is significant in that it (1) provides a broad temporal study of climate in Florida at modern and geologic time scales, including the first high-re solution speleothem record of climate change for west-central Florida during t he Late Holocene; and (2) investigates the utility of cave sediments as a new paleoclimate proxy for subtropical and tropical regions where other proxies may be limited.

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14 From the results, a more thorough understanding of climate change processes and their effects in places like Florida and Belize could lead to improved policies and practices to miti gate climate change impacts by adding to the base of knowledge for climate modeli ng and potential future forecasting of climate change caused by teleconnection influences. Additionally, the use of cave sediments as a paleoenvironment al proxy may prove useful in other geographic areas of the world to enhanc e the existing body of knowledge regarding climate change where tr aditional proxies are absent. 1.9 Dissertation Organization The chapters composing the body of this dissertation focus on various aspects of climate change research in subtropical and tropical karst environments. More specifically, each c hapter investigates a specific time interval, paleoclimate proxy, or methodology that relates to the core focus of elucidating climate change in these setti ngs. Each chapter is framed within the broader context of the theme and objecti ves described in the introduction and literature review (Chapters 1 and 2), and contains additional background information pertinent to the specific data discussed within it where needed. Chapters 3 through 7 are current ly either in preparation for submission, or were previously accepted, as peer-reviewed journal articles and are therefore presented individually as such, causing so me repetition of figures, study areas, and/or methodologies and vary ing structures. However, where applicable, the chapters reference each other with regard to contextu al data comparisons and

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15 interrelated topics. A brief overview of each chapter is provided here, with detailed abstracts provided with in each individual chapter: Chapter 2 discusses the different aspects of climate change and karst concepts covered in the chapt ers that follow. This c hapter delves into the broad theoretical framework and conceptual m odels of speleogenesis, stable isotope analysis, and climate change teleconnection mechanisms to provide a foundation for the topics discussed in more det ail in each subsequent chapter. Chapter 3 presents a pilot study done in Belize, Central America using cave sediments as a paleoenvironmental proxy. It is a low-resolution study of carbon isotopes of organic acids extract ed from cave sediments and provides evidence of how past climate changes infl uenced the collapse of the Maya in Belize, which is an area similar to Flori da in that it is affected by climate processes in the Gulf of Mexico and No rth Atlantic Ocean. This study creates a foundation for the need of be tter understanding past and future climate change in areas like Florida by illustrating the impac ts past climate variability had on other advanced civilizations in a tropical/s ubtropical setting. This chapter was published as a peer-reviewed paper in Quaternary Research in 2007. Chapter 4 attempts a more in-depth invest igation for using cave sediments from Florida for paleoclimate reconstructi on. Both modern (last ~50 years) and longer-term (last ~3,000 years) sedim ent records from Vandal and Jennings Caves, respectively, are presented usi ng a multi-proxy approach of analyzing the various organic and physical fractions of the sediments.

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16 Chapter 5 provides an annual calibration study of stable oxygen and hydrogen isotopes of precipit ation and cave dripwater fo r west-central Florida. These data are combined with atmospheric and surface weather data to assist in determining the variability of precipitat ion in the area and with interpreting the stable isotopic records from Florida speleothems. Chapter 6 presents a high-resolution reco rd of climate change from a Florida speleothem from Brooksville Ridge Ca ve (BRC) for the last ~1,500 years. The data include carbon and oxygen stable isotopes, trace elements, and time series analysis, along with a discussion on how these data expl ain the climatic factors that influence Florida's climate. Chapter 7 presents a longer glacial and midHolocene record of Florida's climate from a different BRC speleothem This record includes evidence of Heinrich Event 2 and explores differences in precipitation, temperature, and vegetation between the Holoce ne and Pleistocene in Florida. Thus, it provides a glimpse of larger scale processes affe cting Florida’s climate variability and possible mechanisms of future climat e change on long-term temporal scales. Chapter 8 consists of a brief synthesis of the data presented within this dissertation, a critical assessment of this resear ch and its achievements, including future recommendations for each chapter, andconcluding remarks.

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17 1.10 Chapter References Alley, R.B. 2003. Paleoclim atic insights into future climate challenges. Philosophical Transactions of the Royal Society of London, Series A 361: 1831-1849. Bates, B.C., Kundzewicz, S.W., and Palu tikof, J.P. (Eds.). 2008. Climate Change and Water. IPCC Technical Paper VI, 210 pp. Bond, G., Kromer, B., Beer, J., Muschel er, R., Evans, M.N., Showers, W., Hoffmann, S., LottiBond, R., Hajdas, I. and Bonani, G. 2001. Persistent solar influence on North Atlantic climate during the Holocene. Science 294: 2130-2136. Bradley, R.S., 1999. Paleoclimatology: Reconstructing climates of the Quaternary 2nd ed. El Sevier Academic Press: San Diego, 613 p. Collcutt, S.N. 1979. The analysis of Quaternary cave sediments. World Archaeology 10(3): 290-301. Curtis, J.H., Brenner, M., Hoddell, D. A., 1999. Climate change in the Lake Valencia Basin, Venezuel a, ~12,600 yr BP to present. The Holocene 9 (5): 609-619. DeMenocal, P., Ortiz, J., Guilderson, T., and Sarnthei n, M. 2001. Coherent highand low-latitude climate variability during the Holocene Warm Period. Science 288: 2198-2202. Ellwood, B.B., Petruso, K.M., and Ha rrold, F.B. 1997. High-resolution paleoclimatic trends for the Holocene identified using magnetic susceptibility data from archaeol ogical excavations in caves. Journal of Archaeological Science 24: 569-573. Enfield, D. B., Mestas-Nuez, A.M., and Trimble, P.J. 2001. The Atlantic multidecadal oscillation and its relati on to rainfall and river flows in the continental U. S. Geophysical Research Letters 28: 277-280. Fairchild, I.J., Claire, C.L., Baker, A., Fu ller, L., Spotl, C., Ma ttey, D., McDermott, F., and E.I.M.F. 2006. Modification and preservation of environmental signals in speleothems. Earth-Science Reviews 75: 105-153. Fernald, E.A. and Pa tton, D.J. 1984. Water Resources Atlas of Florida Florida State University: Tallahassee, 291 p.

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18 Fleury, S. 2009. Land Use Policy and Practi ce on Karst Terrains: Living on Limestone. Springer, 187 p. Ford, D.C. and Williams, P.W. 2007. Karst Geom orphology and Hydrology. Wiley : West Sussex, England, 2nd ed., 576 p. IPCC. 2001 "Climate change 2001: the scientif ic basis", Intergovernmental Panel on Climate Change. http://www.grida. no/climate/ipcc_tar/wg1/index.htm IPCC. 2007 "Climate change 2007: the physical science basis", Intergovernmental Panel on Climate Change. http://www.ipcc.ch/ipccreports/ar4-wg1.htm Johnson, R.H. and Bush, P.W. 1988. Summa ry of the Hydrology of the Floridan Aquifer System In Florida and In Pa rts of Georgia, South Carolina, and Alabama. USGS Profe ssional Paper 1403-A. Jones, P.D., Briffa, K.R., Osborn, T.J., Lough, J.M, van Ommen, T.D., Vinther, B.M., Luterbacker, J., Wahl, E.R., Zwiers, F.W. Mann, M.E., Schmidt, G.A., Ammann, C.M., Buckley, B.M., Cobb, K.M., Esper, J., Goosse, H., Graham, N., Jansen, E., Kiefer, T., Ku ll, C., Kuttel, M., Mosley-Thompson, E., Overpeck, J.T., Riedwyl, N., Sc hulz, M., Tudhope, A.W., Villalba, R., Wanner, H., Wolff, E., and Xopl aki, E. 2009. High-resolution palaeoclimatology of the last millenni um: a review of current status and future prospects. The Holocene 19(1): 3-49. Lachniet, M.S., Asmerom, Y., Burns, S., Patterson, W.P., Polyak, V. and Seltzer, G.O. 2004. Tropical response to the 8200 yr cold event? Speleothem isotopes indicate a weakened early Holocene monsoon in Costa Rica. Geology 32: 957-960. Lachniet, M.S. 2009. Climatic and environmental controls on speleothem oxygenisotope values. Quaternary Science Reviews 28(5-6): 412-432. Lean, J.L., and Rind, D.H. 2008. How natural and anthropogenic influences alter global and regional surface te mperatures: 1889 to 2006. Geophysical Research Letters 35: L18701, doi: 10.1029/2008GL034864. Li, B., Nychka, W., and A mmann, C.M. 2007. The ‘hoc key stick’ and the 1900s: a statistical perspective on recons tructing hemispheric temperatures. Tellus 59A: 591-598. Lynch-Stieglitz, J. 2004. Hemispheric asynchrony of abrupt climate change. Science 304: 1919-1920.

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19 Mann, M.E. 2007. Climate over the past two millennia. Annual Review of Earth and Planetary Sciences 35: 111-136. Mayewski, P.A., Rohling, E.E., Stager, J. C., Karlen, W., Maasch, K.A., Meeker, L.D., Meyerson, E.A., Gasse, F., van Kreveld, S., Holmgren, K., LeeThorp, J., Rosqvist, G., Rack, F., Staubwasser, M., Schneider, R.R., and Steig, E.J. 2004. Holo cene climate variability. Quaternary Research 62: 243-255. McDermott, F., Frisia, S., H uang, Y., Longinelli, A., Spiro, B., Heaton, T. H. E., Hawkesworth, C. J., Borsato, A.,Keppens E., Fairchild, I. J., van der Borg, K., Verheyden, S., and Selmo, E. 1999. Holocene climate variability in Europe: evidence from 18O and textural variati ons in speleothems. Quaternary Science Reviews 18: 1021–38. Mickler, P.J., Banner, J.L, Stern L., Asme rom,Y., Edwards, R.L., and Ito, E. 2004. Stable isotope variations in moder n tropical speleothems: Evaluating equilibrium vs. kinet ic isotope effects. Geochimica et Cosmochimica Acta 68(21): 4381-4393. NOAA Website. 2009. Accessed at http://www.noaa.gov/. Otvos, E.G. 2005. Holocene aridity and st orm phases, gulf and Atlantic coasts, USA. Quaternary Research 63: 368-373. Palmer, A.N. 2007. Cave Geology. Cave Books: Dayton, OH, 454 p. Petit, J. R., Jouzel, J., Raynaud, D., Bark ov, N. I., Barnola, J. M., Basile, I., Benders, M., Cappellaz, J., Davis, M., Delaygue, G., Delmotte, M., Kotlyakov, V. M., Legrand, M., Li penkov, V. Y., Lorius, C., Pepin, L., Ritz, C., Saltzman, E., and Stievenard, M. 1999. Climate and atmospheric history of the past 420, 000 years from the Vostok ice core, Antarctica. Nature 399(3): 429-436. Polk, J.S., van Beynen, P., and Reeder, P. 2007. Late Holocene environmental reconstruction using cave sediments from Belize. Quaternary Research 68(1): 53-63. Richey, J.N., Poore, R.Z., Flower, B.P ., Quinn, T.M. 2007. 1400 yr multiproxy record of climate variability fr om the northern Gulf of Mexico. Geology 35 (5): 423-426. Rohling, E.J. and Palike, H. 2005. C entennial-scale climate cooling with a sudden cold event around 8,200 years ago. Nature 434: 975-979.

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20 Ruter, A., Arzt, J., Vavrus, S., Brys on, R.A., and Kutzback, J.E. 2004. Climate and environmental of t he subtropical and tropical Americas (NH) in the mid-Holocene: comparison of observations with climate model simulations. Quaternary Science Reviews 23: 663-679. Rutherford, S., Mann, M.E. Osborn, T.J., Bradley, R. S., Briffa, K.R., Hughes, M.K., and Jones, P.D. 2005. Proxybased northern hemisphere surface temperature reconstructions: sensit ivity to method, predictor network, target season, and target domain. Journal of Climate 18: 2308-2329. Sirocko, F. 2003. What drove past teleconnections. Science 301: 1336-1337. Southwest Florida Water Management Dis trict Website. 2009. Accessed at http://www.swfwmd.state.fl.us/. Sutton, R.T. and Hodson, L. R. 2005. Atlantic Ocean fo rcing of North American and European summer climate. Science 309: 115-118. van Beynen. P.E., Soto, L., Pace-Graczyk, K., 2007a. Paleoclimate reconstruction derived from speleothem strontium and 13C in Central Florida. Quaternary International doi:10:1016/j.quai nt.2007.03.019. van Beynen, P.E., Asmerom, Y., Polyak, V., Soto, L., Polk, J.S., 2007b. Variable intensity of teleconnections during the Late Holocene in Subtropical North America from an isotopic study of speleothem from Florida. Geophysical Research Letters 34: L18703, doi:10:1029/2007GL031046. van Beynen, P.E., Soto, L., Polk, J., 2008. Variable calcite deposition rates as proxy for paleo-precipitation determinat ion as derived from speleothems in Central Florida. Journal of Cave and Karst Studies 70 (1): 1-19. Visbeck, M. 2002. The ocean’s role in Atlantic climate variability. Science 297: 2223-2224.

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21 Chapter 2 Background and Literature Review 2.1 Chapter Preface This chapter serves to provide ba ckground and context for the remainder of this dissertation. The material is pr esented in the form of a general literature review that broadly covers the main disse rtation topics, which deal mainly with climate change, cave deposits, and stabl e isotope analyses. Thus, serving to provide foundational know ledge of these concepts di scussed within the chapter of this dissertation. The subsequent chapters will discuss, reference, or expand on the material presented in this chapter where necessary. 2.2 Introduction This dissertation focuses on establis hing paleoclimate records from karst environments. Thus, it is useful to provide background information regarding speleogenesis, the formation of cave depos its, and their environmental context. The concepts of stable isotope analysis an d dating techniques are also covered briefly covered in this chapter. Additiona lly, here I present an introduction to the primary atmospheric-oceanic teleconnections and mechanisms involved in

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22 governing global climate change as well as more specific regional systems, which are discussed in future chapters. 2.3 Karst Environments Karst environments are dynamic landsc apes characterized by solutional features, including sinkholes, springs, and caves (White 1988; Ford and Williams 2007; Palmer 2007). Karst landscapes primar ily form due to the dissolution of carbonate rock by meteoric water that becom es acidified as it percolates through the overlying soil and then aggressively dissolves the bedrock as it moves through fractures, fissures, and bedding planes. Speleogenesis, or cave formation, is a process that occurs once a karst landscape develops subsurface drainage (Kaufmann 2002). As aggressive water continues to percolate through bedding planes and fractures dissolving aw ay the limestone, these features enlarge to form cave passages. Cave development continues until a change in the hydrological regime, such as wate r table lowering, or geomorphic change, such as uplift or weathering, changes the hydrologic regime, thereby causing a slowing or cease in dissolution, or the generation of multi-level cave passages as the water table lowers (White 1988; Palmer 2007). Caves are natural rock cavities that can act as conduits for flowing water between inputs, such as sinkholes, and outputs, such as springs (Gillieson 1996). Once cave formation evolves to wher e air-filled cave passages exist in the landscape, caves then can act as prot ective depositional environments for sediments and speleothems (precipita ted calcite), which can provide

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23 paleoclimate information (Gascoyne 1992). The cave environment is stable, usually maintaining a steady temper ature and humidity throughout the year, despite surficial variations (Ford and Williams 2007). Thus, caves provide a uniquely stable setting in which paleoc limate proxies are formed and preserved on the order of milli ons of years. 2.4 Cave Deposits as Proxy Records Cave speleothems, specifically st alagmites and flow stone, are widely accepted as reliable, long-term sources of paleoclimate data (Holmgren et al. 1999; Lauritzen and Lundberg 1999a; Fleitm ann et al. 2003; McDermott 2004; Fairchild et al. 2006). Changes in t he ratios of speleothem oxygen (18O/16O) and carbon (13C/12C) stable isotopes are able to indi cate changes in precipitation, vegetation shifts, and average temperature over time (S chwarcz 1986; Dorale et al. 1992; Frumkin et al. 1999a, 1999b; Harmon et al. 2004; McDermott 2004). Additional information regarding v egetation change may be obtained by examining changes recorded in surfac e soils, which then become protected sedimentary climate proxies when washed into a cave (Ellwood et al. 1997). 2.5 Speleothem Formation Meteoric water (i.e. precipitation in the form of rainfall or snowmelt) contains some atmospheric carbon dioxide (CO2), making it slightly acidic. As this water percolates downward through soil overlying car bonate bedrock, it absorbs additional CO2 produced through plant root re spiration and the decay of

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24 detritus material to form carbonic acid (Schwarcz 1986; White 2004; van Beynen et al. 2004). When the percolating acidic water makes contact with the calcium carbonate (CaCO3) bedrock, dissolution occurs through the following reaction (Schwarcz 1986): CaCO3 + CO2 + H2O Ca 2 + + 2HCO3 (2.1) The acidic water becomes saturated with CaCO3 as it percolates down through fissures and joints in t he bedrock until the dissolved CaCO3 reaches equilibrium with the parti al pressure of CO2 (pCO2) in the seepage water. As percolation depth increases, more CO2 can be absorbed in solution due to increasing pressure, which also increases the amount of CaCO3 dissolved. Upon entering a cave, differences between the high pCO2 of the water and that of the low pCO2 of the cave atmosphere causes the degassing of CO2, which results in the dripwater becoming supersa turated with respect to CaCO3 and the precipitation of calcite occurs either as a soda straw on the ceiling, flowstone on the wall or floor, or as a stalagmite on the cave floor (Figure 2.1) (Hendy 1971; Schwarcz 1986; Dreybrodt 1988; Fairchild et al. 2006; van Beynen et al. 2004). Speleothem formation from cave drip water also incorporates detrital organic matter and trace elements into the cr ystal growth lattice of the calcite (comprised of stable isotopes of C, O, H) (Ford and Williams 2007). Ideally, for paleoclimate reconstructions speleothem form ation occurs in caves far from their entrances, with minimal air circulation and at levels of near 100% humidity, thereby preventing the precip itation of calcite through evaporation, and allowing the precipitated calcite to form in t hermodynamic equilibrium with the dripwater

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25 (Lauritzen and Lundberg 1999a). An examination of the 18O/16O and 13C/12C stable isotopic ratios contained withi n speleothem growth laminae deposited under isotopic equilibrium provide in formation regarding precipitation, temperature, and vegetation shifts abov e the cave (Ford and Williams 2007; Lachniet 2009).Figure 2.1 Conceptual model of speleothem format ion (from Fairchild et al. 2006). 2.6 Stable Isotopes 2.6.1 Stable Isot ope Geochemistry The most commonly used stable isotopes for paleoclimate work are those of oxygen (O), carbon (C), and hydrogen (H ) (which occur naturally and do not decay over time) (Sharp 2007). The isot opes of the element s C, O, and H have

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26 different masses based on the number of ne utrons present in their nuclei, with the stable forms for oxygen (16O and 18O), carbon (12C and 13C), and hydrogen (1H and 2H) existing in varying abundances in the whole earth (Table 2.1). Stable isotope abundances derived from mass spectrometer m easurements are calculated in ratios (R), given as 18O/16O, 13C/12C, and 2H/1H (usually seen as D/H) and reported as (per mil) values with res pect to a known standard using equation 2.2: (2.2) where is expressed in ‰ ( parts per thousand) and Rstandard is the isotopic ratio of a known reference. For water samp les, the primary reference is Vienna Standard Mean Ocean Water (VSMOW), and for carbonates it is the Vienna PeeDee Belemnite (VPDB), which require conversion equations to calibrate the ratio to their respective standards and also to convert between VSMOW and VPDB scales when necessary (see Sharp 2007). Table 2.1 Stable isotopes. Relative abundances, notat ions, and standards for the stable isotopes most commonly used in speleothem and other paleo climate studies (adapted from Sharp 2007). Isotope Abundance (%) Notation Standard 12C 98.892 13C VPDB 13C 1.108 16O 99.759 18O VSMOW or VPDB 18O 0.204 1H 99.85 2H or D VSMOW 2H 0.015 Different ratios of stable isotopes o ccur in substances due to fractionation processes. Isotope fractionation primarily occurs through kinetic or equilibrium

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27 processes when a compound changes its ph ysical or chemical state. Most paleoclimate research focuses on ma ss-dependent fractionation processes, wherein temperature, evaporation, diffusion, and ot her kinetic reactions cause preferential removal of t he lighter isotope due to it s lower dissociation energy (Sharp 2007). One important process in stable isotope work is that of Rayleigh fractionation, wherein isotopic depleti on of the heavy isotope occurs in an open system as it is removed (Sharp 2007). Prec ipitation provides a good example, where the heavier 18O isotope is removed as precipitation occurs, thereby creating more depleted values of rainfall oxygen isotopes. This process occurs in other equilibrium reactions when ther e is little to no back exchange between the phases of the process, su ch as calcite deposition. 2.6.2 Oxygen Isotopes A primary factor in understanding 18O values is the different fractionation processes that can affect the oxygen isotopic compositi on of the calcite beginning at its oceanic or lake water s ource and continuing through to calcite precipitation inside the cave. Several fractionation processes occur within the hydrologic cycle, driven by Rayleigh dist illation and temperatur e effects. These different effects are illustrated in Fi gure 2.2 and explained further below. In general, colder conditions lead to isotopically lighter (more negative) rainfall, due to less availabl e energy to move the heavier 18O isotopes into vapor phase. During warmer interglacial periods the opposite occurs, with rainfall being isotopically heavier (more positive) duri ng its initial vapor phase. Fractionation

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a a c i n i s t h c S i s p lso occurs vapor pha The i c omposition n creases) a s otope fou n h ereby cau s omposition S harp 2007 ) s otope as m recipitatio n Figur e oxyg e both durin g se, and ag a c e-volume of ocean w a nd intergl a n d in water s ing more 1 of the met ) The cont i m oisture m o n with the n e e 2.2 Oxyge n e n isotopes ( a g the transi t a in during c effect refe r w ater durin g a cial period s on Earth is 1 8O enrich e eoric wate r i nental effe o ves inland e cessary t r n isotope effe c a dapted from 28 t ion of liqui d c ondensati o r s to the va r g glacial p e s (when ic e stored in i c e d source w r falling ab o ct causes p from its s o r ansport di s c ts. Diagram Sharp 2007). d source w o n into pre c r iations in o e riods (whe e volume is c esheets d u w ate r there o ve the cav p referential o urce, prod u s tance (Ro z illustrating th e ater to the c ipitation ( S o xygen isot n global ic e minimal). u ring glaci a by affectin g e (Rozans k rainout of t u cing depl e z anski et al e different ef f atmospher e S harp 2007 opic e volume The lighter a l periods, g the isoto p k i et al. 19 9 t he heavie r e ted 18O 1993). f ects on e as ). 16O p ic 9 3; r 18O

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29 Lastly, the amount effect dictates that there is an inverse relationship between precipitat ion amount and the 18O of precipitation, which is especially evident in the subtropics and tropics (Roz anski et al 1993; Lachniet et al. 2004a; van Beynen et al. 2007a, 2007b). This occurs due to the nature of the convection height and intensity of sto rms, and the amount of rain fall during storm events (Figure 2.3 ) Perhaps one of the mo st important factors in the oxygen isotopic composition of speleothem calcite is that of the rainwater composition effect which accounts for fractionation caused by the cumulative effect of varying meteoric water sources, storm tracks, local effects, time (seasonality), and temperature at the site of formati on. There is generally an increase in fractionation of approximately 0.3 0.7‰ per 1C, with a similar decrease in fractionation of precipitation 18O with decreasing temperatures (Dansgaard 1964; Dorale et al. 2002; Harmon et al. 2004, van Beynen et al. 2004). Figure 2.3 The amount effect. Here, it is demonstrated in Central American precipitation, where increased rainfall causes more negative (depleted) 18O values (from Lachniet et al. 2004b, figure 3).

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30 2.6.3 Carbon Isotopes Stable carbon isotopes also undergo several different fractionation processes, and are affected by atmospheric CO2 levels, temperature, metabolic processes, weathering, and other kinetic and equilibrium fractionation processes (Sharp 2007). Here, a focus on the frac tionation of carbon isotopes through the photosynthesis process is provided, as it is the main focus of many paleoclimate studies dealing with organic materi als derived from vegetation. Photosynthesis preferent ially favors the lighter 12C isotope, but isotopic preferences between C3 and C4 plants differ, causing distinctive 13C values for each type. The majority of vegetation (~ 85%), which includes trees, shrubs, and temperate grasses, are considered part of the C3 group, and use the CalvinBenson photosynthetic pathway during photosynthesis (Boutton 1996; Webb et al. 2004; Wynn et al. 2005). C3 plants incorporate less 13C into the plant biomass than C4 plants, having 13C values ranging from -25 to -33‰ (Hendy 1971; Schwartz et al. 1986; Harmon et al. 2004). Conversely, C4 plants, which are mainly tropical grasses and forbs, use t he Hatch-Slack photosynthetic pathway and have 13C values ranging from -16‰ to -9 ‰ (Schwartz et al. 1986; Bottrell 1996; Turney et al. 2001; Huang et al. 2001). The third group of plants uses the Crassulacean Acid Metabolism (CAM) photosynthetic pathway during photosynthesis and includes succul ents like cacti. Changes from C3 to C4 vegetation are often indicated by shifts between more negative 13C values produced by wetter, forested (C3) conditions and less negative 13C values indicating the presence of more arid, scrub-like (C4) vegetation (Dorale et al.

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1 p 2 i n a a t e s c F d 992; Des m lants dicta t .7 Speleot The o n the calcit e l. (2004): nd are rep o e mperatur e peleothem s 18O of the d alcite is pr e F igure 2.4 C a d iscrimination m archelier e t e the isoto p hem Oxyg o xygen isot e matrix, w h o rted relati v e carbonat e s (18Oc) a r d ripwater f r e cipitated ( D a rbon isotope between C3 t al. 2000). p ic signatu r en Isotop e opes in sp e h ich is calc u v e to the V S e s) standar d r e represe n r om which t D orale et a discriminati o and C4 p lant s 31 Variations r e of the to t e s ( 18O) e leothems a u lated by t h S MOW (fo r d s. The ox y n tative of th e t hey form, a l. 1992; Ha o n. Difference s (modified fr o in the abu n t al plant bi o a re a mea s h e followin g r waters sa m y gen isotop e meteoric a nd the te m rmon et al. s in the carb o o m Schwart z n dance of C o mass (Fig u s ure of the r g equation f m ples) or V e ratios in c water abo v m perature a 2004). o n isotope et al 1986). C 3 and C4 u re 2.4). r atio of 18O / f rom Harm o V PDB (for l o c alcite v e the cav e t which the / 16O o n et (2.3) o we the

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32 Due to the complex natu re of the isotopic compos ition of precipitation, each cave location should be considered individually to determine what factors are affecting the speleothem calcite 18O values. Additional factors can also affect the composition of dripwater in the cave, including su rficial evaporation, mixing effects in the epikarst zone, dr ip rate, and preferential recharge seasons (Lauritzen and Lundberg 1999a, 1999b; Soto 2005). Calibration of the 18O relationship between modern rainfall and calcite deposited in isotopic equilibrium allows for a better estimate of the climate conditions under which past calcite was fo rmed (Harmon et al. 2004; Mickler et al. 2004). Calcite 18O values may also provide a scale of temperature change over the growth period of the speleothem; however the re lative contributions of precipitation and source effe cts on the oxygen isotopic signa l of the precipitation, dripwater, and calcite must be quantif ied. The temperature dependence of 18O of speleothem calcite can vary spatially due to the multitude of factors affecting the source water, and can be calc ulated using the following equation: (2.4) where T represent s temperature, 18Oc represents speleothem calcite, and can be positive or negative (Frumkin et al. 1999b, van Beynen et al. 2004). It is expected that variations in magnitude and sign will occur from site to site, but that will remain fairly constant over time at a specific site.

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33 2.8 Speleothem Carbon Isotopes ( 13C) Speleothem 13C values can be used to indicate changing vegetation above a cave in response to changing climate (Dorale et al. 1998). The 13C/12C from dissolved inorganic carbon in drip water is incorporated in speleothem calcite during deposition (Harmon et al. 2004). Water percolating through the soil equilibrates with soil CO2, which is controlled by the plant productivity in the soil and varies over time. Additional carbon inputs from atmospheric CO2 and the limestone bedrock affect the 13C of the calcite forming from the dripwater (Hendy 1971) (Figure 2.5). If the percolating water is able to obtain additional CO2 in the epikarst, or there are carbonates pr esent in the soil, dissolution is said to occur in an open system which could cause lower 13C values in speleothem calcite. In soils without carbonates and epikarst where there is no additional CO2 source, closed-system dissolution occurs and there is potential for speleothem calcite to have higher 13C values (Fairchild et al. 2006).

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a ( D d ( F r a c t h d o Spel e bove the c a D orale et a l uring clim a F igure 2.6 ) a infall r ate s ave (Fairc h h e speleot h ue to dega r while dri p Fi g on Ge e othem 13 C a ve, with d i l 2002). D o a te change s Hence, 1 s estimated h ild et al. 2 0 h em will aff e ssing of se p ping to the g ure 2.5 Car b the carbon i s nty et al. 20 0 C values a r i ffering typ e o rale et al. s recorded 3C in spele from plant 0 06). Kineti e ct the isot o epage wat e cave floor b on isotope e f s otope value s 0 1). 34 r e interpret e e s of plant s (1998) sho w in a speleo othems ca n productivi t c fractiona t o pic comp o e r prior to e and also f f fects. Diagr a s show in spe l e d as a fun s affecting t w shifts fro them from n provide a t y and veg e t ion of the c o sition of th e ntering th e f rom diseq u a m illustrating l eothem calc i ction of ve g he 13C va l m C3 to C4 Crevice C a a n indirect m e tation type c ave drip w e calcite. T e cave in th e u ilibrium be t the various e i te (modified f g etation ty p l ues of the vegetation a ve, Misso u m easure of above the w ater depos T his can oc c e vadose z t ween soil C e ffects f rom p e soil u ri iting c ur z one C O2

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35 and dripwater (Baker et al 1997; Genty et al. 2001). Additionally, changes in the hydrology of recharge waters above a cave can affect the long-term 13C record. 2.9 Speleothem Equilibrium Deposition In order to use speleothem stable is otopes as reliable records of climate change, they must be deposited in equilibr ium conditions with the dripwater from which they form (Hendy 1971; Gascoyne 199 2; Harmon et al. 2004). Both carbon and oxygen isotopes undergo some form of fractionation during their transport and incorporation in speleot hem calcite; however, ki netic fractionation or evaporation can also affect the isotopic signal recorded in a speleothem. (Hendy 1971) prescribes the method of testing for a correlation between 18O and 13C Figure 2.6 Crevice Cave record. Speleothem 1 3 C record from Crevice Cave, MO showing shifts in vegetation between C3 and C4 plants (from Dorale et al. 1998).

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36 along a single growth layer to determi ne isotopic equilibrium deposition of the speleothem. If a correl ation exists between the 18O and 13C values, then kinetic fractionation processes, such as rapid CO2 degassing or evaporation may have influenced the isotopes during calcite pr ecipitation. Additionally, if the 18O varies more than 0.8‰ along a single growth layer, evaporative kinetic fractionation may have occurred during deposition (G ascoyne 1992; Lauritzen and Onac 1999; van Beynen et al. 2004). Testing the Hendy criteria can be difficult due to the varying shape of stalagmite growth layers. Slow growth rates can produce such thin laminae that even drilling with a fine-tipped microbi t during sampling can incorporate contamination from younger or older neighboring layers with varying isotopic compositions. Therefore, t he Hendy test is not an absolute determinant of kinetic or evaporative fractionation (Dorale et al. 2002; Dorale and Liu 2009). An alternative method for testing isotopic equilibrium deposition, the replication test, is presented by Dorale et al. (2002) and Dorale and Liu (2009). The replication test is more comp rehensive and addresses both equilibrium deposition and changes in 18O prior to calcite deposition due to alterations in the vadose zone. Kinetic and evaporative processes differ for seepage waters making their way into the cave to eventual ly become dripwaters that precipitate calcite, with each degassing, pr ecipitating calcite, and dri pping at different rates. Therefore, if two speleothem s from the same cave/area show the same isotopic record, it can be assumed that kinetic or evaporative processes are not affecting the isotopic signal equally (Dorale et al. 2002).

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37 2.10 Speleothem Dating Speleothems are reliable climate proxies because they can be dated using several methods, with the uranium-serie s technique being t he most common and reliable method. Radiocarbon (14C) dating is also used for speleothems, but has a limit of approximately 50,000 years and problems occur with isotopic exchange with dead carbon in the limestone bedro ck (White 2004). Uranium-lead (U-Pb) dating can be used on certain samples that are millions of y ears old if they contain enough radiogenic Pb. Relative paleomagnetic dating techniques can also be used for speleothems, but again, ar e not as reliable or as perfected as the U-series (234U to 230Th) method. U-series dating is based on the decay of 234U to its daughter isotope 230Th and can provide speleothem dates up to 500,000 years old (Dorale et al. 1998; Richards and Dorale 2003; Dorale et al 2004). Speleothems can be dated using the U/Th method because 234U is highly soluble and easily incorporated into speleothem calcite, while 234Th has a low solubility and a negligible amount is incorporated into the crystal lattice of speleothems (Dorale et al. 2002, 2004). White (2004) sets forth the following cr iteria to accurately obtain U-series dates from speleothems ( based on work by Harmon et al. 1975; Dorale et al. 2004): (1) the sample must contain su fficient uranium; (2) there must be negligible amounts of detrital 230Th present in the sample; and (3) the sample must not have undergone dissolution and recr ystallization (i.e. formed in a closed system). Thermal ionization mass spectrom etry (TIMS) or inductively coupled plasma mass spectrometry (ICP -MS) is used to measure the 234U/230Th ratio of

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38 the sample to provide a date. Sample s with low U (<0.1 ppm) and samples with detrital 232Th often provide unreliable dates wi th high errors. Adjustments can be made for samples with high amounts of detrital 230Th using isochrones, which require dating sub-samples of calcite from the same layer, and provide an estimate of the initial 230Th that can be corrected for in the age calculation process (Richards and Dorale 2003; Dorale et al. 2004). 2.11 Atmospheric-Oceanic Teleconnections 2.11.1 Atmospheric-Oceanic Influences There are several different oceanic and atmospheric influences that affect climate in the North Atlantic region, which includes the Gulf of Mexico and Caribbean Basin regions. The major influenc es are the North At lantic Oscillation (NAO), Atlantic Multi-dec adal Oscillation (AMO), El Nio-Southern Oscillation (ENSO), Intertropical Convergence Zone (ITCZ), and Pacific Decadal Oscillation (PDO) (Figure 2.7 ) Variations in the timing, phasing, and intens ity of these different climatic systems affect precipit ation, temperature, and SSTs throughout the North Atlantic.

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39 Figure 2.7 Major teleconnections. Generalized representation of some of the major influencing atmospheric-oceanic teleconnections affecting t he North Atlantic region (base map from Earth Explorer DEM2.5, modified by author). Geographically, many of these systems interact hemispherically in their phasing and positions, thereby affecting similar land ma sses, such as ENSO and the ITCZ, both of which orig inate and strongly affect the in tropical Pacific Ocean. The NAO and the AMO also interact to affe ct climate on a regional scale in the mid-latitude temperate regions of the No rth Atlantic, with both originating in the higher latitudes, where the North Atlantic Deep Water (NADW) also initiates its circulation (Kerr 2005). With the excepti on of NADW formation, which oscillates

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40 on a millennial scale, these other climat e influences fluctuate on decadal to centennial periods, varying in in tensity, position, or both. 2.11.2 North Atlantic Oscillation (NAO) Only in the past few decades has an under standing of the dynamics of the North Atlantic Oscillation been rev ealed from instrumental and proxy reconstructions (Cook et al 1998; Hurrell 2003; Hagemeyer 2006). Recent studies point to the NAO as a major in fluencing factor on precipitation, storm fronts, and both landand sea-surface temperatures throughout the North Atlantic (Cook et al. 1998; Kerr 2000; Enfield et al. 2001; Hagemeyer 2006). The NAO is set up because of the Icelandic Low being out of phase with the large Bermuda-Azores high-pressure system (C ook et al. 1998; Dawson et al. 2002; Hardy and Henderson 2003). When both of these systems strengthen, a large shift in atmospheric mass creates a pressu re gradient in the No rth Atlantic, which affects wind patterns, prec ipitation, cold fronts, and temperature throughout the region (Cook et al. 1998). Research using tree rings and inst rumental measurem ents show that differences between the Icelandic Low and Bermuda-Azores High (North Atlantic High (NAH)) remained in positive or negat ive phases for periods ranging from annual to decadal over the la st few hundred years (Cook et al. 2002; Hagemeyer 2006). Positive NAO phases occur when both the Icelandic Low and BermudaAzores High are strong, creat ing large pressure differences in the North Atlantic, and causing some locations to have mild and wet winters. The reverse is true during negative phases of the NAO, with both the Icelandic Low and Bermuda-

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41 Azores High being weak, thereby causing Atlantic winters to be snowier and cooler in some areas (Dawson et al. 2002; Burroughs 2003). Cook et al. (2002) discusses the problem of asynchronous pro xy records of the NAO index over the past 200 years, and poses a new, robust NAO index for the last 600 years from multiple proxy records, including tree rings, ice core s, and instrumental data. However, to date, this is the longest NAO index record and a longer proxy is necessary to extend the record and to help clarify the mechanisms behind its oscillations throughout the Holocene. 2.11.3 Atlantic Multidecadal Oscillation (AMO) Shifts between NAO phases also drive 65-80 year temperature fluctuations in the North Atlantic and the surrounding cont inents, which are known as Atlantic Multidecadal Osc illations (Kerr 2000; Burroughs 2003). Enfield et al. (2001) found that most of the United States re ceives less precipitation during AMO warm phases, which are global in scale, but most intense in the North Atlantic. They also associate recent increases (since 1990) in global temperature to be associated with the onset of an AMO warm phase. Additionally, Enfield et al. (2001) show that ENSO variability may be modulated in part by fluctuations in the AMO; t hereby causing enhanced ENSO effects in certain areas of the U.S. and weakened effects in others. Kerr (2000) suggests the NAO and AMO have a strong influence on the thermohaline circulation (THC) of the North Atlantic and may affect NADW formation on a long-term scale, but there are few records available to support this supposition. deMenocal et al. (2001) found that there is a 1500 year cycle in sea

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42 surface temperatures (SSTs) of the North Atlantic t hat affects the tropical, subtropical, and temperate regions simu ltaneously, likely influenced by the NAO. 2.11.4 El-Nio-Southern Oscillation (ENSO) Cane (2005) created a 1, 000 year record for ENSO variability, finding a 27 year cycle in its intensity. El Ni o conditions are when anomalously warm SSTs occur in the equatorial eastern Pacifi c, initiated by a positive feedback mechanism that is caused by the coupli ng of oceanic thermocline circulation and atmospheric trade wind processes. This pr ocess is related to pressure system oscillations between the Pacific and I ndian Oceans, known as the Southern Oscillation (SO). Throughout the Holocene, ENSO conditions have varied, but studies have yet to determine the ex act causes of ENSO cyclicity. ENSO affects different regions in different ways, and is considered a global phenomenon (Cane and Cle ment 1999; Rein et al. 2004). Throughout most of the temperate latitudes, El Nio affects temperatures and precipitation. For example, the U.S. experiences mild winters, flooding in the central states, and wetter southern U.S. winters duri ng El Nio periods (Babkina 2003). Hurricane frequency is reduced along the Atl antic Coast of North America, and drought occurs in places such as Br azil and Africa, illustrating the true global teleconnection patterns caused by El Nio events (Nash 2002). Predicting ENSO events is difficult, due to its highly vari able and inconsistent nature, and the lack of accurate long-term record s of past ENSO events.

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43 2.11.5 Intertropical Convergence Zone (ITCZ) Fluctuations of the ITCZ cause the seasonal wet and dry seasons in Central America and the Caribbean Ba sin (Haug et al. 2001). Studies by Lachniet et al. (2004b) and Cane (2005) show that ENSO variability is a primary influence on rainfall amount in Central and North America. Studies in the Venezuelan Cariaco Basin suggest that ENSO variations can enhance or inhibit the normal rainfall and wind patterns of the ITCZ by promoting its southward migration and increasing the frequency of its oscillations, thereby disrupting climate in the region (Peterson et al. 2000; Haug et al. 2001). However, Broccoli et al. (2006) used climate modeling to show that ITCZ migration can also be affected by Northern Hemisphere temperatures, suggesting that tropical and high latit ude teleconnections may be a primary influence on ITCZ migration. Peterson and Haug (2006) recently published data that supports the hypothesis of North At lantic SSTs influencin g the migration of the ITCZ. They found cooler SSTs cause a southward shift in the ITCZ, leaving Central America drier, and wa rm North Atlantic SSTs causing a northward shift in the ITCZ and wetter conditions throughout C entral America. However, the cause for SST-induced ITCZ shifts is still unknown, with potential sources being ENSO variability or high-latitude forcing in t he North Atlantic, possibly from the NAO (Rajagopalan et al. 1998).

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44 2.11.6 Pacific Decadal Oscillation (PDO) The PDO is similar to ENSO in that it reflects anomalous SST differences in the tropical and northern Pacific Ocean, which affect sea level pressure and wind, and influence the climate of Nort h America. Unlike ENSO, the PDO is mainly affected by North Pacific SSTs and influences a different region, with a more persistent cycle (Caon et al. 2007). The PDO is linked with changes in ENSO, but has a longer periodicity, varyi ng in intensity on the order of 20-30 and 50-70 years (Mantua et al. 1997; Caon et al. 2007). Modul ation of the Aleutian Low by the PDO affects precipitation and temperature in the North Pacific and North America, with a positive phase increasing moisture and a negative phase producing less. During simultaneous phasi ng positive phases of ENSO and the PDO, precipitation increases in the s outhwest U.S., where drought effects increase during simultaneous cooling ( negative) phases (Hidalgo and Dracup 2003; Bond and Harrison 2000). Currently, a mechanistic understanding of the PDO is still lacking, but observations of it s phases assist with prediction in storm patterns in North America, especially when combined with ENSO cycles. 2.12 Belize Paleoclimate Only limited knowledge exists rega rding long-term past responses to regional climate change in the tropics (Lachn iet et al. 2004a). Previous studies of lacustrine sediments show distinct regional differences in terms of the severity and timing of arid periods throughout Central America during the Holocene (Hodell et al. 1995; Curtis et al. 1996; H aug et al. 2001; Shaw 2003; Hodell et al.

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45 2005a, 2005b). A lake sediment study by Cu rtis et al. (1998) from Lake PetenItza, Guatemala produced a ~9 ka BP re cord of climate change, indicating dry conditions until a progressively moister climate formed the lake between ~9 and 6 ka BP. Rosenmeier et al. (2002) studied 18O values in lake sediments from Lakes Salpeten and Peten Itz a, Guatemala, determini ng that Holocene climate from ~9 to 6 ka BP was wetter, with t he lakes being full. A much wetter climate prevailed during the late Holocene, indicated by decreasing 18O values. Sharp increases in 18O values around 1.45 ka BP and lasting until 0.7 ka BP indicate a brief period of more arid conditions in the region. Hodell et al. (2001) found a 208-year aridity cycle in precipitation changes in lake sediments from Lake Chichancanab, Yucatan Peninsula. This cycle is inferred to be caused by solar forcing and indicates severe droughts between 1.2 and 1 ka BP. McCloskey and Keller (2009) found increased hurricane acti vity over the last 5 ka in Belize attributed to shifts in the ITCZ and re lated positioning of the Bermuda High. A study performed by Frappier et al (2002) utilized high-resolution laser ablation to sample a Belize speleothem every 20 m for carbon isotope analysis. The speleothem entailed a 35-plus year re cord from the pres ent and the microsampling technique resulted in a weekly to monthly resolution. Results indicated that individual hurricane events were recorded in the carbon isotope data and were shown to correlate with known EN SO cycles, proving t hat precipitationrelated weather pattern changes can be re corded in speleothem calcite layers during rapid calcit e deposition.

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46 While there are data on climate variabi lity in Central America, few of the studies have looked at atmospheric-oc eanic teleconnections as the causal mechanism. Additionally, the paleoclimate fo cus has only recently turned toward the tropics (Frappier et al 2002; Lachniet et al. 2004a). Terrestrial records from the region are sparse, most likely because t hey are difficult to obtain and were previously thought to hold little paleoclimate information. 2.13 Florida Climate Influences Research examining tropical atmos pheric and oceanic influences affecting the region encompassing Florida includes re search in South and Central America on ITCZ movement (Haug et al. 2001; Lac hniet et al. 2004a, 2004b; Hughen et al. 2004). Other research focuses on te leconnections in the North Atlantic temperate latitudes, such as the fluct uation in intensity of and connectedness between the NAO and AMO (Kerr 2000; Enfiel d et al. 2001; Hurrell et al. 2003). A few studies have established a connec tion between the equator ial tropics and higher latitudes, with most of the focu s on ENSO and SST variations (deMenocal et al. 2001; Xie and Carton 2004). Even fewer studies look to the subt ropics of the North Atlantic for paleoclimatic data regarding a possible teleconnection link between the tropics and higher latitudes, resulting in only a handful of published terrestrial records from subtropical regions (e.g. Stahle and Cleaveland 1992; Wang et al. 2004; Da Silva and Chang 2004; van Beynen et al. 2007a, 2007b, 2008; Cane 2005). More data are necessary to unravel the multitude of influences that trigger changes in

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47 the North Atlantic climat e system, especially to underst and processes like that of the North Atlantic Thermohaline Circul ation (THC) and the influence of the NAO (Broecker 1997; Rahmst orf 2002; Kerr 2005). 2.14 Florida Paleoclimate Little research exists on the paleoc limate of Florida because it is climatologically complex. Large scale studies, such as the one by Stahle and Cleaveland (1992) reconstructing spring rain fall over the southeast U.S. for the past 1 ka using tree rings, provide some of the current paleoclimate data for Florida. While this study is helpful in understanding broader infl uences of climate change in Florida, more localized aspects are not addressed, such as regional variations and anthropogenic influences on climate and the environment. Other studies using coastal sediments and changes in storm phases further contribute to the regional study of Florida climate change (Otvos 2005), but address mainly coastal processe s. Studies involving paleoclimate reconstruction from Lake Tulane (Grimm et al. 1993, 2006; Watts and Hansen 1994) and Camel Lake (Watts et al. 1992) pr ovide low-resolution data, especially for long-term paleoclimate reconstruction, due to many lakes in Florida having undergone periods of desiccation during sealevel lowering. Studies by Haug et al. (2001) and Cane (2005) recognized the influences of the ITCZ, the North Atlantic High, and El Nio on Florida’ s climate, but were all performed on broader, more regional scales and in locati ons other than Florida, including the Caribbean Basin and Central America.

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48 To date, the only terrest rial studies to examine regional paleoclimatic data from Florida caves are van Beynen et al. (2007a, 2007b, 2008), who examined several speleothems from caves along the Brooksville Ridge and Ocala area in west-central Florida to create a record of seasonal changes precipitation and vegetation over the last 4000 years usi ng stable isotopes and trace elements in speleothem calcite (based on pr eliminary research by Soto (2005) in Florida). Part of this body of work found that the NAO and PDO were influential in changing Florida’s climate on a decadal scale. Higher resolution stable isotope data are possible from these records and wo uld provide a more accurate record of temporally brief events, such as ENSO variability. Stahle and Cleaveland (1992) found no synchronicity between the NAO, ENSO, or the Pacific/North America (PNA) circulation (reflective of PDO) during periods of precipitation change in the s outheastern U.S. using tree ring records. However, Hagemeyer (2006) attributes storm frequency and severity to interplay between the PNA, NAO, and ENSO. He fou nd that El Nio conditions coupled with negative NAO and positive PNA indice s provide optimal conditions for increased winter precipitation in Florida. Conversely, the opposite occurs during periods of La Nia conditions and pos itive NAO and negative PNA conditions, with reduced winter storm frequency and rain fall amount. Cronin et al. (2002) also found a connection between the NAO, ENSO, and the PNA with regard to winter precipitation since the late 1800’s in Florida. These teleconnections also affect other areas of the North Atlantic, but long-term, high-resolution data are

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49 lacking to provide the information about the persistence and robustness of changes in these atmospheric-oceanic systems. Understanding climate change in Fl orida throughout the Holocene is important to determine the driving forces causing climate variability, including precipitation and vegetation changes. To further understand atmospheric-oceanic teleconnections causing climate change in the North Atlant ic, data from a subtropical location like Florida, which is affected by both highand lowlatitude climate variability, provide information on the spatial extent and strength of these various climate influences. 2.15 Chapter References Armstrong, B., Chan, D., Collazo s, A., Mallams, J.L. 2003. Doline and Aquifer Characteristics within Hernando, Pasco, and Northern Hillsborough Counties. Karst Studies of West Central Florida pp. 39-51. Babkina, A.M. 2003. El Nio: Overview and Bibliography Nova Science Publishers: New York, 196 p. Baker, A., Ito, E., Smart, P. L., and McEwan, R. F. 1997. Elevated and variable values of 13C in speleothems in a British cave system. Chemical Geology 136: 263-270. Bond, N.A., and Harrison, D.E. 2000. T he Pacific Decadal Oscillation, air-sea interaction and central north Paci fic winter atmospheric regimes. Geophysical Research Letters 27(5): 731-734. Bottrell, S. 1996. Organic car bon concentration profiles in recent cave sediments: Records of agricultural pollution or diagensis? Environmental Pollution 91(3): 325-332. Boutton, T.W., and Yamasaki, S. 1996. Mass Spectrometry of Soils Marcel Dekker, Inc.: New York, New York. 517 p.

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50 Broccoli, A.J., Dahl, K.A., and Stouffer, R.J. 2006. Response of the ITCZ to Northern Hemisphere cooling. Geophysical Research Letters 33: L01702, doi:10.1029/2005GL024546. Broecker, W.S. 1997. Thermoha line Circulation, the Achilles Heel of our climate system: Will man-made CO2 ups et the current balance? Science 278: 1582-1588. Broecker, W.S. 2001. Glaciers That Speak in Tongues and other tales of global warming. Natural History 110(8): 60-69. Brook, G.A., Rafter, M.A., Railsback, L. B., Sheen, S., and Lundberg, J. 1999. A high-resolution proxy record of ra infall and ENSO since AD 1550 from layering in stalagmites from Anjohibe Cave, Madagascar. The Holocene 9(6): 695-705. Burroughs, W.J. 2003. Weather Cycles: Real or imaginary ? 2nd ed. Cambridge University Press: Cambridge, 317 p. Cane, M.A. 2005. The evolution of El Nino, past and future. Earth and Planetary Science Letters 230: 227-240. Cane, M.A. and Clement, A.C.1999. A role fo r the tropical Pacific coupled oceanatmosphere system on Milankovich and millenial timescales. Part II: Global impacts. In : AGU Monograph: Mechanisms of millenial scale global climate change. Caon, J., Gonzalez, J., and Valdes, J. 200 7. Preciptation in the Colorado River Basin and tis low frequency associat ions with PDO and ENSO signals. Journal of Hydrology 333: 252-264. Chen, Y., Senesi, N., and Schnitzer M.,1978. Chemical and physical characteristics of humic and fulvic acids extracted from soils of the Mediterranean region. Geoderma 20: 87-104. Cook, E.R., D’Arrigo, R.D., and Briffa, K. R. 1998. A reconstruction of the North Atlantic Oscillation using tree-ri ng chronologies from North America. The Holocene 8(1): 9-17. Cook, E.R., D’Arrigo, R.D., and Mann, M. E. 2002. A well-verified, multiproxy reconstruction of the winter North At lantic Oscillation Index since A.D. 1400. Journal of Climate 15: 1754-1764.

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51 Cronin, T.M., Dwyer, G.S., Schwede, S.B., Vann, C.D., Dowsett, H.,2002. Climate variability from the Florida Bay sedimentary record: possible teleconnections to ENSO, PNA, and CNP. Climate Research 19: 233-245. Curtis, J.H., Hodell, D.A., and Brenner M. 1996. Climate variability on the Yucatan Peninsula (Mexico) during the past 3500 years, and implication for Maya cultural evolution. Quaternary Research 46: 37-47. Curtis, J.H., Brenner, M., Hodell, D.A ., Balser, R.A., Islebe, G.A., and Hoogheimstra, H. 1998. a multi-prox y study of Holocene environmental change in the Maya Lowlands of Peten, Guatemala. Journal of Paleolimnology 19: 139-159. Dansgaard, W. 1964. Stable isotopes in precipitation. Tellus 16: 436-468. Da Silva, M., and Chang, P. 2004. Seasonal variation of the subtropical/tropical pathways in the Atlantic Ocean from an ocean date assimilation experiment. In : Earth Climate: The Ocean-Atmosphere Interaction. C. Wang, S.-P. Xie and J.A. Carton, (eds.), AGU Geophysical Monograph Series 147: 305-318. Dawson, A.G., Hickey, K., Holt, T., Elliott, L., Dawson, S., Foster, I.D.L., Wadhams, P., Jonsdottir, I., Wilkinson, J., McKenna, J., Davis, N.R., and Smith, D.E. 2002. Complex North Atl antic Oscillation (NAO) Index signal of historic North Atl antic storm-track changes. The Holocene 12(3): 363-369. DeMenocal, P., Ortiz, J., Guilderson, T., and Sarnthei n, M. 2001. Coherent highand low-latitude climate variability during the Holocene Warm Period. Science 288: 2198-2202. Desmarchelier, J.M., Hellstrom, J.C., and McCulloch, M.T. 2006. Rapid trace element analysis of speleothems by ELA-ICP-MS. Chemical Geology 231: 102-117. Dorale, J.A., Gonzalez, L.A., Reagan, M.K., Pickett, D.A., Murrell, M.T., and Baker, R.G. 1992. A high-resolution re cord of Holocene climate change in speleothem calcite from Cold Water Cave, Northeast Iowa. Science 258: 1626-630. Dorale, J.A., Edwards, R.L., Ito, E., and Gonzalez, L. A. 1998. Climate and Vegetation History of the Midconti nent from 75 to 25 ka: A Speleothem Record from Crevice Cave, Missouri, USA. Science 282: 1871-1874.

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52 Dorale, J.A., Edwards, R.L., and Onac, B.P. 2002. Stable isotopes as environmental indicators in speleothems In : Karst Processes and the Carbon Cycle, Yuan, D.-X. (ed.). G eological Publishing House: Beijing, China, pp. 107-120. Dorale, J.A., Edwards, R.L., Alexander E.C., Shen, C., Richards, D.S., and Cheng, H. 2004. Uranium-series dating of speleothems: current techniques, limits, and applications. In : Studies of Cave Sediments: Physical and Chemical Records of Pa leoclimate, I.D. Sasowsky and J.E. Mylroie, eds., Klewer: New York, p. 177-197. Dorale, J.A. and Liu, Z. 2009. Limitations of Hendy Test criteria in judging paleoclimatic suitability of spel eothems and the need for replication. Journal of Cave and Karst Studies 71(1): 73-80. Dreybrodt, W. 1988. Processes in Karst Systems: Physics, Chemistry and Geology. Springer Series in Physical Environments 4. SpringerVerlag: Berlin, p. 288. Ellwood, B.B., Petruso, K.M., and Ha rrold, F.B. 1997. High-resolution paleoclimatic trends for the Holocene identified using magnetic susceptibility data from archaeol ogical excavations in caves. Journal of Archaeological Science 24: 569-573. Enfield, D.B., Mestas-Nunez, A.M., and Trimble, P.J. 2001. The Atlantic Multidecadal Oscillation and its rela tion to rainfall and river flows in the continental U.S. Geophysical Research Letters 28: 277-280. Fairchild, I.J., Claire, C.L., Baker, A., Fu ller, L., Spotl, C., Ma ttey, D., McDermott, F., and E.I.M.F. 2006. Modification and preservation of environmental signals in speleothems. Earth-Science Reviews 75: 105-153. Fleitmann, D., Burns, S.J., Mudelsee, M., Neff, U., Kram ers, J., Mangi ni, A., and Matter, A. 2003. Holocene forcing of the Indian monsoon recorded in a stalagmite from southern Oman. Science 300: 1737–1739. Florea, L.J., Kelley, K., Hashimoto, T. Miller, D., and Mrykalo, R. 2003. Karst geomorphology and relation to the phreat ic surface: Briar Cave, Marion County, Florida. In : Florea, L.J., Vacher, H.L., and Oches, E.A., eds., Karst Studies in west-central Florida. University of South Florida/Southwest Florida Wate r Management District, p. 9-19. Ford, D.C. and Williams, P.W. 2007. Karst Geomorphology and Hydrology. Wiley : West Sussex, England, 2nd ed., 576 p.

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53 Frappier, A., Sahagian, D., Gonzalez, L. A., and Carpenter, S.J. 2002. El Nino events recorded by stal agmite carbon isotopes. Science 298: 565. Frumkin, A., Carmi, I., G opher, A., Ford, D., Schwarcz, H.P., and Tsuk, T. 1999a. A Holocene millennial-scale climat ic cycle from a speleothem in Nahal Qanah Cave, Israel. The Holocene 9(6): 677-682. Frumkin, A., Ford, D.C., Schwarcz, H. P. 1999b. Continental oxygen isotopic record of the last 170, 000 years in Jerusalem. Quaternary Research 51: 317-327. Gascoyne, M. 1992. Palaeoclimate determi nation from cave calcite deposits. Quaternary Sciences Reviews 11: 609-632. Genty, D., Baker, A., Mass ault, M., Proctor, C., Gilmour, M., Pons-Branchu, E., Hamelin, B. 2001. Dead carbon in stalagmites: Carbonate bedrock paleodissolution vs. ageing of soil or ganic matter. Implications for 13C variations in speleothems. Geochimica et Cosmochimica Acta 65(20): 3443-3457. Gillieson, D.G. 1996. Caves: processes, devel opment and management Blackwell Publishers Ltd .: Oxford, England, 324 p. Grimm, E.C., Jacobson, G.L., Watts, W.A. Hansen, B.C.S., M aasch, K.A. 1993. A 50,000-year record of climate oscillations from Florida and its temporal correlation with the Heinrich events. Science 261: 198-200. Grimm, E.C., Watts, W.A., Jacobsen Jr., G.L., Hansen, B.C.S., Almquist, H.R., Dieffenbacher-Krall, A.C. 2006. Evidence for warm wet Heinrich events in Florida. Quaternary Science Reviews 25: 2197-2211. Hagemeyer, B.C. 2006. ENSO, PNA and NAO Scenarios for extreme storminess, rainfall and temperatur e variability during the Florida dry season Preprints, 18th Conference on Climate Variability and Change, Atlanta, GA, American Meteorol ogical Society, CD -ROM P2.4. Hardy, J.W. and Henderson, K.G. 2003. Cold front variability in the southern United States and the influence of at mospheric teleconnection patterns. Physical Geography 24: 120-137. Harmon, R.S., Thompson, P., and Sc hwarcz, H.P., and Ford, D.C., 1975. Uranium-series dating of speleothems. National Speleological Society Bulletin 37: 21-33.

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54 Harmon, R.S., Schwarcz, H.P., Gasco yne, G., Hess, J., and Ford, D. 2004. Paleoclimate information from speleothem s: The present as a guide to the past. In Studies of Cave Sediments: Physical and Chemical Records of Paleoclimate, I.D. Sasowsky and J.E. Mylroie, (eds.). Klewer: New York, p. 199-226. Haug, G.H., Hughen, K.A., Sigman, D.M. Peterson, L.C., and Rohl, U. 2001. Southward migration of the Inte rtropical Convergence Zone through the Holocene. Science 293: 1304-1308. Hendy, C. 1971. The isotopic geochemistry of speleothems I. The calculation of the effects of different modes of formation on the isotopic composition of speleothems and their applicabilit y as palaeoclimatic indicators. Geochimica et Cosmochimica Acta 35: 801-824. Henry, J.A., Portier, K. M., and Coyne, J. 1994. The climate and weather of Florida Pineapple Press: Sarasota, Florida, p. 279. Hidalgo, H.G., and Dracup, J.A. 2003. EN SO and PDO effects of hydroclimatic variations of the Upper Colorado River Basin. Journal of Hydrometeorology 4: 5-23. Hiradate, S., Yonezawa, T., and Takesako, H. 2006. Isolation and purification of hydrophilic fulvic acid s by precipitation. Geoderma 132: 196-205. Holmgren, K., Karlen,W., Lauritzen, S. E., Lee–Thorp, J.A., Partridge, T.C., Piketh, S., Repinski, P., Stevenson, C., Svanered, O., and Tyson, P.D. 1999. A 3000-year high-resolution stalagmite based record of palaeoclimate for northeastern South Africa. The Holocene 9: 295-309. Hodell D.A., Curtis, J.H., and Brenner, M. 1995. Possible role of climate in the collapse of Classic Maya civilization. Nature 375: 391-394. Hodell, D.A., Brenner, M., Curtis, J.H., and Guilderson, T. 2001. Solar forcing of drought frequency in the Maya Lowlands. Science 292: 1367-1370. Hodell, D.A., Brenner, M., Curtis, J.H., Medina-Gonz alez, R., Ildefonso-Chan Can, E., Albornaz-Pat, A., and Guild erson, T.P. 2005a. Climate change on the Yucatan Peninsula dur ing the Little Ice Age. Quaternary Research 63: 109-121. Hodell, D.A., Brenner, M., and Curtis, J.H. 2005b. Terminal classic drought in the northern Maya lowlands inferred from multiple sediment cores in Lake Chichancanab (Mexico). Quaternary Science Reviews 24: 1413-1427.

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55 Huang, Y., Street-Perrott, F.A., Metcal fe, S.E., Brenner, M., Moreland, M., and Freeman, K.H. 2001. Clim ate change as the dominant control on glacialinterglacial variations in C3 and C4 plant abundance. Science 293:16471651. Hughen, K.A., Eglinton, T. I., Xu, L., and Makou, M. 2004. Abrupt tropical vegetation response to rapid climate changes. Science 304: 1955-1959. Hurrell, J.W., Kushnir, Y., Otte rson, G., Visbeck, M., 2003. An overview of the North Atlantic Oscillation In : The North Atlantic Oscillation: Climatic Significance and Environmental Im pact. Geophysical Monograph Series, AGU 134: 1-36. Kaufmann, G. 2002. Karst landscape evolution In : Gabrovšek, F., ed., Evolution of karst: from prekarst to cessation Postojna: Ljubljana, Zalozba ZRC, p. 243-258. Kerr, R.A. 2000. A North Atlantic climate pacemak er for the centuries. Science 288(5473): 1984-1985. Kerr, R. A. 2005. Atlantic climate pac emaker for millennia past, decades hence? Science 309: 43-44. Lachniet, M.S., Asmerom, Y., Burns, S., Patterson, W.P., Polyak, V. and Seltzer, G.O. 2004a. Tropical response to the 8200 yr cold event? Speleothem isotopes indicate a weakened early Holocene monsoon in Costa Rica. Geology 32: 957-960. Lachniet, M.S., Burns, S.J., Piperno, D.R., Asmerom, Y., Polyak, V.J., Moy, C.M., and Christenson, K. 2004b. A 1500-year El Nino/Southern Oscillation and rainfall history for the Isthmus of Panama from speleothem calcite. J ournal of Geophysical Research 109: D20117, doi:10.1029/2004JD004694. Lachniet, M.S. 2009. Climatic and environmental controls on speleothem oxygenisotope values. Quaternary Science Reviews 28(5-6): 412-432. Lane, E., and Hoenstine, R.W.1991. Environmental geology and hydrogeology of the Ocala area, Florida Florida Geological Survey Special Publication 31, 71 p. Lauritzen, S.E., and Lundberg, J. 1999a. S peleothems and climate: a special issue of the Holocene. The Holocene 9: 643-647.

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56 Lauritzen, S.E., and Lundberg, J. 1999b. Cali bration of the speleothem delta function; an absolute temperature re cord from the Holocene in northern Norway. The Holocene 9: 659-669. Lauritzen, S.E., and Onac, B. P. 1999. Isotopic stratigraphy of last interglacial stalagmite from northwestern Romani a: correlation with deep-sea record and northern-latitude speleothem. Journal of Cave and Karst Studies 61: 22-30. Mantua, N.J., Hare, S.R., Zhang, Y., Wa llace, J.M., and Francis, R.C. 1997. A Pacific interdecadal climate oscill ation with impacts on salmon production. Bulletin of the American Meteorological Society 78: 1069-1079. Martin, A., Mariotti, A., and Balesden t, J. 1990. Estimate of organic matter turnover rate in a savanna soil by 13C natural abundance measurements. Soil Biology Biochemistry 22(4): 517-523. McCloskey, T.A., and Keller, G. 2009. 5000 year sedimentary record of hurricane strikes on the central coast of Belize. Quaternary International 195: 53-68. Mickler, P.J., Banner, J.L., Stern, L., Asmerom, Y., Edwards, R.L. and Ito, E., 2004. Stable isotope variations in modern tropical speleothems: Evaluating equilibrium vs. kinetic isotope effects. Geochimica et Cosmochimica Acta 68: 4381-4393. Nash, J.M. 2002. El Nio: Unlocking the secrets of the master weather-maker Warner Books: New York, 340 p. Otvos, E.G. 2005. Holocene aridity and st orm phases, gulf and Atlantic coasts, USA. Quaternary Research 63: 368-373. Palmer, A.N. 2007. Cave Geology. Cave Books: Dayton, OH, 454 p. Richards, D.A. and Dorale, J.A. 2003. Uranium-series chronology and environmental applications of speleothems. In : Reviews in Mineralogy and Geochemistry, B. Bourdon, G.M. Henderson, C.C. Lundstrom, and S.P. Turner, (eds.) 52, pp. 407-460. Peterson, L.C., Haug, G.H., Hughen, K.A ., and Rohl, U. 2000. Rapid changes in the hydrologic cycle of the tropical Atlantic during the last glacial. Science 290: 1947-1951. Peterson, L.C. and Haug, G.H. 2006. Variab ility in the mean latitude of the Atlantic Intertropical Convergence Z one as recorded by riverine input of sediments to the Cariaco Basin (Venezuela). Paleogeography, Paleoclimatology, Paeloecology 234: 97-113.

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57 Rahmstorf, S. 2002. Ocean circulati on and climate during the past 120,000 years. Nature 419: 207-214. Randazzo, A.F., and Jones, D.S., eds. 1997. The Geology of Florida: Gainesville Florida University Press of Florida, 327 p. Reeder, P. and Brinkmann, R. 1998. Paleoe nvironmental Reconstruction of an Oligocene-Aged Island Remnant in Florida, USA Cave and Karst Science 25: 7-13. Rein, B., Luckge, A., and Sirocko, F. 2004. A major Holocene ENSO anomaly during the Medieval period. Geophysical Research Letters 31, L17211, doi:10.1029/2004GL020161. Rajagopalan, B., Kushnir, Y., Tourre, Y.M. 1998. Observed decadal midlatitude and tropical Atlantic climate variability. Geophysical Research Letters 25 (21): 3967-3970. Rosenmeier, M.F., Hodell, D.A., Brenner M., Curtis, J.A., Martin, J.B., Anselmetti, F.S., Ariztegui, D., and Guilderson, T.P. 2002. Influence of vegetation change on watershed hydrology : implications of paleoclimatic interpretation of lacustrine 18O records. Journal of Paleolimnology 27: 117-131. Rozanski, K., Araguas-Araguas, L. and Gonfiantini, R. 1993. Isotopic patterns in modern global precipitation In : Climate Change in Continental Isotopic Records. P.K. Swart, K.C. Lohmann, J. McKenzie and S.Savin, (eds). Geophysical Monograph 78, Americ an Geophysical Union, pp. 1-36. Schwartz, D., Mariotti, R., Lanf ranchi, R., and Guillet, B. 1986. 13C/12C ratios in soil organic matter as indicators of vegetation changes in the Congo. Geoderma 39: 97-103. Schwarcz, H.P. 1986. Geochronology and isotopic geoc hemistry of speleothems In : Fontes, J.C., & Fritz, P., (eds.) Handbook of environmental isotope geochemistry. The terrestrial environm ent, B: Elsevier, Amsterdam, pp. 271-303. Sharp, Z. 2007. Principles of Stable Isotope Geochemistry Pearson Prentice Hall: Upper Saddle River, NJ, p. 344. Shaw, J.M. 2003. Climate change and defores tation: Implications for the Maya Collapse. Ancient Mesoamerica 14: 157-167.

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58 Soto, L.R. 2005. Reconstruction of Late Holoc ene Precipitation for Central Florida as Derived from Isotopes in Speleothems University of South Florida, Published Masters Thesis. South East Regional Climate Cent er. Accessed September 2006 at http://cirrus.dnr.state.sc.us/cgi -bin/sercc/cliMAIN.pl?fl1046. Stahle, D.W., and Cleavela nd, M.K. 1992. Reconstruc tion and analysis of spring rainfall over the Southeastern U.S. for the past 1000 years. Bulletin American Meteorological Society 73(12): 1947-1961. Tihansky, A. B., and Knochenmus, L. A. 2001. Karst Features and Hydrogeology in West-Central Florida--A Field Perspective. In : U.S. Geological Survey Karst Interest Group Proceedings. E.L. Kuniansky, (ed.).USGS WaterResources Investigations Report 01-4011. Turney, C.S.M., Bird, M.I., and Roberts, R.G. 2001. Elemental 13C at Allen’s Cave, Nullarbor Plain, Australia: assessing post-depositional disturbance and reconstructing past environments. Journal of Quaternary Science 16(8): 779-784. van Beynen, P.E., Schwarcz, H.P., and Ford, D.C. 2004. Holocene climatic variation recorded in a speleothem fr om McFail’s Cave, New York. Journal of Cave and Karst Studies 66(1): 20-2. van Beynen. P.E., Soto, L., Pace-Graczyk, K., 2007a. Paleoclimate reconstruction derived from speleothem strontium and 13C in Central Florida. Quaternary International 187(1): 76-83. van Beynen, P.E., Asmerom, Y., Polyak, V., Soto, L., Polk, J.S., 2007b. Variable intensity of teleconnections during the Late Holocene in Subtropical North America from an isotopic study of speleothem from Florida. Geophysical Research Letters 34: L18703, doi:10:1029/2007GL031046. van Beynen, P.E., Soto, L., Polk, J., 2008. Variable calcite deposition rates as proxy for paleo-precipitati on determination as derived from speleothems in Central Florida. Journal of Cave and Karst Studies 70 (1): 1-19. Wang, W., Anderson, B.T., Kaufmann, R.K., and Myneni, R.B. 2004. The relation between the North Atlantic Oscillat ion and SSTs in the North Atlantic basin. Journal of Climate 17: 4752-4759. Watts, W.A., Hansen, B.C.S., and Grimm, E.C. 1992. Camel Lake: A 40,000-yr record of vegetational and forest history from northwest Florida. Ecology 73(3): 1056-1066.

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59 Watts, W.A., and Hansen B. C. S., 1994. Pre-Holocene and Holocene pollen records of vegetation hi story from the Florida peninsula and their climate implications. Palaeogeography, Palaeoclim atology, Palaeoecology 109: 163–176. Webb, E.A., Schwarcz, H.P., and Healy, P.F. 2004. Detect ion of ancient maize in lowland Maya soils using stable carbon isotopes: evidence from Caracol, Belize. Journal of Archaeological Science 31: 1039-1052. White, W.A. 1970. The Geomorphology of the Florida Peninsula Florida Bureau of Geology, Bulletin No. 51, 164 pp. White, W.B. 1988. Geomorphology and Hydrology of Karst Terrains Oxford University Press: New York, 464 p. White, W.B. 2004. Paleoclimate records from speleothems in limestone caves In : Studies of Cave Sediments: Ph ysical and Chemical Records of Paleoclimate, I.D. Sasowsky and J.E. My lroie, eds., Klewer: New York, p. 135-175. Wynn, J.G., Bird, M.I., and Wong, V.N.L. 2005. Raleigh distillation and the depth profile of 13C/12C ratios of soil organic carbon from soils of disparate texture in Iron Range National Park Far North Queensland, Australia. Geochimica et Cosmochimica Acta 69 (8): 1961-1973. Xie, S.P. and Carton, J. A. 2004. Tropical Atlantic variability: patterns, mechanisms, and impacts. In : Ocean-Atmosphere Interaction and Climate Variability, C. Wang, S.P. Xie, and J.A. Carton, eds., AGU Geophysical Monograph 147: 121–142.

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60 Chapter 3 Late Holocene Environmental Recons truction Using Cave Sediments from Belize 3.1 Chapter Preface This chapter presents an exploratory st udy investigating the utility of fulvic acids in cave sediments for paleoenvironmen tal reconstruction in Belize. Belize was chosen for geologic and geographic reasons, as well as because of the cultural history of t he landscape. The Maya once densely populated the area before abandoning it, possibly due to dec lining water resources caused by climate change. Ironically, the ever-inc reasing population of Florida and its dependency on plentiful groundwater supplie s could create a modernized version of this scenario. Similar to Florida, Be lize also has a humid, subtropical climate with a distinct monsoon season. Addition ally, much like Florida, speleothem formations are not common in Belizean caves, yet sediment in the form of sands and Maya clays are abundant and their paleo climatic significance is explored here. This chapter was published in Quaternary Research in 2007: Polk, J.S., van Beynen, P., and Reeder, P. 2007. Late Holocene environmental reconstruction using cave sediments from Belize. Quaternary Research 68(1): 53-63.

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61 3.2 Abstract Cave sediments collected from Refl ection Cave on the Vaca Plateau, Belize show variations in the 13C values of their fulvic acids (FAs), which indicate periods of vegetation change caused by climatic and Maya influences during the Late Holocene. The 13C values range from 27.11‰ to -21.52‰, a shift of ~5.59‰, which suggests fluctuating contributions of C3 and C4 plants throughout the last 2.5 ka, with C4 plant input reflecting periods of Maya agriculture. Maya activity in the study ar ea occurred at different intensities from ~2,600 cal yr BP until ~1500 cal yr BP, afte r which agricultural practices waned as the Maya depopulated the area. These changes in plant assemblages were in response to changes in available water re sources, with increas ed aridity leading to the eventual abandonment of agricultural areas. The Ix Chel archaeological site, located in the study area, is a hi ghland site that would have been among the first agricultural settlements to be affect ed during periods of ar idity. During these periods, minimal water resources woul d have been available in this highly karstified, well-drained area, and s upplemental groundwater extraction would have been difficult due to the extr eme depth of the water table. 3.3 Introduction Inferences regarding connections bet ween past climate variability and cultural evolution can be complex, requi ring the incorporation of several dynamic and reciprocating factors, including environmental, cultural, and climatic interactions. Paleoclimate data are used to establish periods of climatic

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62 variability, which can be com pared with the cultural evi dence of a civilization’s growth or decline in response to those fl uctuations. The ancient Maya civilization that inhabited the lowlands of Central Am erica provides an excellent example of complex climatic, cultural, and environment al interactions, but debate continues regarding the cause of the society’s co llapse ~900 AD (Curtis 1998; Lucero 2002; Leyden 2002; Shaw 2003; Neff et al. 2006). The factor most often excluded in the interpretation of these complex interactions, possibly due to lack of preservation or the complexity of reco rds, is the environmental response to climatic and anthropogenic influences (Leyden 2002). One such area of climate and human interaction is the Northern Vaca Plateau in Belize (Figure 3.1), which was populated by the Maya, and is a region susceptible to arid periods because it is a highly karstified upland area (Reeder et al. 1996). Topographically diverse and well-drained, the area is quite susceptible to climatic variability, which would be compounded by the effects of anthropogenic landscape alteration. In this paper, we present an analysis of environmental change on the Vaca Pl ateau, Belize through vegetation reconstruction using 13C values of fulvic acids extr acted from cave sediments, which we propose are a proxy record of Maya alteration of the environment through agricultural practices. Speleot hem carbon and oxygen isotope data from another nearby cave in the study area provide information regarding climate variability in the area (Webster 2000; also see Webster et al. 2007). Previous studies show distinct regional differences in terms of the severity and timing of arid periods that would have affe cted human occupation and agricultural

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63 production throughout Central Am erica (Hodell et al. 1995; Curtis et al. 1996; Haug et al. 2001; Shaw 2003; Hodell et al. 2005b). These arid periods would have impacted the well-drained study area more rapidly and severely than other lowland sites.

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64 Figure 3.1 Study area map. (A) Zoomed inset map of the Northern Va ca Plateau study area (gray box) in Belize, Central A merica. (B) Map of Central America and the surrounding area sh owing the major climatic influences, including the ITCZ, Bermuda High, and the Easterlies (modified from Soto 2005).

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65 Recent evidence has shown that the tropical climate of the Late Holocene was more variable than previously though t, especially in the Central American Lowlands, lending plausibility to the hypot hesis of climate change influencing the collapse of the Maya (Haug et al. 2001, 2003; Hodell et al. 2001; Gunn et al. 2002; Hughen et al. 2004). The Maya were inherently dependent upon agriculture for sustenance, mainly us ing slash-and-burn techniques combined with terracing and irrigation systems to ma intain soil abundance and fertility. In the Central Lowlands of Belize, this agr arian lifestyle was complicated by the well-drained, highly karstified landscape, which is characterized by thin soils, ephemeral water resources, and per iodic droughts (Chase and Chase 1989; Miller 1996; deMenocal 2001; Demarest 2004). The Maya deforested and terraced the hillslopes of the karst landscape to make them suitable for agriculture (Coultas et al. 1993). Over time, the combination of a growing population and periodic droughts leading up to the Terminal Collapse period (~800 to 1000 AD) would have left the Maya susceptible to climate changes affecting water availability (Cowgill 1962; Chase and Chase 1989). However, this suscept ibility to climate change was not consistent throughout the ent ire area of Maya occupation, with certain regions responding more abruptly to environmental and anthropogenic changes (Gill 2000; Gunn et al. 2002). Events such as t he Maya Hiatus (~1470 to 1350 cal yr BP (530 to 650 AD) (deMenocal 2001) and t he Preclassic Abandonment (~1950 to 1850 cal yr BP (150 to 250 AD) (Hodell et al. 2001; Haug et al. 2003) had different effects on the Maya, depending on their location. There are no major

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66 groundwater or river resources in the st udy area, hence, t he Maya population was reliant on rainfall for irrigati on and water storage (Chase and Chase 1989), thereby making it more susceptible to c limate variability than other sites where water resources are more abundant. Previous studies regarding climat e change and the Maya have mainly focused on the analysis of lake sediments from Guatemala (Curtis et al. 1998; Rosenmeier et al. 2002) and the Yucat an Peninsula (Hodell et al. 1995, 2001, 2005b; Curtis et al. 1996). The majority of the lacustrine studies show agreement that periods of aridity occurred during the interval from 1250 to 950 cal yr BP (750 to 1050 AD), which is concurrent with the collapse of the Maya (Hodell et al. 2005b). An analysis of marine sediments from the Cariaco Basin in the Caribbean Sea (Haug et al. 2001, 2003) al so found periodic multi-year droughts between 1240 and 1090 cal yr BP ( 760 and 910 AD) that agree with the lacustrine records of the Yucatan, prov iding further evidence of climatic change influencing the decline of the Maya. Webster (2000; also see Webster et al. 2007) performed the only terrestrial paleoclimate study of any signi ficant length in or around Belize, analyzing the 13C and 18O values of a speleothem coll ected from a cave in the study area, which provided a dated record from 2700 cal yr BP (700 BC) to ~200 cal yr BP (1800 AD). The speleothem isot ope values indicate periodic aridity recurring approximately every 280 years. Extended dry periods in the record occurred from ~2350 to 2200 cal yr BP (350 to 200 BC) and from ~1400 to 900

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67 cal yr B.P. (600 to 1100 AD). However, this study is an indirect measure of climate-human interactions. Other than the Webster (2000; also s ee Webster et al. 2007) study, few have analyzed Maya environmental impact on the Central Lowlands of Belize, because the highly karstified landscape pres erves little in the way of suitable proxy records. The well-drained nature of the karst landscape in our study area does not allow water to collect and form lakes; hence, no lacustrine sediment is deposited. Additionally, tree ring studies in the tropics are in their infancy, and to provide meaningful data they require mo re mountainous terrain than what is available in Belize. Consequently, underta king a study of the paleoclimate/human interactions on the Vaca Plateau requir ed the novel approach of carbon isotope analysis of organic substances extracted from cave sedi ments. This exploratory approach allows the most dire ct investigation into these interactions, because we are analyzing cave sediments derived from the same soil that the Maya utilized for agricultural production. 3.3.1 Cave Sediments Cave sediments can result from the allogenic depos ition of surface soils into caves (Brinkmann and Reeder 1995). These sediments record the environmental history of the land above the cave in their stratigraphic layering, providing robust records of terrestrial changes in vegetation and land use, which are not preserved in ever-changing surf ace soils (Bottrell 1996; Courty and Vallverdu 2001; Panno et al. 2004). Previ ous studies regarding cave sediments have mainly focused on stable carbon is otope analysis of bulk organic matter to

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68 provide records of depositional distur bance (Turney et al. 2001), agricultural pollution (Bottrell 1996), or the presence of certain vegetation types (Panno et al. 2004). The latter study used the 13C values from organic matter in cave sediments to determine vegetation and clim ate change in southern Illinois during the Pleistocene and Early Holocene (Panno et al. 2004). They found that cave sediments provide detailed and well-pres erved records of environmental change over thousands of years. To date, no studies have investigated the fulvic acid (FA) fraction of organic matter extracted from cave sedi ments; however, FAs from soils have been used for paleoenvironmental interpre tation (Yamskikh 1998). FAs are low molecular weight, easily transported, hydrophilic acids, and most closely represent the humic fraction of the decaying organic matter derived from vegetation growing above the cave during se diment deposition (Aikin et al. 1985; van Beynen et al. 2000; Doane et al. 2003) However, calcareous clays dominate the study area, preferentially binding FAs to create microaggregates, reduces FA lability (Liao et al. 2006) and movement in the sediment column (Stevenson et al. 1994; Qualls et al. 2003, 2004; Grunewal d et al. 2006). Humic substances are not easily degraded by biolog ical processes, such as microbial breakdown (Spaccini 2000, 2006), thus having high preser vation (Biggs et al. 2002; Claret et al. 2005; Grunewald et al 2006). Calderoni and Sc hnitzer (1984) found FAs preserved over the last ~29000 yr BP in a paleosol on Italy, with no effect of age on their chemical structure or compositi on. In southwest China, core sediments from Erhai Lake provided fulvic acids r anging in age from ~1900 to 5700 yr BP

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69 (Xu and Zheng 2003). These studies attest to the durability and utility of using FAs as a paleoenvironmental proxy. 3.3.2 Carbon Isotopes Paleoecological information is derived from carbon isoto pes in soil organic matter because soil isotopic composition re flects the type of local plant matter (Quade et al. 1989). Shifts in vegetation between C3 and C4 plants are recorded in the 13C data from the soil organic acids (S chwartz et al. 1986; Clapp et al. 1997). Plants preferentially favor the lighter 12C isotope, but isotopic preferences between C3 and C4 plants differ, causing distinctive 13C values for each type. Changes from C3 to C4 vegetation are indicated by shifts between depleted 13C values, indicative of dense forested (C3) conditions, and enriched 13C values, indicative of the presence of more arid (C4) vegetation, such as grasses and scrub (Desmarchelier et al. 2000; Dora le et al. 1992). On average, C3 plant 13C values range from -33‰ to -27‰, whereas C4 vegetation ranges from -16‰ to 9‰ (Schwartz et al. 1986; Bottrell 1996; Huang et al. 2001; Turney et al. 2001). The surface soil, containing or ganic matter with its associated 13C values, is then washed into the cave forming sedim ents, which provide a long-term record of vegetation change above the cave (Panno et al. 2004). 3.4 Study Area The Ix Chel archaeological site study area (Figure 3.2), centered at 1652.84’N and 8906.68’W, is a 25 km2 area located on the northern Vaca Plateau, Belize (Figure 3.2). The Ix Chel ruins comprise a medium-sized site,

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Fig Ma c p at h cor r rep o ure 3.2 Map c al Chasm a n h ways. Dista n r ect distance s o rt). of Ix Che l N o n d Reflection n ces to Maca s noted on m a 70 o te the archa e Cave. Dotte d l Chasm and a p ( modified f e ological site d lines indica t Reflection C a f rom Colas e t and its relati v t e ancient ro a a ve are not t o t al. 2006, un p v e location t o a ds and/or m a o map scalep ublished o a jor

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71 containing three groups of buildings, a ballcourt, and a Sak Beh (Figure 3.2) (Colas et al. 2006). Despite cultural re ference to this area being the Lowlands during Maya occupation, the region’s physi cal landscape is part of the Southern Karst Uplands. The Vaca Plateau, locat ed near the Guatemala border, exhibits high relief, encompassing well-drained, extensively karstified limestone characterized by several moderately-siz ed residual hills and dry valleys (Reeder et al. 2003; Webb et al. 2004). The area’s limestone consists of the extensively brecciated, Cretaceous Campur Formation, which extends over large areas of both Belize and Guatemala (Reeder et al. 1996). The only other exposed unit is the granitic Mountain Pine Ridge area of the Maya Mountains to the east (Reeder et al. 1996). The highest elevation in t he study area is ~520 m.a.s.l., with the greatest relief being 120 m from the highest residual h ills to the valley floor. Besides the rugged topography, the area has numerous sinkholes and deep vertical caves. Miller (1990) estimated t hat regional karstification of the area began approximately 700 ka BP. Ancient Maya terraces are still present in the landscape, along with abandoned cultural remains. 3.4.1 Vegetation Vegetation in the area consists of tr opical and sub-tropical rainforest-type palms and other plants, including dominant mahogany and ceiba trees. Understory vegetation consists of sapodi lla, fig, Spanish cedar, and a diverse variety of palms (Penn et al. 2004). In t he well-drained mountainous hilltops, cacti are also present. The soil is predominant ly derived from weathered limestone and consists mostly of Cabro stony cl ays, which are predominantly kaolinite

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72 (Furley 1976). Soils are fairly sparse on t he hillslopes, with soil depths of 5 to 10 cm on average (Reeder et al. 2003). Howeve r, the valley bottoms contain several meters of clayey soils due to the accumu lation of slope wash from the hillslopes. 3.4.2 Climate The region’s climate is tropical rain forest, however, there is a prevailing rainy season from June to November and annual rainfall amounts are between 2,000 and 2,400 mm. Peak precipitati on amounts occur in June and July, reaching maximums of 100 mm per hour (Furley and Newey 1979). Highest temperatures occur in May, with a mean annual temperature of 25 C. The main atmospheric influences on precipitation are the Intertropical Convergence Zone (ITCZ) and the North Atlantic High (B ermuda-Azores High). Precipitation increases when the ITCZ is positioned more northerly during the summer and drier conditions prevail when it is displa ced further to the south by the North Atlantic High (Figure 3.1) (Haug et al. 2003; Hodell et al. 2005a). 3.4.3 Reflection Cave Reflection Cave (Figure 3.3) lies at the base of a steep hill approximately 3 km southeast of the Ix Chel ruins (Figure 3.2), the largest abandoned Maya settlement in the study area. The ca ve has an 11-m-deep vertical entrance, branching off into two short opposing passa ges on either side of the entrance. Sediments are abundant in the cave, repr esenting surface soils washed in from an area around the cave entrance, which t hen accumulate in a small, confined passage in the cave. Maya activity in t he cave, usually indicated by artifacts, remains, structures, or broken format ions, could have disturbed the sediments

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73 during or after deposition; however, there is no evidence of prior human activity in the cave. Figure 3.3 Map of Reflection Cave. Located on the Vaca Plateau, Belize with marked location of sediment bank exposure where samples were collected (cartography by P. Reeder).

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74 3.5 Methodology 3.5.1 Field Sample Collection In 2004, fifteen cave sediment sample s were collected in stratigraphic order at ~5 cm intervals from a ~82 cm thick sediment bank along a narrow, isolated passageway halfway down the nor th branch of Reflection Cave (Figure 3.3). Samples were taken at this resolution because the scope of the study was exploratory, and was intended to determi ne whether these cave sediments had any value for paleoenvironmental recons truction. The samples were bagged, sealed, and brought back to the University of South Florida’s Soils and Physical Geography Lab, where each sediment sample was air-dried for 24 hours prior to analysis. 3.5.2 Radiocarbon Dating Radiocarbon dates were obtained fo r layers where sufficient organic carbon was present in the form of char coal, seeds, wood, and organic matter, to establish a chronological record of deposit ion for the sediment bank. The dating was performed at the University of Arizona AMS Lab using a General Ionex accelerator mass spectrometer. Dates were calibrated to calendar ages using the CalPal computer program and reported to within the 95.4% confidence limits of the calibration (Weninger et al. 2005). 3.5.3 Stable Carbon Isotopes FAs were extracted from the sediments for carbon isotope ( 13C) analysis according to the methods described by Haye s et al. (1997). Initially, the sediment samples were dried and ground, and then mixed in a 1:10 soil to 0.1 M HCl ratio

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75 in centrifuge tubes and shaken overnight. This mixture was then centrifuged for 30 minutes at 13,000 rpm. After decanting, the residue was washed with distilled water, centrifuged at 13,000 rpm for 30 minutes, and the supernatant was decanted and added to the HCl extract from the first round of centrifuging. To precipitate the humic acids and l eave the FAs in solution, the sediment residues were mixed in a 1:10 ratio with 0.1 M NaOH and shaken for 3 hours under an atmosphere of N2. Individual slurries were then centrifuged (13,000 rpm for 30 minutes) and the yellowish-brown supernatant was decanted and acidified with 6 M HCl to a pH of 1.0. This pr ocess was repeated on each residue until the supernatants were virtually clear (~ 8 times). The acidified supernatants were combined for each sample once clarity was obtained, refrigerated, and left overnight to allow flocculation. After fl occulation, the FA fractions were then obtained by centrifuging (13,000 rpm fo r 30 minutes) and the supernatant from each was added to the previously combi ned acidified supernat ants obtained prior to flocculation, leaving the solid FAs suspended within ~50 ml of brine water. The isolated FA fractions then had the excess water removed using a Buchi Rotavapor R-114 to ~30 ml. Each sample was then put in a deep-freezer at -75 C and left overnight. Completion of the drying process was performed by placing the samples in a Labconco Vac uum Freeze-Dry Syst em for 72 hours, until they became powdered and crystalline. The powdered FAs were placed in sealed containers and kept cool and dry until they were analyzed. The 13C of the FA fractions was measured with a Carlo-Erba NA2500 Series II EA coupled to a ThermoFinnigan Delta+XL IRMS in continuous flow

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76 mode located at the Universi ty of South Florida’s Co llege of Marine Science Paleoclimatology, Paleoceanography and Biogeochemistry Laboratory in St. Petersburg, Florida. Samples of ~30 g were placed in tin containers and dropped from a Costech Zero-blank Autosa mpler into an EA combustion furnace thermostatically stabilized at 1000C, where they were combusted with an excess of UHP O2. Combustion products were entrained in a UHP He carrier stream and passed through a reducti on furnace (to remove excess O2 and reduce NOx to N2), a water trap and a GC column (3 m, 0.25" dia. 5A mol sieve) before entering the IRMS via an open-spli t interface (ThermoFinnigan ConFlo II). Analyzed gases were measured against reference gases (UHP N2 and UHP CO2) and are expressed in per mil (‰) rela tive to their respective reference materials (VPDB for 13C). Estimates of analytical precision were obtained by replicate measurements of internal lab reference materials and yield a precision of 0.3‰ for 13C. 3.6 Results 3.6.1 Chronology Radiocarbon dates from charcoal, wood, seeds, and organic matter from nine layers of sediment in Reflection Cave provide a chronology of deposition (Table 3.1, Figure 3.4). The age of the s ediment bank’s surface was assumed to be modern based on the post-bomb 14C date of the top layer. Dates at depths of 45 and 58 cm were out of sequence, possibly due to old organic material used for the dates being stored on the surface, and later flushed into the cave by a

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77 severe rain event. These dates were still used in constructing the age model (Figure 3.4) and all other dates were in chronological order. The depth-to-age model was constructed using a secondorder polynomial regression model to provide a chronological record for the 13C values of the FAs (Figure 3.5). Although the r2 of the regression is 0.80 (p < 0.001), the number of dates used (nine) provides acceptable confidence in the timescale reconstruction. Table 3.1 AMS Radiocarbon dates. Shown are calibrated ages, and errors from charcoal, wood, and organic matter in Reflection Cave sediments.Dates were calibrates using the CalPal radiocarbon calibration program (Beyond the Ghost version 2005). Accession No. Sample ID Depth (cm) Age( 14 C yr B.P.) (1 ) Age (cal yr B.P.) (2 ) AA60342 REF04-01 0 Post-bomb 0 AA63332 REF04-02 12 817 39 737 68 AA60341 REF04-03 22 1975 39 1935 82 AA63333 REF04-04 38 2072 64 2050 160 AA60340 REF04-05 45 1437 38 1342 54 AA63334 REF04-06 58 2690 120 2792 320 AA60339 REF04-07 63 2071 41 2050 110 AA63335 REF04-08 68 2361 37 2403 98 AA60338 REF04-09 78 2586 39 2688 128

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3 2 p b 2 v 5 F f r o c a n 3 .6.2 Interp r The c 1.5 ex h eriod from ecoming m 400 cal yr B alues shift f 00 AD) th e igure 3.4 De p r om Table 1. C c cupation. S o n d transition s r etation of F c arbon isot o h ibiting vari a 2,500 to 2, m ore negati v B P (400 B C f rom -26 re is a prol o p th to age m o C ircles indic a o il profile and s and periods F A Carbon o pe record a bility of ~ 5 400 cal yr B v e from ~ 2 C ). Around to -21.5 o nged peri o o del for Refle a te clusters o f legend are i n of Mayan de p 78 Isotopes for Reflect i 5 .6 (Figu B P (500 to 2 2.5 at 2 2400 to 21 and from 2 o d of enric h ction Cave s e f dates repre s n cluded to sh p opulation a s i on Cave r a re 3.5). As 400 BC) s h 2 500 cal yr 00 cal yr B 2 100 to 15 0 h ed 13C v a e diments. Cr e s enting sugg e ow relations h s shown by d i a nges from seen in Fi g h ows 13C v BP (500 B C P (400 to 1 0 0 cal yr B P a lues ~-22 e ated using r a e sted periods h ip between l a i agona l -hatc h -27.1 t o g ure 3.5, th v alues C ) to -26 00 BC), 1 3 P (100 BC t This pe a diocarbon d a of Mayan a yer charact e h ed bars. o e by 3 C t o riod a tes e ristics

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79 is punctuated by a short interval of is otopic depletion approx imately 1900 cal yr BP (100 AD). After 1,550 cal yr BP (450 AD ) there is a steady decline toward more depleted values (-27 ‰). At ~850 cal yr BP (1150 AD), the sediments record a brief period of relative enrichment (Figure 3.5). Three possible causes for this vari ability are sediment transport, residence time of the FAs in the so il, and changing vegetation type. Pertaining to sediment transport and residence time, the age model (Figure 3.4) shows a fairly linear relationship between sediment depth and age. This suggests a continuous input of sediment into the cave, whereby the 13C values are representative of decaying surface vegetation. Therefore, the remaining explanation is that the cave sediments record c hanges in vegetation type.

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F 0 r u s e o f s p h u a g s e 1 c l s h W v o igure 3.5 Re f 0 .3724x2 + 5 9 u nning mean ) e diment reco r f dead carbo n p eleothem 1 3 u man impact g riculture du r e diment core 1 8O records a l imate variab i h ifts in the o x W ebster 2000 ) The t w egetation ( C ccurs duri n f lection Cave 9 .022x + 162. ) is also provi d r d. Speleoth e n input durin g 3 C data indic a relationship, r ing Maya oc c (Curtis et al. a re provided o i lity shown b y x ygen isotope ) w o isotopi c C 3) and ag r n g Maya oc sediment 1 3 87. The Mac a d ed to illustr a e m 13C valu e g radiocarbon a te importan t where wette r c upation of th 1996 and Ho d o n the right t o y these recor d s, while whit e c end mem b r icultural v e cupation. T 80 3 C record. De a l Chasm sp e a te the relatio n e s are shifted dating. Gra y t periods whe r r (drier) cond i e site. Promi n d ell et al. 20 0 o illustrate qu a d s. Dark bars e bars indicat e b ers of veg e getation, p T he relative rived from d e e leothem 13 C n ship betwe e ~200 years e y highlights a c r e the two re c i tions equate n ent periods o 0 1), and spel e a litative (wet v indicate peri o e relatively w etation in t h p redomina n quantities e pth to age m C data (Webs t e n the speleo t e arlier to acc o c ross the cav e c ords illustrat e to increased o f wetness/a r e othem (Web s v s. dry) inter p o ds of aridity, w etter conditio n h e study a r n tly maize ( C of each de odel equatio n t er 2000, 3po t hem and ca v o unt for adju s e sediment a n e the climate (decreased) r idity in lake s ter 2000) p retations of t h as indicated n s (modified r ea are nat u C 4), which termine th e n : y = o int v e s tment n d and h e by from u ral e

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81 isotopic values of the surface soils, whic h then collect in the cave as sediment. Therefore, the overall isot opic values for a certain per iod of time represent the relative proportions of natural and agricultural vegetation. It is doubtful, due to the steep topography of the study area and amount of forest cover, that complete shift to agricultural (C4) vegetation occurred. Conseque ntly, even during periods of Maya occupation both types of veget ation will be present. Reflection Cave’s catchment area incorporates both te rraced (agricultural) and non-terraced (natural) slopes, thereby creating an ideal depository of relative change in vegetation over time. Taking this ex planation and applying it to the cave sediment 13C values, -27.1‰ is r epresentative of natural vegetation and -21.5‰ is representative of contribution from Maya agriculture. Theref ore, the periods of Maya occupation in the study area are before 2400 cal yr BP (400 BC) and between 2300 cal yr BP (300 BC) to 1500 cal yr BP (500 AD) (Figure 3.5). 3.7 Discussion 3.7.1 Interpretation of Cave Sediment Record The cave sediments from Reflection Cave provide a robust archive for environmental reconstruction, having been deposited fairly continuously over the past 2,500 years, according to the age model (Figure 3.4). Vegetation changes in the surrounding landscape above Refl ection Cave are seen in the 13C data, which displays a maximum shift of 5.6‰ (Figure 3.5), suggesting substantial environmental changes during the depos itional period. The sedimentary 13C values do not show major shifts between C3 and C4 -dominated systems, as

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82 discussed previously, but rather indicate variable contributions of agricultural (C4) plants to the overall carbon isotope signal. More depleted (enriched) cave sediment 13C values suggest less (more) maize on the surface. The cause of declining agriculture is suggested to be per iods of prolonged aridity (Pessenda et al. 2001, 2005). Suppression of the natural forest 13C values in the cave sediments during Maya occupation likely occurred during we t periods suitable for agriculture. Not only would this deforestation have decr eased the density of the natural C3 vegetation, but the additi on of isotopically heavy C4 crops, such as maize ( 13C value ~ -14.4‰) (Fronza et al. 20 01), would have created more enriched 13C values in the surface soils (van N oordwijk et al. 1997) Therefore, the 13C values between -22.5‰ and -21.5‰ dur ing the period of Maya occupation of the site reflect contribution from agricultural C4 plants, thus causing 13C values related to a mixed C3-C4 environment. The natural C3 vegetation is likely to have developed resilience towards recurring, periodic droug hts over time, and would be able to recover once agriculture wanes because of arid conditions. The Maya are presumed to have been utilizing the area for agriculture, although less intensively, around 2, 600 years ago, when the population was lower. The area around the much larger Caracol archaeological site, located approximately 8 km to the south, has an occupation history that dates back to ~2600 cal yr BP (600 BC) (Chase and Chas e 1998). Activities associated with Caracol likely affected our study area durin g this time as well, given their close proximity to each other (and the si ze of Caracol). The sediment 13C data record

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83 suggests some agriculture was occurring within the study area prior to 2500 cal yr BP (500 BC), and decreasing for a s hort period at ~2400 cal yr BP (400 BC) (Figure 3.5). We propose this was a s hort, pronounced dry period that led to a decline in agricultural production in the area. The carbon isotope values between -22.5‰ and -21.5‰ from 2300 to 1500 cal yr BP (300 BC to 500 AD), coincides with the period of Maya occupation at the site (Colas et al. 2006, unpublished report). A brief period of agricultural dec line occurred during this period at ~1900 cal yr BP (100 AD), which coincides with the timing of the Preclassic Abandonment (Webster 2000; Haug et al. 2003). About 1500 cal yr BP (500 AD), 13C values in the sediment record indicate the declining practice of agri culture, becoming more negative (-27‰), which is characteristic of a C3-dominated environment rece iving little contribution from the isotopically heavier C4 agricultural plants. This period of agricultural decline coincides with the Maya Hiatus (~1470 to 1350 cal yr BP (530 to 650 AD) (deMenocal 2001), and a contributing factor to depopulation would have been the lack of available water resources needed to sustain agriculture and a large population. The study area would likel y have been among the first sites to be affected by aridity due to its naturally well-drained upland terrain, causing a shift away from agricultural land use that preceded many other lowland areas. By 1200 yr cal BP (800 AD), the 13C values indicate the site was no longer used for agriculture, coinciding with the Terminal Classic collapse (Curtis et al. 1996, Hodell et al. 2001; Haug et al. 2003).

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84 3.7.2 Proxy Climate Record Comparisons Webster (2000; also see Webster et al. 2007) reconstructed a useful carbon and oxygen isotope record from a speleothem in Macal Chasm, located only a few kilometers from Reflection Cave. The carbon isotopes from the speleothem record are interpreted to show periods of variable precipitation for the study area. Depleted ( enriched) carbon isotope valu es in the speleothem correspond to increased (decreased) soil productivity caused by wetter (drier) conditions (Webster 2000; Dorale et al. 1992, 1998, 2002) (Figure3.5). Oxygen isotopes from this same speleothem agree with the climate interpretation from the carbon isotopes. A comparison between the s peleothem and cave sediment 13C values provides support for our interpretation of the contribution of Maya agriculture (Figure 3.5). There is a consistent offs et of ~200 years between the two records, and the Macal Chasm record has been shi fted ~200 years earlier to allow better comparison. We feel this is justifi ed due the larger error associated with Webster’s (2000) 14C dates, since speleothem radiocarbon dating suffers from variable input of dead carbon, whereas our record does not. Such a shift is not unreasonable based on prelimin ary U-series dates of the speleothem, which suggests the radiocarbon ages are too y oung by this increment (Webster 2006, personal communication, unpublished data). A comparison of the speleothem carbon isotope data interpretation of changing climate, and the cave sediment carbon isotope data, reveal matching periods of aridity (decline of Maya agr iculture), while periods of increased

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85 wetness agree with increased agricultural ac tivity (Figure 3.5). We propose the speleothem carbon isotopes show changes in the natural vegetation in response to climate variability, because Macal Chas m (speleothem cave site) is located at a high elevation near the Ix Chel ruins above the terraced landscape, which often remained forested and was not used for agr iculture (Coultas et al. 1993; van Noordwijk et al. 1997). Consequently, during arid periods, the speleothem carbon isotopes recording a decrease in soil produc tivity would possess enriched values. This proposal is supported by the s peleothem oxygen isotopes (Figure 3.5). However, the cave sediment carbon isot opes record the presence of Maya agriculture on the landscape in addition to the natural vegetation. This is because Reflection Cave is located in a shallo w, terraced valley that was used for agriculture, approximately 100 m lower in elevation than Macal Chasm, incorporating sediment fr om a larger catchment ar ea in the landscape. In summary, the isotopic trends from both reco rds, while showing the same climate events, move in opposite directions. The Webster (2000; also see Webster et al. 2007) record shows a brief period of aridity ~2400 cal yr BP (400 BC ), which corresponds to a decrease in agriculture indicated by the more depleted 13C values in the cave sediment record (Figure 3.5). The decrease in agriculture, likely a result of Maya depopulation of the area, allowed the natural vegetation to dominate the landscape and cause depleted 13C values. After 2400 cal yr BP (400 BC), a shift toward depleted 13C values in the speleothem 13C data indicates wetter conditions and higher soil productivity, providing conditions conducive to

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86 increased agriculture, as shown by enriched 13C values recorded by the cave sediments, which reflect the input of C4 (maize) vegetation (Figure 3.5). Moist conditions suitable for agriculture continue in the area until ~1500 cal yr BP (500 AD), when the speleothem 13C values begin to show enrichment because of drier conditions suppressing the natural C3 vegetation. The cave sediment 13C values agree with the speleothem 13C values during this period, showing an enrichment of 13C values from ~2300 to 1500 cal yr BP (300 BC to 500 AD), then moving toward depleted 13C values associated with natural forest recovery, no longer being affected by human alterati on of the landscape (Figure 3.5). Around 1900 cal yr BP (100 AD) there is a brief period of aridity seen in the speleothem 13C data, which coincides with a dec line in agricultural activity, as indicated by a slight depl etion in the cave sediment 13C data. Our resolution does not enable a closer decada l examination of this pe riod; however, the timing only slightly leads the Preclassic Aband onment (~1950 to 1850 cal yr BP (150 to 250 AD)) seen in many other records from the region (Hodell et al. 2001; Haug et al. 2003). This difference in timing is most likely a result of the high susceptibility of our study area to aridity, stressing t he Maya population to the point of a shortterm decline in agriculture. The continuous decline in agricultu re occurring from ~1500 to 1200 cal yr BP (500 to 800 AD), as reflected in the more depleted cave sediment 13C values, suggests the area was heavily im pacted by drought during this time (as reflected in more enriched speleothem 13C values), which began during the Maya Hiatus ~1470 to 1350 cal yr BP (530 to 650 AD) (deMenocal 2001). It is

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87 possible the study area, being naturally more susceptible to drought, due to deforestation and abundant agricultural alte ration of the landscape, caused the Maya to depopulate the area and prevent ed population numbers from reaching those prior to the Hiatus. However, the area would not have been entirely deforested, due to the st eep topography, and consequently major decreases in evapotranspiration due to deforestation ar e unlikely to have been the main cause of aridity in this region. From ~12 00 cal yr BP (800 AD) until the present, the speleothem and cave sediment 13C values show a general trend toward more negative values, indicating the absence of Maya influence on the landscape, which allowed both records to respond onl y to natural vegetation change, hence they are in isotopic agreement. The slight differences in the inte rpretation of the two records can be attributed to resolution (speleothem reco rd is a 3-point running mean) and the calibration of radiocarbon dates in t he speleothem, which must estimate the amount of dead carbon contributing to the 14C dates, but this is not a problem for dates obtained from the cave sedim ents (Gascoyne 1992; Webster 2000; Fairbanks et al. 2005). Comparisons with the well-documented regional lacustrine records, as seen in Figure 3.5, help corroborate our cave sediment 13C data regarding environmental reconstruction during the Late Holocene. These include lake sediment 18O data from Guatemala and Mexi co, which show prolonged episodes of drought, although the timing and severity of these events are not always synchronous due to regionality e ffects (Curtis et al. 1998; deMenocal

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88 2001; Shaw 2003; Demarest et al. 2004). The Lake Punta Laguna record from Mexico (Curtis et al. 1996) reported aridity between 1750 and 1100 cal yr BP (250 and 900 AD), with maximum dryness at ~1300 and 1100 cal yr BP (700 and 900 AD), during the Maya Hiatus and Terminal Classic periods, respectively. The former period coincides with the start of the agricultu ral decline shown in the cave sediment 13C data (Figure 3.5). Further lacustrine studies in the Yucatan by Hodell et al. (2001) found tw o periods of aridity that coincide relatively closely to decreasing agriculture indicated in the cave sediment record 13C data, including the period ~2400 cal yr BP (400 BC) and from 1300 to 900 cal yr BP (700 to 1100 AD). 3.7.3 Climatic Causes of Aridity Increasingly frequent periods of cyclic aridity have occurred in Mesoamerica during the last 2,600 years, and atmospheric influences affecting climate in the region are the probable cause (Haug et al. 2003; Hodell et al. 2005a). The migration of the ITCZ is the ma in factor influencing precipitation in the Caribbean region, due to its seasonal la titudinal migration (Haug et al. 2001) (Figure 3.1). When the ITCZ is locat ed to the north, the Easterly trade winds, positioned by the North Atlantic High, push warm, moist Caribbean air up the Maya Mountains, increasing convective activity and precipitation (Haug 2003; Hodell 2005a). The dry season occurs w hen the ITCZ is in its southernmost position. Haug et al. (2001, 2003) proposed that when the ITCZ mean annual position is further to the south, nort hern South America experiences prolonged

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89 drought. This would affect precipitation am ount in Belize as well, decreasing the strength of the Easter lies, which direct moist air to the Vaca Plateau. In the past, this scenario has occurred for durations of decadal and even centennial lengths, causing reduced precipitation and long-te rm drought episodes in Mesoamerica. During wetter conditions, expansion of Maya occupation and agriculture would likely have occurred on the Vaca Plateau, due to increased availability of water resources. The concurrence of Haug et al.’s (2003) Maya collapse and the southern position of the ITCZ correspond closely with the major shift in our 13C values in the sediment record. Therefore, the likely mechanism for such a shift in our carbon isotopes (decline in agriculture) was the changing mean position of the ITCZ, which would have led to decreased precipitation. 3.8 Conclusions Carbon isotopes extracted from sedi ments in Reflection Cave record changing environmental conditions over the last 2,500 years on the Northern Vaca Plateau in west central Belize. T he location of the cave on the landscape collects sediment from a la rge catchment area, thereby allowing it to record changes in agriculture during Maya occ upation. Cave sediment fulvic acid 13C values indicate the presence of Maya agriculture in the study area around 2500 cal yr BP (500 BC), which declines until ~2300 cal yr BP (400 BC). After this, agriculture again increases, as evidenced from more enriched 13C values, which last throughout the Maya occupation unt il ~1500 cal yr BP (500 AD). At ~1900 cal yr BP (100 AD) there is an abrupt decli ne in agriculture, consistent with the

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90 Preclassic Abandonment period. B eginning 1500 cal yr BP (500 AD) and coinciding with the Maya Hiatus, c onditions became drier and agricultural activities begin to decline, thereby reducing agricultural (C4) plant presence on the landscape and causing a shift in the sediment 13C values toward depletion. Carbon and oxygen isotopes from a speleothem collected in Macal Chasm (Webster 2000; also see Webster et al. 2007) a cave within the study area, show changes in aridity and its affect on natural vegetation. The speleothem 13C and 18O data closely support the cave s ediment record interpretation. Intensive agriculture and landscape m anipulation at this site seems to have waned earlier than other records of Ma ya activity around the region (Curtis et al. 1996, Haug et al. 2003; Hodell et al. 2005b), punctuated by declining agriculture beginning during the Maya Hiatu s. This provides evidence for our supposition that a highly karstified, we ll-drained, upland occ upation site would have been among the first areas to be a ffected during periods of prolonged drought. As the area was depopulated, land once used for agriculture began to return to forest. The consensus of the proxy climate records from Mesoamerica indicate that regional aridity occurred at differi ng times and severity across the region, providing substantial evidenc e of abrupt climate change that was detrimental to cultural evolution (Haug et al. 2003; Hodell et al. 2005b; Neff et al. 2006). Prolonged periods of southward ITCZ and NAH migration may be responsible for periodic episodes of extended drought condi tions in the area, and the Northern Vaca Plateau would have been highly suscept ibility to such events. While the

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91 sediments from Reflection Cave provide on ly one small piece of the much larger puzzle, they provide another means by which past environmental changes in Mesoamerica can be understood. Further use of cave sediments in the area to reconstruct environmental change at a hi gher resolution will provide continued insight into environmental change and the Maya impact on the area’s landscape. 3.9 Chapter Acknowledgements The authors would like to thank t he members of the 2004 Vaca Plateau Geoarchaeological Project field expedition. We thank Ethan Goddard (USFSt. Pete.) for assistance with processing samples for 13C and Grant Harley for help with radiocarbon dating sample extraction. We are grateful to Dr. James Webster for access to his dissertation data and information through personal communication. We thank Dr. Jaime Awe, Director of the Belize Institute of Archaeology, and Dr. John Morris, Directo r of Research for the Archaeology Institute, for their continued support of th is project. We also thank the late Dr. Pierre Robert Colas, from the Depar tment of Anthropology at Vanderbilt University, for his assistance with the arc haeological interpretations of the study area. We also thank Dr. Peter Harries for his insightful review of this chapter. This research was funded in part by a National Speleological Society International Travel Grant and the University of South Florida.

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92 3.10 Chapter References Aiken, G.R., McKnight, D.M., Wershaw, R.L., MacCarthy, P. (eds.).1985. Humic substances in soil, sediment, and water John Wiley and Sons: New York, 692 p. Biggs, T.H., Quade, J., and Webb, R.H. 2002. 13C values of soil organic matter in semiarid grassland with mesqui te (Prosopis) encroachment in southeastern Arizona. Geoderma 110: 109-130. Bottrell, S. 1996. Organic car bon concentration profiles in re cent cave sediments: Records of agricultural pollution or diagensis? Environmental Pollution 91(3): 325-332. Brinkmann, R. and Reeder, P. 1995. The relationship between surface soils and cave sediments: An example from west central Florid a, USA. Cave and Karst Science 22: 95-102. Calderoni, G. and Schnitzer, M. 1984. Effect s of age on the chemical structure of paleosol humic acids and fulvic acids. Geochimica et Cosmochimica Acta 48: 2045-2051. Chase, A.F. and Chase, D.Z. 1989. The investigation of Classic Period Maya warfare at Caracol, Belize. Mayab 5: 5-18. Chase, A.F. and Chase D.Z. 1998. Scale and intensity in Classic Period Maya Agriculture: Terracing and settlement at the “Garden City” of Caracol, Belize. Culture and Agriculture 20(2/3): 60-77. Clapp, C.E., Layese, M.F., Hayes, M.H. B., Huggins, D.R., and Alimaras, R.R., 1997. Natural Abundances of 13C in Soils and Water. In : Humic Substances in Soils, Peats, and Waters: Health and Environmental Aspects, M.H.B Hayes and W.S. Wilson, (eds.). The Royal Society of Chemistry: Cambridge, p. 159-175. Claret, F., Schafer, T., Rabung, T., Wolf M., Bauer, A., and Backau, G. 2005. Differences in properties and Cm(III) complexation behavior of isolated humic and fulvic acid derived from Opalinus clay and Callovo-Oxfordian argillite. Applied Geochemistry 20: 1158-1168. Colas, P.R., Stengert, K. C., and Wolfel, U. 2006. T he Mapping of Ix Chel: A Terminal Classic secondary Maya si te on the Northern Vaca Plateau, Belize, Central America. Technical report to government of Belize. Ed. Philip P. Reeder.

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93 Coultas, C.L., Collins, M.E., Chase, A.F. 1993. The effect of Mayan agriculture on terraced soils of Caracol, Belize. In : Proceedings of the First International Pedo-Archaeology Conference J.E. Foss, M.E. Timpson, and M.E. Morris (eds.). Special Pu blication No. 93-4. Agricultural Experiment Station, Universi ty of Tennessee, Knoxville. Courty, M.A. and Vallverdu, J. 2001. T he microstratigraphic record of abrupt climate changes in cave sediment s of the Wester n Mediterranean. Geoarchaeology 16(5): 467-500. Cowgill, U. M. 1962. An agricultural study of the southern Maya Lowlands. American Anthropologist 64(2): 273-286. Curtis, J.H., Hodell, D.A., and Brenner M. 1996. Climate variability on the Yucatan Peninsula (Mexico) during the past 3500 years, and implication for Maya cultural evolution. Quaternary Research 46: 37-47. Curtis, J.H., Brenner, M., Hodell, D.A ., Balser, R.A., Islebe, G.A., and Hoogheimstra, H. 1998. A multi-prox y study of Holocene environmental change in the Maya Lowlands of Peten, Guatemala. Journal of Paleolimnology 19: 139-159. Demarest, A.A., Rice, P.M. and Rice, D.S. 2004. The Terminal collapse in the Maya Lowlands: Assessing collapse s, terminations, and transformations. In : Demarest, A.A., Rice, P.M., and Rice, D.S. (eds.), The Terminal Classic in the Maya Lowlands: Colla pse, Transition, and Transformation University Press of Co lorado, Boulder, p. 545-572. DeMenocal, P., Ortiz, J., Guilderson, T., and Sarnthei n, M. 2001. Coherent highand low-latitude climate variability during the Holocene Warm Period. Science 288: 2198-2202. Desmarchelier, J.M., Goede, A., Ayliffe, L.K., McCulloch M.T., and Moriarty, K. 2000. Stable isotope record and its pal eoenviornmental interpretation for a late Middle Pleistocene speleothem fr om Victoria Fossil Cave, Naracoorte, South Australia. Quaternary Science Reviews 19: 763-774. Doane, T.A., Devevre, O.C., and Horw ath, W.R. 2003. Short-term carbon dynamics of humic fractions in low-input and organic cropping systems. Geoderma 114: 319-331. Dorale, J.A., Gonzalez, L.A., Reagan, M.K., Pickett, D.A., Murrell, M.T., and Baker, R.G. 1992. A high-resolution re cord of Holocene climate change in speleothem calcite from Cold Water Cave, Northeast Iowa. Science 258: 1626-1630.

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94 Dorale, J.A., Edwards, R.L., Ito, E., and Gonzalez, L. A. 1998. Climate and Vegetation History of the Midconti nent from 75 to 25 ka: A Speleothem Record from Crevice Cave, Missouri, USA. Science 282: 1871-1874. Dorale, J.A., Edwards, R.L., and O nac, B.P. 2002. Stable isotopes as environmental indicators in speleothems. In : Yuan, D.-X. (ed.), Karst Processes and the Carbon Cycle Geological Publishing House: Beijing, China, p. 107-120. Fairbanks, R.G., Mortlock, R.A., Chiu, T ., Cao, L., Kaplan, A., Guilderson, T., Fairbanks, T.W., Bloom, A.L., Gr ootes, P.M., and Nadeau, M. 2005. Radiocarbon calibration curve spanning 0 to 50,000 years BP based on paried 230Th/234U/238U and 14C dates on pristine corals. Quaternary Science Reviews 24: 1781-1796. Fleitmann, D., Burns, S.J., Mudelsee, M., Neff, U., Kram ers, J., Mangi ni, A., and Matter, A. 2003. Holocene forcing of the Indian Monsoon recorded in a stalagmite from southern Oman. Science 300: 1737-1739. Fronza, G., Fuanti, C., Grasselli, P ., Serra, S., and Guillou, F.R.C. 2001. 13C and 18O-values of glycerol of food fats. Rapid Communication in Mass Spectrometry 15: 763-766. Furley, P.A. 1976. Soil-slope-plant relati onships in the Northern Maya Mountains, Belize, Central America. III. Variati ons in the properties of soil profiles. Journal of Biogeography 3(3): 303-319. Furley, P.A. and Newey, W.W. 1979. Va riations in plant communities with topography over tropical limestone soils. Journal of Biogeography 6: 1-15. Gascoyne, M. 1992. Palaeoclimate determi nation from cave calcite deposits. Quaternary Sciences Reviews 11: 609-63. Gill, R.B. 2000. The Great Maya Droughts: Water, Life, and Death University of New Mexico Press: Albuquerque. Grunewald, G., Kaiser, K., Jahn, R ., and Guggenberger, G. 2006. Organic matter stabilization in young calcareous soils as revealed by density fractionation and analysis of lignin-derived constituents. Organic Geochemsitry 37: 1573-1589. Gunn, J.D., Matheny, R.T., and Folan, W. J. 2002. Climate-change studies in the Maya area: A diachronic analysis. Ancient Mesoamerica 13: 79-84.

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95 Harmon, R.S., Schwarcz, H.P., Gasco yne, G., Hess, J., and Ford, D. 2004. Paleoclimate information from speleot hem: The present as a guide to the past. In : Studies of Cave Sediments: Ph ysical and Chemical Records of Paleoclimate, I.D Sasowsky and J.E. Mylroie, (eds.), Klewer: New York, p. 135-174. Haug, G.H., Hughen, K.A., Sigman, D.M. Peterson, L.C., and Rohl, U. 2001. Southward migration of the Inte rtropical Convergence Zone through the Holocene. Science 293: 1304-1308. Haug, G.H., Gnther, D., Peterson, L. C., Sigman, D. M., Hughen, K.A., and Aeschlimann, B. 2003. Climate and the co llapse of the Maya Civilization. Science 299: 1731-1735. Hayes, M. H. B. and Wilson, W. S. 1997. Humic Substances, Peats and Sludges: Health and Environmental Aspects Royal Society of Chemistry: Cambridge. Hodell D.A., Curtis, J.H., and Brenner, M. 1995. Possible role of climate in the collapse of Classic Maya civilization. Nature 375: 391-394. Hodell, D.A., Brenner, M., Curtis, J.H., and Guilderson, T. 2001. Solar forcing of drought frequency in the Maya Lowlands. Science 292: 1367-1370. Hodell, D.A., Brenner, M., Curtis, J.H., Medina-Gonz alez, R., Ildefonso-Chan Can, E., Albornaz-Pat, A., and Gu ilderson, T.P. 2005a. Climate change on the Yucatan Peninsula dur ing the Little Ice Age. Quaternary Research 63: 109-121. Hodell, D.A., Brenner, M., and Curtis, J.H. 2005b. Terminal classic drought in the northern Maya lowlands inferred from multiple sediment cores in Lake Chichancanab (Mexico). Quaternary Science Reviews 24: 1413-1427. Huang, Y., Street-Perrott, F.A., Metcal fe, S.E., Brenner, M., Moreland, M., and Freeman, K.H. 2001. Clim ate change as the dominant control on glacialinterglacial variations in C3 and C4 plant abundance. Science 293: 16471651. Hughen, K.A., Eglinton, T. I., Xu, L., and Makou, M. 2004. Abrupt tropical vegetation response to rapid climate changes. Science 304: 1955-1959. Leyden, B.W. 2002. Pollen evidence for climatic variability and cultural disturbance in the Maya Lowlands. Ancient Mesoamerica 13: 85-101.

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96 Liao, J.D., Boutton, T.W., and Jastrow, J.D. 2006. Organic matter turnover in soil physical fractions following woody plant invasion of grassland: evidence from natural 13C and 15N. Soil Biology and Biochemistry 38: 3197-3210. Lucero, L.J. 2002. The collapse of the Classi c Maya: A case for the role of water control. American Anthropologist 104(3): 814-826. Moholy-Nagy, H. 2003. The Hiatu s at Tikal, Guatemala. Ancient Mesoamerica 14: 77-83. Miller, T. 1990. Caves and Caving in Belize: An Overview. Caves and Caving 46: 2-4. Neff, H., Pearsall, D.M., Jones, J.G., Arro yo de Pieters, B., and Freidel, D.E. 2006. Climate change and population hist ory in the Pacific Lowlands of Southern Mesoamerica. Quaternary Research 65: 390-400. Panno, S.V., Curry, B.B., W ang, H., Hackley, K.C., Liu, C.L., Lundstrom, C., and Zhou, J. 2004. Climate change in sout hern Illinois, USA, based on the age and 13C of organic matter in cave sediments. Quaternary Research 61: 301-313. Penn, M.G., Sutton, D.A., and Monro, A. 2004. Vegetation of the Greater Maya Mountains, Belize. Systematics and Biodiversity 2(1): 21-44. Quade, J., Cerling, T.E ., and Bowman, J.R. 1989. Development of Asian monsoon revealed by marked ecological shift during the latest Miocene in northern Pakistan. Letters to Nature 342: 163-166. Qualls, R.G., Takiyama, A., and Wers haw, R.L. 2003. Formation and loss of humic substances during decompo sition in a pine forest floor. Soil Science Society of America Journal 67: 899-909. Qualls, R.G. 2004. Biodegradability of humic substances and other fractions of decomposing leaf litter. Soil Science Society of America Journal 68: 17051712. Pessenda, L.C.R., Boulet, R., Aravena, R., Rosolen, V., Gouveia, S.E.M., Ribeiro, A.S., and L amotte, M. 2001. Origin and dynamics of soil organic matter and vegetation changes during the Holocene in a forest-savanna transition zone, Braz ilian Amazon region. The Holocene 11(2): 250-254.

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97 Pessenda, L.C.R., Ledru, M. P., Gouveia, S.E.M., Ar avena, R., Ribeiro, J.A., Bendassolli, J.A., and Boulet, R. 2005. Holocene paleoenvironmental reconstruction in northeastern Braz il inferred from pollen, charcoal, and carbon isotope records. The Holocene 15(6): 812-820. Reeder, P., Brinkmann, R., and Alt, E. 1996. Karstification on the Northern Vaca Plateau, Belize. Journal of Cave and Karst Studies 58(2): 121-130. Reeder, P. 2003. Physical and cultural landscapes on the Northern Vaca Plateau, Belize. Journal of Belizean Affairs 5(1): 5-30. Rosenmeier, M.F., Hodell, D.A., Brenner M., Curtis, J.A., Martin, J.B., Anselmetti, F.S., Ariztegui, D., and Guilderson, T.P. 2002. Influence of vegetation change on watershed hydrology : implications of paleoclimatic interpretation of lacustrine 18O records. Journal of Paleolimnology 27: 117-131. Schwartz, D., Mariotti, R., Lanf ranchi, R., and Guillet, B. 1986. 13C/12C ratios in soil organic matter as indicators of vegetation changes in the Congo. Geoderma 39: 97-103. Shaw, J.M. 2003. Climate change and defores tation: Implications for the Maya Collapse. Ancient Mesoamerica 14: 157-167. Spaccini, R., Piccolo, A., Haber hauer, G., and Gerzabek, M. 2000. Transformation of organic matter from maize residues into labile and humic fractions of three European soils as revealed by 13C distribution and CPMAS-NMR spectra. European Journal of Soil Science 51: 583-594. Spaccini, R., Mbagwu, J.S.C., Conte, P., and Piccolo, A. 2006. Changes of humic substances characteristics from forested to cultivated soils in Ethiopia. Geoderma 132: 9-19. Soto, L.R. 2005. Reconstruction of Lat e Holocene Precipitation for Central Florida as Derived from Isotopes in Speleothems. University of South Florida, Unpublished Masters Thesis. Stevenson, F.J. 1994. Humus ChemistryGensis, composition, reactions 2nd ed. Wiley: New York. Turney, C.S.M., Bird, M.I., and Roberts, R.G. 2001. Elemental 13C at Allen’s Cave, Nullarbor Plain, Australia: assessing post-depositional disturbance and reconstructing past environments. Journal of Quaternary Science 16(8): 779-784.

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98 van Beynen, P.E., Ford, D., and Schwar cz, H. 2000. Seasonal variability in organic substance in surface cave waters at Marengo Cave, Indiana. Hydrological Processes 14: 1177-1197. van Noordwijk, M., Cerri, C., Woomer, P. L., Nugroho, K., and Bernoux, M. 1997. Soil carbon dynamics in the humid tropical forest zone. Geoderma 79: 187-25. Wahl, D., Byrne, R., Schreiner, T., and Hansen, R. 2006. Holocene vegetation change in the northern Peten and its im plications for Maya prehistory. Quarternary Research 65: 380-389. Webb, E.A., Schwarcz, H.P., and Healy, P.F. 2004. Detect ion of ancient maize in lowland Maya soils using stable carbon isotopes: evidence from Caracol, Belize. Journal of Archaeological Science 31: 1039-1052. Webster, J. 2000. Speleothem Evidence of Late Holocene Climate Variation in the Maya Lowlands of Belize, Central America and Archaeological Implications. University of Georgi a, Unpublished Doctoral Dissertation, 233 p. Webster, J. 2007, personal communication, U.S. EPA. Webster, J.W., Brook, G.A., Railsback, B ., Cheng, H., Edwards, R.L., Alexander, C., Reeder, P.P. 2007. Stalagmite evidence from Belize indicating significant droughts at the time of Preclassic Abandonment, the Maya Hiatus, and the Classic Maya collapse. Palaeogeography, Palaeoclimatology, Palaeoecology 250(1-4): 1-17. Weninger,B., Joris, O., Danzeglocke, U. 2005. CalPal Radiocarbon Calibration Package University of Cologne: Germany. Xu, S. and Zheng, G. 2003. Variations in radiocarbon ages of various organic fractions in core sediments from Erhai Lake, SW China. Geocemical Journal 37: 135-144. Yamskikh, A. 1998. Late Holocene soil fo rmation in the valley of the River Yenisei, Central Siberia. Catena 34: 47-60.

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99 Chapter 4 Investigating a Multi-proxy Appr oach to Paleoenvironmental Reconstruction in Florida using Cave Sediments 4.1 Chapter Preface This chapter presents an exploratory st udy investigating the utility of cave sediments for paleoenvironmental reconstructi on in Florida. It serves as a followup to the Belize sediments research to determine their usefulness in an area similar in climate. Speleothems and sedime nts are readily available in many of Florida’s dry caves, particularly within those located in the Ocala Plain and Brooksville Ridge (Harley 2007). Howeve r, the caves that contain abundant sediment deposits provide new and intere sting data regarding t he climate history of Florida during the past several thous and years. This was accomplished by utilizing a novel approach using carbon isotopes of fulvic acids in cave sediments, thereby creating a new paleoenv ironmental proxy. This chapter is more in-depth and rigorous in its forma t and length due to the novel techniques presented within it and the gap it attempts to fill within cave sediment and climate change research.

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100 4.2 Abstract Cave sediments show promise fo r paleoenvironmental reconstruction and few studies have investigated the vari ous organic fractions preserved within sediment layering for this purpose. Here, a multi-proxy study of cave sediments from two different caves from west-centra l Florida is presented. Cave sediments collected from Jennings Cave in Marion County, Florida and Vandal Cave in Citrus County, Florida were tested to det ermine the most useful organic fraction for paleoclimate reconstruction. Fulvic acids (FAs), humic acids (HAs), bulk organic matter, and pollen were extracted fr om the Jennings Cave sediments for carbon isotope analysis to determine peri ods of vegetation change caused by climatic change during the Lat e Holocene and provide a ~3,000 year record of vegetation change. The carbon isotope reco rd ranges from -21‰ to -35‰, and indicates changes in the abundance of C3 vegetation in the region. The 13C record shows the MWP and LIA, and matches to speleothems records of precipitation change in the r egion, demonstrating that pr ecipitation controls the vegetation in the area. A calibration of the modern 13C was attempted using a core from Vandal Cave, which showed high variability in its sediment layering, but low variability in its 13C values, hence being impractica l for a calibration tool. Overall, cave sediments in Florida pr ovide a unique paleoenvironmental record, with fulvic acids appearing to be the most robust recorders of landscape change.

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101 4.3 Introduction Finding suitable paleoclimatic proxies in subtropical regions like Florida can be difficult due to the nature of the environment. Unlike many high latitude regions, the Florida platform possesses no deposits for ice core analysis, and tree ring studies are limited due to the stable temperature and young life span of existent species (Evans and Schrag 2004). Most of Florida’s over 8,000 lakes underwent desiccation during some period in the past due to sea-level lowering, human impacts, or karst-related hydrol ogical changes, thereby significantly limiting the usefulness and av ailability of long-term lacustrine records of climate change (Brenner et al. 1999; Kindinger et al 1999; Grimm et al. 2006). Studies of corals and marine sediment cores near the Florida platform are plagued by dating issues, short-term (mult i-centennial to millennial) chronologies, sea-level transgression and regression, and di sturbance from hurricane and human impacts (Bradley 1999; Otvos 2005; Willard et al. 2007). Despite its significant karst terrain, only recently have suitabl e cave speleothem proxies been found that provide insight to Florida’s paleoc limate (see Chapters 6 & 7; van Beynen et al. 2007a-c). With such limited proxies of climate change to compare to the speleothem record, the question that remain s is if cave sediments can fill this void as useful long-term, terrestrial paleoclimate proxies in Florida? While speleothems, when present, can provide detailed paleoclimate data, cave sediments also provide informa tion regarding vegetation and climate change, landscape evolution, hydrology, and geomorphology (Ellwood et al. 1997; Springer et al. 1997; Ford and W illiams 2007). Surface soils, primarily

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102 comprised of detrital clay, sand, grav el, organic matter, and other regionally specific clastic components, are transpor ted into caves by overland flow, streams, gravity, or other natural pr ocesses. Sediments enter the cave via several different inputs including entr ances, small fissures and cracks in the bedrock, sinkhole piping, enlarged condui ts, and fluvial-groundwater interaction (White 1988; Palmer 2007). If left undisturbed, a sequence of te rrigenous cave sediment lithofacies can record changes in the landscape above the cave in their layering, as well as processes occurring within the cave. A wide range of analytical methods are employed to determine the age, origin, and environmental hist ory of sediments found in caves. Depending on the type and th ickness of the sediment record and method of analysis, the resulting paleo environmental record can span from hundreds to millions of years (Granger et al. 2001). The main proponent for using cave sediments for paleoenvironmental re search is the protected environment the cave offers, preventing pedogenesis and the in situ alteration of sediments over long periods of time (Ellwood et al. 1997). Researchers have analyzed cave sediments for various purposes, including biological, archaeologi cal, diagenetic, environmental, geomorphological, and hydrological st udies (e.g. Brinkmann and Reeder 1995; Springer et al. 1997; Panno et al. 2004). However, previous studies mainly focused on physical analysis of clastic ca ve sediments, or using sediments to contextually constrain the evolution of paleo-drainage, and t he timing of other events or artifacts within a specific per iod (e.g. Cordier 1998; Foos et al. 2000;

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103 Forbes and Bestland 2007). This study in troduces a more holistic, novel multiproxy physical and geochemical approach to analyze specific fractions of cave sediments for paleoenvironmental rec onstruction and to determine the most accurate proxy variable contained withi n the sediments for this purpose. 4.4 Research Purpose Determining paleoenvironmental changes in Florida, presumably driven by precipitation variability over the last few thousand years, is important for understanding the environmental response to paleohydrologic variability and also to add to the limited base of knowledge regarding Florida’s paleoclimate. An investigation of the org anic acids and pollen trapped in cave sediments can provide an accurate and robust signal of vegetation change above the cave, thereby providing information about paleoenvironmental change contemporaneous with the deposition of the sediments over time. Based on successful preliminary work done on fulvic acid (FA) carbon isotopes to reconstruct paleoenvironmental change in Belize (see Chapter 3, Polk et al. 2007), here I attempt to furt her evaluate use of this technique at a higher resolution, including the investi gation of additional pr oxy variables from cave sediments in a subtropical setting to determine their usefulness in recording past climate change. This study delve s further into corroborating known environmental factors (climat e, vegetation, precipitat ion, geomorphology) to the deposition of sediment in Florida caves in both the shortand long-term, and attempts to determine the mo st useful proxy variables of cave sediments for

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104 paleoenvironmental reconstruction. By conducting an in-depth study on cave sediments based on the hypothe sis that changes in vegetation will be evident in the various longand shortterm 13C data and long-term pollen data of cave sediments in Florida, it is expected t hat cave sediments will prove useful in reconstructing climate change in Florida, with carbon is otope values from fulvic acids providing the most accurate paleoclimate record. 4.4.1 Research Questions In testing the hypothesis, this study attempts to answer several questions: (1) What is the best proxy variable to use from cave sediments to determine climate and paleoenvironment al changes in Florida? (2) Can the cave sediment paleoclimatic record be corroborated with existing speleothem records? (3) Can modern cave sediment deposits pr ovide a calibration for the mechanism of past cave sediment deposition as it relates to climate change? 4.5 Background 4.5.1 Cave Sediments Cave sediments derive from a myri ad of sources, but can mainly be grouped into two types, autochthonous (from within the cave) or allochthonous (from outside the cave) (White 1988; Ford and Williams 2007). Autochthonous sediments include the weathering of rock and detritus within the cave, such as mechanical breakdown rubble and organi c debris. These sediments include clays, organic matter (wood, humic subs tances, detritus, etc.), and larger

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105 brecciated materials, such as grav el and cobbles, and are important in understanding the geomo rphology and developm ent of a cave. Cave sedimentation also results from the allogenic deposition of surface soils into caves (Brinkmann and Reeder 1995). Allogenic deposition can occur from several sources, including glac ial and aeolian deposit s, but is most commonly derived from fluvial inputs (rive rs, streams, and overland flow), which can infiltrate the cave and cause sedim ent deposition (White 1988). In caves where fluvial action is irregular du e to periodic flooding or water table fluctuations, sediments are deposited or eroded away depending upon the nature of the water passing through the cave passage. Allogenic deposition can also occur from simple infiltra tion of surface waters bringing the soil through fractures and spaces within the rock, eventually dep ositing in the cave in stratigraphic sequences (Ford and Williams 2007). Due to their preserved nature within a cave, sediments can provide many different types of environmental and geom orphological information about both the cave environment and the surface processes occurring above the cave on the surface. Many studies, such as t hose by Quinn (1996) and Lowe and Gunn (1994), focus on allogenic cave sedim ents and show how they record the geomorphic development and pal eoenvironment of the su rface above the cave. Sroubek et al. (2001) used paleomagnetic analysis of cave sediments to reconstruct climate over the Last Glacia l Stage, based on the weathering effects on magnetic minerals, show ing an agreement between t heir data and the marine SPECMAP record.

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106 Further physical analysis of cave s ediments by Springer et al. (1997) determined the genesis and incision history of Cheat River in West Virginia by examining fluvial deposits in caves fl anking the river bed. Using paleomagnetic analysis of terraced cave sediments from several different base-level passages, they found the rate of incision of the river and the future implications of its continuing modern-day incision, but la cked accurate dating techniques. The depositional history of sediments in Franchthi Cave in Greece spanning the last 30 ka (based on radiocarbon dates) included periods of cave development, sedimentation, and landscape alterati on (Farrand 2000). Zhou et al. (2000) examined climate change cycles in Ch ina using thermal ionization mass spectrometry (TIMS) dating of traver tine within cave sediment to determine climatic change and to assess the dating accuracy of the Peking Man’s remains. The aforementioned studies indicate the pot ential for cave sediments to preserve a record of landscape and anthropogenic evolution on long timescales. The analysis of pollen from cave sediments can yield information on vegetation change above the cave over time (Carrion et al. 1999; Navarro et al. 2000). A study of cave sediment pollen in Spain examined the transport of pollen into several caves and the preservation of pollen grains over time, taking into consideration the geometry and size of the caves (Navarro et al. 2001). The results showed that pollen from cave sediment coul d be a good representative of surficial vegetation regimes simila r to speleothems and other carbonate materials. However, the lack of data on using cave sediment palynology for

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107 environmental reconstruction limits t he amount of information regarding methodology and broader applications for the technique. 4.5.2 Carbon Isotopes While many of the previously me ntioned studies focused on the physical analysis of cave sediments to underst and long-term climate change and cave development, other studies have shown that cave sediments record the environmental history of the land above the cave in their stratigraphy; thereby, providing robust records of terrestrial changes in vegetation and land use, which are not preserved in ever-changing surfac e soils (Bottrell 1996; Panno et al. 2004). For example, Courty and Vallverdu (2001) found that sedimentation rates of cave sediments are indicative of climate change events and land use changes above the cave. Variations in the carbon isotope ratios recorded in cave sediments provide a record of vegetation change ab ove the cave (Panno et al. 2004). Paleoecological information is derived from carbon isotope values of soil organic matter (SOM), which form from plant bioma ss and contributes directly to local soil CO2 (Quade et al. 1989). Shifts in vegetation between C3 and C4 plants above a cave are recorded in the 13C signal present in the organic matter trapped in the cave sediment layers (Clapp et al. 1997; Schwartz et al. 1986). Turney et al. (2001) performed stable isotopic analysis on cave sediments from Allen’s Cave in South Australia and linked the changes in organic carbon ( 13C) to an onset of aridity that occurred in the area, from 45 to 12 ka, after which the warmer, wetter Holocene began. However, the sensitivity of the record

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108 was too low to record mild drought ev ents, and only used bulk organic matter for stable isotope analysis. Combining radioc arbon dating and 13C values from sediments can provide the best overall temporal re cord of climate change inferred from vegetation shifts recorded in the sediments. Another study where 13C was extracted from organic matter in cave sediments from Speedwell Cavern in Derbyshire produced a record of constant C3 vegetation for the last 17 years. This corresponded with known vegetation conditions, with values averaging around -27.4 ‰ for the area (Bottrell 199 6), thus solidifying the technique’s accuracy over both short and long periods of deposition. 4.5.3 Organic Acids Previous studies regarding cave sediments mainly focused on bulk organic matter or stable isotope analysis of 13C to provide records of climate disturbance (Turney et al. 2001), agricul tural change (Bottrell 1996), or the presence of certain vegetation types (W ebb et al. 2004). To date, few studies investigated the specific fractions of organic acids extracted from bulk organic matter in cave sediments, which incl ude humic and fulvic acids and humin. Humic acids (HAs) are large molecula r weight, colloidal substances, often insoluble at low pHs, and represent a large percentage of the older fraction comprising SOM (Calace et al. 2004). Humin is the highest molecular weight substance in SOM, insoluble, and resist ant to alteration, thereby persisting for long periods of time in the soil. Fulvic acids are low molecular weight, easily transported, hydrophilic acids and are t he most contemporaneous humic fraction

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109 of vegetation preserved wit hin sediments (Aikin et al. 1985; van Beynen et al. 2000; Webb et al. 2004; Polk et al. 2007). Additionally, these ac ids preferentially bind to clays within sediment, and are we ll-preserved because they are resistant to biological degradation (Biggs et al. 2002; Polk et al. 2007). Additionally, FAs are the main organic com ponent contributing to the 13C values derived from speleothem calcite analysis, thus having a commonality with accepted speleothem proxies for veget ation change in cave environments (Lauritzen et al. 1986; van Beynen et al. 2000). The 13C values from fulvic acids indi cate periods of vegetation change, which may be difficult to discern in la ke sediment and speleothem data due to contributions of carbon from ot her sources (Webb et al. 2004). The 13C of fulvic acids in cave sediments from Reflection Cave, Belize, show a robust signal of vegetation and landscape change in the area over the last 2.6 ka (Polk et al. 2007; Chapter 3). The FAs in cave sedi ments are protected from disturbance, decay, or problems with contamination fr om outside sources of carbon in the preserving cave environment. In a welldeveloped karst system, organic matter in surface soils can easily be transported to t he protective environ ment of caves by surface and groundwater percolation through entrances and the highly permeable carbonate bedrock (White 1988) (Figure 4.1).

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110 4.5.4 Pollen Few studies have investigated how pol len in cave deposits can provide paleoenvironmental information. Gale et al. (1984) noted that palynological studies of cave sediments were rare, in part due to the difficulty in locating and extracting abundantly preserved pollen deposits. In a study in Britain, Gale et al. (1984) successfully showed changes in pollen in cave sediments as indicators of human occupation in the area. Burney and Burney (1993) more closely examined the accumulation of pollen in caves in New York to determine its usefulness for paleovegetation reconstruction, finding that certain cave conditions could provide pollen assemblages represent ing the regional vegetation. However, they also Figure 4.1 Cave sediment model. Conceptual model of how sediments on the surface are washed into the cave, thereby depositing in the cave in layers and preserving the signal of the vegetation above the cave. Limestone Variations in 13C of sediment record changes in vegetation type above cave Meteoric Water Surface sediments are washed into cave More Negative (-) 13C Signal When (C3) Vegetation Above Cave More Positive ( + ) 13C Signal When C4Vegetation Above Cave Organic acids derived from plant debris contain 13C, incorporated into washed in sedimentsSediment Accumulation

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111 noted that method of trans port, location within the ca ve, and episodic deposition could affect the pollen record. More recently, several studies in Spain analyzing cave sediment pollen assemblages indicate their usefulness in paleoecological research, despite the complexity of pollen deposit ion in cave settings and the stochastic variables that must be considered (Carrion et al. 1998; Camacho et al. 2000; Navarro et al. 2000). Using six caves in southeastern Spai n, Navarro et al. (2001) found that pollen concentration from fluvial transpor t, and to a lesser degree airborne fallout, provided the most reliable records of vegetation change from pollen analysis. Speleothems deposited near the entrance could also yield accurate palynological records (Navarro et al. 2001). More work is needed in the area of pollen analysis from cave deposits in order to understand the most reli able analytical conditions for obtaining useful pollen deposits fo r paleoenvironmental reconstruction. 4.5.4 Florida Cave Sediments Studies of terrestrial caves in Florida are sparse mainly due to lack of dry caves and cave access (Harley et al. 2009, in press). A fair amount of literature exists regarding Florida’s geology and hydrol ogy, but only recent work by Florea et al. (2006a; 2007a) provides detaile d data regarding speleogenesis and cave geomorphology in west-central Florida. While this research does elaborate on cave morphology and karst processes in the area, it does not lend itself to the study of deposits preserved inside the cave, which can provide paleoclimate and landscape evolution informa tion about the region.

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112 The depositional regime of sedim ents into cave environments is complicated and one must understand the proc esses by which the sediment is deposited and preserved within the cave to assist with interpretation of its analysis. Most importantly, the age of t he sediment and mec hanism of transport into the cave can determine its usefulness for paleoenvironmental reconstruction. Additionally, the morphologic al and hydrogeological proper ties of the cave should be noted to determine its potential for a ccumulating and preserving sediments well-suited to paleoenvironmental reconstruction (White 1988). Sedimentation in Florida caves may be continuous from regular seasonal pluvial wash-in, or be more episodic in nature occurring infrequently, such as during hurricane events, but rarely does it occur from fluvial action because the low-topography and subsurface drainage of Florida’s karst landscape is not conducive to fluvial activity in dry caves (Florea 2006; Harley 2007). A good example of sedimentation in a Florida cave is illustrated by Morris Cave in the Withlacoochee State Forest, which accumulat ed significant sediment (2 m) to the point of being inaccessible, when multiple hurricanes crossed over Florida in a short period of time depositing signific ant amounts of precipitation in 2004 (Florea and Vacher 2007). Part of the reason for the cave’s infill is its location in a sinkhole within an abandoned quarry, w here erosion rates are high and the landscape is undergoing denudation. An investigation of the stratigraphy of siliclastic sediments in Dead Man’s Cave in north Florida by Cordier (1998) found evidence of sedimentation caused by sea-level and groundwater fluctuations through the Late Pleistocene. This

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113 study focused on the physical litholog ic variations between deposits in wall cavities of the cave, but the type of s ediment and sampling resolution provided only coarse data regarding cl imate change and interpretations were more aligned with understanding the geomorphological res ponse of karst systems to sea-level changes in Florida. Brinkmann and Reeder (1995) perform ed a study on cave sediments from Peace Sign Cave in Brooksville, Florida to determine their relationship to surface soils. They found that the cave sediment s were a product of allogenic input of sandy surface soils, proposing evidence of seasonal variation in the layering of the sediment deposit. The sediments were highly disturbed in the upper strata from human activity in the cave and sedi mentation rates were accelerated (half of the 1-meter deep sample deposited in the last 18 years) because of recent anthropogenic changes on the l andscape above the cave. Despite the important information provided by this study, only limited geomorphic and climatic knowledge is gained from physical exami nation of sediments, such as grain shape analysis, texture, and sieve anal ysis, and a more in-depth analysis of climatically-sensitive variables and better dating control are required for accurate paleoenvironmental reconstruction. Wood (1996) performed a similar pre liminary study in Vandal Cave in Brooksville, Florida examining the nature and deposition of sedi ments in the cave using physical analyses. Following the theory of Brinkmann and Reeder (1995), Wood (1996) postulated the layered sedim entary deposit could be attributed to the rainy season depositing light-color ed sands and the darker organic layers

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114 occurring during the drier winter season. The low-resolution sampling of this study only allows for a broad speculat ion to the mechanism of sediment deposition related to climat e change, assuming constant deposition and climate stability, and does not account for prol onged periods of climate change affecting seasonality and precipitation, such as drought or ENSO ye ars. Wood’s (1996) study further explains the relationship between surface soils, cave sediments, and climate, but still lacks quantitative data to explain long-term, natural environmental and climatic variati on influencing the deposition and paleoenvironmental signal of sedi ments in Florida caves. 4.6 Study Areas This study was conducted in west-cent ral Florida, where the majority of Florida’s air-filled caves are located, forming within the Brooksville Ridge and Ocala Uplift (Florea et al. 2007). Two cave s, Jennings Cave in Ocala and Vandal Cave in Brooksville, were chosen based on the criteria previously set forth regarding suitability for this study (Figure 4.2). The two caves, while uniquely and independently different in their geomor phology and location, share the similar characteristic of extensive and accessible sedim ent deposits.

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115 4.6.1 Jennings Cave Jennings Cave is located in Ma rion County in west-central Florida approximately 15 kilometers west of Ocal a (Figure 4.2). The cave is privately owned by the Southeast Cave Conserv ancy and is gated to prevent unauthorized access and destruction. Jennings Cave has an 8 m-deep, 2 m-wide vertical entrance that opens into several fractu re-controlled vadose passages totaling Figure 4.2 Study area map. The red dots indicate the locations of Jennings and Vandal Caves in west-central Florida. MARION CITRUS HERNANDO 02040 10 KilometersStudy Area CavesMap by Jason Polk Data Source: Florida Geographic Data Libray NAD_1983_HARN-ZONE_17NLegend west-central FloridaVandal Cave Jennings Cave

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116 about 200 m in length. Minor sediment i nput is visible through several thin fractures and conduits that extend upward several meters into the cave ceiling (Figure 4.3). Major sediment ation occurs through the ve rtical entrance shaft as observed during rain events. Sediment ation on the cave floor is widespread throughout the cave and exists up to seve ral meters in depth before bedrock is reached. The cave is located in a forest ed area, with a few dirt roads nearby and little in the way of development or urbanization.

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117 Figure 4.3 Map of Jennings Cave. Located in Marion County, Florida. Square box denotes where trench and core were taken.

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118 4.6.1 Vandal Cave Vandal Cave, part of the Dames Cave s complex, is located in the Withlacoochee State Forest (WSF) on t he Citrus Tract in Citrus County, approximately 7 miles northwest of Broo ksville (Figure 4.2). In contrast to Jenning’s Cave, Vandal Cave’s morpholog y allows modern, rapid sedimentation to occur from direct wash in from t he surface through several large entrances. Anecdotal information from local cavers and WSF personnel indicated that over a meter of sediment had deposited in the cave in their lifetimes, spanning the last 40 to 60 years. The cave contains minimal passage and is surrounded by an open area where forest roads intersect, with access on a permit-authorized basis. However, the cave is heavily visited and is part of a complex of nearby caves that are frequented by locals. The main passage is approximately 7 m deep, with two small leads along joints heading in the nor thwest (NW) and sout h (S) directions. Sediments wash in via a north-north west, south-southeast sloping entrance (walking-size) at the surface and through the large 4 m-long by 3 m-wide collapse opening into the main room, w here they are deposited (Figure 4.4). The cave is hydrologically closed, with no flow of water through the cave, so sediments are captured as they wash in and remain there.

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119 Figure 4.4 Map of Vandal Cave. Located in Citrus County, Fl orida. Square box denotes where core sample was taken.

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120 4.6.2 Geologic Setting The areas surrounding both Jennings and Vandal contain many karst features, including sinkholes, dry valleys, caves, and interfluvial hills (Reeder and Brinkmann 1998; Florea 2007a). The geology c onsists of the fossiliferous, highly karstified Ocala Limestone and is intermittently covered (~8 to 10 m thick) by the Hawthorne Formation’s undifferentiated clay s and sands, which overlie most of the state’s limestone (Florea et al. 2003; Lane and Hoenstine 1991). Additional Plio-Pleistocene quartz sands, clayey s ands, and clays overlie the Hawthorn in some areas in varying th icknesses (White 1970). The average elevation of the area near Jennings Cave is approximately 30 meters above sea level (m.a.s.l.) and it lies along the Ocala Uplift. The majority of dry caves in the area exist in Ocala Limestone, which is a white, fossiliferous Eocene limestone (Lane and Hoens tine 1991; Florea 2006). Most of the caves are moderately-siz ed, horizontal or vertical caves, with a few being partially flooded in their lower levels w here they intersect the aquifer (Florea 2007a, 2007b). The average elevation of the area near V andal Cave is approximately 25 m.a.s.l. and it lies al ong the Brooksville Ridge with similar bedrock geology as that of Jennings Ca ve. The cave contains no standing or flowing water and is at least 20 m above the local water table. 4.6.3 Climate The study area’s climate is humid subtropical, with an average annual temperature of 22 C and an average annual precipitati on total of 1,300 mm (SE Regional Climate Center). The maximum m onthly mean of 33.2 C occurs in July

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121 and the minimum monthly mean of 8.8 C occurs in January. The maximum monthly mean precipitation volume of 190 mm occurs in July and a minimum monthly mean of 50.8 mm occurs in J anuary (SE Regional Clim ate Center). The area exhibits an almost monsoonal-like cl imate, with a wet summer wherein twothirds of the annual rainfall occurs in average years between June and October, with the occasional hurricane, and a drier winter season from November to May (Winsberg 2003; Alvarez-Zarikian et al 2005). The main atmospheric influences affecting precipitation and temperature are the Intertropical Convergence Zone (ITCZ), El Nino/Southern Oscillation (ENSO), the Atlantic Multi-decadal Oscillation (AMO), and the No rth Atlantic Oscillation (N AO) (Enfield et al. 2001; Cane 2005). 4.6.4 Soil and Vegetation Vegetation around Jennings Cave main ly consists of flatwood and mixed hardwood forests, common in this area of Florida (Watts and Collins 2008). This type of environment incl udes longleaf pine ( Pinus palustris) slash pine ( Pinus elliottii ) turkey oak ( Quercus laevis ), live oak ( Quercus virginiana), saw palmetto (S erenoa repens ), wire grass ( Aristida sp.), ericads, species of Holly ( Ilex ), forbs, and various scrub vegetation (Figure 4.5) These species include mainly C3 plants, with some C4 plants occurring in varying abundances throughout the landscape in more arid upland sites. So me deforestation has occurred in areas where isolated homes exist, but the area directly around the cave is not densely populated. Soil cover mostly consists of l eaf litter and detrital material on the surface, with medium to fine sand and di rectly below the surface, and the

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122 occasional clay layer with silty organi cs. The common soil ty pe is the Candler fine sand series (Watts and Collins 2008). Vandal Cave, being loca ted within the WSF, is unaffected by urban growth, but forestry practices, including logging and visitation, have affected soil and vegetation minimally at certain time s in the past (Colleen Werner, pers. comm. 2008). Vegetation is similar to that near Jennings Cave and mainly consists of flatwood and mixed hardw ood forests (Watts and Collins 2008). This type of environment incl udes longleaf pine ( Pinus palustris) slash pine ( Pinus elliottii ) turkey oak ( Quercus laevis ), live oak ( Quercus virginiana), saw palmetto (S erenoa repens ), wire grass ( Aristida sp.), ericads, species of Holly ( Ilex ), forbs, and various scrub vegetation (Figure 4.5) These species include mainly C3 plants, with some C4 plants occurring in varying abundances throughout the landscape. Soil cover mainly includes t he Candler fine sand series (Watts and Collins 2008).

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123 MARION CITRUS HERNANDO 02040 10 KilometersStudy Area VegetationMap by Jason Polk Data Source: Florida Geographic Data Libray NAD_1983_HARN-ZONE_17NLegendVegetation Types FORESTS OF LONGLEAF PINE AND XEROPHYTIC OAKS FRESH WATER MARSHES HARDWOOD FORESTS MANGROVE SWAMP FORESTS AND COASTAL MARSHES PINE FLATWOODS SAND PINE SCRUB FORESTS SWAMP FORESTS MOSTLY OF HARDWOODS WATERVandal Cave Jennings Cave Figure 4.5 Vegetation map. Map of common vegetation types located within the study area of west-central Florida. Both Jennings and Vandal Cave have mixed hardwood and pine forest above them.

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124 4.7 Methodology Through fieldwork and personal obse rvation during exploration of hundreds of dry caves in west-central Flor ida, I sought to find suitable locations to conduct paleoclimatological research on surface sediments deposited within the caves based on previous research and aforementioned criteria. While many caves in west-central Florida contain sedi ment deposits, only those that satisfied the conditions of having inputs from the surface (entrance, fractures, conduits, etc.), being free from biotur bation, devoid of aquifer presence or stream passage, being hydrologically closed, and having layered deposition were considered for this research to ensure the highest probability for successfully understanding how cave sediments in Florida, which is geologically and hy drologically unique compared to most karst areas respond to climate change. 4.7.1 Jennings Cave In 2007, a trench was dug laterally ac ross the widest part of the main south-western passage in Jennings Cave at the terminus of the passage (Figure 4.3, 4.6). This was done to ensure that sedimentation was consistent throughout the passage and that coring c ould be replicated in multiple areas if necessary. Figure 4.6 illustrates the consistent nature of the sediment throughout the passage, ensuring that the sampling loca tion was representativ e of the entire deposit. A 10 cm-diameter schedule 40 PVC core, which minimized compaction and deformation, was taken at the end of the main south-western passage in the cave floor next to the trench near the southern cave wall in Jennings Cave.

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125 Figure 4.6 J1-07 core and trench. On the left is a photo of the J1-07 core with 10 cm intervals marked along its length. The photo on t he right is the trench dug across the cave p assage prior to coring demonstrating continuous layering.

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126 The 110 cm long core sample (Fi gure 4.5) was brought back to the University of South Florida’s Soils and Physical Geography Lab for analysis. The core was cut in half lengthwise using a ci rcular saw. One half of the core was divided into 1 cm sections, which we re further analyzed to produce a detailed description of each individual layer existing within the core, including sublayers thinner than 1 cm. The description includ ed color, layer properties, grain type, texture, and any other discernable proper ties (Appendix A). The second half of the core was marked into 1 cm interval s corresponding to t he first half of the core, but left intact, covered, and refrigerated to preserve it for pollen extraction. 4.7.2 Radiocarbon Dating Each 1 cm layer was examined for t he presence of sufficient organic carbon in the form of charcoal, seeds, wood, and/or organic matter to use for establishing a chronological record of deposition for the sediment core through radiocarbon dating. Amounts of 0.5 grams or more we re collected in layers providing sufficient material and sent fo r radiocarbon dating at BETA Analytic in Miami, Florida, using Accelerator Mass Spectrometry. Dates were calibrated to calendar ages using the CALIB 5.0.1 program and the INTCAL 04 radiocarbon database (Talma and Vogel 1993; Stui ver et al. 1998; IntCal04 2004) 4.7.3 Bulk sediment, HA, and FA 13C Analysis HAs and FAs were extracted from the sediments for 13C analysis according to a modified method from Hiradat e et al. (2006). Initially, 5 g of each of the sediment samples were ground, and then mixed in a 1:10 soil to 0.1 M NaOH ratio in 55 mL polypropylene centrifuge tubes. This mixture was then

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127 shaken for 24 hours in the presence of 3% NaCl. Samples were then centrifuged for 15 minutes at 10,000 rpm, decanted into separate flasks, and this process was repeated. The collected supernatants (mixed crude humic and fulvic acids) were acidified to a pH of 1.0 with 4 M HCl, stored ov ernight, then centrifuged at 10,000 rpm for 15 minutes to collect the precipitated HAs, which were refrigerated for later analysis. Samples were then filtered through a 0.2 micron pore-sized filter membrane and the super natant was neutralized to a pH of 5.0 and left overnight. The precipitated FAs we re collected by centrifuging at 6,000 rpm for 15 minutes. The wet precipitants in a mild brine solution were placed in a deep-freezer at -75 C and left overnight. Completion of the drying process was performed by placing the HA and FA samp les in a Labconco Lypholizer Vacuum Freeze-Dry System for 72 hours, until they becam e powdered and crystalline. The powdered HAs and FAs were placed in sealed containers and kept cool and dry until they were analyzed. Bulk sediment samples of 20 gram s from each layer were ground with a mortar and pestle. Samples were then treated with 2.0 M HCl solution to remove carbonate material and rinsed 7 times with deionized water. Samples were dried in a 40C oven for 24 hours prior to loadi ng in tin boats for isotopic analysis (Schelske and Hodell 1995). The 13C of the bulk sediment, HA, and FA fractions were measured with a Carlo-Erba NA2500 Series II EA coupled to a ThermoFinnigan Delta+XL IRMS in continuous flow mode located at the USF College of Marine Science Paleoclimatology, Paleoceanography and Biogeochemistry Laboratory in St.

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128 Petersburg, Florida. Samples of ~80 g were placed in tin boats and dropped from a Costech Zero-blank Autosampler into the EA combustion furnace thermostatically stabilized at 1000C, where they were combusted with an excess of UHP O2. Combustion products were entrained in a UHP He carrier stream and passed through a reducti on furnace (to remove excess O2 and reduce NOx to N2), a water trap and a GC column (3 m, 0.25" dia. 5A mol sieve) before entering the IRMS via an open-spli t interface (ThermoFinnigan ConFlo II). Analyzed gases were measured against reference gases (UHP N2 and UHP CO2) and are expressed in per mil (‰) rela tive to their respective reference materials (VPDB for 13C). Estimates of analytical precision were obtained by replicate measurements of internal lab reference materials and yield a precision of 0.3‰ for 13C. 4.7.4 Pollen Analysis Pollen analysis was performed on the Jennings Cave sediments at the United States Geological Survey (USGS) headquarters in Reston, Virginia under the supervision of Dr. Debra W illard. One half of the s ediment core was taken to the Palynology Lab at the USGS, w here it was cleaned, photographed, and sampled at 5 cm intervals for pollen extrac tion according to methods by Willard et al. (2001; 2003). Each 5 cm section was dried in an oven overnight at 60C. A tablet with known marker grains ( Lycopodium ) was added to each sample to allow calculation of known poll en grains/dry gram sediment. To remove carbonates and silicates, each sample was treated with 10% HCl and neutralized before being were treated with HF and neutralized. Then

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129 each sample was heated to boiling in 10% KOH for 10 minutes at 70C, then washed and acetolyzed (1 part sulfuric acid:9 parts acetic anhydride) before sieving through 150 (remove coarse fracti ons) and 10 m (remove clay fractions) sieves. Next, samples were stained with Bismarck Brown and mounted in glycerine jelly on microscope slides for counting (Willard et al. 2001). Each slide was then examined under a microscope to achieve a 300-count of the pollen grains to determine pollen distri bution and percent abundance. Percent abundance was plotted using TILIA and TI LIAGRAPH software and zones were identified using CONISS (constrained clus ter analysis) (Grimm 1992; Willard et al. 2007). 4.7.5 Vandal Cave Analysis In 2008, a pit was excavated in the c enter of the main passage of Vandal Cave to expose sediment layering in the passage (Figure 4.7). A 10-cm-diameter schedule 40 PVC core (V1-08) was tak en beside the pit until an impenetrable hardpan layer was reached, producing a 74 cm long sediment core (Figure 4.7). The core was removed, capped, and brough t back to the University of South Florida’s Soils and Physical Geography Lab where it was cut in half lengthwise. One half of the core was divided into 1 cm sections, which were used to produce a detailed description of each individual layer existing within the core, including sublayers thinner than 1 cm. The description included color, layer properties, grain type, characteristic, texture, and any other discernable properties. The second half of the core was divided into 1 cm intervals corresponding to the first half of the core, which were air-dried for 24 hours prior to further analysis.

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130 Figure 4.7 V1-08 core and trench. On the left is a photo of the V1-08 core with 10 cm intervals marked along its length. The photo on t he right is the trench dug across the cave p assage prior to coring demonstrating continuous layering.

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131 4.7.6 Lead-210 (210Pb) Dating Due to the expectation t hat the Vandal Cave sedi ment was more modern, Pb-210 dating was utilized to date the sediment. Ten fairly evenly spaced individual layers were sampled from the first half of the V1 -08 sediment core, weighed to obtain their wet weight, dried overnight in an oven at 40C, and reweighed to obtain their dry weight. The bulk density was calculated for each sample, and then they were ground using a pestle and mortar, bagged, sealed, and sent to Micro Analytical (subsidiary of BETA Analytic) in Miami, Florida for Pb-210 dating. 4.7.7 FA 13C Analysis Carbon isotope analysis was performed on FAs in each 1 cm layer from the V1-08 core, per the technique descr ibed above for Jennings Cave for both the extraction procedure and isotopic analysi s. Bulk sediment and HAs were not analyzed, nor was pollen fo r this core sample. 4.8 Results 4.8.1 Cave Sediment Cores Both Vandal and Jennings Caves pr oved to be sensitive to external geomorphologic, climatic, and environmental processes, recording changes at differing rates and magnitudes over different periods of time. Both cave sediment sequences indicate primarily allo genic input, with almost no autogenic sedimentation occurring within the obs erved sediments. Vandal Cave was chosen for study as a modern calibrati on record to atte mpt to explain and

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132 potentially corroborate the climate event s found within the Jennings Cave sediment record, including the caus es of layering and isotopic shifts. 4.8.2 Jennings Cave Sediments The sediment core J1-07 from Jennings Cave was representative of the entire accumulation of sediment in t he main passage of the cave. This was evidenced by the trench dug laterally acro ss the passage to expose the sediment layers before coring, whic h upon examination showed consistency in their deposition and stratigraphy throughout t he passage upon examination (Figure 4.6). Additionally, the core width of 10 cm and the sampling resolution of 1cm layers provided layer-averaged values for the various analyses and eliminated any minute intracore discrepancies in sediment deposition. 4.8.3 Physical Description The physical description of the J1 -07 core provides generalized information of each 1 cm layer, includi ng thinner sublayers, color, physical characteristics (grain type, size, compos ition), and groupings of similar layers (i.e. multiple cm that comprise a la yer unit) (Appendix A) From the physical description, the variability of the sediment layering and the episodic nature of its deposition are evident. Primar ily, the core consists of recurring sand and organic layers, somewhat rhythmitic in nature, although not consistently alternating throughout the entire depth of the core (Figure 4.6; see Appendix A). In summation, the sediment core consists of 64 fine sand layers, 69 organic matter layers (comprised of silt y, clayey, organic-rich sand), 16 mixed sandy organic layers, and 2 orange iron-stai ned clayey-sand layers, all of varying

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133 thicknesses and fairly abrupt horizons. Overa ll, the entire core consists mostly of quartz sand, based on qualitative HCl fizz test ing, which is present within every layer in varying amounts and is expec ted in west-central Florida, where Quaternary quartz sand dominates the so il matrix (Watts and Collins 2008). Prior textural and grain size analyses indicate minimal physical variation within the layers of the core (Harley and Polk 2006). 4.8.4 Radiocarbon Dating Radiocarbon dates from charcoal, wood, seeds, and organic matter, and a rabbit jawbone from nine fairly evenly spac ed layers of sediment from Jennings Cave core J1-07 provide a chronology of sediment depositi on. Table 4.1 shows the dates with errors at core depths where they were obtained and used in constructing the age model. Sample IDDepth (cm)Description Age (14C yr BP) (1 )Age (cal yr BP) (2 ) BETA-2286431.5 Charcoal Post-bomb0.4 pMC50BETA-2286442.5 Charcoal 3704034040 BETA-22864515.5 Wood 6104060040 BETA-22865636.5 Charcoal 156040156040 BETA-2864751.5 Organics 161040158040 BETA-22864863 Charcoal 193040182040 BETA-22864982.5 Charcoal 221040221040 BETA-228650100.5 Organics 268040267040 BETA-228651104 Jaw Bone 265040271040 AMS radiocarbon dates from J1-07, given in cal yr BP. Table 4.1 Radiocarbon ages for core J1-07 Core from Jennings Cave. Calibrations are based on the CALIB 5.0.1 program and the INTCAL 04 r adiocarbon database (Talma and Vogel 1993; Stuiver et al. 1998; IntCal04 2004).

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134 The depth-to-age model was construct ed using a fourth-order polynomial regression (r2= 0.987, p<0.001) model to provide a chronological record for the sediment deposition (Figure 4.8). The num ber of dates used (nine) provides acceptable confidence in the timescale rec onstruction for this study as compared to similar methodologies used in lacust rine and marine sediment studies (Curtis et al. 1998, 1999; Hodell et al. 2005). Figure 4.8 J1-07 age model. Based on the J1-07 radiocarbon dates using a 4th order polynomial regression equation. 4.8.5 Cave Sediment Carbon Isotope Data The age model was applied to the humic acid, fulvic acid, and bulk sediment 13C values to create chronological records of isotopic change for the y = 2E-05x4-0.001x3-0.324x2+ 47.77x + 74.38 R = 0.987 0 500 1000 1500 2000 2500 3000 020406080100Age (cal yr BP)Core Depth (cm)

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J v b 4 r a v Fi g c o 1-07 sedi m ariables in 13C values ulk sedim e 4 .8.6 Humi c The h a nge from alues span13C values g ure 4.9 J10 o re. m ent core. T their respe for all thre e nt exhibitin c Acid 13C h umic acid s 17.7 to -3 5 the range of the FAs 0 7 isotope da T here exist s ctive 13C v e isotope r e g the high e s carbon is o 5 .6‰, exhi b of C3 and C Little vari a ta. Bulk sedi m 135 s high vari a v alues, as s e cords ran g e st variabili t o tope 13C b iting a ran g C 4 vegetati o a bility exist s m ent, fulvic a c a bility amo n s how in Fi g g ed from -1 t y. values for t g e of ~18 ‰ o n and fall w s except d u c id, and hum i n g the thre e g ure 4.9. R a 2.2‰ to -3 9 t he J1-07 s ‰ (Figure 4. w ithin the r a u ring the p e i c acid 13 C d e different p a nges in th e 9 .5‰, with s ediment c o 10). Thes e a nge of th e e riod from d ata for the J 1 p roxy e the o re e e 1 -07

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136 approximately 2000 to 3000 cal yr BP, wher e the major peak of -17.7‰ occurs around 2000 cal yr BP and the most negative 13C value of -35.6‰ occurs around 2400 cal yr BP. The 13C values for the prior period from modern until around 2000 cal yr BP have a range of approx imately 6‰ and average around 23‰, with a minor negative excursion near 1300 cal yr BP (-27‰) and the least negative 13C value occurring around 1400 cal yr BP (-21‰) (Figure 4.10). 4.8.7 Fulvic Acid 13C The FAs carbon isotope 13C values for the J1-07 sediment core range from -21.1 to -34.5‰, ex hibiting variability of ~13‰ which clearly indicates Figure 4.10 J1-07 HA data. Humic acid 13 C from the J1-07 sediment core. -37.00 -32.00 -27.00 -22.00 -17.00 05001000150020002500300013C (‰ VPBD)Age (cal yr BP)J1 07 HA 13C Data

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137 variability in the surface vegetation in the past 3000 cal yr BP and also a predominantly C3-rich carbon isotope signal, which is to be expected in a humid, subtropical environment (Webb et al. 2004) As seen in Figure 4.11, a general trend towards more negative 13C values from around 1200 cal yr BP reaches the most negative (depleted) value of -34.5‰ around 800 cal yr BP. Then, the 13C values sharply become less negative (enriched) peaking at -21.1‰ about 500 cal yr BP. The 13C values then become more negative averaging approximately -26‰ towards the present. The 13C values of the last 1500 cal yr BP illustrate the most extreme variability in the record, encompassing the periods of the Little Ice Age (LIA,~250 to 650 cal yr BP) and Medieval Warm Pe riod (MWP, ~800 to 1200 cal yr BP) (Broecker 2001). From about 1500 cal yr BP unt il the start of t he record at 3,000 cal yr BP, a generally steady isotopic reco rd except at ~1600 cal yr BP (-21.1‰), 1800 cal yr BP (-21.4‰), 1950 cal yr BP (-28‰) and 2150 cal yr BP (-28.8‰). Fluctuating values during the period fr om 1500 cal yr BP to 3000 cal yr BP may indicate a natural environmental disturbanc e, such as the Holocene Neoglacial (Jerardino 1995), but lack any major, prolonged isotopic shifts.

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138 Figure 4.11 J1-07 FA data. Fulvic acid 13C from the J1-07 sediment core. 4.8.8 Bulk Sediment 13C The bulk sediment carbon isotope 13C values for the J1-07 sediment core range from -12.2 to -39. 5‰, exhibiting a wide range of ~27‰ (Figure 4.12). These values span the range between C3 and C4 vegetation and are highly variable, showing more extreme excu rsions than either the FAs or HAs 13C data. The data exhibits no clear pattern of isotopic variability, with several dramatic excursions of more negative through the last 1500 ca l yr BP, then less negative 13C values at 1700 and 2200 cal yr BP (Figure 4.12). These cannot be attributed to any long-term shifts in veget ation, being comprised mainly of single -35.00 -32.00 -29.00 -26.00 -23.00 -20.00 05001000150020002500300013C (‰ VPBD)Age (cal yr BP)J1-07 FA 13C Record

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139 data points. Additionally, several data points are missing, due to analytical problems with the samples, despite severa l attempts at rer uns. Explanations for the wide range of isotopic values include pr oblems with dilution of the samples’ large organic fractions during combustion, and/or the complexity of the heterogeneous composition of the bulk sediment introduced by other carbon sources, which also likely cont ributes to the wide range of 13C values in the data (Turney 1999). Figure 4.12 J1-07 bulk sediment data. Bulk sediment 13C from the J1-07 sediment core. -40.00 -35.00 -30.00 -25.00 -20.00 -15.00 -10.00 05001000150020002500300013C (‰ VPBD)Age (cal yr BP)J1 07 Bulk 13C Data

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140 4.8.9 Pollen Data Four pollen zones were identified in core J1-07 based on a combination of visual inspection of pollen assemblages (Figure 4.13) and objective zonation using the program CONISS (Grimm 1992). Zone 1 (70-110 cm) is dominated by Pinus pollen (45-82%), with fern s pores subdominant (7-29%). Asteraceae (daisy family) pollen is common in this zone (2-13%), and Poaceae (grass family), Carya (hickory), and Taxodiaceae (cypress) pollen also are common in certain intervals. Zone 2 (40-70 cm) is characterized by subdominance of Pinus and Asteraceae pollen, comprising 36-50% and 26-33% of assemblages, respectively. In zone 3 (5-40 cm), Pinus pollen is dominant (56-83%) and fern spores are subdominant. Asteraceae pollen is less abundant than in zone 3. Uppermost zone 4 consists of one sample (0-1 cm), which is dominated (55%) by Quercus pollen with Pinus pollen subdominant (29%). For unknown reasons, the sample at 35 cm did not yield enough pol len for use in the analysis, but may have been due to an anomalous sediment puls e devoid of pollen, or most likely analytical error.

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141 Figure 4.13 J1-07 pollen data. Percent abundance of pollen of major taxa vs depth for J1-07 core from Jennings Cave (age in cal yr BP p lotted next to depth). Boundaries of pollen zones are visible base d on CONISS results. No pollen was available for analysis whe re the gra y line crosses the chart.

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142 4.9 Jennings Cave Sediment Discussion 4.9.1 Interpretation of 13C Isotopes As covered in Chapter 2, a variet y of studies have identified that C3 and C4 plants have unique 13C signatures due to isotopic fr actionation of carbon during their differing photosynthetic mechanisms. The difference in 13C values occurs from the preferentia l discrimination or incorporation of 13C during photosynthesis, with C3 plants having more depleted 13C values (avg. -27‰) and C4 plants being more enriched in 13C, with 13C values averaging -13‰ (Martin et al. 1990; Boutton et al. 1998; Wynn et al. 2005; Huang et al. 2006). The isotopic signatures of vegetation translate relati vely unaltered to the soil organic matter (SOM) during decomposition, providing an isot opic record of shifts in the relative abundance of C3 to C4 plants comprising the local vegetation (Boutton et al. 1998, Vagen et al. 2005). These shifts in the proportion of C3 to C4 plants are indicative of changes in precipitat ion, temperature, atmospheric CO2, or other limiting factors that control plant eco system dynamics (Turney et al. 2001; Wynn et al. 2005). Climate (precipitation and temperature) is the most variable and important controlling factor of vegetation type, with C3 plant representative of wetter environments and C4 plants indicating drier condi tions (Dawson et al. 2002; Panno et al. 2002; Huang et al. 2006). Using this widely accepted interpretation of 13C values, in the J1-07 cave sedim ent proxy variables, more negative (depleted) 13C values indicate a wetter, C3-dominated environment, while less

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143 negative (enriched) 13C values indicate a drier, C4-dominated environment (Pessenda et al. 2001; Panno et al. Huang et al. 2006; Polk et al. 2007). From this interpretation, the vari ability of the car bon isotopic records derived from the HA, FA, and bulk s ediment analyses suggest substantial environmental changes during the deposit ional period (Schwartz et al. 1986; Bottrell 1996; Desmarchelier et al. 2000; Huang et al. 2001; Turney et al. 2001). However, agreement between the isotopic re cords of three different components of the cave sediment is lacking. Reasons for the FAs 13C being the most reliable and accurate record are outlined below. 4.9.2 Fulvic Acid Carbon Isotopes Fulvic acids are among the most abundant organic materials found in surface soils around the world (Yanagi et al. 2002; Ussiri and Johnson 2003), are highly resistant to microbi al decay (Zech et al. 1997; Polk et al. 2007), adsorb well to clays and other particles to prevent removal and decomposition (Zech et al. 1997), and are the most contemporaneous organic co mponent comprising soil organic matter that closely record changes in vegetation over time, and are able to persist for thousands of years (Zec h et al. 1997; Zalba and Quiroga 1999; Dai et al. 2006; Polk et al. 2007). Additional ly, studies show FAs are more abundant than HAs in subtropical and tropical soils, thereby providing a more robust record of the vegetation growing in the soil (Theng et al. 1989). Since surface sediments are washed into the cave and remain preserved, the organic acids trapped within each sediment layer preserve the 13C signal of the vegetation growing above the cave dur ing the sediment depos ition. Previous

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144 studies have shown that the 13C values of FAs are the most isotopicallyequivalent to the vegetation contributing to the soil organic matter (Nissenbaum and Schallinger 1974, Polk et al. 2007). Theref ore, it is expected that the FAs 13C record should be the most accurate nat ural tracer of v egetation change over time in the study area. 4.9.3 Discounting Humic Acid and Bulk Carbon Isotopes Studies show progressive diminuti on in the humic acid and humin fractions of surface soil over time co mpared to initial am ounts, especially with changing vegetation regimes, from ox idation and decomposition processes including microfungal degradatio n (Rezacova et al. 2006). Additionally, HAs are known to be older and exist longer in t he soil, and most importantly are usually more isotopically-depleted than FAs in relation to the source vegetation (Nissenbaum and Kaplan 1972; Ni ssenbaum and Schallinger 1974). Traditionally, bulk soil organic matte r (SOM) provides a generalized indication of vegetation changes over time (Krull et al. 2005). Several factors may explain why the bulk 13C record does not accurately reflect vegetation changes over time in the sediment record, incl uding the isotopic enr ichment of SOM with depth on the surface and the differing com ponents that comprise SOM. In most surface soils, SOM at a dept h of more than 30-50 cm shows enrichment of its 13C values due to microbial fractionation and decomposition processes (Krull et al. 2005; Wynn et al. 2005). An important fa ctor is that the multiple components comprising bulk SOM oft en exhibit different 13C values, which can be further affected by pedogenic and decomposition proc esses that may alter the carbon

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145 isotopic composition of the bulk soil rela tive to the plant biomass. Another contributing factor to t he variability of bulk SOM 13C values besides its dynamic state are the multiple co mponents, including microor ganisms, macromolecular compounds, roots, minerals, and fungi (Zech et al. 1997; Cayet and Lichtfouse 2001) that contribute to the 13C signal of the SOM and vary over time. 4.9.4 Interpretation of Cave Sediment FAs 13C Data Having shown inherent problems wit h using HA and bulk sediment 13C data for paleoclimate interpretation, this leaves the FAs 13C record as the most robust indicator of changes in vegetation over the last 3000 cal yr BP in westcentral Florida. The FA 13C isotopic values appear most consistent with changes in abundance of a mixed C3-C4 environment. A study by Wright et al. (1976) proposed that a treeless Florida land scape existed before 6000 cal yr BP, consisting mostly of xeric shrubs and gr asses. However, more recent studies (e.g. Grimm et al. 2006, Huang et al 2006) indicate a more mixed C3-C4 environment during this period. It c an be postulated that due to Florida’s subtropical climate, a complete shift in dominance to either C3 or C4 vegetation is unlikely during the Late Holocene, but it is possible that certain areas of the landscape underwent periods of low tr ee abundance for long durations of time, such as open oak-grass savannas (Huang et al. 2006). Modern vegetation is dominated by C3 trees and plants, with a likely minimal input of C4 vegetation, but does vary in the type of tree and gr ass species present depending on the location and the local environm ent (Watts and Collins 2008).

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146 Another possible explanation is a te mporal shift in dominance between oak ( Quercus) and pine ( Pinus) species, both of which vary slightly in their 13C values (approximately 1-3‰) between s pecies due to photosynthetic differences (Huang et al. 2006; Grimm et al. 2006). Studies indicate shifts in the relative abundances of pine and oak over the last 50,000 cal yr BP in Florida based on pollen assemblage from lake sediments (Grimm et al. 2006; Watts et al. 1992). However, these records extend into the last glacial period, whereas the J1-07 record only spans the more climatically stable Late Holocene and likely did not experience complete shifts in species dominance in the study area. The pollen record from the J1-07 sediment core supports this reasoning, based on the constant presence of pine pollen and the persistence of a low abundance of oak species throughout most of the record (F igure 4.13); thus, supporting the most likely explanation of the variable 13C values being changes in abundance of other C3 C4 vegetation related to climat e and environmental factors. Two abrupt periods of 13C variability occur in the FA carbon isotope record during the MWP and LIA, where periods of carbon isotopic excursion occur for prolonged periods of time (F igure 4.14). The MWP (~800 to 1200 cal yr BP) shifted towards more negative 13C values in the FA carbon isotopes, indicative of a wetter climate and po ssible increase in the abundance of C3 vegetation. The timing of the MWP in t he sediment record closely agrees with several other climate studies covering th is period in other areas from climate proxies (e.g. Chapter 6; Haug et al. 2001; Broeker 2001 ). Comparatively, the brief shift to less negative 13C values during the LIA (~ 350 to 650 cal yr BP) is

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147 also seen in the FA carbon isotope record and indicates a drier, possibly cooler environment more prohibitive to C3 plant growth in the region. Figure 4.14 J1-07 LIA and MWP. The Little Ice Age (350-600 cal yr BP) and Medieval Warm Period (~800-1200 cal yr BP) seen in the J1-07 13C record. 4.9.5 Pollen Data Unfortunately, the relatively coarse sa mpling interval (5 cm) for pollen in the J1-07 core precludes any detailed paleoenvironmental interpretation (Willard, D., pers. comm. 2009), but there appear to be fluctuations between assemblages characteristic of relatively wetter and drier climatic conditions. The strong dominance of Quercus in zone 4 is consistent with dry conditions. As is the abundance of Asteraceae pollen, produced by weedy species, in zone 2, which

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148 corresponds well with the low abundance of Pinus and a period of less negative FA 13C values between 1500 and 2000 cal yr BP (Figure 4.13). The abundance of Pinus pollen in zones 1 and 3 indicates relatively wetter conditions; high Pinus pollen abundance in the southea stern United States is pos itively correlated with a warm, wet climate (Willard et al. 2005, 2007). There are several factors that prev ent a detailed comparison of the pollen and FA 13C records. The major issues with the pollen are (1) it is not possible to identify these arboreal species any more finely than the genus level, wherein certain groups contain both C3 and C4 species that could be present in the pollen assemblage; (2) variability in preservati on; (3) different mechanisms of transport; and (4) external environmental factors a ffecting the pollen assemblages washed in the cave. It is important to note that the pollen assemblages indicate the presence of Pinus in relatively high abundance throughout t he sediment record for the last 3000 cal yr BP, which agrees with other Late Holocene records indicating a resurgence of Pinus since the last glacial maximu m in Florida (Grimm et al. 1993). Quercus is also found consistently, despi te in low abundances, throughout the entire sediment sequenc e, which supports the interpretation of the FA 13C values being indicative of shifts in the overall contribution of C3 and C4 plants to a mixed 13C signal. The dramatic spike in Quercus in the pollen assemblage in zone 4, which is slightly deceiving on the graph since the spike consists of only a single data point between 0 and 1 cm, could be attributed to anthropogenic alteration of the environment over the last few decades due to logging of long

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149 leaf pine and development affecting the loca l pollen distribution in the study area near the cave. However, pollen records from Lake Tulane also show this spike in Quercus in recent times, possibly indicati ng a more widespread cause, such as recent droughts (Grimm et al 1993; Watts and Hansen 1994). 4.9.6 Comparison of J1-07 13C to Speleothem Records A well-established speleothem isotopi c record from west-central Florida provides the opportunity to compare and substantiate the interpretation and accuracy of the J1-07 FA 13C record to reliable proxies of vegetation and precipitation changes. A study by van Be ynen et al. (2007a) produced a carbon isotope curve for the last 3000 cal yr BP fr om a speleothem from Briar Cave in Marion County, Florida, approximately 15 km southeast of the Jennings Cave study area (Figure 4.15). A compar ison of the Jennings Cave FA 13C and the Briar Cave speleothem (BRIARS04-02) 13C records indicates close agreement (Figure 4.15). The speleothem 13C record is a higher resolution isotopic record of the carbon signal derived from the veget ation above the cave, and still exhibits a close match to the J1-07 sediment 13C record.

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150 Figure 4.15 J1-07 vs BRIARS04-02. Comparison between the J1-07 sediment core and BRIARS04-02 speleothem 13C shows close agreement (van Beynen et al. 2007a). Both records prominently record the Little Ice Age (350-600 cal yr BP) and Medieval Warm Period (~800-1200 cal yr BP). The BRIARS04-02 speleothem record shows 13C values ranging from 8.5‰ to -11‰, reflecting similar, although less pronounce d trends in the vegetation shifts in the region over the la st 3 ka. Both record s indicate a shift toward more negative values leading in to the MWP (800 to 1200 cal yr BP), supportive of a wetter, C3-dominated environment. Differences between the dating techniques used for both record s and their resultant age models could explain the slight offset in the 13C records around the MWP. The sediment and speleothem records both become le ss negative during t he LIA, from approximately 300 to 650 cal yr BP, i ndicating drier conditions and more

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151 abundance of C4 plants, and then both 13C records begin to return to a more negative, mixed C3-C4 13C signal up to the present (Figure 4.15). Soto (2005) interprets the variations in the speleothem 13C values as major vegetation changes from a C3to C4-dominated environment. Although the carbon isotope records of the Jennings Cave sediment FAs and BRIARS04-02 speleothem closely match, one major difference is the range of the 13C values of each proxy. Dorale et al (1998) interpreted a 4‰ shift in the 13C values of speleothem calcite to indicate a transition between C4 grassland and C3 forested environments. Denniston et al. (2001) found a ~2‰ shift in carbon isotopes in a speleothem to indicate changes between a C3 forested and C4 prairie environment. However, both of these studies were done in temperate regions and do not account for t he fact that s peleothem calcite 13C values are fractionated due to the input of inorgani c carbon from the overlying bedrock and evaporative processes during speleothem formation. Baker et al. (1997) show that speleothem calcite 13C values can vary ~6‰ in the same type of vegetated environment, illustrating that complete shifts in the vegetation regime do not have to occur for large isotopic fluc tuations to take place. In consideration of these possibilities, my interpretation of the 13C values of the BRIARS04-02 speleothem in comparison with the J1-07 13C record disagrees with that of Soto (2005). Instead, I propose t hat the ~3‰ shift in the 13C speleothem isotopes indicates changes in the abundance of C3 vegetation in a subtropical environment, rather t han a complete shift in dominance to C4 vegetation, based on the more accurate 13C signal recorded in the sediments,

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152 which are derived from the soil in whic h the vegetation was actually growing (Pessenda et al. 2001). 4.9.7 Precipitation Proxy Comparisons to J1-07 FA 13C Record Another possible explanation of t he variations in the J1-07 FA 13C record relates to the modulation of the 13C signal by regional prec ipitation fluctuations, wherein enrichment in 13C by C3 plants occurs during drier periods due to changes in their photosynthetic process to adapt to arid conditions (Boutton 1996; Turney et al. 2001; Dawson et al. 2002). Comparison of the J1-07 FA 13C record to the 18O records from BRIARS04-02 and BRC03-02, which are established records of precipitation vari ability over the last ~3000 cal yr BP, indicates a close agreement between the speleothem 18O and sediment 13C records (Figure 4.16). The 18O data from the speleothems indica te changes in precipitation in the region, with more negativ e, depleted values indicative of wetter periods, and less negative, enriched values indicating dr ier periods (see Chapter 6; Soto 2005; van Beynen et al. 2007a, 2007b) The match of the J1-07 13C record is closer to the 18O record from BRIARS04-02 than the BRC03-02 speleothem, which is expected based on the close pr oximity of Jennings and Briar Caves, with BRC being located approximately 65 km southwest of Jennings Cave (Figure 4.17). However, agreement betw een all three records implies a more regional signal of climate change reco rded by the Jennings Cave sediments based on the influence of precipitation amount.

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153 Figure 4.16 J1-07 proxy comparisons. A comparison between the J1-07 sediment core, BRIARS04-02 and BRC0302 (low-resolution) 18O shows close agreement.

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154 Prolonged fluctuations in precipitation would affect vegetation type and growth on a regional scale, and also possibly influence the 13C values of the J107 cave sediment FAs based on the response of vegetation to moisture availability. In revisiting the pr oposed interpretation of the J1-07 13C record indicating fluctuations in the abundance of C3 vegetation over time, another possible influencing factor is that C3 plants may undergo shifts in their 13C values within certain species based on pr ecipitation changes, regardless of the proportion of C4 plants. Studies show that the 13C values within C3 species can become more enriched (depleted) during periods of decre ased (increased) rainfall from water stress (Stewart et al. 1995; Fall et al 1998; Menot and Burns 2001; Paulsen et al. 2003; Turner et al. 2008). This provi des another mechanism that may account for the variations in the J1-07 13C values over time, which would provide a record of climate change based on a consistently C3-dominated subtropical environment, supported to some degree by the pollen record, yet remain consistent with the climate interpre tation of the shifts in the J1-07 13C and speleothem 18O data. Determining the exact influence of precipitation on the 13C and the relationship between the 18O and 13C plant values is beyond the scope of this research, but should be noted as another possible influence on the cave sediment 13C record.

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155 The data from Chapter 6, the high-resolution 13C and 18O record from BRC03-02 for the last 1500 ca l yr BP provides a proxy for comparison to the J107 13C record during this period (Figure 4. 18). Some agreement exists between the high-resolution BRC03-02 13C and J1-07 13C records, but discrepancies in MARION CITRUS HERNANDO 02040 10 KilometersStudy Area CavesMap by Jason Polk Data Source: Florida Geographic Data Libray NAD_1983_HARN-ZONE_17NLegend west-central FloridaBRC Cave Vandal Cave Jennings Cave Briar Cave Figure 4.17 Proxy location map. Map of the locations showing the proximity of Jennings Cave to Briar Cave, Vandal Cave, and BRC Cave. Red and blue dots indicate cave locations (Red = sediment records, blue = speleothem records.

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156 the match exist, as the BRC03-02 13C data exhibits slightly different variations over time. These could be attributed to the local vegetation response and hydrological properties of the drip water source of the speleothem, and also because of the sensitivity of the high-resolution speleothem data to more subtle changes in these parameters (discu ssed further in Chapter 6). However, a closer agreement exists between the J1-07 13C and highresolution BRC03-02 18O records (Figure 4.18), although slight discrepancies exist, likely due to differences in the age models, dating techniques, and resolution. Regardless, agr eement among the BRIARS04-02 18O, the highand low-resolution BRC03-02 18O records, and the J1-07 FA 13C records demonstrate the influence of changing prec ipitation amount on vegetation in west-central Florida.

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157 Figure 4.18 Proxy comparison to BRC03-02. A com parison between the J1-07 sediment core and high-resolution BRC03-02 18O and 18O for the last 1,500 cal yr BP.

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158 4.9.8 Climate Implicati ons from the J1-07 FA 13C Record Since precipitation is influenced by broader regional, atmospheric-oceanic phenomena, it is likely these influences would affect all three proxy sites somewhat equivocally. Recent studies on the causal mechanisms of climate change discerned from Florida speleothem records may lend insight to the factors influencing the vegetation-response to precipitation changes (van Beynen et al. 2007a-c, Chapter 6). These studies suggest decadal to centennial shifts in the intensity of atmospheric-oceanic teleconnections, including the NAO, AMO, ENSO, and ITCZ, affect precipitation am ounts in west-central Florida, thereby also affecting vegetation. 4.9.9 Sediment Layering and Nature of Deposition One other important attribute of the J1-07 sediment core requiring discussion, while not as clearly interpreted as the 13C data, is how the sediment accumulates in the cave to form the layers seen in Figure 4.6. The geomorphology of the cave is maze-like and extensively fracture-controlled, with a single 10 m deep vertical entrance (Figur e 4.3). From personal observation, sedimentation occurs mainly through the entrance during wash-in events, and is present throughout the entire ca ve at a fairly uniform, hor izontal level. It is likely that major storm ev ents are required to meet t he necessary Hjulstrom Curve conditions required to transport the sand, silt, clay, and organic matter into the cave to deposit the layers seen in the co re (Selley 1982, p.180) (Figure 4.6). No relationship seems to exist between the 13C values and the type of sediment layer(s) from which they were derived, as many 1 cm thick sample intervals

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159 contain several thinner layers, and exist in too low of a resolution to test individually (Appendix A). Additionally, vegetation type is somewhat independent of the ability of precipitation to wash sediment into the cave. If deposition were continuous for t he duration of the J1-07 sediment record, then based on the age model the s edimentation rate is about 1 cm every 30 years. This could allude to a possibl e multi-decadal cycle of hurricanes or major frontal storms producing enough rain to cause sedimentation. Dating errors and inconsistencies in deposition are not conduc ive to time series analysis to test this hypothesis. Furthermore, layer thick ness varies within the core and from the physical description and it is evident that deposition likely is more intermittent and episodic, thus providing snapshots of the environmental conditions during the time of deposition. The composition and thickness of t he layers could be dependent upon the magnitude and duration of the wash-in event, prolonged periods of wetter or drier conditions, or some settling mechanism. While it is difficult to determine the mechanism of sedimentation and cause of the layering found in the Jennings Cave sediment, an examin ation of a cave undergoi ng modern sedimentation could provide insight to this process and how it relates to climate change. Hence, the Vandal Cave sediment core, discuss ed below, was collected for analysis to determine if known environmental paramet ers affecting sedimentation in a hydrologically and sedimentologically sens itive cave would provide insight and a calibration of the process of cave sedi mentation in Florida related to climate change over a period of instrumental reco rd. In addition, a study by Wood (1996)

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160 from Vandal Cave showed similar sedimentar y structure to that of Jennings Cave and attributed it to changes in seasonal climate. 4.10 Vandal Cave Sediment Results 4.10.1 Vandal Cave Sediments The sediment core V1-08 from Vandal Cave represents the upper portion of the accumulated sediments in the main passage of the cave. Several test pits were dug throughout the main room to ex pose the sediment layering, revealing consistent strata found thr oughout the entire sediment depos it (Figure 4.7). As in the J1-07 sample, the core width of 10 cm and the sampling resolution of 1cm provide layer-averaged values for the various analyses and eliminated any minute intracore discrepancies in sediment deposition. Analyses was limited to a physical description, FA 13C data, and comparison to historic weather data since this core is meant to be a modern, high -resolution proxy in an attempt to calibrate the J1-07 core data with regard to clim ate and sedimentati on processes. 4.10.2 Vandal Cave Sediment Physical Characteristics The physical description of the V108 core (see Appendix B) provides generalized information on each 1 cm layer, including thinner sublayers, regarding the color, physical characteristi cs (grain type, size composition), and groupings of similar layers (i.e. multiple cm that comprise a layer unit). The physical description illustrates the variabi lity of the sediment layering and the episodic nature of its deposition, which is similar to that of the J1-07 core. Primarily, the core consists of recu rring sand and organic layers, somewhat

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161 rhythmitic in nature, although not consis tently alternating throughout the entire depth of the core (Figure 4.7; see Appendix B). There is evidence of previous anthropogenic presence in cave, with rem nants of glass, plastic, and metal present in a few of the upper la yers in minimal quantities. The V1-08 sediment shows more variabi lity in sediment character than the J1-07 core, consisting of 19 organic matter layers (comprised of silty, clayey, organic-rich sand), 11 mixed sandy organi c layers, 3 orange iron-stained clayeysand layers, 18 pure, fine sand layers, 1 ve ry fine sand layer, 1 grey, charcoal layer, and 1 black, unconsolidated ,sandy, old floor layer, all of varying thicknesses and horizon types, ranging from abrupt to wavy (Figur e 4.7). Overall, the entire core consists mostly of quar tz sand, based on HCl fizz testing, similar to that of J1-07. Wood (1996) performed textural and grain size analyses for a sediment bank from Vandal Cave, but littl e of the data was useful for delineating climate change solely on ph ysical sediment data. 4.10.3 Pb210 Dating Bulk sediment lead-210 (210Pb) dates from ten layers provide a chronology of sediment deposition for the V1-08 sediment core. Pb-210 dating was used because of the expected young age of the sediments and provides greater dating precision for materials less than 150 year s old. Table 4.2 shows the dates with errors corresponding to core dept hs where they were obtained.

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162 Sample No. Depth ( cm ) Grams Wet Grams Dr y Rho Pb-210(total) ( dpm/ g) MA-2819 142.3629.61.793.2 +/-0.382.1+/-0.272.48+/-0.260.91+/-0.32008+/-1>0.05 +/---1.31+/-0.03 MA-2820 563.4349.191.992.82 +/-0.212.37+/-0.162.39+/-0.140.44+/-0.172007+/-10.24+/-0.061.96+/-0.05 MA-2821 1083.1757.751.782.69 +/-0.22.17+/-0.121.91+/-0.120.65+/-0.152005+/-10.28+/-0.062.32+/-0.05 MA-2822 1554.0143.982.082.27 +/-0.191.59+/-0.141.7+/-0.120.62+/-0.152003+/-10.23+/-0.060.46+/-0.01 MA-2823 2549.0943.382.261.86 +/-0.181.69+/-0.131.71+/-0.110.15+/-0.142002+/-12.98+/-0.110.4+/-0.01 MA-2824 3046.5840.132.211.93 +/-0.191.18+/-0.141.38+/-0.130.65+/-0.152000+/-20.23+/-0.060.5+/-0.01 MA-2825 4056.4742.051.913.64 +/-0.231.95+/-0.151.98+/-0.131.68+/-0.171991+/-30.39+/-0.071.9+/-0.04 MA-2826 5065.3959.342.321.52 +/-0.160.98+/-0.120.62+/-0.10.62+/-0.121979+/-70.22+/-0.050.4+/-0.01 MA-2827 6570.3365.882.41.31 +/-0.141.08+/-0.121.03+/-0.080.25+/-0.111971+/-110.2+/-0.060.85+/-0.02 MA-2828 7464.846.591.843.7 +/-0.231.89+/-0.161.73+/-0.141.89+/-0.171964+/-141.02+/-0.092.65+/-0.06 Pb-214 (dpm/g) Pb-210(excess) (dpm/g) CRS(year) Cs-137 (dpm/g) K-40(dpm/g) Bi-214(dpm/g) Table 4.2 Pb210 dating. Lead-210 ages with errors and calculated 137 Cs versus core depth (BETA Analytic, Miami).

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163 A simple linear age model was constr ucted based on the constant rate of supply (CRS) age calculation model used for the Pb-210 dating (Figure 4.19). This model implies a constant sedi ment flux with c onstant initial 210Pb concentrations, but does not require a c onstant rate of s edimentation. The presence of 137Cs in the sediments indicates a ll are younger than 19632 years, when nuclear weapons testing began (Schelske and Hodell 1995). The dating model supports a relatively constant sedimentation rate until about 25 cm, when a spike in the 137Cs and associated shift in depositi on rate occurs, with the dating model supporting a much faster rate of sedimentation occurring after 2000. Figure 4.19 V1-08 age model. Age depth plot for V1-08 from Pb-210 dates. Error bars define 1 sd. 137Cs is shown versus depth and was used in the CRS age model. 0 0.5 1 1.5 2 2.5 3 3.5 1940 1944 1948 1952 1956 1960 1964 1968 1972 1976 1980 1984 1988 1992 1996 2000 2004 2008 01020304050607080Calendar YRDepth (cm)V1 08 Pb 210 Dating Pb-210 Date Cs-137

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164 4.10.4 V1-08 Fulvic Acid 13C Results The V1-08 FA 13C values range from -23.6‰ to -26.9‰ (Figure 4.20), and fall within the range of a C3-dominated 13C signal (Huang et al. 2006). The isotopic data points were collected in correspondence with the ten layers used for dating, thus providing fairly accurate age estimates for the 13C values. Three minor excursions occur in 1964 (-23.8‰ ), 1979 (-23.6‰), and 2002 (-23.7‰) (Figure 4.20). Other wise, for the remainder of the record, the values fall within 1‰ of the av erage for the entire 13C data of -25.4‰. Figure 4.20 V1-08 isotope data. Age model applied to V1-08 13C data -27.50 -27.00 -26.50 -26.00 -25.50 -25.00 -24.50 -24.00 -23.50 -23.00 13C (‰ VPBD)Age (Cal Yr BP)V1 08 13C Data

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165 4.11 Vandal Cave Sediments Discussion The analysis of the sediment core from Vandal Cave (V01-08) provides insight on the mechanism of recent, shor t-term sediment deposition in a Florida cave, and illustrates the complexity of the ever-changing surface environment and corresponding processes influencing sedim ent deposition in caves. It must first be pointed out that the uniquely di fferent geomorphology and locations of Jennings and Vandal Caves clearly affect s the sensitivity and mechanism by which each receives surface sediment deposits and records paleoenvironmental changes over time. 4.11.1 Deposition Rates and Age While similar sediment characterist ics are seen in both the J1-07 and V108 cores, the depositional process and rate of sedimentation differences between the two complicates the reconstruction and calibration of the Vandal Cave sediments to the Jennings Cave sedim ents. Most notably, the V1-08 core contains 74 cm of sediment deposited si nce 1964 in contrast to the J1-07 core, which contains 110 cm of sediment deposit ed since 3,000 cal yr BP. Part of this distinct difference in sedimentation rates and amount is attributed to the fact that Vandal Cave’s large unroofed entrance allows direct, rapi d sedimentation into the terminal passage of the cave where t he sediment accumulates, therefore allowing sediment to travel only a s hort distance before rapidly accumulating (Figure 4.4). Additionally, the cave is the lowest topographic point on the landscape and drains a large basin, thereby increasing the potent ial for sediment

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166 input through erosion, whereas Jennings Ca ve lies at the average elevation of the surrounding landscape (Figure 4.21). Anthropogenic disturbance of the area around the cave, including forestry activities and heavy visitation might also have impacted the sedimentation rate in the last few decades (Brinkmann and Reeder 1995). The input of sediment in Jennings Cave, which has more total passa ge, a smaller vertical entrance, and further distance for sediment to travel before deposition, most likely affects its sensitivity to wash-in events, requiring mo re intense storms for sedimentation to occur where the core was collected. T hese differences must be considered for any calibration or interpretation betw een the two cave sediment records. Figure 4.21 GTOPO60 DEM map of Vandal Cave. Map sh ows its high potential for drainage of the landscape and rapid sedimentation (adapt ed from USGS National Map Seamless Server http://gisdata.usgs.net).

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167 4.11.2 Vandal Cave S ediment Layering One easily discernable characteristic of the V1-08 sedime nt core is its prominent layering, which merits further discussion with regard to climate and depositional influences (Figur e 4.7). Based on dating of the sediment layers, almost half (~30 cm) of the sedim ent was deposited since 2000 (Appendix B). The remaining 44 cm was deposited in 36 years, from 1964 to 2000, indicating variable rates of deposition that could be related to changes in precipitation. Physical description indicates multiple layers within 2003 to 2005, which encompasses multiple hurricanes in 2004, and shows increased sediment layering. However, thick depositions of sand and organic interbedding from 2002 to 2003, a relatively stable, average precipitation period, seem more indicative of multiple major storm events. An analysi s of annual precipitation during these depositional periods does not indicate any distinct increase that would account for the variations in sedimentation, suggesting that other factors, perhaps vegetation changes, erosion, and anthropogeni c disturbance, have affected the cave’s sedimentation rate. Ruling out a direct connection to pr ecipitation or major storm-related events accounting for every layer present in the sediment core, other possible explanations for the vari ation in the character and thickness of the V1-08 sediment layers include three plausible scenarios: Scenario 1. Couplets and settling : Couplets caused by seasonality, as suggested by Brinkmann and Reeder (1995) and Wood (1996), are not continuous for every year in the V1-08 sedi ment core, as too many layers exist to

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168 account for seasonal couplets for every year of sediment deposition. Several areas do not exhibit couplet formati on of alternating sand/organic layers, therefore supporting that eit her hiatuses or interannual variations exist within each layer of deposition, with the latter more likely based on the number of layers and age model. The creation of couplets during single wash-in events from settling is plausible in some layers. Ho wever, overall it does not explain the existence of wavy boundaries, lack of cons ist couplets, variation in sediment composition, or lack of evi dence of upward fining or sett ling out of larger particles during lateral transport along the cave pa ssage, which would be consistent with settling mechanisms. Scenario 2. Event size : Another possible scenario to account for variations in the layer thicknesses and c haracter (dark vs light ) is that larger storm events erode more of the surfac e soil away until the underlying pure sand is eventually also eroded and transported to the cave because of higher energy. This would occur after the initial remo val of the surface organics and continued erosion into the sandy subsoil layers. Normally, intensely convective summer storms would cause this phenomenon to o ccur. However, differences in winter and summer storm frequency an d magnitude in Florida could also influence the type of sediment washed into the cave, creat ing the alternating layers in a similar fashion proposed by Brinkmann and R eeder (1995) and Wood (1996), except that larger, more frequent summer stor ms and strong winter low-pressure systems could both cause increased sand erosion and transport resulting in layered, coupled deposition in the cave irrespective of season. A confounding

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169 problem caused by this scenario is that often wet years in Florida are due to a combined wetter winter and average summer, as with El Nio phases, which would cause integrated mixing of sandy and organic layers to occur during severe winter frontal events and summer st orms, thereby making interpretation of the couplets with respect to annual or s easonal causes challenging. This also could affect the pollen distribution, as winter rainfall affects the growing season and pollen variability of many species in Florida (Donders et al. 2005). Scenario 3. Long-term Climate : A third explanation for the layered character of the V1-08 character is that the predominance of sand or organics in the layering is indicative of the longer-t erm climate in the area prior to and during wash in events. In this scenario, wetter climate periods would wash more sand into the cave during regular storm ev ents due to increased er osion, a potential dominance of pine species, which like sandy, low-organic soils, and a low organic matter content on the surface from an increased growing season (Watts and Collins 2008). Thinner organic layers w ould still wash in during the shorter dry season if rain occurred. Conversely during drier climates, siltier organic layers would form in the cave due to infrequent, low-energy wash in and depositional events combined with accumulat ed detrital materials on the surface, with sand layers washing in only during extreme, isolated st orms. A problem with this scenario is that vegetation produc tivity, soil turnover, and decomposition rates would also slow during drier c limates, possibly limiting the amount of organic matter accumulation on the surface over extended droughts that could be deposited in the cave.

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170 Most likely, the process causing of the layering of the sediment in Vandal Cave includes all three of the afor ementioned scenarios, with no discernable single mechanism accountable based on the modern climat e data or V1-08 sediment record. From this, I infer t hat the complexity of the depositional mechanism and the variable resolution of each layer, which could encompass anywhere from a single event to several small events during a prolonged period of sustained climate, is impossible to def ine at this low-resolution sampling. Limitations on sample size for additi onal analysis, combined with possible anthropogenic disturbance of the surrounding area, prevents a better understanding of how precipit ation and vegetation change may affect the layering of sediments in Vandal Cave. 4.11.3 V1-08 Carbon Isotope Data If sediment deposition in Jennings Cave was continuous over the period of record, then the temporal resolution of the J1-07 core is approximately 30 years/cm, in which case the V1-08 co re, providing about 44 years of record, would encompass only a snapshot in time of the climate and vegetation history equivalent to one of the layers of the J107 sediment core. Therefore, despite the higher temporal resolution of the V1-08 core a single layer in the J1-07 record is more likely a manifestation of an av erage of all the va lues depicting the 13C signal of the vegetation duri ng what appears, at least at a higher resolution, to be a more variable signal of vegetation c hange in the 44 year period encompassed by the V1-08 core. In reality, it is unlikely that vegetation has changed

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171 significantly enough in the last few decades to account for the variations in the V1-08 13C values as being indicative of major climate change. To determine the influence of known annual precipitatio n amounts on the 13C values of dated sediment layers, a regression analysis was performed on the annual precipitatio n versus the V1-08 13C values, resulting in an r2 value of 0.15 and indicating no significant relati onship between precipitation amount and 13C values for the V1-08 sediment core Several reasons for this may exist, including higher dating errors with depth and age of the sediment in the core, the temporal lag between rainfall amounts and vegetation response, and the episodic nature of the sediment layering. T he sediment layers with less negative 13C (drier) excursions do coincide with peri ods of drought preceding their deposition in 1979 and 2002; however, possible anthr opogenic disturbance in the form of logging, clear-cutting, and possibly wild fires would have more likely influenced the 13C signal during these short intervals, and supposedly occurred in the area at some point in the past, although the ti ming and extent of these activities is debated (Colleen Werner, pers. comm. 2008; Brinkmann and Reeder 1995). Errors within the age model increase with depth, and also prevent an accurate comparison between annual precipitation amount and 13C values. As discussed previously, layer thickness is not a definitive indicator of climate conditions or wash-in events. An analysis of the correlation between sediment layer thickness and annual precipit ation is difficult, because individual layers cannot correlated to a single y ear, with some years showing deposition of multiple indiscriminate layers, or a single layer corresponding to multiple years of

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172 deposition (see Appendix B). T hese occurrences also s upport the plausibility of scenario 3, where prominently sand or or ganic dominated sections of the core may indicate prolonged periods of wette r or drier conditions, with individual events occurring on a seasonal or annual sca le, which then contribute to the overall 13C signal over time. Sediment deposition in Vandal Ca ve, while not an entirely stochastic process, is complex and episodi c in nature. Therefore, it is difficult to ascertain a definitive understanding of t he relationship between sto rm events, sedimentation rates, seasonality, vegetation, and c limate change based on layer thickness and characteristics and 13C values in the V1-08 core. It is more feasible that layering is a product of multiple complex influences that include episodic deposition from storm events, settling mechanisms, pos t-depositional anth ropogenic processes, and longer-term seasonal and climatic influences. 4.11.4 Vandal Cave Calibration Potential Vandal Cave demonstrates a comple x system of sediment deposition and illustrates some of the various processe s by which sediment is deposited in a hydrologically-closed cave with a sensitive and direct connection to the surface. Changes in vegetation can be dynamic and rapid, on the order of 100 years or less, and more intense due to extreme climatic events (Boutton et al. 1998). However, the temporal span the V1-08 s ediment core, approxim ately 44 years, is likely too short to encompass entire shifts in vegetation regime s as dramatic as that found during major climat ic events, such as the LIA or glacial-interglacial periods (Krull et al. 2005). Additionally, the instrumental record indicates a

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173 relatively stable climate for Florida in t he last 50 years compared to that of last few millennia, which would not be conduciv e to major sh ifts in vegetation based on prolonged temperature or pr ecipitation variability. It is possible that short-term (decadal) droughts, years with ENSO-rela ted wetter winters, and periods of increased hurricane activity could lead to subtle changes in relative abundances of C3 and C4 vegetation, thereby affecting the average 13C signal over decadal timescales, but is unlikely in a subtropical setting like Florida where the vegetation is adapted to these conditions (Diels et al. 2001). To revisit the possibility of us ing the data from V1-08 as a modern calibration and interpretation for the env ironmental and climatic processes affecting the J1-07 sediment core, se veral factors must be considered. The difference between rates of deposition, anthropogenic disturbance, and most importantly lack of clear relationship between known climate fluctuations and sediment data reveals a much more co mplex system of sediment deposition and response to external factors during the short-term than prev iously thought. For example, average sediment thi ckness in V1-08 is 7.3 mm/layer, whereas average thickness in J1-07 is 4. 4 mm/layer, suggesting a much greater rate of sedimentation in Vandal Cave Also, size of the cave passage and distribution of the washed-in sediment could account fo r the thickness of layers, with the overall average in Jennings Cave being lower due to larger floor surface area. These factors contribut e considerably in the interpretation of the different sediment data for both caves, requiri ng a more individualized approach to examining and understanding the influences affecting cave sedimentation.

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174 Overall, it is impractical to use the V108 core as a calibration for the J1-07 core regarding climate-isotope and layer-precipi tation relationships. Furthermore, the complexity of the sediment deposition process is not elucidated based on the resolution of sampling and limited analyses on both cores to establish seasonal or annual resolution for layering or isotopic events. 4.12 Conclusions The 13C of fulvic acids from sediment in Jennings Cave robustly record paleoenvironmental change over the last 3, 000 years. Analysis of bulk sediment and humic acid 13C show they appear to suffer fr om intrinsic or external processes that prevent them from being as accurate of a proxy as fulvic acids. The centennial resolution of the FA 13C record shows the MPW and LIA clearly, and matches well to the BRC03-02 and BRIARS04-02 speleothem records, thereby indicating that prec ipitation amount directly a ffects the vegetation signal recorded in the cave sediments in the r egion. Pollen analysis, although at a lower resolution, also appears to support the interpretation of the FA 13C record. It is possible that long-term variations in te leconnections affecting precipitation in west-central Florida are responsible for the vegetation changes seen in the 13C record. This is covered in more detail in Chapter 6. A calibration attempt using a sedi ment core from Vandal Cave to determine the cause of the complex layeri ng seen in both it and Jennings Cave proved challenging. The sensitivity of Vandal Cave’s sediment deposits, while complex, show that interannual to decadal climate fluctuations are recorded in

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175 both the deposition of the sediments and the carbon isotopes of fulvic acids within them. This supports the paleoenvironm ental interpretation of the Jennings Cave sediment record, which receives less rapid sedimentation and likely shows a multi-decadal average of the vegetation signal above the cave. Jennings is also more sensitive to episodic depositional ev ents, in part due to its morphology, thereby allowing it to better record long-term changes in climate. Future research includes additional sediment cores from cave in westcentral Florida in attempts to calib rate and extend the paleoclimate record. Improved dating, additional analyses, including bulk density and magnetic susceptibility, and a modern sediment trap in both J ennings and Vandal Caves to capture modern sedimentation events and their depositional layering would greatly improve understanding of how cave sediments in Florida record climate and vegetation change. 4.13 Chapter Acknowledgements I would like to thank the Florida Ca ve Conservancy and the Southeastern Cave Conservancy for allowing me a ccess to Jennings Cave for coring and sample collection. Thanks to Colleen We rner and Withlacoochee State Forest for access and permission to core at Vandal Ca ve. I also would like to extend thanks to all those who assisted me with t he coring and testing dozens of caves, especially Grant Harley, Tom Turner Robert Brooks, Jon Sumrall, and my advisor, Dr. van Beynen. Additionally, s pecial thanks to all those who helped in the lab with sediment sample processing, including Travis Stull, Chris Lizzardi,

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176 Emily Wakley, and Ray Vinson. Thanks to Ethan Goddard for his expertise in mass spectrometry and running the sample s and to Dr. Philip Reeder for his insights on the Vandal sediment core. Spec ial thanks to Deb Willard of the USGS for assistance with pollen analysis. This studied was funded in part by the Geological Society of America and SWFWMD. 4.14 Chapter References Aiken, G.R., McKnight, D.M., Wershaw, R.L., MacCarthy, P., (eds.).1985. Humic substances in soil, sediment, and water. John Wiley and Sons: New York, 692 p. Alvarez Zarikian, C.A., Swart, P.K., Giff ord, J.A. and Blackwelder, P.L. 2005. Holocene Paleohydrology of Little Slat Spring, Florida, based on ostracod assemblages and stable isotopes. Palaeogeography, Palaeoecology, Palaeoclimatology 225: 134-156. Baker, A., Ito, E., Smart, P. L., and McEwan, R. F. 1997. Elevated and variable values of 13C in speleothems in a British cave system. Chemical Geology 136: 263-270. Biggs, T.H., Quade, J., and Webb, R.H. 2002. 13C values of soil organic matter in semiarid grassland with mesqui te (Prosopis) encroachment in southeastern Arizona. Geoderma 110: 109-130. Bottrell, S. 1996. Organic car bon concentration profiles in re cent cave sediments: Records of agricultural pollution or diagensis? Environmental Pollution 91(3): 325-332. Boutton, T.W., Archer, S. R., Midwood, A.J., Zitzer S.F., and Bol, R. 1998. 13C values of soil organic carbon and their use in documenting vegetation change in a subtropi cal savanna ecosystem. Geoderma 82: 5-41. Brenner, M., T.J. Whitmore, J.H. Curtis, D.A. Hode ll, and C.L. Schelske. 1999. Stable isotope ( 13C and 15N) signatures of sedimented organic matter as indicators of historic lake trophic state. Journal of Paleolimnology 22: 205-221.

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177 Brinkmann, R. and Reeder, P. 1995. The relationship between surface soils and cave sediments: An example fr om west central Florida, USA. Cave and Karst Science 22: 95-102. Burney, D.A., and Burney, L.P. 1993. M odern pollen deposition in cave sites: experimental results from New York State. New Phytology 124: 523-535. Calace, N., Giglio, F., Mirante, S., Petronio, B.M., and Ravaioli, M. 2004. Sedimentary process inferences from humic substances analysis and deposition rates (Western Ross Sea, Antarctica). International Journal of Environmental and Analytical Chemistry 84(6–7): 423–439. Camacho, C.N., Carrion, J.S., Navarro, J., Munueta, M., and Pr ieto, A.R. 2000. An experimentsal approach to th e palynology of cave deposits. Journal of Quaternary Science 15(6): 603-619. Cane, M.A. 2005. The evolution of El Nino, past and future. Earth and Planetary Science Letters 230: 227-240. Carrion, J.S., Munuera, M. and Navarro, C. 1998. The palaeoenvironment of Carihuela Cave (Grandada, Spain) : a reconstruction on the bases of palynological investigations of cave sediments. Review of Palaeobotany and Palynology 90: 317-340. Cayet, C., and Lichtfouse, E. 2001. 13C of plant-derived n -alkanes in soil particule-size fractions. Organic Geochemistry 32: 253-258. Clapp, C.E., Layese, M.F., Hayes, M.H. B., Huggins, D.R., and Alimaras, R.R., 1997. Natural Abundances of 13C in Soils and Water. In : Humic Substances in Soils, Peats, and Waters: Health and Environmental Aspects, M.H.B Hayes and W.S. Wilson, (eds.). The Royal Society of Chemistry: Cambridge, p. 159-175. Cordier, D.J. 1998. Sequence stratigraphy of siliciclastic cave sediments: depositional response to a paleohyd rologic cycle, Western Alachua County, Florida. University of Florida Thesis. 195 pp. Courty, M.A. and Vallverdu, J. 2001. T he microstratigraphic record of abrupt climate changes in cave sediment s of the Western Mediterranean. Geoarchaeology 16(5): 467-500. Curtis, J.H., Brenner, M., Hodell, D.A ., Balser, R.A., Islebe, G.A., and Hoogheimstra, H. 1998. a multi-prox y study of Holocene environmental change in the Maya Lowlands of Peten, Guatemala. Journal of Paleolimnology 19: 139-159.

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178 Curtis, J.H., Brenner, M., Hoddell, D.A. 1999. Climate change in the Lake Valencia Basin, Venezuel a, ~12,600 yr BP to present. The Holocene 9(5): 609-619. Dai, J., Ran, W., Xing, B., Gu, M., and W ang, L. 2006. Characterization of fulvic acid fractions obtained by sequential extractions with pH buffers, water, and ethanol from paddy soil. Geoderma 135: 284-295. Dawson, A.G., Hickey, K., Holt, T., Elliott, L., Dawson, S., Foster, I.D.L., Wadhams, P., Jonsdottir, I., Wilkins on, J., McKenna, J., Davis, N.R., and Smith, D.E. 2002. Complex North Atl antic Oscillation (NAO) Index signal of historic North Atl antic storm-track changes. The Holocene 12(3): 363369. Denniston, R.F., Gonzalez, L.A., Asme rom, Y., Polyak, V., Reagan, M.K., and Saltzman, M.R. 2001. A high-resoluti on speleothem record of climatic variability at the Alle rod-Younger Dryas transiti on in Missouri, central United States. Palaeogeography, Palaeocli matology, Palaeoecology 175: 147-155. Diels, J., Vanlauwe, B., Sanginga, N., Coolen, E., and Merckx, R. Temporal variations in plant delta C-13 valu es and implications for using the C-13 technique in long-term soil organic matter studies. Soil Biology and Biochemistry 33: 1245-1251. Donders, T.H., Wagner, F., and Visscher, H. 2005. Quantification strategies for human-induced and natural hydrological changes in wetland vegetation, southern Florida, USA. Quaternary Research 64: 333-342. Dorale, J.A., Edwards, R.L., Ito, E., and Gonzalez, L. A. 1998. Climate and Vegetation History of the Midconti nent from 75 to 25 ka: A Speleothem Record from Crevice Cave, Missouri, USA. Science 282: 1871-1874. Ellwood, B.B., Petruso, K.M., and Ha rrold, F.B. 1997. High-resolution paleoclimatic trends for the Ho locene identified using magnetic susceptibility data from archaeol ogical excavations in caves. Journal of Archaeological Science 24: 569-573. Enfield, D. B., Mestas-Nuez, A.M., and Trimble, P.J. 2001. The Atlantic multidecadal oscillation and its rela tion to rainfall and river flows in the continental U. S. Geophysical Research Letters 28: 277-280.

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179 Evans, M.N., and Schrag, D.P., 2004. A stable isotope-based approach to tropical dendroclimatology. Geochimica et Cosmochimica Acta 68(16): 3295-3305. Fall, M., Trimborn, P., and Feri, A. 1998. 13C in modern plants: an indicator of rainfall for Sahel. Earth and Planetary Sciences 326: 407-412. Farrand, W.R. 2000. Depositional histor y of Franchthi Cave: Stratigraphy, sedimentology, and chronology Indiana University Press: Indianapolis, 135 p. Florea, L.J., Kelley, K., Hashimoto, T. Miller, D., and Mrykalo, R. 2003. Karst geomorphology and relation to the phreat ic surface: Briar Cave, Marion County, Florida. In : Florea, L.J., Vacher, H.L., and Oches, E.A., eds., Karst Studies in west-central Florida. University of South Florida/Southwest Florida Wate r Management District, p. 9-19. Florea, L.J. 2006. Architecture of ai r-filled caves within the karst of the Brooksville Ridge, west-central Florida. Journal of Cave and Karst Studies 68(2): 64-75. Florea, L.J., Vacher, H.L., Donahue, B., and Naar, D. 2007. Quaternary cave levels in peninsular Florida. Quaternary Science Reviews 26:1344-1361. Florea, L.J. and Vacher, H.L. 2007. Eogenet ic Karst Hydrology: Insights from the 2004 Hurricanes, Peninsular Florida. Groundwater 45(4): 439-446. Foos, A.M., Sasowsky, I.D., LaRock, E.J. and Kambesis, P.N. 2000. Detrital origin of a sedimentary fill, Lec huguilla Cave, Guadalupe Mountains, New Mexico. Clay and Clay Minerals 48(6): 693-698. Forbes, M.S., and Bestland, E.A. 2007. Orig in of the sedimentary deposits of the naracoorte Caves, South Australia. Geomorphology 86: 369-392. Ford, D.C. and Williams, P.W. 2007. Karst Geomorphology and Hydrology. Wiley : West Sussex, England, 2nd ed., 576 p. Gale, S.J., Hunt, C.O., and Sout hgate, G.A. 1984. Kirkhead Cave: biostratigraphy and magnetostratigraphy. Archaeometry 26(2): 192-198. Granger, D. E., Fabel, D., and Palmer, A. N. 2001. Pliocene-Pleistocene incision of the Green River, Kentucky, dete rmined from radioactive decay of cosmogenic 26Al and 10Be in Mammoth Cave sediments. Geological Society of America Bulletin 113(7): 825-836.

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180 Grimm, E. C. 1992. CO NISS: a Fortran 77 program for stratigraphically constrained cluster analysis by t he method of incrememtnal sum of squares. Computers & Geosciences 13:13-35. Grimm, E.C., Jacobson, G.L, Watts, W. A., Hansen, B.C.S., and Maasch, K.A. 1993. A 50,000 year record of climat e oscillations from Florida and its temporal correlation with the Heinrich events. Science 261(5118): 198200. Grimm, E.C., Watts, W.A., Jacobsen Jr., G.L., Hansen, B.C.S., Almquist, H.R., Dieffenbacher-Krall, A.C. 2006. Evidence for warm wet Heinrich events in Florida. Quaternary Science Reviews 25: 2197-2211. Harley, G.L. and Polk, J.S. 2006. An Analys is of Cave Sediments from Jennings Cave, Marion County, Flori da: Geomorphic Implications. Geological Society of America Abstracts with Programs 38(7): 62. Harley, G.L. 2007. A GIS-Based Inventory of Terrestrial Caves in West-central Florida: Implications on Sens itivity, Disturbance, Ownership, and Management Priority. University of South Florida, thesis, 306 p. Harley, G.L., Reeder, P., Po lk, J.S., and van Beynen, P. 2009. Using a GISbased inventory for cave management implementation at Withlacoochee State Forest, Florida. Journal of Cave and Karst Studies In Press. Hiradate, S., Yonezawa, T., and Takesako, H. 2006. Isolation and purification of hydrophilic fulvic acid s by precipitation. Geoderma 132: 196-205. Hodell, D.A., Brenner, M., and Curtis, J.H. 2005. Terminal classic drought in the northern Maya lowlands inferred from multiple sediment cores in Lake Chichancanab (Mexico). Quaternary Science Reviews 24: 1413-1427. Huang, Y., Shuman, B., Wang, Y., Webb, T., Grimm, E.C., and Jacobson, G.L. 2006. Climatic and environmental c ontrols on the variation of C3 and C4 plant abundance in central Flor ida for the past 62,000 years. Palaeogeography, Palaeoclimat ology, Palaeoecology 237: 428-435. IntCal04. 2004. Calibration Issue. Radiocarbon 46(3). Jerardino, A. 1995. Late Holocene N eoglacial episodes in southern South America and southern Africa: a comparison. The Holocene 5(3): 361-368.

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181 Krull, E.S., Sklemstad, J. O., Burrows, W.H., Bray, S.G., Wynn, J.G., Bol, R., Spouncer, L., and Harms, B. 2005. Recent vegetation changes in central Queensland, Australia: Evidence from 13C and 14C analyses of soil organic matter. Geoderma 126: 241-259. Lane, E., and Hoenstine, R.W.1991. Environmental geology and hydrogeology of the Ocala area, Florida Florida Geological Survey Special Publication 31, 71 p. Lauritzen, S.E., Ford, D.C., and Schwar cz, H.P. 1986. Humic substances in speleothem matrix – paleoclimatic significance. Proceedings, 9th International Speleological Congress, Barcelona 1: 77-79. Lowe, D.J. and Gunn, J. 1994. Conference Abstracts: Changing Karst Environments: Hydrogeology, Geomorphology and Conservation. Cave and Karst Science, Transactions of the British Cave Research Association 21(1): 1. Menot, G., and Burns, S.J. 2001. Carbon isotopes in ombrogenic peat bog plants as climatic indicators: calibrati on from an altitudinal transect in Switzerland. Organic Geochemistry 32: 233-245. Navarro, C., Carrion, J.S., Munuera, M., and Prieto, A.R. 2000. An experimental approach to the palynology of cave deposits. Journal of Quaternary Science 15(6): 603-617. Navarro, C., Carrion, J.S., Munuera, M. and Prieto, A.R. 2001. Cave surface pollen and the palynologi cal potential of karstic cave sediments in palaeoecology. Review of Palaeobot any and Palynology 117: 245-265. Nissenbaum, A. and Kaplan, I.R. 1972. Chemical and isotopic evidence for the in situ origin of marine humic substances. Limnology and Oceanography 17: 570–582. Nissenbaum, A., and Schallin ger, K.M. 1974. The dist ribution of the stable carbon isotope (13C/12C) in fractions of soil organic matter. Geoderma 11: 137-145. Palmer, A.N. 2007. Cave Geology. Cave Books: Dayton, OH, 454 p. Panno, S.V., Kelly, W.R., Hackley, K.C. and Hwang, H.H. 2002. Distribution and sources of heterotropic bacteria in wells, caves and springs of a karst aquifer in the Midwestern U.S. In Karst Waters Institute Special Publication no. 7 p. 92-94.

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182 Panno, S.V., Curry, B.B., W ang, H., Hackley, K.C., Liu, C.L., Lundstrom, C., and Zhou, J. 2004. Climate change in sout hern Illinois, USA, based on the age and 13C of organic matter in cave sediments. Quaternary Research 61: 301-313. Pessenda, L.C.R., Boulet, R., Aravena, R., Rosolen, V., Gouveia, S.E.M., Ribeiro, A.S., and L amotte, M. 2001. Origin and dynamics of soil organic matter and vegetation changes during the Holocene in a forest-savanna transition zone, Braz ilian Amazon region. The Holocene 11(2): 250-254. Polk, J.S., van Beynen, P., and Reeder, P. 2007. Late Holocene environmental reconstruction using cave sediments from Belize. Quaternary Research 70: 53-63. Quade, J., Cerling, T.E ., and Bowman, J.R. 1989. Development of Asian monsoon revealed by marked ecological shift during the latest Miocene in northern Pakistan. Letters to Nature 342: 163-166. Quinn, A. 1996. Quaternary climate c hanges derived from surface-subsurface coupling in karst geomorphic syst ems: Matienzo, Northern Spain Karst Waters Institute Special Publication no. 2 pp. 123-126. Reeder, P. and Brinkmann, R. 1998. Paleoe nvironmental Reconstruction of an Oligocene-Aged Island Remnant in Florida, USA Cave and Karst Science 25: 7-13. Rezacova, V., Hrselova, H., Gryndlerova, H., Miksik, I., and Gryndler, M. 2006. Modifications of degradation-resistant soil organic matter by soil saprobic microfungi. Soil Biology and Biochemistry 38(8): 2292-2299. Schelske, C.L. and Hodell, D. A. 1995. Using carbon isotopes of bulk sedimentary organic matter to reconstruct the history of nutrient loading and eutrophication in Lake Erie. Limnology and Oceanography 40(5): 918-929. Schwartz, D., Mariotti, R., Lanf ranchi, R., and Guillet, B. 1986. 13C/12C ratios in soil organic matter as indicators of vegetation changes in the Congo. Geoderma 39: 97-103. Selley, R.C. 1982. An Introduction to Sedimentology Academic Press: New York, pp. 417. Soto, L.R. 2005. Reconstruction of Late Holoc ene Precipitation for Central Florida as Derived from Isotopes in Speleothems University of South Florida, Unpublis hed Masters Thesis.

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183 Spaccini, R., Mbagwu, J.S.C., Conte, P., and Piccolo, A. 2006. Changes of humic substances characteristics from forested to cultivated soils in Ethiopia. Geoderma 132: 9-19. Springer, G.S., Kite, J.S., and Schmidt, V.A. 1997. Cave sedimentation, genesis, and erosional history in the Cheat River Canyon, West Virginia. GSA Bulletin 109(5): 524-532. Sroubek, P., Diehl, J.F., K adlec, J., and Valoch, K. 2001. A Late Pleistoncene paleoclimate record based on mineral magnetic properties of the entrance facies sediments of Kul na Cave, Czech Republic. Geophysical Journal International 147: 247-262. Stewart, G.R., Turnbull, M.H., Schm idt, S., and Erskine, P.D. 1995. 13C natural abundance in plant communities along a rainfall gradient: a biological integrator of water availability. Australian Journal of Plant Physiology 22: 51-55. Stuiver, M., Reimer, P.J., Bard, E., Be ck, J.W., Burr, G.S., Hughen, K.A., Kromer, B., McCormac, G., van der Plich t, J. and Spurk, M. 1998. IntCal98 radiocarbon age calibration, 24,000–0 cal BP. Radiocarbon 40(3): 1041– 83. Talma, A.S., and Vogel, J. C. 1993. A Si mplified Approach to Calibrating C14 Dates. Radiocarbon 35(2): 317-322. Theng, B.K.G., Tate, K.R., Sollins, P., Nor hayati, M., Nadkarni, N. and Tate III, R.L. 1989. Constituents of organic ma tter in temperate and tropical soils. In D.C. Coleman, J.M. Oades and G. Uehara (eds.). Dynamics of soil organic matter in tropical ecosystems. Hawaii: University of Hawaii, pp. 532. Turner, N.C., Schulze, E., Nicolle, D. Schumacher, J., and Kuhlmann, I. 2008. Annual rainfall does not directly det ermine the carbon isotope ration of leaves of Eucalyptus species. Physiologia Plantarum 132: 440-445. Turney, C.S.M. 1999. Lacustrine bulk organic 13C in the British Isles during the last glacial-Holocene transition. Antarctic and Alpine Research 31(1): 7181. Turney, C.S.M., Bird, M.I., and Roberts, R.G. 2001. Elemental 13C at Allen’s Cave, Nullarbor Plain, Australia: assessing post-depositional disturbance and reconstructing past environments. Journal of Quaternary Science 16(8): 779-784.

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184 Ussiri, D.A.N., and Johnson, C.E. 2003. Char acterization of organic matter in a northern hardwood forest soil by 13C NMR spectroscopy and chemical methods. Geoderma 111: 123-149. van Beynen, P.E., Ford, D., and Schwar cz, H. 2000. Seasonal variability in organic substance in surface cave waters at Marengo Cave, Indiana. Hydrological Processes 14: 1177-1197. Watts, W.A., Hansen, B.C.S, and Grimm, E.C. 1992. Camel Lake: a 40,000-yr record of vegetational and forest history from Northwest Florida. Ecology 73(3): 1056-1066. Watts, W.A., and Hansen, B.C.S. 1994. Pre-Holocene and Holocene pollen records of vegetation hi story from the Florida peni nsula and their climatic implications. Palaeogeography, Palaeoclim atology, Palaeoecology 109: 163-176. Watts, F.C., and Collins, M.E. 2008. Soils of Florida Soil Science Society of America Inc.: Madison, WI, 88pp. Webb, E.A., Schwarcz, H.P., and Healy, P.F. 2004. Detect ion of ancient maize in lowland Maya soils using stable carbon isotopes: evidence from Caracol, Belize. Journal of Archaeological Science 31: 1039-1052. Werner, C. 2008. Personal communica tion, Withlacoochee State Forest. White, W.A. 1970. The Geomorphology of the Florida Peninsula Florida Bureau of Geology, Bulletin No. 51, 164 pp. White, W.B. 1988. Geomorphology and Hydrology of Karst Terrains Oxford University Press: New York, 464 p. Willard, D.A., Weimer, L.M., and Riegel, W.L. 2001. Pollen assemblages as paleoenvironmental proxies in the Florida Everglades. Review of Palaeobotany and Palynology 113: 213-235. Willard, D.A., Cronin, T.M., and Verardo, S. 2003. Late Holocene climate and ecosystem history from Ches apeake Bay sediment cores. The Holocene 13: 201–214. Willard, D.A., Bernhardt, C.E., Korejwo, D.A., and Meyers, S.R. 2005. Impact of millennial-scale Holocene climate variability on eastern North American terrestrial ecosystems: pollenbased climatic reconstruction. Global and Planetary Change 47: 17-35.

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185 Willard, D.A., Bernhardt, C.E., Brooks, G.R., Cronin, T.M., Edgar, T., and Larson, R. 2007. Deglacial climate variabi lity in central Florida, USA. Palaeogeography, Palaeoclimat ology, Palaeoecology 251: 366-382. Willard, D.A., 2009. Personal communication, USGS. Winsberg, MD. 2003. Florida Weather University of Florida Press: Gainesville, Florida. Wood, H.R. 1996. Recent s edimentation in Vandal Cave Citrus County, Florida. University of South Florida, Unpublished Honors Thesis, 41 p. Wright Jr., H.E., 1976. The dynamic nature of Holocene vegetation a problem in Paleoclimatology, Biogeography, and Stratigraphic nomenclature. Quaternary Research 6: 581-596. Wynn, J.G., Bird, M.I., and Wong, V.N.L. 2005. Rayleigh distillation and the depth profile of 13C/12C ratios of soil organic carbon from soils of disparate texture in Iron Range National Park Far North Queensland, Australia. Geochimica et Cosmochimica Acta 69(8): 1961-1973. van Beynen. P.E., Soto, L., Pace-Graczyk, K., 2007a. Paleoclimate reconstruction derived from speleothem strontium and 13C in Central Florida. Quaternary International 187(1): 76-83. van Beynen, P.E., Asmerom, Y., Polyak, V., Soto, L., Polk, J.S., 2007b. Variable intensity of teleconnections during the Late Holocene in Subtropical North America from an isotopic study of speleothem from Florida. Geophysical Research Letters 34: L18703, doi:10:1029/2007GL031046. Yanagi, Y., Tamaki, H., Otsuka, H., and Fujitake, N. 2002. Comparison of decolorization by microorganisms of humic acids with different 13C NMR properties. Soil Biology and Biochemistry 34: 729-731. Zalba, P. and Quiroga, A.R. 1999. Fulvic acid carbon as a diagnostic feature for agricultural soil evaluation. Soil Science 164: 57-61. Zech, W., Senesi, N., Guggenberger, G., Kaiser, K., Lehmann, J., Miano, T.M., Miltner, A., and Schrot h, G. 1997. Factors controlling humification and mineralization of soil organi c matter in the tropics. Geoderma 79: 117-161. Zhou, C., Liu, Z., Wang, Y. 2000. Climatic cycles in vestigated by sediment analysis in Peking Man’s Cave, Zhoukoudian, China. Journal of Archaeological Science 27: 101-109.

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186 Chapter 5 An Isotopic Calibration Study of Precipi tation, Cave Dripwater, and Climate in West-central Florida 5.1 Chapter Preface The purpose of this chapter is to pr esent a calibration study of oxygen and hydrogen isotopes of precipitat ion and cave dripwater. Fr om this, an attempt is made to understand the relationship betwe en variations in the isotopic composition of rainfall in west-central Fl orida and how it is manifested in cave dripwater. By establishing a calibration of th is relationship, it is possible to further determine how the oxygen isotopes from speleothems record changes in seasonal and annual cycles of prec ipitation in Florida, wh ich are often driven by synoptic and intense mesoscale atmospheric processes. 5.2 Abstract A calibration study of the stabl e oxygen and hydrogen isotopes from precipitation and cave dripwater was c onducted in west-central Florida at Legend Cave during 2007-2008. The amount effect was shown to dominate the area, with a negative relationship between rainfall amount and t he precipitation 18O values. A meteoric water line of 6.7 s uggests evaporative effects occur, however

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187 cave dripwater 18O values averaged near the mean annual amount-weighted average of the precipitation. A weak seasonal influence was observed in the dexcess values, with summer precipitation being more depleted. Comparison of the precipitation 18O values to synoptic weather data shows the amount effect dominates due to strong convective sto rms causing more depleted rainfall in greater amounts year round. The constant 18O values of the dripwater indicate that speleothem reconstructions in th is area would show changes in annual to interannual scales and would be suitable fo r long-term, high-resolution studies. 5.3 Introduction Florida is well-known for its wa rm, humid weather, distinct summer monsoon season, and exposure to hurricane activity. In reality, the region’s climate system is dynamic and complex, varying both temporally and spatially throughout the state, with differences of up to 50 cm in the average annual precipitation for a given location ranging from the Panhandle to the Florida Keys (Winsberg 2003). With precipitation play ing a major role in river discharge and groundwater recharge is a need for a more in-depth understanding of how teleconnections affect the region’s c limate (Kelly 2004). Recent work demonstrates the increasing importance of understanding the linkages between interannual and multi-decadal cl imate oscillations and their influence on ocean temperature and precipitation (Ha gemeyer 2006; Kelly and Gore 2008). Long-term fluctuations in the hydrol ogic cycle are caused by changes in globaland regional-scale atmospheric-oce anic influences affecting precipitation

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188 patterns in Florida, including the frequency and magnitude of hurricanes, convective storms, and frontal activity (Sun and Furbish 1997; Winsberg 2003). Impacts of prolonged peri ods of drought and unstable precipitation patterns include decreased recharge to the Floridan aquifer and, consequently, an increase in water scarcity, which coul d negatively affect Florida’s continued growth and development, as well as many environmental issues (Kelly 2004). Calcite speleothems are the product of interaction between precipitation and bedrock and are deposited from percolati ng dripwater in caves, thereby retaining the isotopic signature of thei r formation water (Gascoyne 1992; Ghosh and Brand 2003; Ford and Willia ms 2007). Several studies investigated how the climate signal from meteor ic precipitation is manifested in cave dripwater and speleothem calcite, but of considerabl e importance is how the atmospheric influences on precipitation patterns are re corded during this process (Cobb et al. 2007). Numerous studies have examined the major environmental controls on the oxygen (18O and 16O) and hydrogen (1H and 2H) isotopes of meteoric precipitation (Epstein and Mayeda 1953; Dansgaard 1964; Craig 1961; Rozanski et al. 1993; Kendal and Coplen 2001; O nac et al. 2008), and groundwater and cave dripwater (Williams and Fowler 2002; Cobb et al. 2007; Fuller et al. 2008; Onac et al. 2008). These studies highli ght a complex and dynamic system that varies on a spatial in spatial and geographic scale. In Florida, the major cont rols of seasonal variations in rainfall are the El Nio/Southern Oscillation (ENSO), the No rth Atlantic Oscill ation (NAO), the Atlantic Multidecadal Oscillation (AMO ), and the Pacific/North America (PNA)

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189 teleconnection (Hagemeyer 2006; van Beynen et al. 2007a; Kelly and Gore 2008). The impact these phenomena have on Florida’s short-term, seasonal weather is severe and weather event s, including tornadoes, hurricanes, and increased storminess can be indirectly a ttributed to their influence (Hagemeyer 2006). During certain correlated phases of the different intensities of ENSO, NAO, and PNA, Florida experiences dramatic increases in winter precipitation, storminess, and/or drought periods. Figur e 5.1 illustrates the many different observed scenarios of how ENSO, the NAO, and PNA interact to affect Florida’s storminess and dry season ra infall (Hagemeyer 2005). Forecasting the timing and intensity of these major teleconnections is difficult, even with an existing instrumental record, due to their variable phasing and intensity changes at interannual and mu lti-decadal scales. However, various proxy record studies have shown how thes e teleconnections vary in intensity (Bond and Harrison 2000; Enfield et al. 2001; Haug et a. 2001; Lachniet et al. 2004) but only two studies to date looked at their past influence in Florida (e.g. van Beynen et al. 2007a, 2007b). An improved understanding of how the modern climate is expressed under the influence of these different teleconnections in terrestrial proxy records through the stabl e isotopes of precipitation and cave dripwater aids in elucidating the reco rd of past climate conditions and their corresponding teleconnection influences.

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190 A B Figure 5.1 Teleconnection influences in Florida. A study by Hagemeyer (2005) found that certain p hases of ENSO, the NAO, and the PNA cause increased dry season storm and rainfall. (A) shows the phasing patterns associated with incr eased winter storms, shaded in blue and red. (B) shows the associated patterns with increased dry season rainfall, where grey shading indicates uncommon conditions (rarely happen), and brown sh ows the lowest observed rainfall with green indicating the highest observed amounts.

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191 5.3.1 Research Objectives The purpose of this study is to calibrate the relationship between teleconnection linkages, precipitation 18O, and cave dripwater 18O to better understand the process by whic h the isotopic composition of modern cave calcite records the modern climate signal. The following research questions will be addressed to meet this purpose: 1. What are the primary influenc es on the isotopic composition of precipitation in we st-central Florida? 2. Are seasonal or episodic events discernable in t he precipitation and cave dripwater 18O values? 3. What signal does the cave dripwater 18O record in relation to the 18O composition of rainfall? 4. Under the current teleconnection conditions, what do the precipitation and cave dripwater 18O signals show? By establishing these relationships, it is possible to further determine how oxygen isotopes from speleothems record c hanges in seasonal and annual cycles of precipitation in west-cent ral Florida. Understanding th e influence of atmosphericoceanic teleconnections on precipitation fluctuations beyond the instrumental record through proxy ca libration will provide guidance for managing and predicting changes in Florida’s water resources. 5.4 Study Area This study was conducted at Legend Cave, which lies on Withlacoochee State Forest property near Br ooksville, Florida in Citru s County (Figure 5.2). The

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192 cave is closed to the general public. Legend Cave has a single, small entrance approximately 55 cm wide an d 40 cm tall leading to 2 m vertical drop onto a sediment and breakdown debris cone. The cave is ~70 m long, trends N/NW, and is a series of three small cham bers connected by tight (~45 cm tall) crawlways terminating in a collapsed room where a large, active formation (dripping speleothems) is located (Figure 5.3). Figure 5.2 Study area map. Map of Legend Cave in Citrus County Florida on Withlacoochee State Forest Land.The closest town is Brooksville FL. Access is closed to the general public. CITRUS 01020 5 KilometersStudy AreaMap by Jason Polk Data Source: Florida Geographic Data Libray NAD_1983_HARN-ZONE_17NLegend Citrus CountyLegend Cave

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193 Figure 5.3 Legend Cave map. Map of Legend Cave with drip station location marked.

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194 5.4.1 Geologic and Hydrologic Setting Legend Cave lies within approximately 10 km of over forty air-filled caves formed along the topographically-high Brooksv ille Ridge at the el evation of the Penholoway terrace (White 1970; Flor ea and Vacher 2007). Most caves form within the highly porous, soft, white, fo ssiliferous Ocala Limestone, which is the predominant bedrock in the area, or at the contact between the mostly eroded, thin, unconformably overlying pale-or ange, cross-bedded Suwannee Limestone (Randazzo 1997; Florea 2006). The heter ogeneously mixed siliclastic sand, phosphatic clay, and partially laminated Ha wthorn Group intermittently overlies the Suwannee Limestone at various thickn esses up to 50 m, having infilled many sinkholes and exposed caves, and acting as a confining layer for the Upper Floridan Aquifer (UFA) (Randazzo 1997; Florea 2006; Onac et al. 2008). The confined to semi-confined portion of the UFA intersecting the Brooksville Ridge exists mainly within the permeable (~10-6 m/s) and porous (~30%) matrix of the Ocala Limestone (F lorea and Vacher 2006; Florea et al. 2007). The confinement is mainly dependent upon the existence of the Hawthorn Group. More extensive descrip tions of the UFA exist in the literature and provide in-depth information on its properties, char acteristics, and hydrogeology (e.g. Budd and Vacher 2004; Florea 2006; Florea and Vacher 2006). The landscape is characterized by numerous sinkholes, caves, sinking streams, first-magnitude springs (i.e. Weeki Wachee, Homosassa, Chassahowitzka, and Crystal River), and dry valleys (Florea 2006; Brinkmann and Reeder 1994; Scott et al. 2004). Legend Cave is overlain by approximately 5

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195 m of bedrock with interspersed chert layers and a thin soil cover. Near the cave’s entrance is an abandoned quarry that was mined several decades ago, several exposed fractures and large sinkholes provi de rapid infiltration points for rainfall. Standing water rarely occurs in the imm ediate vicinity of the cave, even after large precipitation events. 5.4.2 Climate and Vegetation The climate of west-central Flori da is humid subtropical and varies significantly both temporally and spat ially. Jordan (1984) estimates over 80 thunderstorm events occur each year in the study area based on a 30-year average (1948-1977), mainly occurring between June to September. On average, summer precipitation accounts fo r over 60% of the total annual rainfall amount, with the rest deriving from midlatitude winter frontal systems dipping south and delivering large amounts of rainfall to the state (Jordan 1984). The climate above Legend Cave, has a mean annual temperature of 21.3 C and mean annual precipitation of ~1350 mm. Mean maximum monthly temperatures occur in August (27.6C) and the minimum in January (13.6C). August also possesses the monthly ma ximum precipitation with 219 mm and October the least with 48.8 mm (SE Regi onal Climate Cente r). Vegetation is minimal in the area, as it is primaril y open range-land, but consist of hardwoods and saw grass.

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196 5.5 Methodology The precipitation calibration conc eptual methodology and theory is illustrated in Figure 5.4. Water collect ion sites were set up above Legend Cave for precipitation and inside of it for dripwa ter. Collection for all water samples was conducted weekly from October 27, 2007 to November 7, 2008, except when a lack of dripwater or precipitatio n prevented sample collection. Precip Amount (mm)B)Paleoprecipitation Reconstruction Time (ka)18Oc A)Calibration Study H2O collectors for 18O of meteoric water (mw) Onset Hobo Weather Station tipping rain gauge (Precip Amount) Meteoric WaterRotating water collector (18Odw)& plate collecting calcite ( 18Oc) Speleothem stable isotopes ( 18O) give precip amount changes + +18OcPrecip Amount+18OmwPrecip Amount+-+-1 4 + 18Odw18Oc-+18Omw18Odw+-+-2 3 Meteoric H2O vs. Amount Calcite 18Ovs. Amount Meteoric 18Ovs. Drip 18ODrip 18Ovs. Calcite 18O Past speleothem calcite 18Oc should reflect Precip Amount vs. Time Drill at high resolution to achieve annual interannual comparison 18Oc‰ = Precip Amount Figure 5.4 Calibration conceptual model. A) H2O collected from precipitation on surface with rain gauge to record amount. Dripwater collected using rota ting collector. To prevent isotopic fractionation (evaporation) of the collected water, a 0.5 cm layer of paraffin oil was placed in each dripwater vial and the rain collector, in accordance with IAEA instruct ions for collecting water fo r isotopic analysis. Water and calcite samples were collected weekly for one year. B) Conceptual theory behind calibration study applied to speleothem calcite 18O to determine past precipitation amounts from calibration.

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197 5.5.1 Cave Dripwater Collection A dripwater collection device was placed inside Legend Cave at the back of the main room at the terminus of the main passage (Figure 5.3). To facilitate regulated collection and prevent unnecessary disturbance of the cave environment from excessive visitation, an automated water colle ctor was custombuilt to collect dripwater from a stalactite in the cave. The automated water collector is comprised of industrial marine-grade polymer plastic, military grade connectors two 6-volt batteries, and a sealed circuit box. The collector contains a funnel with 8 drain holes and 8 numbered (#1-8) high-density polypropy lene collection vials ( 55 mL), and was programmed to cycle between a drain hole (2 hrs 55 mins) and a numbered collection vial (5 mins) continually for one week (168 hours) before rotating to the next numbered vial (Figure 5.5). This cycle was repeated to allow for sample collection and changing of the batteries once every 2 months. This programming was based on initial dripwater observations and volume/rat e calculations for three months prior to collector installation to determine the maximum size vial needed to collect dripwater without overflowing. A 0.5 cm la yer of Paraffin oil was placed in each vial to prevent evaporation and subseque nt fractionation of the dripwater samples (IAEA instructions). The collect or was placed under a rapid drip with sufficient spacing away from any other dripping stalactites in the terminal chamber of the cave (Figure 5.3 and 5. 5). Samples were collected on a weekly basis for just over one year, sealed, and refrigerated at 4C until analyzed.

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198 Figure 5.5 Water collector setup in Legend Cave. (A) Automated water collector with battery supply (6V in yellow dry box) and circuit board (in gray dry box). (B) Closeup of water collector with collection vials in place in the Legend Cave. (C) Water collector, HOBO datalogger, and drip location used in Legend Calibration study. To pr event isotopic fractionati on (evaporation) of the dripwater, a 0.5 cm layer of paraffin oil was placed in each dripwater vial in accordance with IAEA instructions for collecting water.

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199 An Onset Hobo datalogger measuring 30-minute relative humidity and temperature readings was in stalled at the dripwater collection site in Legend Cave to record the cave’s climate stability (equilibrium calcite deposition and evaporative conditions) (Figure 5.5). Thes e readings were converted to weekly averages for each week of water collecti on. Additionally, modern calcite forming from stalactite dripwater was precipitat ed during the periods when the drip was over a drain hole onto a burnished gla ss plate beneath the water collector. This calcite was meant to be co llected from the dripwater site after one year for isotopic analysis (Mickler et al. 2004), but too little calcite was precipitated during the period of study for analysis. 5.5.2 Precipitat ion Collection Surface precipitation amount was recorded using a Log Series Tipping Bucket Rain Gauge, with an accuracy of 0. 0254 cm/tip. This data was collected by a Campbell Scientific, Inc. CR10 data logger, which measured rainfall amounts every 15 minutes and provided hourly rainfall totals (Figure 5.6). Data was downloaded every three months using PC206W 3.3 software. A separate Belfort Instruments Rain Gauge was modified by removing the data logger and tipping bucket, and replac ing them with a 4000 mL Erlenmeyer flask placed inside directly under the funnel tip to collect precipitation. A 0.5 cm layer of paraffin oil was placed in the fl ask to prevent evaporat ion of the collected precipitation for analysis. This was plac e directly beside t he data logging rain gauge and collected weekly for the year (Fi gure 5.6). Samples were kept sealed and refrigerated at 4C until analyzed. Pr ecipitation occurred throughout the

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200 collection period, with at least 2 wee ks out of each month producing rainfall, yielding 41 weeks of total data. Figure 5.6 Precipitation collection setup. Rain gauge, data logger, and rainfall collection setup above Legend Cave.

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201 Due to problems with intermittent equi pment failure additional rainfall data was obtained from two SWFWMD rain gauge stations located within close proximity to Legend Cave. The two stations were Lecanto (10 km N) and Ringold (7 km S), and both collect 15 minute rain fall using the same program parameters as the cave site rain gauge. Data from the three rain gauges were compiled into daily amounts then averaged between the th ree stations before converting to weekly totals corresponding to water collection dates. 5.5.3. Stable Isotope Analysis A total of 192 Legend Cave dripwa ter, surface meteoric water (precipitation), and precipitated calcite ( powdered) samples were analyzed at the University of South Florida Center for Geochemical Analysis (USF CGA). Analysis was done on a combined Isotope Ra tio Mass Spectromet er (IRMS) built around a Thermo Finnigan Delta V 3 kV mass spectrometer with 5 Faraday collectors which can measur e H,C,N,O and S stable isotope ratios. A peripheral Finnigan Gasbench II was used for the online preparation of gas samples for both 18O and 2H analysis, which were meas ured by equilibration methods (based on Epstein & Mayeda 1953). For 18O, 200 L of sample water (40 g calcite) was equilibrated for 24 hrs with CO2 (3,000 ppm in balance of He). For 2H 200 L of sample water was equilibrated for ~8 hrs with 2H (10,000 ppm in balanced He) in the presence of a Pt catal yst. The isotopic ratios of equilibrated CO2 and 2H were measured by continuous flow IRMS and were normalized to the Vienna PeeDee Belemnite (VPDB) scale using two internal standards: VEEN and HTAMP. These standards are calibra ted to the Vienna Standard Mean Ocean

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202 Water (VSMOW) scale using IAEA standards GISP2, VSMOW2 and VSLAP (VEEN 18O, 2H = -13.17‰, -96.80‰; HTAMP 18O, d2H = +15.05‰, +40.50‰). Average precision for all measur ements was better than 0.1‰ ( 18O) and 1‰ ( 2H), respectively. The amount-weighted mean annual 18O and 2H values for precipitation were calculated using the follo wing equation (Zhang et al. 2007): (5.1) and deuterium-excess ( d -excess) for the precipitati on data was calculated using the equation from Dansgaard (1964): d = 2 H 8 18 O (5.2) 5.5.4 Synoptic and Mesoscale Climate Data Meteorological data, in cluding precipitation amount, humidity, and wind speed/direction were obtained for Brooksvill e, FL from the National Oceanic and Atmospheric Administration (NOAA) Qualit y Controlled Local Climatological Data (QCLCD) database to provide insights into how synoptic conditions may influence the precipitation amount and its isotopic. Unit ed States surface daily weather maps giving 500-millibar height contours, color-shaded temperature, and wind readings at 7:00am EST were obt ained from the NOAA Daily Weather Map database (Appendix H). Surfac e temperature for 200708 was obtained from the NOAA Chinsegut Hill weather station and reported in degrees Celsius.

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203 Storm convection height was obtained through the NOAA National Climatic Data Center (NCDC) by download ing archival NEXRAD Level II data for selected dates from the KT BW station in Tampa, FL. The raw radar data was imported into GR2Analyst program for anal ysis, wherein the base reflectivity (BR), which measures radar return from storm intensity up to 100 km radius, was plotted on an altitudinal axis in feet. Int ensity is measured in dBZ (decibels of Z, where Z equals reflected energy), with higher values indicating higher rainfall amounts. This data was collected to determine how convection height may influence the isotopic the is otopic composition of rain fall, thereby potentially providing insight regarding convective pr ocesses and their effect on speleothem isotopic values. 5.5.5 Data Analysis The local meteoric water line (LMWL) was calculated using least squares regression of the precipitation 18O and 2H data. To determine the predominant controls on precipitation, 18O values were regressed against the two most common influential parameters, precipitat ion amount (cm) and temperature (C). Cave dripwater 18O and 2H were regressed and plotted against the LMWL to determine their relationship with precip itation controls. D euterium-excess was plotted against time to test for se asonality and variable moisture sources. 5.6 Results and Discussion Legend Cave exhibited a temperat ure range between 22.9 and 23.5C, varying less than 0.6C throughout the per iod of data collectio n (Figure 5.7). The

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204 average annual cave temperature (23. 29C) also corresponds well with the average annual surface temperature (25. 56C) recorded at Chinsegut Hill (~12 km SE) during the period of data collection, and is likely slightly cooler due to air exchange between the cave and surface du ring seasonal fluctuations in temperature. Relative humidity was also above 95%, exhibited by readings at or near 100% all year, indicated by the satu ration of the data logger’s sensor. These conditions provide for a stable climate in which to perform a dripwater calibration study by minimizing evaporation and va riable temperature influences within the cave that could affect the isotopic com position of the dripwater (Gascoyne 1992). Figure 5.7 Temperature data for Legend Cave. Total for the year of data collection, exhibiting less than 0.6C variability. Surface temperat ure is shown for nearby Chinsegut hill. 0 5 10 15 20 25 30 0 5 10 15 20 25 30 35 40 Legend Cave Temp CLegend Surface Tmep CWeekLegend Cave & Surface Temperature Legend Surface Temp Legend Cave Temp

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205 5.6.1 Precipitation Isotopic Data The isotopic composition of the prec ipitation collected above Legend Cave ranges between -9.12‰ and 1.15‰ for 18O (‰ VSMOW) and -59.82‰ and 18.59‰ for 2H (Figure 5.8). Characteristic of Florida, the commonly dry months of April and May (Winsberg 2003) yielded less rainfall, with only 2 weeks of each month having precipitation events. Howeve r, the majority of the other months produced rain almost every week, prov iding a representative sampling of precipitation distributed thr oughout the year to develop a local meteoric water line (LMWL). Figure 5.9 shows the Local Meteor ic Water Line (LMWL) derived from the precipitation 18O and 2H values, defined by a least square regression as: 2H = 6.77( 18O) + 9.13 (r2=0.83) n=41 (3) (5.3) This is plotted next to the Global Me teoric Water Line (GMWL), as defined by Rozanski et al. (1993), in Figure 5.8 and has a lower slope and y-intercept common to tropical and subtropical r egions (Sharp 2007). The LMWL slope (6.77) and y-intercept (9.13) also reflec t the likelihood of post-rainfall evaporative processes affecting the precipitation 18O values (Kendall and Coplen 2001; Lachniet and Patterson 2006). It differs slight ly from that found by Onac et al. (2008) of 5.63 during 2006-2007 for this same area, and also differs slightly from the value shown for south Florida by Kendall and Coplen ( 2001) of 5.43 from river water isotopic analysis, which is mo re susceptible to evaporation. A major cause of the LMWL slope value differ ence is a single tropical storm event, Tropical Storm Fay (TS Fay), in August 200 8, which when removed from the data set causes a shift in the slope to 6.2, which is much closer to the expected

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206 average for a region where most of the precipitation is derived from the Gulf of Mexico (Kendall and Coplen 2001). -70 -60 -50 -40 -30 -20 -10 0 10 20 30 -10 -8 -6 -4 -2 0 2 2H (‰ VSMOW) 18O (‰ VSMOW) WeekLegend Precipitation Isotopes Precip 2H Precip 18O Figure 5.8 Legend Cave precipitation 18 O and 2 H values. Measured from 10/2007 to 11/2008. In the bottom right corner is TS Fay, which varies greatly from the other rain events in its isotopic composition.

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207 5.6.2 Controls on Isotopic Co mposition of Precipitation Several controls on the isotopic compos ition of precipitat ion could account for the variability and range of 18O and 2H values, with temperature, amount of precipitation, lati tude, continental/distance rai nout, storm trajectory, and local vapor source dominating or combining to produce the local precipitation signal (Dansgaard 1964; Price et al. 2008). In Fl orida, several of these, including altitude, rainout (continental and altit ude), and latitude can be eliminated based on its geographic and climatic se tting. Florida exhibits lo w elevation, which would discount the altitude effect, and being a narrow peninsula, it is unlikely rainout/continental effects would alter t he isotopic composition of rainfall. Its Figure 5.9 Legend Cave LMWL. The LMWL for precipitation above Legend Cave, with a slope of 6.77, is shown against the GMWL. TS Fay is also notated at the bottom left corner. LMWL = 2H = 6.77* 18O + 9.13 R = 0.8258 GMWL = 2H = 8.17* 18O + 11.27 -70.00 -60.00 -50.00 -40.00 -30.00 -20.00 -10.00 0.00 10.00 20.00 30.00 -10.00-8.00-6.00-4.00-2.000.002.002H (‰ VSMOW) 18O (‰ VSMOW) Legend Precipitation LMWL Legend Cave Precip GMWL Legend LMWL GMWL TS Fay

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208 subtropical latitude also minimizes the rainout and temperature effects seen at higher latitudes (Sharp 2007). The broad range within the 18O and 2H values indicates multiple controls that could a ccount for the variability, and the most likely causes are temperature, amount of precipitation, varying vapor sources, and storm trajectory/convection processes. As seen in Figure 5.10, no significant relationship (r2=0.0009) exists between average weekly temper atures and precipitation 18O values. This relationship is expected in subtropica l Florida with its st eadily high average annual temperature and less distinct seas onality compared to temperate regions where temperature more strongly influences rainfall’s isotopic signal (Rozanski et al.1993; Welker 2000; Sharp 2007). y = -0.0144x -2.3196 R = 0.0009 -10 -8 -6 -4 -2 0 2 152025303518O (‰ VSMOW) Temperature (C)Legend Rainfall vs Temperature Effect Figure 5.10 Legend Cave rainfall vs temperature. Plotted versus temperature for the year, it yields no correlation with an r2=0.0009.

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209 The amount effect is a dominant control on the precipitation 18O signal in the study area (Figure 5.11), with a significant negative correlation between amount of prec ipitation and 18O values (r2=0.41). The amount effect is known to dominate in tropical regions (Lachniet et al. 2004; Sharp 2007) and therefore is expected to affect Florida’s humid subtr opical climate to some degree, but does not entirely account for the 18O variations, with vapor source, seasonality, and convective processes also likely influenc es (Rozanski et al. 1993; Zhang et al. 2007; van Beynen et al. 2007). y = -0.2791x -1.5602 R = 0.41-10 -8 -6 -4 -2 0 2 0510152018O (‰ VSMOW) Precipitation (cm)Legend Rainfall vs Amount Effect Figure 5.11 Legend Cave rainfall vs amount. Plotted versus amount (cm) for the year, it yields strong correlation with an r2=0.41, and shows the amount effe ct is a dominant control on the isotopic composition of rainfall.

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210 Onac et al. (2008) found little corr elation between precipitation amount and precipitation 18O values for 2006-07 in the study area, but saw evidence of the amount effect in their summer rainfa ll. Lachniet et al. (2004) showed that thunderstorms in Central America have a strong negative relationship between rainfall amount and isotopic composition of precipitation. Holm gren et al. (2001) obtained similar findings while investigating convective storms in Africa. Larger storms have stronger convection (Flori da’s summer), therefore creating more precipitation at higher alti tudes due to a higher condens ation line (Figure 5.12). Consequently, the resultant precipitation is isotopicall y depleted. Larger storms, such as those convective and convergent storms in Florida during summer, also lift more water vapor into the atmosphere, leading to higher amounts of precipitation, a relationship clearly show n in Figure 5.12. This relationship is investigated in more detail for this area in Section 5.5.4. Winter low-pressure systems normally have lower condensati on heights, although they create a similar scenario, but usually produce less intense rainfall amounts and are shorter in duration. Using regression analysis, it is diff icult to identify seasonality in the precipitation isotopes, with some weeks having lower precip itation amounts with isotopically depleted 18O values. In part, this could be attributed to both precipitation intensity and duration driving the amount effect relationship. Nevertheless, the amount-weighted mean 18O for summer-fall (June-October) of -4.63‰ and winter-spring (November-May) of -2.99‰ shows a distinct difference in the 18O values, overall attributable to t he amount effect. In the study area,

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211 winter storms often produces less rainfa ll (~2.4 cm/week) that is isotopically enriched compared to the higher amounts (~ 5.5 cm/week) of isotopically depleted rainfall produced from summe r storms. This seasonal isotopic characteristic is expected in monsoonal climates where drier, cooler winters produce less rainfall (Clark and Fritz 1997). Figure 5.12 Conceptual model of amount effect. Diagram illustrating the amount effect in the study area, wherein storms with higher conv ection height and more rainfall produce more negative (depleted) 18O values. The red circle on the graph indicates less negative values and a lower condensation height, and the blue indicates the opposite.

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212 5.6.3 Deuterium Excess Deuterium excess ( d -excess) values for precip itation near Legend Cave ranged between 1.4‰ and 31.5‰ for each week of collection, with an average of 12.4‰ during the 2007-08 year (Figure 5.13). The d -excess value of precipitation depends upon the relative humidity and wate r temperature of its origin water source and evaporative kinetic fractionation, with higher values usually indicating increased evaporative processes (K endall and Coplen 2001; Sharp 2007). However, d -excess values are also complexly affected by temperature, air mass source, and mixing contributions from multiple sources of vapor depending upon the geographic location of t he study area (Sharp 2007). The d -excess values for each week were calculated from Equation 5.2 and plotted against rainfall and temperature weekly averages for the study area. No significant correlations were found for either parameter, sim ilar to the findings of Onac et al. (2008). However, seas onality is evident with the increased d excess values in summer compared to winter, likely due to increased evaporation and frequency of deep convective activity during this summer season (Figure 5.13). As previously discu ssed, the precipitation 18O values show intensification due to seasonality in combination with the amount effect to a ffect the isotopic composition of precipitation in west-central Florida. Du ring drier periods when the water table is lower, such as dry winte rs, faster infiltration may also reduce evaporation, thereby further enhancing the amount effect in the area (AlvarezZarikian et al. 2005).

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213 Figure 5.13 Deuterium excess plot. D-excess values from the Legend Cave rainfall over the year of collection. The blue dots circled on the lower left represent winter-spring d-excess, whereas the red dots in the upper right corner show the summer-fall precipitation d-excess, thus illustrating the effects of season on the d-excess values. 5.6.4 Cave Dripwater Isotopic Data Isotopic values for cave dripwa ter ranged between -2.84‰ and -3.6‰ for 18O (‰ VSMOW) and -6.78‰ and -36.75‰ for 2H. The range in the 18O is less than 1.0‰ for the ent ire year, with an annual aver age of 3.19‰ (Figure 5.14). The 2H values are more variable, an d the average is -14.82‰. Compared to the average dripwater isotopic values reported by Onac et al. (2008) for the 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 Dec-07Jan-08Mar-08May-08Jun-08Aug-08Sep-08Nov-08d -excess (‰)MonthsLegend Cave Precipitation d excess Winter-Spring d-excess Summer-Fall d-excess

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214 previous year at Legend Cave ( 18Oavg =3.08‰, 2Havg = -14.82‰), the 2007-08 values fall within +0.11‰ ( 18O) and -0.04‰ ( 2H) of their reported values, illustrating minimal variation over a mult i-year period in the study area. Figure 5.14 shows the dripwater 18O and 2H values plotted against the LMWL and GMWL. There is no significant correlation between the dripwater 18O and 2H, as they lack enough variability to achi eve an accurate MWL slope, instead plotting in a cluster intersecting the LM WL and GMWL, mainly falling below the LMWL (Figure 5.14). This implies mixing of meteoric waters in the epikarst zone during percolation and may represent the complex nature of Florida’s eogenetic karst; wherein, even thin overburden contai ns significant frac ture porosity and matrix permeability to allow homogenizati on of percolating waters with stored waters in weeks to months (Florea and Vacher 2007). The dripwater 18O values vary considerably less than the precipitation 18O values, but the 18O annual average (-3.19‰) co mpares well with the precipitation 18O annual amount-weighted average (-3 .93‰). The dripwater’s annual average 18O is slightly enriched and is attributable to several possible causes: (1) slight evaporation at the surface during summer rain events and (2) several anomalous isotopically-deplet ed storms which affected the amountweighted average precipitation 18O values. In Florida, often intense tropical storms and winter storm events account for more recharge than most summer monsoonal rainfall events, thereby havi ng a greater influence on the groundwater isotopic signature over time (Marti n and Gordon 2000; Florea and Vacher 2007). Additionally, the arithmetic mean of the precipitation 18O values is -2.69‰,

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215 which is enriched ~1.3‰ from the amount-weighted average 18O value and indicate a slight bias towards depleti on, common with this calculation method (Onac et al. 2008). Confounding events (i.e. intense tropi cal storm and winter frontal systems) with varying isotopic signatures may acc ount for the variation between the 200708 amount-weighted precipitation 18O average and the average dripwater 18O. Regardless, it can be cons trued that the dripwater 18O annual average of 3.19‰ is likely represent ative of a homogeneous mixing of both isotopically enriched and depleted percolating met eoric waters, along with stored Precip LMWL = 2H = 6.77* 18O + 9.13 R = 0.8258 GMWL = 2H = 8.17* 18O + 11.27 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 -10-8-6-4-2022H (‰ VSMOW) 18O (‰ VSMOW) Legend Cave LMWL & Dripwater Isotopes Legend Cave Precip GMWL Cave Drip MWL Legend Precip LMWL GWML Figure 5.14 Legend Cave 18 O and 2 H values. Plotted against the LMWL and GMWL, showing the values cluster in a tight pattern because of mixing in the epikarst prior to reaching the cave.

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216 groundwater, within the epikarst and repr esents the long-term average of the regional precipitation isot opic signal. The similarity of the average annual dripwater 18O values between the 2007-08 and 2006-07 (Onac et al. 2008) periods further illustrates the attenuation of the precipitation isotopic signal by the homogeneous mixing of epikars t water over time. 5.6.5 Synoptic Weather Data and Climate Change Florida’s weather is affected by storm events and low-pressure systems originating in the Atlantic Ocean, Gulf of Mexico, and sometimes low-pressure systems moving west to east from the Pacific Ocean across the continental United States (Kendall and Coplen 2001). The three main types of storms that occur are frontal (warm air meets cool air and is pushed upward), localized convectional (daytime heat warms mo ist air and lifts it), and convergent (opposing sea breezes meet over warm land and are sent aloft) and all potentially create intense storms (Wins berg 2003). A comparis on of the study area’s different precipitation isotopic val ues to longand short-term synoptic and mesoscale influences lends clarity to how different atmospheric processes affect the isotopic signature of the precipitation and possibly c ontributes to that of the dripwater as well. Several large, intense storm events during the 2007-08 year in the study area provided the opportuni ty to examine surfac e weather data and storm convection height to distinguish how t he source, direction, and atmospheric conditions are manifested in the precipitation 18O values (see Appendix G). Due to data collection and proce ssing limitations, a small r epresentative data set of

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217 two distinctly different winter storms c haracterized by high intensity and rainfall amounts were examined for convec tion height and synoptic data. The weeks ending on 12/7/07 and 12/21/ 07 both contained isolated storm events producing distinctly diffe rent precipitation amounts and 18O values. The storm on 12/3/07 produced an average of 0.144 cm of rainfall with a 18O value of -0.11‰ ( 2H= 4.58) from a passing cold front moving southeast from the southern continental U.S. across the Gulf of Mexico and had a maximum convection height of 10,500 ft (3,200 m) and dBZ of 35 over the study area (Figure 5.15). In contrast, the storm on 12/16/07 produced 7.48 cm of rain with a 18O value of -4.88‰ 2H= -28.62‰) from a low-pressure system moving eastward across the southern U.S. and Gulf of Mexico with a maximum convection height of 49,000 ft (14,935 m) and dBZ of ~60 (Figure 5.16). The substantial difference in convecti ve height of these two storms clearly illustrates how the 18O values of the precipitati on reflect the amount effect derived from storm intensity and durati on. Commonly, seasonal changes in monsoon intensity invoke the amount effe ct in tropical and subtropical areas causing an isotopic deplet ion of precipitation 18O values. However, the data show intense, high-rainfall convective storms during the winter, as seen the week of 12/21/08, also have depleted 18O values produced by the amount effect (Lee and Fung 2008).

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218 Figure 5.15 Radar for 12/3/07. NEXRAD radar image of rain storm on 12/3/07 producing 0.144 cm of rainfall and the 18O=-0.11. Scale on the left reflects amount of rainfall, with intensity and amount increasing with positive values (NOAA 2009).

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219 Figure 5.16 Radar for 12/21/07. NEXRAD radar im age of an intense rain storm on 12/21/07 producing 7.48 cm of rainfall with 18O=-4.88. Scale on the left reflects amount of rainfall, with intensity and amount increasing with positive values (NOAA 2009). The most significant excursion in the 18O and 2H values occurred during TS Fay ( 18O= -9.12, 2H=-59.82, Figure 5.9). TS Fay crossed the peninsula four times between August 18 and 23, 2008 setting a record for number of landfalls (NOAA 2009). Figure 15.17 shows the path and average rainfall amounts of TS Fay. Some areas received up to 64 cm ( 25 in) of precipitation, with Melbourne breaking its 50-year record rainfall fo r 28 cm (11 in) in 24 hours (NOAA 2009).

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220 The study area received its hi ghest amount of daily and w eekly rain from TS Fay on August 22, 2008, with a daily total of 14 cm and a weekly total of 18 cm. TS Fay also produced the most depleted 18O (-9.12‰) and 2H (-59.82‰) values for 2007-08 in the record, which is comm on for tropical storms and hurricanes due to increased convection and more int ense rainfall (Lawrence et al. 2004). Figure 5.17 TS Fay radar. Radar data showing rainfall amounts from Tropical Storm Fay in 2008. The yellow line indicates the path the storm traveled over. This intense storm p roduced the most depleted isotopic values, with a 18O= -9.12 and 2H= -59.82 (NOAA 2008).

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221 5.6.6 Teleconnection Influences During the collection period, ENSO has been in a more negative (cool-La Nia) phase which usually produces less ra infall in Florida, especially in the winter (Hagemeyer 2006). This agrees with the decreased rainfall amounts (drought period) the region has experi enced over the last 3 years (SWFWMD 2009). The other major influence on precip itation is the NAO, which oscillated from a more positive NAO index (warm phase) in late 2007 to a deeper negative index (cool phase) during mid-2008. An earlier study (Hagemeyer 2006) found a negative NAO combined with a positive ENSO index produces more rainfall in west-central Florida. T he in-phase nature of EN SO and NAO during 2007-08 may explain why Florida is ex periencing drought conditions. The influence of these atmospher ic-ocean phenomena on the isotopes of the speleothem derived from cave dripwate rs cannot clearly be surmised. As the collection period represents a drought, the is otopic signal of the drips (which is fairly homogenous) provides the signal for such a climate state. However, to complete the interpretation, I would need a period of enhanced precipitation with a negative NAO and El Nio characteristics to determine whether the overall isotopic signature of the drips changed. With another y ear of water collection underway, that information may still be provided in the near future, but unfortunately is beyond the scope of this study. That being stated, van Beynen et al. (2007) showed a strong relationship between a positive NAO index and more negative speleothem 18O values, which will be further discussed in the interpretation of teleconnection influences in Chapter 6.

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222 5.6.7 Applicability to Speleothem Calibration Based on the conceptual model present ed in Figure 5.4, by determining the relationship between the isotopic sign al of rainfall in an area, its amount, and the isotopic signal produced in dripwa ter precipitating modern calcite, a calibration of rainfall amount to calcit e isotope values can be established and extrapolated back in time (Cobb et al. 2007). In this study, the isotopic signal of rainfall is recorded in the cave dripwa ter and subsequently should be transferred to speleothem calcite (Burns et al. 2002; Fleitmann et al. 2003; van Beynen and Febberollio 2006). Both Lachniet et al. (2004) and Holmgren et al. (2001) used this relationship to interpret variations in the 18O isotopic composition of their speleothem records. Therefore, the 18O of cave calcite can quantitatively record the hydrological parameter of precipit ation amount when it is the dominating influence of isotopic signal, such as in the study area. By also determining the teleconnection influences acting on the areas modern rainfall, these too can be reconstructed in the past based on amounts calculated from speleothem calcite 18O values. Additional years of data co llection, along with m odern calcite, are necessary to more quantitatively assess this relationship, but a qualitative relationship between speleothem 18O values and precipitation, wherein more negative (depleted) values equate to higher rainfall amounts, can be assumed. The extension of this chapter’s findings will be incorporated into Chapter 6 to calibrate the isotopic values derived from a high-resolution speleothem record collected from a nearby cave.

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223 5.7 Conclusions The results of this study show the amount effect strongly controls the isotopic composition of pr ecipitation in west-central Florida. A seasonal difference is also evident in the 18O values of precipitation between summer and winter periods for 2007-08, with dominatin g influences from convection height and vapor source exerting the most in fluence on the average annual isotopic signal of precipitation. Studies have established that the isotopic composition of the average annual precipitation at mid-latitude sites are reflected in cave dripwaters (see Yonge et al. 1985 in Fuller et al. 2008; Ca ballero et al. 1996; Williams and Fowler 2002). The average isotopic composition of precipitation in subtropical westcentral Florida is also accurately reflec ted in the isotopic composition of cave dripwater. Even an event with a significant isotopic excursion from the average annual value and high precipitat ion amount, such as TS Fay was not discernable in the dripwater isotope values, indi cating either a rapid homogenization of percolating water after a st orm event, lack of significant recharge from the event (Florea et al. 2007), or a evidence of its is otopic signature in the cave dripwater. While this study encompasses only a single location’s precipitation and dripwater isotopic data, the weekly resoluti on sampling provides data for a variety of precipitation events, in cluding winter storm fronts, convective summer storms, and even a tropical storm. Despite the variety of isotopi cally-heterogeneous precipitation sources th roughout the 2007-2008 collect ion period, the cave dripwater isotopic composition is indi cative of a homogenization of meteoric

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224 water in the epikarst and provides a 18O value representative of the annual average mean isotopic compositi on of meteoric rainfall. An application of this relationshi p indicates dripwater precipitating speleothem calcite in the area could prov ide a reliable indication of long-term changes in average annual isotopic values of precipitation caused by significant regional climate changes affecting precip itation sources, am ounts, and season which is then manifested in the spel eothem calcite isotopic signal. Although discerning extreme hurricane events in t he resultant speleothem isotopic record may be difficult, ma jor climate shifts affecti ng the area on annualto decadalscales should be robustly reflected with depleted isotopic values indicating wetter periods and enriched isot opic values representing of drier periods. 5.8 Chapter Acknowledgements I would like to thank all those who assisted me with the water collector, water collection, and setup. Special than ks to my Dad (Sid) and Joann Sullivan for their time, energy, technical expertise in electronics, and ingenuity to help design and build the water collector. I also would like to thank Colleen Werner and Withlacoochee State Forest for permi ts and cave access. Thanks to Zac Atlas for assistance with running samples. I would like to recognize Dr. Jonathan Wynn for his last-minute assistance with verifying and interpreting the isotope datahe is a lifesaver! Dr. Jennifer Collins and Sara Giunta were instrumental in the surface weather data mining and compil ation and deserve much thanks! This study was funded by SWFWMD.

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225 5.9 Chapter References Budd, D and Vacher, HL, 2004, Matrix Pe rmeability of the confined Florian Aquifer, Florida, USA. Hydrology Journal 12: 531-549. Burns, S.J., Fleitmann, D., Mudelsee, M., Neff, U., Matter, A., Mangini, A. 2002. A 780-year annually resolved record of Indian Ocean monsoon precipitation from a sp eleothems from south Oman. Journal of Geophysical Research 107 (D20): 4434-4443. Caballero, E., Jimenez de Cisneros, C., and Reyes, E. 1996. A stable isotope study of cave seepage waters. Applied Geochemistry 11(4): 583–587. Clark, I, and Fritz, P. 1997. Enviro nmental Isotopes in Hydrology. Lewis Publishers: New York. 328 pp. Cobb, K.M., Adkins, J.F., Partin, J.W., and Clark, B. 2007. Regional-scale climate influences on temporal variations of rainwater and cave dripwater oxygen isotopes is northern Borneo. Earth and Planetary Science Letters 263: 207-220. Craig, H, 1961, Isotopic Variations in Meteoric Waters. Science 133: 1702-1703. Dansgaard, W. 1964. Stable isotopes in precipitation. Tellus 16: 436-468. Epstein, S., and Mayeda, T. 1953. Variation of O18 content of waters from national sources. Geochimica et Cosmochimica Acta 4: 213-224. Fleitmann, D., Burns, S.J., Mudelsee, M., Neff, U., Kram ers, J., Mangi ni, A., and Matter, A. 2003. Holocene forcing of the Indian monsoon recorded in a stalagmite from southern Oman. Science 300: 1737–1739. Florea, L.J. 2006. Architecture of ai r-filled caves within the karst of the Brooksville Ridge, west-central Florida. Journal of Cave and Karst Studies 68(2): 64-75. Florea, L.J., and Vacher, H.L. 2006. Springflow Hydrographs: Eogenetic vs. Telogenetic Karst. Groundwater 44(3): 352-361. Florea, L.J., Vacher, H.L., Donahue, B., and Naar, D. 2007. Quaternary cave levels in peninsular Florida. Quaternary Science Reviews 26:1344-1361. Florea, L.J. and Vacher, H.L. 2007. Eogenet ic Karst Hydrology: Insights from the 2004 Hurricanes, Peninsular Florida. Groundwater 45(4): 439-446.

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226 Ford, D.C. and Williams, P. 2007. Karst Geomorphology and Hydrology : Unwin Hyman: Winchester, Massachusetts, 320 p. Fuller, L., Baker, A., Fairchild, I.J., Spotl, C., Marca-Bell, A., Rowe, P., and Dennis P.F. 2008. Isotope hydrology of dripwaters in a Scottish cave and implications for stalagm ite palaeoclimate research. Hydrology and Earth System Sciences 12: 1065-1074. Gascoyne, M. 1992. Palaeoclimate determi nation from cave calcite deposits. Quaternary Sciences Reviews 11: 609-632. Ghosh, P., and Brand, W.A. 2003. Stable isotope ratio mass spectrometry in global climate change re search. International Journal of Mass Spectrometry 228: 1-33. Hagemeyer, B.C., and Almeida, R.J. 2005. Toward greater understanding of inter-seasonal and multi-decadal variabi lity and extremes of extratropical storminess. In: Florida, Preprints, 16th Symposium on Global Change and Climate Variations. San Diego, CA, American Meteorology Society, P5.9 (on CD-ROM). Hagemeyer, B.C. 2006. ENSO, PNA and NAO Scenarios for extreme storminess, rainfall and temperatur e variability during the Florida dry season Preprints, 18th Conference on Climate Variability and Change, Atlanta, GA, American Meteorol ogical Society, CD -ROM P2.4. Harmon, R.S., Schwarcz, H.P., Gasco yne, G., Hess, J., and Ford, D. 2004. Paleoclimate information from speleothems: The present as a guide to the past In : Studies of Cave Sediments: Physical and Chemical Records of Paleoclimate, I.D. Sasowsky and J.E. Mylroie, (eds.). Klewer: New York, p. 199-226. Holmgren, K., Moberg, A, Svanered, O. and Tyson, P.D. 2001. A preliminary 3000-year regional temperature reconstruction for South Africa. South African Journal of Science 97: 49-51. Jordan, CL. 1984. Florida’s weather and climate: Implications for water. In : Water Resources Atlas of Florida Fernald, EA, Patton, DJ (eds), Institute of Science and Public Affairs, Florida state University, 18-35. Kelly, M.H. 2004. Florida river flow patterns and the Atlantic Multidecadal Oscillation. Southwest Florida Water Management District, Ecological Evaluation Section, p. 80.

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227 Kelly, M.H., and Gore, J.A. 2008. Florida river flow patterns and the Atlantic multidecadal oscillations. River Research and Applications 24: 598-616. Kendall, C., and Coplen, T.B. 2001. Distr ibution of oxygen-18 and deuterium in river waters across the Untied States. Hydrological Processes 15: 13631393. Lachniet, M.S., Asmerom, Y., Burns, S., Patterson, W.P., Polyak, V. and Seltzer, G.O. 2004. Tropical response to the 8200 yr cold event? Speleothem isotopes indicate a weakened early Holocene monsoon in Costa Rica. Geology 32: 957-960. Lachniet, M.S., and Patterson, W.P. 2006. Use of co rrelation and stepwise regression to evaluate physical cont rols on the stable isotope values of Panamanian rain and surface waters. Journal of Hydrology 324: 115-140. Lawrence, J.R., Gedzelman, S.D., Dex heimer, D., Cho, H., Carrie, G.D., Gasparini, R., Anderson, C.R., Bo wman K.P., and Bigger staff, M.I. 2004. Stable isotopic composition of water vapor in the tropics. Journal of Geophysical Research 109, D06115. Lee, J. and Fung, I. 2008. “Amount effe ct” of water isotopes and quantitative analysis of post-condensation processes. Hydrological Processes 22 (1): 1-8. Martin, J.B., and Gordon, S.L. 2000. Surface and groundwater mixing, flow paths, and temporal variations in the chemical composition of karst springs. In : Sasowsky, I.D. and Wicks, C.M. Groundwater flow and contamination transport in carbonate aquifers Rotterdam, Netherlands, pp. 65-92. NOAA. 2009. Accessed at www.noaa.gov. Onac, B.P., Pace-Graczyk, K., and Atudire i, V. 2008. Stable isotopic study of precipitation and cave drip water in Florida (USA): implications for speleothem-based paleoclimate studies. Isotopes in Environmental and Health Studies 44(2): 149-161. Price, R.M, Swart, P.K., and Will oughby, H.E. 2008. Seasonal and spatial variation in the stabl e isotopic composition ( 18O and D) of precipitation in south Florida. Journal of Hydrology 358:193-205. Randazzo, A.F., and Jones, D.S., eds. 1997. The Geology of Florida: Gainesville Florida University Press of Florida, 327 p.

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228 Rozanski, K., Araguas-Araguas, L. and Gonfiantini, R. 1993. Isotopic patterns in modern global precipitation In : Climate Change in Continental Isotopic Records. P.K. Swart, K.C. Lohmann, J. McKenzie and S.Savin, (eds). Geophysical Monograph 78, Americ an Geophysical Union, pp. 1-36. Scott, T.M., Means, G.H., Meegan, R.P., Me ans, R.C., Upchurch, S., Copeland, R.E., Jones, J., Roberts, T., and Willet, A. 2004. Springs of Florida. Florida Geological Survey Bulletin no. 66. Fl orida Geological Survey: Tallahassee, FL. Sharp, Z. 2007. Principles of Stable Isotope Geochemistry Pearson Prentice Hall: Upper Saddle River, NJ, p. 344. Sun, H. and Furbish, D.J. Annual precipit ation and river discharges in Florida in response to El Nioand La Nia-s ea surface temperature anomalies. Journal of Hydrology 199: 74-87. van Beynen, P.E. and Febberollio, P.J. 2006. Stable isotope record of precipitation and cave water for Indian Oven Cave, NY. Hydrological Processes 20: 1793-1803. van Beynen, P.E., Asmerom, Y., Polyak, V., Soto, L., Polk, J.S., 2007a. Variable intensity of teleconnections during the Late Holocene in Subtropical North America from an isotopic study of speleothem from Florida. Geophysical Research Letters 34: L18703, doi:10:1029/2007GL031046. van Beynen. P.E., Soto, L., Pace-Graczyk, K., 2007b. Paleoclimate reconstruction derived from speleothem strontium and 13C in Central Florida. Quaternary International doi:10:1016/j.quai nt.2007.03.019. van Beynen, P.E., Soto, L., Polk, J., 2008. Variable calcite deposition rates as proxy for paleo-precipitation determinat ion as derived from speleothems in Central Florida. Journal of Cave and Karst Studies 70 (1): 1-19. Welker, J.M. 2000. Isotopic ( 18O) characteristics of weekly precipitation collected across the USA: an initial analysis with application to water source studies. Hydrological Processes 14: 1449-1464. White, W.A. 1970. The Geomorphology of the Florida Peninsula Florida Bureau of Geology, Bulletin No. 51, 164 pp. Williams, P.W., and Fowler, A. 2002. Re lationship between oxygen isotopes in rainfall, cave percolation waters and speleothem calcite at Waitomo, New Zealand. Journal of Hydrology 41(1): 53-70.

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229 Winsberg, MD. 2003. Florida Weather University of Florida Press: Gainesville, Florida. Yonge, CJ, Ford, DC, Gray, J and Schw arcz, HP. 1985. Stable Isotope Studies of Cave Seepage Water. Chemical Geology 58: 97-105. Zhang, X., Liu, J., Sun, W., Huang, Y. and Zhang, J. 2007. Relations between oxygen stable isotopic ratios in pr ecipitation and releva nt meteorological factors in southwest China. Science in China Series D-Earth Sciences 50(4): 571-581.

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230 Chapter 6 High-resolution Late Holocene Paleoclimate in Florida 6.1 Chapter Preface The primary goal of this chapter is to present high-resolution speleothem isotope data showing climate variability fo r Florida and place it within the context of existing regional and global paleoc limate records influenced by major atmospheric-oceanic teleconnection processe s. This chapter is an extension of previous speleothem paleoclimate work done in Florida, and connects together the calibration study from Chapter 5, as well as the cave sediments study from Chapter 4 to provide a holistic view of climate change in Florida and its major causal factors. 6.2. Abstract Teleconnections between the tropical-s ubtropical regions of the Americas during the last millennia only recent ly began to receive attention from paleoclimatologists. Here, high-resolution, precisely dated speleothem record is presented spanning the last 1,500 years fo r the Florida peninsula. Comparisons between speleothem 18O values and Gulf of Mexico marine records reveal a strong connection between the Gu lf region and the terrestri al subtropical climate. Warmer sea surface temperatures corre spond to enhanced evaporation, leading

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231 to more intense atmospheric convection in Florida, and thereby modulating the isotopic composition of rainfall above t he cave. Trace element analysis confirms this process. These regional signals in c limate extend from the subtropics to the tropics, with a clear match between t he speleothem signal and the titanium record from the Cariaco Basin and Peruvian ice core 18O values. These latter connections appear to be driven by changes in the mean position of the Intertropical Convergence Zone. Time series analysis of the 18O values reveals significant multidecadal periodicities in the record, which are evidenced by comparison to ENSO, AMO, NAO, and PDO reconstructions, with the multidecadal influences (NAO and PDO) including the ITCZ, demonstrating the closest agreement. 6.3 Introduction Investigating long-term climate change at high-resolution (annual to interannual) is fundamental for the diffe rentiation of natural and anthropologic influences. Glacial periods receive cons iderable attention in paleoclimate research, and provide high-resolution reco rds of high-latitude climate variability and its causations during those periods. Ho wever, recent attention has focused on Holocene (the last ~ 10,000 years) climate variability and atmospheric teleconnections affecting the tropical and subtropical latitudes (Barber et al. 1999; deMenocal et al. 2001; Bond et al. 2001; van Beynen et al. 2004; Mayewski et al. 2004; White 2004).

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232 Several anomalous climatic ev ents occurred during the Holocene, including the Medieval Warm Period (MW P ~A.D. 800-1300), Little Ice Age (LIA ~A.D. 1400-1850), 8.2 ka cooling event, and several cyclic millennial-scale cooling events, such as Bond Cycles, similar to those occurring during glacial times (deMenocal et al. 2001, Marchitto and deMenocal 2003; Lachniet et al. 2004a; Rohling and Palike 2005; Siddall et al. 2006). Recent evidence points to global atmospheric-oceanic te leconnections as the contri buting factors for these climate anomalies; however, their e ffects on subtropical and tropical paleoclimates are still unclear (Lachniet et al. 2004a, 2004b). Synchronous changes in sea-surfac e temperatures (SSTs) between tropical marine records (deMenocal et al. 2001) and abrupt climate changes recorded in the Greenland ice cores (Rohling and Palike 2005) indicate a possible connection between the highand low-latitude North Atlantic. Understanding the timing, m agnitude, and causal mechani sms of abrupt regional climatic changes in the North Atlantic tropics and their connection to the other latitudes may allow a more comprehensiv e approach to predicting future climate change. One of the most under-researched areas of climate change is the subtropical western North Atl antic, which should serve as a transition zone of oceanic and atmospheric teleconnections between the tropics and high latitudes. While research in this area has progressed over the last few decades, overall relatively little is known about how local paleoclimates vary and the extent to which regional climate connections come into play. Although studies have begun to emerge from the terrestrial subtr opics of North Americ a, including the

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233 Gulf of Mexico (Poore et al. 2003; Meckler 2006; Richey et al. 2007), only a few long-term, low resolution studies from lake s (Alvarez Zarikian et al. 2001; Grimm et al. 2006) provide a window into Florida’s changing climate. Several speleothem based papers have appeared on Florid a’s climate covering the last few millennia (van Beynen et al. 2007a-b; van Beynen et al. 2008). Speleothems provide reliable records of climate change fo r a variety of regions and are robust recorders of climate change (Dorale et al. 1992; Burns et al. 2002; Fleitmann et al. 2003; Polyak et al. 2004). The climate of Florida is complex and varies with latitude. The panhandle is dominated by winter rainfall from c ontinental fronts passing over the region, while the southern part of the state is ma inly influenced by summer convectional rainfall. West-central Florida has a comb ination of both influences, with 60% of the rainfall occurring in the summer, alt hough this dominance fluctuates (Jordan 1984). The surrounding Gulf of Mexico (GOM) and Atlantic Ocean have a moderating influence on Florida’s climate, advecting moisture towards the peninsula and influencing interann ual precipitation patterns. Both the North Atlantic Oscillation (NAO) and El Ni o-Southern Oscillation (ENSO) can affect winter prec ipitation levels on the peninsula (Enfield et al. 2001; Hagemeyer 2006). Although the nor thward shift of the Inter-tropical Convergence Zone (ITCZ) does not directly cover Florida, it affects the region indirectly through its influence on the NAO (Rajagopalan et al. 1998). It is suggested changes in tropi cal Atlantic heating ma y affect the northern

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234 hemisphere atmospheric circulation, particula rly the North Atlant ic High, which is known to affect Florida di rectly (Winsberg 2003). In this study, a high-resolution speleothem record is provided to investigate the regional c limate over the last 1,500 years, including possible teleconnections between the North Atlantic, Gulf of Mexico ( GOM), and Pacific Ocean. This period is of great interest as it encompasses two geologically-abrupt shifts in climate, the Little Ice Age (L IA) and the Medieval Warm Period (MWP). 6.4 Study Area 6.4.1 Brooksville Ridge Cave The speleothem was collected Brooksville Ridge Cave (BRC), in Hernando County, Florida (Fi gure 6.1). This cave is situated in the Brooksville Ridge section of the Ocala Arch (R eeder and Brinkmann 1998; Florea et al. 2007). BRC has only one entrance opened by quarrying around 50 years ago and is the longest air-filled cave in Hernand o County with over 1 km of surveyed passage. The cave contains a series of chambers connected by low, tight crawls with several highly decorated rooms c ontaining hundred of active formations (Figure 6.2). It possesses relative humidity levels >98% and a constant temperature near 22C. 6.4.2 Geologic and Hydrologic Setting The bedrock is primarily the Eo cene Ocala and Suwannee Limestones, which are unconformably overlain by the Hawthorn Group, carbonates interspersed with siliclastics and phosphorite redeposition (Scott 1997). In some

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235 places, the bedrock is topped with severa l meters of Pleistocene-aged quartz sands, but the majority of the study area consists of exposed limestone outcrops and little soil cover. Several infiltration point s in the form of sinkholes and sinking streams are present in the landscape, but very little standing wa ter occurs due to rapid drainage to the subsurface. Figure 6.1 Location of BRC in Hernando County, Fl orida. Black circle indicates approximate location; no further detail provided due to cave’s sensitivity and private ownership. 0714 3.5 KilometersStudy AreaMap by Jason Polk Data Source: Florida Geographic Data Libray NAD_1983_HARN-ZONE_17NLegend Hernando County BRC

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236 6.4.3 Climate and Vegetation The climate above BRC has a mean annu al temperature of 21.3C and mean annual precipitation of ~1350 mm. Mean maximum monthly temperatures occur in August (27.6C) and the minimu m in January (13.6C). August also possesses the monthly maximum prec ipitation with 219 mm and October the least with 48.8 mm (SE Regional Climat e Center). The area is upland hammock, with thin soil cover and significant ex posures of bedrock. Vegetation mainly consists of flatwood and mixed hardw ood forests (Watts and Collins 2008). This type of environment incl udes longleaf pine ( Pinus palustris) slash pine ( Pinus elliottii ) turkey oak ( Quercus laevis ), live oak ( Quercus virginiana), saw palmetto (S erenoa repens ), wire grass ( Aristida sp.), ericads, species of Holly ( Ilex ), forbs, and various scrub vegetation. Soil cover ma inly includes the Candler fine sand series (Watts and Collins 2008).

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237 Figure 6.2 Map of BRC. Arrow indicates location where speleothem was collected. 6.5 Methodology 6.5.1 234U-230Th Chronology Adhering to methods described by Po lyak and Asmerom (2001), uraniumseries (234U-230Th) isotope measurements were performed at the Radiogenic Isotope Laboratory, University of New Mexico. 50 to 20 0 mg of clean carbonate powders for 6 dates were dissolved in nitric acid and spiked with a mixed 229Th-233U-236U spike to eliminate propagation erro r. U and Th were co-precipitated using FeOH3 and separated using conventional anion exchange chromatography. The U and Th isotopic measurements were performed on a Micromass Sector 54 multi-collector thermal ionization mass spectrometer

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238 (TIMS). The TIMS analyses utilized a single i on-counting Daly multiplier in peak jumping mode. Both U and Th isotopes are measured on the ion-counting Daly multiplier with abundance sensitivity in the range of 20 ppb at one mass distance in the mass range of U and Th, requiring ve ry little background correction, even for samples with large 232Th content. Multiplier dark noise is approximately 0.12 counts per second. 233U/236U ratio (1.0046) was used for fractionation correction for U analyses. Th fractionation in TIMS is negligible. A CRM145 U isotope standard was meas ured with every batch obtaining the conventionally accepted 234U value of -37.09 0.23 ‰ (n=82). 234U= ([234U/238U sample/ 234U/238U secular equilibrium]-1) x103 where, 234U/238U secular equilibrium is equal to the ratio of t he decay constants of 238U and 234U ( 238/ 234). U and Th procedural blanks were in the range of 5-10 picograms and therefore have no effect on ages. Typical analytical uncerta inties are in the range of 0.2% for U isotope composition, with si milar or somewhat lower precision for Th, depending on the age and size of the sample measured. The ages were corrected for initial 230Th (see Table 6.1 for 230Th/232Th ratios used). Linear interpolation between dates was used to create an age model for each sample based on U-series dating results. 6.5.2 Stable Isotope Analysis Oxygen stable isotope ratios (16O and 18O) were measured for 1,200 calcite samples drilled at discrete 100 micron interval s using a computer-aided triaxial micromill system fitted with a Dremel tool and 0.24 mm dental bit. Approximately 50 m of calcite was we ighed for each sample and reacted with

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239 anhydrous phosphoric acid at 70C in indivi dual reaction vessels of a Keil III carbonate-extraction system coupled to a ThermoFinnigan DeltaPlus XL mass spectrometer. Precision (2 ) was monitored by daily analyses of the NBS-19 standard and was within <0.1‰ for both ox ygen and carbon. Values are reported in standard ‰ notation relative to Vienna Peedee belemnite (V-PDB). 6.5.3 Trace Element Analysis Trace elements were analyzed at 1 mm in tervals (total of 120) along the growth axis of BRC03-02 using laser ablation combined with an inductivelycoupled plasma mass spectrom eter (ICP-MS). The stalagmi te was first cut into 2 cm by 2 cm thin sections using a Buehler Isomet Low Speed saw. Cuts were made diagonally across the growth axis of the stalagmite to allow for overlap and reproducibility during laser ablation. Ea ch section was polished on a Buehler Handimet Roll Grinder with 240, 320, 400, and 400 grit paper. Final polish for each section was achieved using 1 mi cron aluminum-oxide powder on a glass polishing plate. The samples were t hen sonicated to remove any residual material with a Branson 2510 sonicator for 10 minutes each. Samples were dried at 65C for 48 hrs prior to analysis. A Cetac LSX 213 Nd-YAG laser coupled to a Perkin Elmer Elan DRC II quadrupole ICP-MS was used to analyze the elements 26Mg, 44Ca, 88Sr, and 138Ba. Surface contamination was abl ated for several seconds before measurements were taken. Operating c onditions in the ICP-MS were 1500 W RF Power with Nebulizer and lens voltage opt imized by standard routines within the operating software calibrated by counts per second (cps) on Mg, In and U. Oxide

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240 and double charges produced by the plasma were minimized to less than 3%. The laser was operated at 100% power in pulse mode. Spot size was 100 microns and counting times were 1 minute on background and 1 minute on sample spot. Pure He carrier gas introduced the sample to the ICP-MS. Calibration for the elements was done using the NIST 612 standard. Measurements were calculated by dividi ng each element’s cps with respect to that of 44Ca and multiplied by 1000 to give wei ght % ratios (Cruz et al. 2007). 6.5.4 Petrographic Analysis Petrographic analysis of spel eothems was undertaken using a Nikon Stereoscopic Zoom Microscope SMZ1500 to investigate the occurrence of hiatuses or recrystallization. The s peleothems were polished with a 3000 grain diamond puck to remove any surface defects that could obscure the examination of the sample. Only the period of intere st, the last 1500 years of deposition, was examined for each speleothem. 6.5.5 Time Series Analysis Time series analysis was performed on the oxygen isotopes for BRC03-02 using the Multi-Taper Method (MTM) (Thomson 1982); Lomb-Scargle Fourier transform (LS) (Lomb 1976; Scargle 1982); and wavelet analysis (Torrence and Campo 1998). By utilizing these different tools, prominent periodicities are revealed in the record in both time and frequency space. The sample meets all necessary criteria for robus t time series analysis to ex tract decadal to centennial cycles, which include (1) approximate annual resolution, (2) adequate temporal

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241 length (over 1,000 years), (3) absolutedated age model, and (4) coherence with the targeted variables (DeLong et al. 2009, in preparation). Spectral analysis using the LS method allows for the analysis of unevenlyspaced time series data and assumes ages and dating errors are known. This Fourier transform was performed in MatLab. Higher variance and the lack of statistically-established confidence inte rvals are products of using an uneven time step, but also provide resolution for higher frequencies that may be lost during constant time step interpolation methods. Spectral analysis using MTM (G hil et al. 2002) required a linear interpolation of the time interval pr oduce a constant time step (dT). A Monte Carlo simulation to determine depositi on rate within dating error produced an average sediment rate of 1.234 0.1423 ye ars/sample (Figure 6.3). Tapers were established and a Nyquist frequency of 2.5 was used based on the constant linear interpolation. Due to the deposition rate and sampling interval being slightly variable over time, the data were detr ended, prewhitened (removes white noise correlations), and the mean was remov ed before processing. A first-order autoregressive model (AR(1)) was used to test against red noise as the null hypothesis to establish confidence interval s for the spectral powers (CI) (Schulz and Mudelesee 2002). Wavelet analysis was performed on the detrended 18O time series to show significant periodicities and t heir occurrence in time-frequency space (Torrence and Campo 1998). The same constant time step of 1.234 years/samples was used. Wavelet analysis with Morlet mother wavelet and zero

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242 padding was performed with CI set at 95% and an estimated red noise background using AR(1). Figure 6.3 Monte Carlo simulation of BRC03-02. Performed with ages assuming constant sediment ation rate and U/Th analytical p recision errors are normally distributed. Frequency distribution of delta T with a top age of zero produced t of 1.2340.1423 years/sample. Slopes define deposition rate within errors.

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243 6.6 Results and Discussion 6.6.1 Petrography For the BRC03-02 speleothem there was no evidence of hiatuses or recrystallization layers found over the last 1,500 years of deposition. BRC03-02 consists of extremely pure translucent calcite, where even growth layers are extremely difficult to discern (Fi gure 6.4). The speleothem has no color suggesting minimal organic compounds within the calcite and detrital Th levels are extremely low.

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244 Figure 6.4 BRC03-02 speleothem. Dated layers indicated by black ovals. The clear, clean calcite provides low-error U/Th dates and an age of ~1,400 years.

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245 6.6.2 Chronology and Stable Isotopes The 230Th-234U dates show the sample grew nonlinearly based on deposition rates (see van Beynen et al 2008), but continuously (if linearly regressed r2= 0.96), over the past 1,500 y ears (Table 6.1) and a linear interpolation between dates was used to construct an age model. The sample is clean, pure calcite and contains minimal detrital Th, thus the age corrections were minor (Figure 6.4). The age model wa s applied to the various isotopic data derived from the speleothem calcite. T he high-resolution (annual to sub-annual) isotopic record from BRC03-02 provides the opportunity to examine well-dated nuances in climate duri ng the Late Holocene for the study area. Table 6.1 U/Th dates from BRC03-02. Due to the purity of the BRC03-02 calcite and the absence of discernable layering (Figure 6.4), a Hendy (1971) te st was impractical. The sample was collected from the deep interior of t he cave, which exhibits a constant temperature and high relative humidity (> 95%), thereby negati ng the effects of kinetic fractionation from rapid CO2 degassing or dripwater evaporation (Hendy Sample mm from top238U (ppb)232Th (ppt)230Th/232Th (atomic ratio x 1 0 6 ) 234Ui234Um 230Th/238U Uncorrected Age (yr B.P.) Corrected Age (yr B.P. ) 1BRC03-0210890 3.429 2184 2.068.3 2.768.3 2.70.004 0.0003367 32347 33 BRC03-0220964 4.139 3202 2274.6 3.374.6 3.30.005 0.0003500 36475 38 BRC03-02411093 4.546 3212 1768.8 6.468.8 6.40.005 0.0003550 29524 32 BRC03-02621103 4.583 2183 15770.7 6.470.7 6.40.008 0.0006851 66805 70 BRC03-0284921 7.4170 3118 872.8 7.472.8 7.40.013 0.00081,350 851,236 102 BRC03-02100818 4.363 2300 1575.9 3.875.9 3.80.014 0.00061,424 561,377 61crustal material at secular equilibrium, using the crustal 232Th/238U value equal to 3.8. All errors are absolute 2 BRC03-02 U/Th CALCULATED AGESU-series ages corrected using initial 230 Th/ 232 Th atomic ratio of 4.4 x 10 6 50%, which is the average value for a

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246 1971). However, the assumption of isot opic equilibrium deposition of BRC03-02 is supported by two additional factors: (1 ) no correlation over time between the 18O and 13C values (r2= 0.03) and (2) a close agreement with another speleothem isotopic record, BRIARS04-02, from a nearby cave (van Beynen et al. 2007a). The two speleothems show very similar stable isotope trends, thereby suggesting they the primary c ontrol on their isotopes is the regional climate of central Florida. Close co llinearity between speleothem s from different caves provides support for the assumption that isotopic fractionation did not occur within each cave (Dorale et al. 1992). BRIA R04-02 does have a greater range in values compared to BRC03-02, likely due to less mixing of percolation waters above Briar Cave as they travel through the epikarst (van Beynen et al. 2007a). However, BRC03-02 was selected for this study because it possesses the cleaner calcite, hence lower dating errors which are important for increasing confidence in the results of the time series analyses. A study of dripwaters in numerous ca ves in the region (Onac et al. 2008) found their isotopic composition matches the annual amount-averaged value of precipitation above the cave, which supports the suitability of caves in the area for paleoclimate studies. Chapter 5 also supports these findings and illustrates the close relationship between the aver age annual amount-weight ed precipitation 18O and that of cave dripwater in near by Legend Cave. The amount effect (see Chapter 5; Paulsen et al 2003; Sharp 2007) strongly dom inates the precipitation 18O signal in the area, thus likely also modulating the isotopi c composition of speleothems, with seasonality playing a lesser role. A previous study (van

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247 Beynen et al. 2007a) also suggested that c hanges in the isotopic composition of the precipitation falling above the caves is the main controlling factor of variability in the speleothem isotopic values in th is area. The main focus of the discussion below is on the variability within the BRC03-02 18O values within the context of teleconnection processes that influence mo isture availability and precipitation amounts in the study area. The speleothem 18O values show a maximum range between -4.09‰ and -5.46‰ during the last 1,500 years (Figure 6.5), with a few distinct anomalous excursions in the isotopic va lues near the MWP (~800 to 1200 yr BP) and LIA (~250 to 500 yr BP). Variation also exists in the BRC03-02 13C values, ranging from -10.57‰ to -12.54‰, which is somewhat minimal for speleothem carbon isotopic shifts, and may reflect the more stable climate of the Holocene and attenuated signal of the dripwater perco lating through the bedrock (Baker et al. 1997). However, during the LIA, the 13C values coincide with the 18O, showing drier conditions contributing to less abundant vegetation and a possible increased contribution from C4 plants (see Chapter 4; van Beynen et al. 2007b). Isotopic excursions in the 13C are less pronounced during the MWP (Figure 6.5). A large shift in the 13C towards less negative (enriched) values around 100 years BP is likely attributed to anthropogen ic deforestation. The area was heavily logged and mined for phosphate near the turn of the cent ury until it became State Forest land in recent times (Figure 6.6).

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248 Figure 6.5 The BRC03-02 isotope record. The LIA and MWP and are clearly illustrated. Figure 6.6 Photo of the area near BRC in 1940. This photo shows heavy deforestation during phosphate mining and logging. Today, the Withlacoochee State Forest owns the surrounding land and the forest has replenished (from http://smathersnt 13.uflib.ufl.edu/fta2/viewer.htm).

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249 6.6.3 Local Proxy Influences & Isotope Interpretation The study by van Beynen et al. ( 2007b) found that the NAO had a major influence on seasonal shifts of precipit ation with the ENSO and the PDO to a lesser extent. However, this previous study covered only the last 600 years, whereas this new record spans the la st 1500 years. While the short term fluctuations are somewhat explained by changes in the isotopic composition of precipitation caused by t he NAO (van Beynen et al. 2007a), longer-term trends in oxygen isotope values show increased va riability from to 900 to 1500 yr BP (Figure 6.5) and may involve the influence of other local and teleconnection processes. It should be noted though that the short-term oscillations from the last 600 years persist during this longer-period change. A broad period of more negative oxygen isotope values coincides with the Medieval Warm Period (MWP), which likely affected precipitation amounts and changed the annual average temper atures within caves, t hereby resulting in an overall decrease (depletion) in the s peleothem isotopic values. Lower calcite oxygen isotope values are caused by preferential depletion in 18O of the water flowing over the speleothem (Gascoyne 1992). Cooler temperatures occurred prior to and after the MWP, which expl ains the overall higher oxygen isotope values. The total difference in the av erage oxygen isotope values of BRC03-02 between the LIA and MWP is ~0.8‰; using the relation of -0.24 ‰/1C, this would be a ~3 C shift from maximum warm th to cold over the last millennia (Friedman and O’Neil 1977). Such a change is along the lines of temperatures suggested by Mg/Ca records from the Pi gmy Basin (Richey et al. 2007), and

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250 likely an overestimation, but nonetheless indi cate major shifts in climate during these two periods. However, it shoul d be noted that the contribution from changing temperature is present in the long-term average of the cave calcite isotopic values, while the short-term oscillations are being influenced by precipitation above the cave which is discussed below. 6.6.4 Trace Elements Trace element analysis yielded suffi cient counts of Sr (~14 x 103), Mg (~2 x 104), Ca (2 x 106), and Ba (~4 x 103) to produce values for each element in enough abundance to create a chronol ogical record of vari ability. The ratios of Sr/Ca, Mg/Ca, and Ba/Ca are plott ed in Figure 6.7 against the BRC03-02 18O data. Sr/Ca and Mg/Ca ratios (x 103) range from 2.86 to 10.12 and from 7.03 to 10.36, respectively. Ba/Ca ratios (x 103) are lower ranging from 0.96 to 3.46. It is observed that the Sr/Ca and Ba/Ca show a positive relationship throughout most of the record, whereas Mg/Ca values are antiphased with both Sr/Ca and Ba/Ca. Together, all three trace element reco rds are in close agreement with the BRC03-02 18O data, with the Sr/Ca and Ba/Ca having an inverse relationship compared to the Mg/Ca in relation to the 18O record (Figure 6.7). Abrupt changes in the trace element ratios closely track those of the oxygen isotopes throughout most of the record, with a few exceptions around 600-800 yr BP and 1,400 yr BP. Part of t he explanation for these offsets is a difference in resolution, as the trace el ements are drilled at millimeter increments providing decadal to multidecadal resolution, whereas the 18O isotopes are at 100 micron (annual to sub-annual) resolution. This also would affect the ages

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251 attributed to the trace element values, as they are averages of longer time steps comprised within 1 mm of calcite, wh ich could encompass several years. Figure 6.7 BRC03-02 trace element data. It is compar ed to the BRC03-02 oxygen isotope record.

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252 In following with the interpretation of the oxygen isotope data as a proxy for precipitation amount, trace element values correspond with more negative (depleted) 18O values indicating wetter condit ions above the cave. For BRC0302, this equates to low Sr/Ca and Ba/C a and high Mg/Ca during drier periods, with high Sr/Ca and Ba/Ca and low Mg/Ca dur ing wetter periods (Table 6.2). This relationship can be attributed to resi dence time of seepage waters, where increased contact with the bedrock during drier periods allows for increased dissolution (Roberts et al. 1998; Desmar chelier et al. 2006). In Florida groundwater, Plummer (1977) demonstrated that low Mg/Ca ratios equate to shorter residence time during wetter conditi ons. In Briar Cave, van Beynen et al. (2007b) suggested that Sr/Ca increases with enhanced soil productivity from wetter conditions, thereby increasing root respiration and subsequent carbonic acid formation, further allo wing soluble cations to be removed from the soil and bedrock. The relationship between Sr/Ca, Ba/Ca, and Mg/Ca further support the interpretation of the BRC03-02 18O data; however, the low resolution prohibits more in-depth analysis for seasonal cycles or time-series analysis. Table 6.2 Trace element model. Simple interpretation of the trace element data with respect to oxygen isotopes. BRC03-02 18O Mg/Ca Sr/Ca Ba/Ca Wetter _ + + Drier + + _

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253 6.6.5 Time Series Analysis Time series analysis using LS, MT M, and wavelet analyses provides insight to periodicities within the BRC03-02 18O data with certain caveats. Each of these spectral analysis tools provides a slightly different method by which the data are analyzed, thereby producing a mo re comprehensive overview of the cycles present in the record by allowin g for comparison between interpolated and uneven time intervals. The LS periodogram indicates strong spectral peaks at ~11 years, ~60-80 years, and quasi-centennial cycles (~180200 years), which may be amplitude modulations of multidecadal periodicities similar to those observed in the NAO, PDO, AMO, and sunspot cycles (Figure 6. 8). These are not established within confidence intervals due to the uneven ti me step, but the data show skill in the multidecadal and centennial periodicities within the chronology error of the Useries dates. The quasi-centennial periodicities may reflect phasing of sunspot cycles, which are modulated by the Suess Cycle (~210 years) and Gleissberg Cycle (~90 and ~172 years) (Burroughs 2003; Fairchild et al. 2006; van Beynen et al. 2007b).

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254 MTM analysis reveals bands of significant (90% CI) periodicities occur at decadal (~20-30, 30-40, 50-60 yr) frequencies (Figure 6.9). Significant powers also exist in the 2-6 year bands, but these high frequencies are likely smoothed out by time interpolation (Nyquist frequen cy = 2.5) and as white noise, as is the 11 year cycle. Centennial frequen cies are also present at significant CI, as seen visually in the 18O record, but the short length of the record combined with the interpolation of the time interval causes broader spectral pow er peaks, which are difficult to pinpoint to a certain centennial periodicity and may be artifacts of the multidecadal frequencies overlapping. Figure 6.8 Lomb-Scargle plot. Smoothed over 3 bands of the uninterpolated time series of the BRC03-02 oxygen isotope record normalized by st andard deviation. Red boxes highlight peaks with strong spectral powers (major peaks above the mean).

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255 Figure 6.9 Multi-taper spectrum. MTM of the BRC0302 oxygen isotopes (tapers=5, resolution=3) of the interpolated ( t=1.2341 years/sample) time series with CI tested against a AR(1) background with significant (>90%) pe riodicities highlighted (gray boxes). Based on LS and MTM analyses combined with the known influences affecting Florida’s precipitation ov er time, the interannual and decadal frequencies likely correspond with ENSO’s 2-7 year periodicity and decadal variability (Cane 2005) and the PDO’s ~15-25 and 50-70 year cycles (Rasmussen et al. 2006). Solar forcing is present in the reco rd at the 11 year frequency (Schwabe solar cycle), which also comprises the multidecadal Gleissberg Cycle of 70-100 years when amp lified. The multidecadal bands could

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256 represent various phases of established NAO (interannual to multidecadal), AMO (60-80 years), and ITCZ cyclicity (Kerr 2005; Hurrell 2003; Rajagopalan et al. 1998), although coherence among the timing of these cycles requires further cross spectral analysis. Discerning and separating the multidecadal frequencies in the BRC03-02 18O data is difficult due to their close periodicities and sometimes common harmonic behaviors, in addi tion to uncertainties in the age models for each respective record. Wavelet analysis of the BRC03-02 18O data temporally deconvolves the peak frequencies and shows how periodicities vary over time, thus indicating whether periodicities are a function of time, frequency, or individual occurrences Torrence and Compo 1998). The wavelet spectrum (Figure 6.10) displays increased decadal variability around 250 to 400 and 800 to 1100 yr BP, An overall increased variance in the decadal band (30-80 years) exists throughout the record until ~1200 yr BP. The quasi-centennial shows a str ong variance between 800 and 1100 yr BP, coinciding with the multidecadal cycle and wetter MWP conditions. There appears to be pulsing (recur consistently together) of the phases of the multidecadal and quasi-centenni al during the MWP. Anot her interesting period is between 450 and 600 yr BP when the mult idecadal and quasi-centennial bands coincide again during a wetter interval prio r to the onset of th e LIA (Figure 6.10). Several other anomalous periods of high va riance in the multidecadal band are seen throughout the record, appearing to show pulses on a centennial basis, with the caveat that they fall outside of the cone of influence or show little significance

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257 due to the time interpolation. The in tricate linkages and interrelationships between the various aforementioned clim atic periodicities, their related teleconnections, and their effect on prec ipitation as recorded by BRC03-02 18O values are further evaluated below thr ough comparisons with ot her climate proxy reconstructions (Figure 6.11). Figure 6.10 BRC03-02 wavelet analysis. Wavelet analysis with Morlet mother wavelet and zero padding. The thick black line indicates the con of influence and data underneath it should be considered with caution. The thin black cont our lines indicate the 95% CI assuming a AR(1) spectrum.

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258 Comparisons between the BRC03-02 oxygen isotope record and other local, regional, and global paleoclimate and teleconnection records are based on visual matches between the various peaks and troughs, especially the major changes, within each record, as well as the known teleconnection periodicities and those within the speleothem record (using the time-series analysis data). Figure 6.11 Proxy record map. Map depicting areas where ot her proxy records for the last 1,500 years p rovide proxy comparisons for the BRC0 3 -02 record from both tropical and subtropical locations (map by author).

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259 6.6.6 Local Climate Influences The GOM is a key source of moisture for Florida’s precipitation (Winsberg 2003). Currently, high resolution records of climate change for the study area region are mainly derived from marine s ediments in the GOM. Richey et al. (2007) and Meckler (2006) both worked in t he Pigmy Basin of the northern GOM, with the former finding close corresponde nce between their estimates of SSTs and those of the eastern Caribbean (Winte r et al. 2000; Watanabe et al. 2001), thereby suggesting the GOM and the tropical Atlantic have a strong teleconnection. A comparison between the speleothem record and Richey et al. (2007) GOM sea surface temperature ( SST) estimates and Mg/Ca ratios (from G. ruber species) (Figures 6.11 & 6.12) show close agreement, albeit with minimal asynchronies around 200 and 600 yr BP, which are likely attributable to difference in dating techniqu es between the records. The MWP climate caused the most pronounced shift in both records towards warmer SSTs and wetter conditi ons. Generally, as annual SSTs increase, evaporation woul d be enhanced, augmenting at mospheric convection, and thereby leading to larger storms and pr ecipitation forming at higher altitudes. Such a shift would decrease (deplete) the isotopic composition of the precipitation falling above the caves in Florida, as was found in Chapter 5. Richey et al. (2007) found that solar vari ability likely affected the SSTs of the GOM on a centennial scale from corre sponding SST lows and four sunspot minima during the LIA, which could possi bly also have affect ed the NAO (Ogi et al. 2003), thereby subsequently influencing pr ecipitation in Florida. Spectral

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260 analysis of the BRC03-02 18O record supports quasi centennial-scale variability affecting precipitation am ounts and the possibility of solar forcing mechanisms. Figure 6.12 Local proxy record map. Comparison between the BRC03-02 18 O data and the Richey et al. (2007) Mg/Ca and SST data show a close agreement and point to large scale mechanisms affecting the GOM and Florida region. Blue and brown lines indicate wetter and drier, respectively.

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261 Meckler (2006) provides a Ti record fo r a marine core from the same basin as Richey et al. (2007). Her study suggest ed that Ti increased in the core during higher rainfall in the Mississippi Basin. As with Florida, the source of this moisture is the GOM. As with the Richey et al. (2007) Pigmy Basin record, the close synchrony between the Florida spel eothem record and the Meckler (2006) Ti record (Figure 6.13) suggests the BRC03-02 18O interpretation that increased evaporation causes more convection in Florida has merit. Meckler (2006) suggests changes in solar intensity affe cting GOM SSTs, with the ITCZ being responsible for changes in moisture availability in the area. The close relationship of the BRC03-02 18O and Pigmy Basin records suggest that teleconnections influencing the GOM also strongly affect precipitation variability in Florida. A record from Little Salt Spring (L SS), a sinkhole lake in west-central Florida, also indicates that varying pr ecipitation affected groundwater recharge over the last 1500 years (Alvarez-Zar ikian et al. 2005). Comparison of the BRC03-02 and LSS ostracod 18O data show similar trends in climate change affecting precipitation (Figur e 6.13). The coarse resolution LSS record shows that variations in precipitation amount and s ubsequent water table changes affected the 18O values of the LSS water. Pe riods like the MWP saw increased precipitation, as seen in the agreement between the LSS and BRC03-02 18O records. These changes in climate are attributed to centennial-scale atmospheric-oceanic climate forcing inte ractions affecting Florida (AlvarezZarikian et al. 2005) and possibly relate to periodicities shown in the higherresolution BRC03-02 18O record.

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262 Figure 6.13 Proxy record comparisons. (A) Comparison between the BRC03-02 18O data and LSS 18O data showing a close match (Alvarez-Zarikian et al. 2005). (B) The Pigmy Basin Ti record also closely agrees with the BRC-03-02 data (Meckler 2006). Blue and brown lines indicate wetter and drier, respectively.

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263 The southeast (SE) precipitat ion index developed by Stahle and Cleaveland (1992) provides the most direct record of precipitation variability related to teleconnection influences for t he last ~1000 years in the southeastern United States. Although no locations from Fl orida were directly used in the treering reconstruction of precipitatio n, a comparison of the BRC03-02 18O data to the SE precipitation index clearly shows the relations hip between precipitation amount and the speleothem record, wher ein higher rainfall amounts correspond to more negative (depleted) 18O values (Figure 6.14) This close agreement suggests influences from the North Atl antic may also be affecting Florida’s precipitation. The Stahle and Cleavela nd (1992) record is based on spring (March-June) rainfall records, and consequ ently they found little connection with their data and ENSO or the NAO; however a strong correlation with the North Atlantic High (NAH) was observed. Dec adal and interannual anomalies in the position of the NAH significantly affect rainfall over the southeastern United States during the spring and summer, theref ore extending this influence to westcentral Florida is plausible, although not straightforward based solely on this comparison due to the possibility of other influences. A comparison of the BRC03-02 18O to Jennings Cave sediment carbon isotopes from west-central Florida is found in Chapter 4 shows the close relationship between precipitation amount and vegetation response at a more localized spatial scale. The cave sediment 13C isotopes support the interpretation of BRC03-02 18O data and also clearly show the related

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264 vegetation response to precipitation va riability during the LIA and MWP in the study area. Figure 6.14 SE Precipitation proxy comparison. Comparison between the BRC03-02 18O data and the Southeast Precipitation Index 20-point running mean shows close agreement (Stahle and Cleaveland 1992), demonstrating the regional con nections between BRC and the southeastern US, which derives much of its moisture from the GOM. Blue and brown lines indicate wetter and drier, respectively. 6.6.7 Regional Teleconnection Influences Van Beynen et al. (2007b) previous ly demonstrated that the NAO is influential on Florida’s climate, more so than ENSO and the PDO. Rajagopalan et al. (1998) found the NAO was strongly in fluenced by the tropical Atlantic. Consequently, it is prudent to invest igate whether close connections exist

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265 between this speleothem-derived Florida climate record and the low latitude climate proxies of the Am ericas region. If there is indeed agreement, then the spatial extent of these teleconnections c an be determined for the low latitudes of the Americas. Regarding the influence of the tropical Atlantic on the northern Atlantic, Rajagopalan et al. (1 998) stated that “Changes in tropical Atlantic heating (e.g. deep convection in the ITCZ and the Amazon) may affect the northern hemisphere atmospheric circulation in much the same way tropical Pacific heating anomalies does.” (p. 3969) raising the issue of how the ITCZ and tropi cal Atlantic may affect the study area region’s climate through modulation of the NAO. One possibility is the position of the NAH east of its mean extreme, which c an direct moist air in to Florida (Stahle and Cleaveland 1992), while anot her is the ITCZ’s influence on convection in the GOM. Increased solar intensity during t he MWP raised GOM SSTs, shifting the ITCZ northward and thereby causing in creased monsoonal winds and convective precipitation in the regi on, with the opposite occurri ng during the LIA (Meckler 2006). Movement of the ITCZ affecti ng the North Atlantic and GOM would influence the NAO to some degree. The most widely accepted reconstruction of the ITCZ is that of Haug et al. (2001), although Peterson and Haug (2006) prov ide the most direct discussion of the ITCZ as reconstructed from the Cari aco Basin Ti record. There is a strong agreement between the Ti% fr om the Cariaco Basin and the Florida speleothem record (Figure 6.15), suggesting that nor thward movement of the ITCZ may

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266 accentuate atmospheric moisture in the GOM, thereby causing greater convection, as seen in other circu m-Caribbean regions (Hoddell et al. 1991; Haug et al. 2001; Poore et al. 2003, 2005) that would also affect Florida (van Beynen et al. 2008). As with Peterson and Haug (2006), a close agreement with the Quelccaya ice core was found (Thompson and Mo sley-Thompson 1989), where more negative 18O values in the ice suggest a drier climate (Baker et al. 2001) compared to opposite conditions found in the BRC03-02 speleothem 18O record (Figure 6.15). When the ITCZ’s relative summer position is further north than its mean location, Florida experiences great er convective precipitation, while precipitation at Quelccaya is reduced. 6.6.8 Large-scale Teleconnection Influences Several of the aforementioned studies have addressed the importance of large-scale atmospheric-oceanic circul ation patterns on Florida’s climate, introducing the possibility of multiple te leconnection influences interacting to create a complex and dynamic climate syst em with regard to precipitation. Revisiting the suggestion by Rajagopalan et al (1998) that the tropical and north Atlantic may behave similarly to tropica l Pacific heating anomalies regarding northern hemisphere atmospheric-oceanic circulations, a comparison of the BRC03-02 18O record to North Atlantic and Pacific teleconnections may clarify the dominating influences affect ing west-central Florida.

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267 Figure 6.15 Regional proxy comparisons. (A) Comparison between the BRC03-02 18 O data and Quelccaya ice core (20 point running mean), showing a close match (Thompson and Mosley-Thompson 1989). (B) Close agreement is seen between the Cariaco Basin (Haug et al. 2001) Ti record and the BRC03-02 speleothem data. Blue and brown lines indicate wetter and drier, respectively.

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268 Teleconnection influences in the tr opical and North Atlantic affecting subtropical Florida include the NAO and AMO, with the NAO being more variable on shorter timescales and known to infl uence Florida’s precipitation during negative phases, especially when posit ively phased with ENSO and the PDO (Hagemeyer 2005; 2006). However, this relationship appears to be more complicated when extended beyond the instrum ental record, as studies show the NAO’s periodicity and intensity are highly variable over the long-term (Kerr 2005). Contrasting the aforementi oned relationship between NAO and precipitation amount, when co mpared to the NAO reconstr uction of Cook et al. (2002), the BRC03-02 18O values indicate that positive phases of the NAO correspond with an increase in precipitation (more negative 18O values) for much of the last 1500 years (Figure 6. 16). This supports the findings of van Beynen et al. (2007b) from another west-central Florida speleothem 18O record. While asynchronies do exist between the tw o records, partly attributed to dating discrepancies, it appears that long-term fluctuations in the NAO strongly influence the BRC03-02 18O values.

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269 Figure 6.16 NAO and AMO proxy comparisons. (A) Comparison between the BRC03-02 18 O data and the NAO reconstruction (20 point running mean) by Cook et al. (2002) showing a close agreement (B) A weaker relationship is seen between the BRC03-02 record and the A MO reconstruction by Gray et al. (2004). Blue and brown lines indicate wetter and drier, respectively.

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270 In comparing the BRC03-02 18O to the AMO reconstruction (Gray et al. 2004), the relationship is similar, wit h positive AMO phases corresponding to more negative (depleted) BRC03-02 18O values and wetter conditions (Figure 6.16). The AMO teleconnection is weaker which may be in part due to the greater scope of the records brought in to reconstruct the Gray et al. (2004) AMO record, thereby introducing potentially local influences. Enfield et al. (2001) saw a relationship between the AMO and ENSO, with the AMO affecting how ENSO changes in intensity, and t herefore may also affect how ENSO influences the region over time. Teleconnection influences originati ng from the Pacific include ENSO and the PDO, where positive phases of ENSO (El Nio) are often associated with positive phases of the PDO (Jackson et al. 2008). Figure 6.17 shows the BRC0302 18O record compared to the D’Arrigo et al. (2005) NINO3 ENSO reconstruction, showing an intermittently weak relationship between the two, wherein during certain phases of ENSO (i.e. the period near ~350 y BP), there exists little agreement between them, but dur ing other periods the relationship is stronger. This may be attributed to anti phasing between ENSO and the PDO, or a possible stronger link to the PDO in Florida, as discussed below.

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271 Figure 6.17 ENSO and PDO proxy comparisons. (A) Comparison between the BRC03-02 18O data and the NINO3 (ENSO) reconstruction ( 10 point running mean) by D’Arrigo et al. (2005). (B) The PDO record (20 point running mean) (MacDonald and Case 2005) demonstrates a closer coherence to the BRC0 3-02 data than ENSO, and may be related to solar forcing on longer-term scales more heav ily influencing Florida’s climate. Blue and brown lines indicate wetter and drier, respectively.

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272 Comparison of the BRC03-02 18O data to the PDO reconstruction by (MacDonald and Case 2005) also shows per iod of strong agreement, yet the relationship is not consistent throughout the record (Figure 6.17). The PDO may exert more influence on the region’s precip itation than previous ly suggested, as shown by van Beynen et al. (2007a). Simila r to ENSO, during certain periods the two records agree, yet out of phase areas occur likely due to the influence of other teleconnections on the climate (preci pitation regime) of the area. However, the Pacific influences must also be in phase with one another for there to be a discernable effect on hemispheric c limate (McCabe and Dettinger 1999). This could be the main reason why the combin ed influence of these phenomena is not as pronounced as the Atl antic teleconnections. The coupling of Pacific and Atlantic te leconnections influencing Florida is not easily deconvolved, with congruency bet ween the records being inconsistent at times, which is to be expected based on t he shifts in intensity characteristic of many of these phenomena due to the myri ad of parameters influencing their intensities and periodicities. However, on long-term scales it appears that positive phasing in the AMO, NAO, ENS O, and PDO acts to modulate Florida’s precipitation at varying intensities based on the coher ence of the various proxy records of these oscillations with the BRC03-02 18O record, and they may be mutually influenced by solar fo rcing to differing degrees. The influence of solar forci ng on these various atmospheric teleconnections is seen in their periodicities and been suggested in previous studies (Ogi et al. 2003; Wang et al. 2005; Meckler et al. 2006; Rasmussen et al.

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273 2006; Asmerom et al. 2007; Richey et al 2007). A comparison of the BRC03-02 18O record to the Bard et al. (2000) solar irradiance record shows a close agreement to the BRC03-02 18O record and demonstrates similar cyclicity between them with some offset likely (i.e. 850 to 1100 yr BP) due to dating error (Figure 6.18). The salient feat ure of this comparison is that it may establish the linkage between solar forcing and the mo re influential teleconnections in agreement with the BRC03-02 18O record. Figure 6.18 Solar irradiance proxy comparison. Comparison between the BRC03-02 18 O data and solar irradiance (Be10) from Bard (200 0) demonstrates a possible relationship to solar forcing. Blue and brown lines indicate wetter and drier, respectively.

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274 Black et al. (2004) attributes decadal to centennial changes in the position of the ITCZ as the major causes of Ca riaco Basin climate variability based on solar variability and the 11 year sunspot cycle. This finding supports the evidence of the solar cycles found in the BRC03-02 18O spectral analysis and gives plausibility to solar influence on the teleconnections influencing the region’s climate. The strength of agreement between the low-lati tude precipitation records based on ITCZ migration on both short and long-term scales is reflected in the spectral analysis of the BRC03-02 18O record, which indicates several possible solar cycle influences superimposed on the longer-term oceanic-atmospheric oscillations present in the record. 6.6.9 Complexity of Teleconnections Many studies have inexorably linked the ITCZ to ENSO, PDO to AMO and ENSO, and the NAO to the AMO, (Roger s 1984; Bond et al. 2001; Haug 2001; Enfield 2001; Kerr 2005; Rasmussen et al 2006; etc.), but few have the unique geographic advantage that Florida’s locati on provides as a transitional hingepoint affected by the interactions of t hese teleconnections. However, Hagemeyer (2006) attributes storm frequency and seve rity to interplay between the PNA, NAO, and ENSO. He found that El Nio co nditions coupled with negative NAO and positive PNA indices provide optimal conditions for increased winter precipitation in Florida. The opposite occu rs during periods of La Nia conditions and positive NAO and negative PNA condi tions, with reduced winter storm frequency and rainfall amount. Cronin et al. (2002) also found a connection between the NAO, ENSO, and the PNA with r egard to winter precipitation since

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275 the late 1800’s in Florida. Conversely, in this record positive PDO and ENSO together both reflect increased precipit ation in Florida. The NAO acts independently of ENSO and PDO in the m odern record, as well is in the BRC0302 record, but if it is inherently rela ted to the ITCZ, t hen the close agreement between the NAO and ITZC records to the BRC03-02 18O record is justified. Shifts in the ITCZ affected by the NAO/A MO would cause winds to divert warm, moist air into the GOM and affect SSTs, thereby increasing the likelihood of storm activity and precipitation amounts. A strong linkage between the NAO and ITCZ would account for the close agreem ent between the BRC03-02 speleothem record and the ITCZ-affected r egions (i.e. Cariaco Basin). The instrumental studies by Hagemeyer (2005, 2006) concentrated primarily on the interannual and seasonal oscillations of the NAO, PDO (PNA), and ENSO. Similar to these teleconnecti ons, the ITCZ may demonstrate longerterm multidecadal variability in its mean position and intensity and be more dominant during anomalous periods of clim ate change, thereby overprinting other various influences during shorter-term periods, as seen in the BRC03-02 18O record. An underestimation by previous st udies of the influence of the ITCZ and the long-term variability of North Atlantic and Pacific teleconnection phasing likely stems from a lack of records beyond the instrumental period. However, the BRC03-02 18O record, in combination with l ong-term reconstructions of the NAO, AMO, ENSO, and PDO, provides robust evidence of the complex interactions of these atmospheric-oc eanic teleconnections on multidecadal to centennial timescales. Thus, further clarifying some of the possible

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276 synchronicities in their behavior and more in timately relating Atlantic and Pacific teleconnection influences on Florida, with solar forcing being a possible common driver of climate change in the region. Teleconnections control precipitation patterns in west-central Florida, thereby modulating the amount effect show n to be dominant in the precipitation and speleothem 18O values (Chapter 5). The linkages between the BRC03-02 18O record and the various teleconnec tions described here shows these mechanisms may have operated together in different phases throughout the Holocene, with solar forcing a likely candidate as the driver of climate variability. Combined, these causal mechanisms of climate change have variable effects on precipitation in Florida, which serves as a geographical transition zone ideally situated to record the complex interrelati onships controlling climate change in the subtropics of North America. 6.7 Conclusions Discerning coherence in the time or frequency domain of various atmospheric-oceanic teleconnections and the BRC03-02 18O record is challenging. Deconvolving the intermitt ent coeval phasing of the varying intensities of each of these phenomena throughout the last 1,500 years is best achieved through time series analysi s, wherein the periodicities of teleconnections and solar influences can be determined. The BRC03-02 record illustrates strong periodicities in t he multidecadal and centennial bands, with some evidence of the 11 year solar cycle. Overall, the speleothem record is a

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277 robust surrogate for precipitation amount in Florida, and provides a means to ascertain how teleconnection mechanism s influence climate in the region. Close comparison between the Florida sp eleothem record and the Cariaco Basin and GOM marine records suggests strong teleconnections between these regions. The strong similarities betw een the records dem onstrate potential common causal factors ranging from t he Peruvian Mountains in the Southern Hemisphere to the subtropics of No rth America. Increased sea surface temperatures and aligned enhancement of atmospher ic convection in the subtropics appear to be connected to shifts in the tropics through movement in the mean position of the ITCZ, which ma y be affected by the NAO and AMO to some degree. When the phasing of ENSO and the PDO is synchronous, the Pacific influence can be discerned in the pr ecipitation of Florida as recorded by the speleothem isotopes, with the PDO being the stronger influence. Only through the development of more proxy records at higher resolution (annual to interannual) can we delve into mo re detailed investigations of causal factors of the regional climate change that can be modeled by climate dynamists. A better understanding of teleconnection mechanisms influencing climate will aid in forecasting and mitigating for related changes in precipitation and has implications for water management practices in Florida. Future work to improve the understanding of Florida’s paleoclim ate includes additional speleothem dating to improve spectral analysis, a l onger surface precipit ation and dripwater calibration study within BRC, and higher-re solution trace element analysis. Cross spectral analysis between the BRC03-02 stabl e isotope record with the existing

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278 teleconnection reconstructions and other hi gh-resolution records will better allow for the deconvolving of the phasing of t he influential teleconnections controlling precipitation in west -central Florida. 6.8 Chapter Acknowledgements First and foremost, this research w ould not have been possible were it not for the dedication of Robert Brooks and Tom Turner. They spent endless amounts of time searching for the Holy Grail, fortuitously and unknowingly stumbling upon Brooksville Ridge Cave, whose secrets we have only begun to unlock. I wish to thank Ethan Goddard of t he University of South Florida for the preparation and analysis of the stable is otope data. Thanks to Zac Atlas for assistance with trace element analysis. I also would like to thank Limaris Soto for sample preparation assistance and pre liminary analysis. Thanks to Lee Florea for assistance with sample collection. I wish to extend my deepest gratitude to Kristine DeLong of the USGS for selflessly providing her time and expertise in time series analysis to help me discover its usefulness and teach me what she could in such a short time and with such a lost pupil! This work was funded by an internal grant from the Univ ersity of South Florida a nd by the Southwest Florida Water Management District (SWFWMD).

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279 6.9 Chapter References Alvarez Zarikian, C.A., Swart, P.K., Giff ord, J.A. and Blackwelder, P.L. 2005. Holocene Paleohydrology of Little Sl at Spring, Florida, based on ostracod assemblages and stable isotopes. Palaeogeography, Palaeoecology, Palaeoclimatology 225: 134-156. Baker, P.A., Rigsby, C,A., Seltzer, G.O ., Fritz, S.C., Lowenstien, T.K., Bacher, N.P., Veliz,C. 2001. Tropical climat e changes at millennial and orbital timescales on the Bolivian Atliplano. Nature 409: 698-700. Barber, K.E., Battarbee, R.W., Brook, S.J., Eglinton, G., Haworth, E.Y., Oldfield, F., Stevenson, A.C., Thompson, R ., Appleby, P.G., Austin, W.E.N., Cameron, N.G., Ficken, K.J., Goldi ng, P., Harkness, D.D., Holmes, J.A., Hutchinson, R., Lishman, J.P., Maddy D., Pinder, L. C.V., Rose, N.L., and Stoneman, R.E. 1999. Proxy records of c limate change in the UK over the last two millennia: doc umented change and sedimentary records from lakes and bogs. Journal of the Geological Society London 156: 369380. Black, D.E., Thunell, R.C., Kaplan, A., Peterson, L.C., and Tappa, E.J. 2004. A 200-year record of Caribbean and tr opical North Atlant ic hydrographic variability. Paleoceanography 19: PA2002, doi: 10.1029/2003PA000982. Bond, G., Kromer, B., Beer, J., Muschel er, R., Evans, M.N., Showers, W., Hoffmann, S., LottiBond, R., Hajdas, I. and Bonani, G. 2001. Persistent solar influence on North Atlantic climate during the Holocene. Science 294: 2130-2136. Burns, S.J., Fleitmann, D., Mudelsee, M., Neff, U., Matter, A., Mangini, A. 2002. A 780-year annually resolved record of Indian Ocean monsoon precipitation from a sp eleothems from south Oman. Journal of Geophysical Research 107 (D20): 4434-4443. Burroughs, W.J. 2003. Weather Cycles: Real or imaginary ? 2nd ed. Cambridge University Press: Cambridge, 317 p. Cane, M.A. 2005. The evolution of El Nino, past and future. Earth and Planetary Science Letters 230: 227-240. Cook, E.R., D’Arrigo, R.D., and Mann, M. E. 2002. A well-verified, multiproxy reconstruction of the winter North At lantic Oscillation Index since A.D. 1400. Journal of Climate 15: 1754-1764.

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280 Cruz, F.W., Stephen, J.B., Jercinovic, M., Karmann, I., Sharp, W.D., and Vuille, M. 2007. Evidence of rainfall variat ions in Southern Brazil from trace element ratios (Mg/Ca and Sr/Ca) in a Late Pleistocene stalagmite. Geochimica et Cosmochimica Acta 71: 2250-2263. D’Arrigo, R., Cook, E.R., Wilson, R.J., Allan, R., and Mann, M.E. 2005. On the variability of ENSO over the past six centuries. Geophysical Research Letters 32: L03711 doi:10. 1029/2004GL022055. Dansgaard, W. 1964. Stable isotopes in precipitation. Tellus 16: 436-468. DeLong, K., Quinn, T.M., Mitchum, G.T., and Poore, R.Z., 2009. Multi-Decadal Scale Climate Variablity in Highly Resolved Proxy Records: Evaluating Paleoclimate Records in the Frequency Domain. In Preparation DeMenocal, P., Ortiz, J., Guilderson, T., and Sarnthei n, M. 2001. Coherent highand low-latitude climate variability during the Holocene Warm Period. Science 288: 2198-2202. Desmarchelier, J.M., Hellstrom, J.C., and McCulloch, M.T. 2006. Rapid trace element analysis of speleothems by ELA-ICP-MS. Chemical Geology 231: 102-117. Dorale, J.A., Gonzalez, L.A., Reagan, M.K., Pickett, D.A., Murrell, M.T., and Baker, R.G. 1992. A high-resolution re cord of Holocene climate change in speleothem calcite from Cold Water Cave, Northeast Iowa. Science 258: 1626-630. Enfield, D. B., Mestas-Nuez, A.M., and Trimble, P.J. 2001. The Atlantic multidecadal oscillation and its relati on to rainfall and river flows in the continental U. S. Geophysical Research Letters 28: 277-280. Fleitmann, D., Burns, S.J., Mudelsee, M., Neff, U., Kram ers, J., Mangi ni, A., and Matter, A. 2003. Holocene forcing of the Indian monsoon recorded in a stalagmite from southern Oman. Science 300: 1737–1739. Friedman, I. and O'Neil, J.R. 1977. Comp lication of stable isotope fractionation factors of geochemical interest. In : K.K. Chapter, Editor (6th ed.), Data of Geochemistry, United States Geological Su rvey (USGS), Professional Paper: 440 p. Gascoyne, M. 1992. Palaeoclimate determi nation from cave calcite deposits. Quaternary Sciences Reviews 11: 609-632.

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281 Ghil, M., Allen, R.M., Dettinger, D. M., Ide, K., and Kondrashov, D. 2002. Advanced spectral methods for climatic time series. Reviews of Geophysics. 40(1): 3.1–3.41, doi : 10.1029/2000RG000092 Gray, S.T., Graumlich, L. J., Betancourt, J.L., and P ederson, G.T. 2004. A treering based reconstruction of the Atl antic Multidecadal Oscillation since 1567 A.D. Geophysical Research Letters 31: L12205. Grimm, E.C, Watts, W.A., Jacobson, Jr., G.L., Hansen, B.C., Almquist, H.R., Dieffenbacher-Krall, A.C. 2006. Evidence for warm wet Heinrich events in Florida. Quaternary Science Reviews 25(17-18): 2197-2211. Hagemeyer, B.C., and Almeida, R.J. 2005. Toward greater understanding of inter-seasonal and multi-decadal variabi lity and extremes of extratropical storminess. In: Florida, Preprints, 16th Symposium on Global Change and Climate Variations. San Diego, CA, American Meteorology Society, P5.9 (on CD-ROM). Hagemeyer, B.C. 2006. ENSO, PNA and NAO Scenarios for extreme storminess, rainfall and temperatur e variability during the Florida dry season Preprints, 18th Conference on Climate Variability and Change, Atlanta, GA, American Meteorol ogical Society, CD -ROM P2.4. Haug, G.H., Hughen, K.A., Sigman, D.M. Peterson, L.C., and Rohl, U. 2001. Southward migration of the Inte rtropical Convergence Zone through the Holocene. Science 293: 1304-1308. Hendy, C. 1971. The isotopic geochemistry of speleothems I. The calculation of the effects of different modes of formation on the isotopic composition of speleothems and their applicabilit y as palaeoclimatic indicators. Geochimica et Cosmochimica Acta 35: 801-824. Hodell, D.A., Brenner, M., Curtis, J.H., and Guilderson, T. 2001. Solar forcing of drought frequency in the Maya Lowlands. Science 292: 1367-1370. Hurrell, J.W., Kushnir, Y., Otterson, G., Visbeck, M. 2003. An overview of the North Atlantic Oscillation. In : The North Atlantic Oscillation: Climatic Significance and Environmental Impact Geophysical Monograph Series, AGU 134: 1-36. Jackson, A.S., McDermott, F., and Mangini, A. 2008. Late Holocene climate oscillations and solar fluctuati ons from speleothem STAL-AH-1, Sauerland, Germany: A numerical perspective. Geophysical Research Letters 35: L06702, doi: 10.1029/2007GL032689.

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282 Kerr, R. A. 2005. Atlantic climate pac emaker for millennia past, decades hence? Science 309: 43-44. Lachniet, M.S., Asmerom, Y., Burns, S., Patterson, W.P., Polyak, V. and Seltzer, G.O. 2004a. Tropical response to the 8200 yr cold event? Speleothem isotopes indicate a weakened early Holocene monsoon in Costa Rica. Geology 32: 957-960. Lachniet, M.S., Burns, S.J., Piperno, D.R., Asmerom, Y., Polyak, V.J., Moy, C.M., and Christenson, K. 2004b. A 1500-year El Nino/Southern Oscillation and rainfall history for the Isthmus of Panama from speleothem calcite. J ournal of Geophysical Research 109: D20117, doi:10.1029/2004JD004694. Marchitto, T.M. and deMenocal, P.B. 2003. Late Holocene variability of upper North Atlantic Deep Wate r temperature and salinity. Geochemistry, Geophysics, and Geosystems 4(12): 100, doi:10.1029/2003GC000598. Mayewski, P.A., Rohling, E.E., Stager, J. C., Karlen, W., Maasch, K.A., Meeker, L.D., Meyerson, E.A., Gasse, F., van Kreveld, S., Holmgren, K., LeeThorp, J., Rosqvist, G., Rack, F ., Staubwasser, M., Schneider, R.R., and Steig, E.J. 2004. Holo cene climate variability. Quaternary Research 62: 243-255. McCabe, G.J. and Dettinger, M.D. 1999. Dec adal variability in the strength of ENSO teleconnections with precipitat ion in the western United States. International Jour nal of Climatology 19: 1399–1410. Meckler, A.N. 2006. Late Quaternary changes in nitrogen fixation and climate variability recorded by sediments fr om the Gulf of Mexico and the Caribbean Sea University of Bayreuth, Dissertation. Ogi, M., Yamazaki, K., and Tachibana, Y. 2003. Solar cycle modulation of the seasonal linkage of the North Atlantic Oscillation (NAO). Geophysical Research Letters 30(22): 2170. Onac, B.P., Pace-Graczyk, K., and Atudire i, V. 2008. Stable isotopic study of precipitation and cave drip water in Florida (USA): implications for speleothem-based paleoclimate studies. Isotopes in Environmental and Health Studies 44(2): 149-161. Paulsen, D.E., Li, H.C., and Ku, T.L. 2003. Climate variability in central China over the last 1270 years revealed by high-resolution stalagmite records. Quaternary Science Reviews 22: 691-701.

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283 Peterson, L.C. and Haug, G.H. 2006. Variab ility in the mean latitude of the Atlantic Intertropical Convergence Z one as recorded by riverine input of sediments to the Cariaco Basin (Venezuela). Paleogeography, Paleoclimatology, Paeloecology 234: 97-113. Plummer, L.N. 1977. Defining reactions and mass transfer in part of the Floridan Aquifer. Water Resources Research 13(5): 801-812. Polyak, V.J. and Asmerom, Y. 2001. Late Holocene climate and cultural changes in the Southwestern United States. Science 294: 148-151. Polyak, V.J., Rasmussen, J.B., Asmero m, Y. 2004. Prolonged drought period in the southwestern United Stat es through the Younger Dryas. Geology 32: 5-8. Poore, R.Z., Dowsett, H.J., Ve rardo, S., Quinn, T.M. 20 03. Millennialto centuryscale variability in Gulf of Mexico Holocene climate records. Paleoceanography 18(2): 1048, doi: 10.1029/2002PA000868. Poore, R.Z., Pavich, M.J., and Grissino-Ma yer, H.D. 2005. Record of the North American southwest monsoon from Gu lf of Mexico sediment cores. Geology 33(3): 209-212. Rajagopalan, B., Kushnir, Y., Tourre, Y.M. 1998. Observed decadal midlatitude and tropical Atlantic climate variability. Geophysical Research Letters 25(21): 3967-3970. Reeder, P. and Brinkmann, R. 1998. Paleoe nvironmental Reconstruction of an Oligocene-Aged Island Remnant in Florida, USA Cave and Karst Science 25: 7-13. Richey, J.N., Poore, R.Z., Flower, B.P ., Quinn, T.M. 2007. 1400 yr multiproxy record of climate variability fr om the northern Gulf of Mexico. Geology 35(5): 423-426. Roberts, M.S., Smart, P.L., and Baker, A. 1998. Annual trace element variations in a Holocene speleothem. Earth and Planetary Science Letters 154: 237246. Rohling, E.J. and Palike, H. 2005. C entennial-scale climate cooling with a sudden cold event around 8,200 years ago. Nature 434: 975-979.

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284 Schelske, C.L., and Hodell, D.A. 1995. using carb on isotopes of bulk sedimentary organic matter to reconstr uct the history of nutrient loading and eutrophication in Lake Erie. Limnology and Oceanography 40(5): 918-929. Schulz, M. and Mudelsee, M. 2002. RE DFIT: estimating red-noise spectra directly from unevenly spaced paleoclimatic time series. Computers and Geosciences 28: 421-426. Scott, T.M. 1997. Miocene to Holocene History of Florida. In : Jones, D.S. and Randazzo, A.F., (eds.). The Geology of Florida University Press of Florida: Gainesville, p. 1-12. Selley, R.C. 1982. An Introduction to Sedimentology Academic Press: New York, pp. 417. Siddall, M., Stocker, T.F., Blunier, T ., Spahni, R., McManus, J.F., and Bard, E. 2006. Using a maximum simplicity paleoclimate model to simulate millennial variability during t he last four glacial periods. Quaternary Science Reviews 25: 3185-3197. Sharp, Z. 2007. Principles of Stable Isotope Geochemistry Pearson Prentice Hall: Upper Saddle River, NJ, p. 344. South East Regional Climate Cent er. Accessed September 2006 at http://cirrus.dnr.state.sc.us/c gi-bin/sercc/cliMAIN.pl?fl1046. Stahle, D.W., and Cleavela nd, M.K. 1992. Reconstruc tion and analysis of spring rainfall over the Southeastern U.S. for the past 1000 years. Bulletin American Meteorological Society 73(12): 1947-1961. Thomson, D. J. 1982. Spectrum esti mation and harmonic analysis. Proc. IEEE 70(9): 1055-1096. Thompson, L.G., Mosley-Thompson, E. 1989. One-half millenia of tropical climate variability as recorded in the stratigraphy of the Quelccaya ice cap, Peru. In : Peterson, D.H., (Ed.). Aspects of climate variability in the Pacific and western Americas. American Geophysical Union Geophysical Monograp h 55, p. 15-31. Torrence, C., and Compo, G. P. 1998. A Practical Guide to Wavelet Analysis. Bulletin of the American Meteorological Society 97(1): 61-78.

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285 van Beynen, P.E., Schwarcz, H.P., and Ford, D.C. 2004. Holocene climatic variation recorded in a speleothem fr om McFail’s Cave, New York. Journal of Cave and Karst Studies 66(1): 20-27. van Beynen, P.E., Asmerom, Y., Polyak, V., Soto, L., Polk, J.S., 2007a. Variable intensity of teleconnections during the Late Holocene in Subtropical North America from an isotopic study of speleothem from Florida. Geophysical Research Letters 34: L18703, doi:10:1029/2007GL031046. van Beynen. P.E., Soto, L., Pace-Graczyk, K., 2007b. Paleoclimate reconstruction derived from speleothem strontium and 13C in Central Florida. Quaternary International doi:10:1016/j.quai nt.2007.03.019. van Beynen, P.E., Soto, L., Polk, J., 2008. Variable calcite deposition rates as proxy for paleo-precipitation determinat ion as derived from speleothems in Central Florida. Journal of Cave and Karst Studies 70 (1): 1-19. Watanabe, T., Winter, A., Oba, T. 2001. Seasonal changes in sea surface temperature and salinity during the Li ttle Ice Age in the Caribbean Sea deduced from Mg/Ca and 18O/16O ratios in corals. Marine Geology 173: 21-35. White, W.B. 2004. Paleoclimate records from speleothems in limestone caves In : Studies of Cave Sediments: Ph ysical and Chemical Records of Paleoclimate, I.D. Sasowsky and J.E. My lroie, eds., Klewer: New York, p. 135-175. Winsberg, MD. 2003. Florida Weather University of Florida Press: Gainesville, Florida. Winter, A., Ishioroshi, H., Watanabe, T., Oba, T., Christy, J. 2000. Caribbean Sea surface temperatures: two-to-three degrees cooler than present during the Little Ice Age. Geophysical Research Letters 27: 3365-3368.

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286 Chapter 7 Late Pleistocene and Mid-Holocene Climate Change from a Florida Speleothem 7.1 Chapter Preface This chapter presents a speleothem record of mid-Holocene and Late Pleistocene paleoclimate in Florida using a stalagmite collected from Brooksville Ridge Cave in west-central Florida. This study extends the interpretation from Chapters 5 and 6 back in time and it serves to provide a comparison of the drastically different climate in Florida during the last glacia l period compared to that of modern times. It al so provides a glimpse of the subtropical response to Heinrich event 2 and shows the temporal evolution of climate change in Florida from oxygen and carbon isotope values fr om speleothem calcite since 30,000 years ago. 7.2 Chapter Abstract A stalagmite collected fr om Brooksville Ridge Cave in west-central Florida was deposited from ~30 to 20 kyr BP, enc ompassing Heinrich Event 2 (H2), and from ~5 to 4 kyr BP, du ring the mid-Holocene. The timing of H2 in the speleothem record is at ~24 kyr BP, which is temporally similar to the occurrence

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287 of this event in other areas of the wo rld. However, the oxygen and carbon isotope values indicate the climate in Florida was relatively warm and wet for a glacial period, rather than extremely cool and dry, as seen in other regions, with increased precipitation and a shift towards enhanced vegetation (dense forest) during this period. One possible cause is the faltering of the North Atlantic Conveyor Belt due to increased glacial me ltwater input, thereby preventing heat transfer via the Gulf Str eam from the tropics to th e northerly latitudes and causing warmer Gulf of Mexico and subtropical Atlantic sea surface temperatures. This mechanism would also allow for an increase in convective thunderstorm activity due to higher evaporation rates. In contrast to the glacial values the average mid-Holocene speleothem oxygen isotope values were depleted by ~1‰, indicating wa rmer temperatures and higher precipitation am ounts than during the glacial period. Additionally, the carbon isotopes show a ~3‰ shift towards more negative values, indicating more heavily forested conditions during that ti me. The speleothem isotopes during the mid-Holocene reflect a warmer and we tter environment than the end of the glacial period. The variabi lity within both t he mid-Holocene and Late-Pleistocene data support the possibility of atmo spheric teleconnections between the tropics/subtropics and northerly latitudes c ontributing to shorter-term shifts in precipitation amount super imposed on the larger-scale glacial-interglacial isotopic composition of the speleothem. Possible causes include changes in the migration patterns of the Intertropica l Convergence Zone (ITCZ) and North Atlantic Oscillati on (NAO) over time.

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288 7.3 Introduction Few paleoclimate records in Florida extend into the last glacial period, mostly due to the lack of preservation or av ailability of suitable, high-resolution climate proxies (Grimm et al. 1993; 2006, Huang et al. 2006). Even rarer in Florida are those proxies that provide a glimpse into both interglacial (Holocene last ~10 kyr) and glacial (Pleistocene ~10 kyr to 1.8 Myr) climate. These periods are both characterized by abrupt clim ate events from changing atmospheric teleconnections, ice sheet advance and retreat, varying ocean circulations, and major shifts in global temperature. Spel eothems from cave environments offer a proxy that is protected from surfac e processes and able to record long-term changes in the environment (Gasco yne 1992; Ford and Williams 2007). Presented here is a speleothem record of climate change from west-central Florida spanning the mid-Ho locene and Late Pleistocene. A myriad of research papers exist in vestigating climatic change during the last glacial period, with the CLIMAP res earch project being the most prominent of these (CLIMAP 1984), with the expectation that a better understanding of climate extremes will aid in preparing for po ssible future climate change scenarios. Research mainly focused on Milankovit ch-cycles and millennial-scale climate changes using numerous ice cores from Greenland and Antarctica, and marine sediment cores from the North Atlantic Ocean (Masson et al. 2000; Bard et al. 2000; Alley et al. 2001). More recent work also includes lacustrine sediments and speleothem records, which provide ev idence of terrestrial responses to millennial-scale climate forcing and abrupt climatic events, including Dansgaard-

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289 Oeschger and Heinrich events (Dansgaard et al. 1985; Heinrich 1988; Grimm et al. 1993, 2006; Frumkin et al. 1999; Holm gren et al. 2003; Genty et al. 2003; Huang et al. 2006). The evidence of millennial-scale events over the last ~100 ,000 kyr is welldocumented in the Northern Hemisphere fr om a multitude of ice and marine core studies (Arz et al. 1998; Clark et al. 2001; Peck et al 2007). What is less wellknown is the response of other parts of the world, including the Southern Hemisphere and subtropics (Lynch-Steglitz 2004). Heinrich events (HEs) were first discovered by German geologist Hart mut Heinrich while analyzing marine sediments in a core from the North At lantic Ocean (Heinrich 1988). These abrupt events are seen in the paleoclimate record for the North Atlant ic through the last glacial period. Heinrich events occur approx imately every 7 kyr to 10 kyr, and last on average ~750 years, although some di screpancies exist regarding the length of each event based on the various proxy records analyzed since their initial discovery (Hemming 2004). While the origin, timing, and cause of Heinrich events are much debated, new dating techniques and more accurate analysis of proxies provide a general consensus of the timing and cyclicity of He inrich events as seen in the marine record of ~7 kyr (Hemming 2004; Peck et al. 2007). Despite this new information, several paleoclimate proxies show a differ ent response to Heinrich events than those seen in the Greenland ice cores and North Atlantic marine sediment records (Stoner et al. 2000; Grimm et al. 2006; Ellwood and Gose 2006).

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290 Related to Heinrich events, Dansgaard-Oeschger (DO) events are characterized by large abrupt warming episodes followed by a series of alternating gradual cooling and warming periods occurring approximately every 1,500 years during the last glacial peri od (Bond and Lotti 1995; Bond et al. 1999). These cyclic millennial events occurred approximately 24 times during the last glacial period, and are terminated by He inrich events in couplings known as Bond cycles (Bond et al. 1999; Grimm et al. 2006). Previous long-term paleoclimate work in Florida is mainly limited to lacustrine and marine studies. Willard et al. (2007) analyzed pollen and ostracods in a sediment core from Ta mpa Bay and found much cooler and drier conditions than modern times, with the IT CZ possibly influencing climate during the last deglaciation in Florida. Grimm et al. (1993) reconstructed climate over the last 50kyr using pollen analysis from a Lake Tulane sedi ment core, first proposing cool, wet Heinrich events in Florida, then later refined their interpretation of Heinrich events as warm and wet based in increases in Pinus species (Grimm et al. 2006). Watts et al. (1994) also propose warm, wet Heinrich events based on a pollen study from a Lake Tulane sediment core, while another from Lake Tulane by Huang et al. (2006) spanning 62 kyr also found increased Pinus during Heinrich events and the mid-Ho locene, attributed to warm, wet conditions, with a higher abundance of C4 vegetation during the last glacial period. The objective of this study is to use speleothem 18O and 13C data from west-central Florida to evaluate t he climate conditions during the Late Pleistocene and mid-Holocene, including the response to Heinrich event 2.

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291 7.4 Study Area 7.4.1 Brooksville Ridge Cave The speleothem was collected from Brooksville Ridge Cave (BRC), in Hernando County, Florida (Fi gure 7.1). This cave is situated in the Brooksville Ridge section of the Ocala Arch (R eeder and Brinkmann 1998; Florea et al. 2007). BRC has only one entrance opened by quarrying around 50 years ago and is the longest air-filled cave in Her nando County with over 1 km of surveyed passage. The cave contains a series of chambers connected by low, tight crawls with several highly decorated rooms c ontaining hundred of active formations (Figure 7.2). It possesses relative humidity levels >98% and a constant temperature near 22C. 7.4.2 Geologic and Hydrologic Setting The bedrock is primarily the Eo cene Ocala and Suwannee Limestones, which are unconformably overlain by the Hawthorn Group, carbonates interspersed with siliclastics and phosphorite redeposition (Scott 1997). In some places, the bedrock is topped with severa l meters of Pleistocene-aged quartz sands, but the majority of the study area consists of exposed limestone outcrops and little soil cover. Several infiltration point s in the form of sinkholes and sinking streams are present in the landscape, but very little standing wa ter occurs due to rapid drainage to the subsurface.

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292 Figure 7.1 Location of BRC in Hernando County, Fl orida. Black circle indicates approximate location; no further detail provided due to cave’s sensitivity and private ownership. 7.4.3 Climate and Vegetation The climate above BRC has a mean annu al temperature of 21.3C and mean annual precipitation of ~1350 mm. Mean maximum monthly temperatures occur in August (27.6C) and the mini mum in January (13.6C). August also possesses the monthly maximum prec ipitation with 219 mm and October the least with 48.8 mm (SE Regional Climate Center). The area is upland hammock, with thin soil cover and significant ex posures of bedrock. Vegetation mainly consists of flatwood and mixed hardw ood forests (Watts and Collins 2008). This 0714 3.5 KilometersStudy AreaMap by Jason Polk Data Source: Florida Geographic Data Libray NAD_1983_HARN-ZONE_17NLegend Hernando County BRC

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t y e ( S a s F s p y pe of envi r e lliotti i ) tur k S erenoa re p nd various eries (Wat t igure 7.2 M a p eleothem w a r onment in c k ey oak ( Q u p en s ), wir e scrub veg e t s and Colli a p of BRC. S p a s collected. c ludes lon g u ercu s lae vi e grass ( Ari s e tation. Soi ns 2008). p eleothem ph o 293 g leaf pine ( P vis ), live oa k s tida sp.), e l cover mai o to and arro w P inus palu s k ( Quercus e ricads, sp e nly include w indicate loc a s tris) slash virginiana) e cies of H o s the Cand a tion where B pine ( Pinu s saw palm e o lly ( Ilex ), f o ler fine sa n B RC03-03 s e tto o rbs, n d

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294 7.5 Methodology The BRC03-03 sample (Figure 7.3) wa s cut in half down its central growth axis using an MK Diamond 10 in wet saw with a diamond-tipped blade, then polished to show the location of the lami nae. The calcite in the top 8 cm was transparent and layers were hard to disce rn. Calcite samples (~200 to 300 mg) were taken from one half of the speleot hem along visible growth layers and hiatuses using an automated CNC milling mach ine fitted with a fine dental bit for Uranium-series dating. Samples were dated at the University of New Mexico’s Radiogenic Isotope Lab, under the supervi sion of Dr. Yemane Asmerom. Stable isotope samples were taken from t he opposing half using a handheld dremel device with a 0.24 mm dental bit to collect ~80g of sample and processed at the University of South Florida’s College of Marine Science Paleoclimatology, Paleoceanography and Biogeochemistry La boratory in St. Petersburg, Florida under the supervision of Ethan Goddard. 7.5.1 234U-230Th Chronology Adhering to methods described by Po lyak and Asmerom (2001), uraniumseries (234U-230Th) isotope measurements were performed at the Radiogenic Isotope Laboratory, University of New Mexico. 50 to 200 mg of clean carbonate powders for 12 dates were dissolved in ni tric acid and spiked with a mixed 229Th-233U-236U spike to eliminate propagation erro r. U and Th were co-precipitated using FeOH3 and separated using c onventional anion exchange chromatography. The U and Th isotopi c measurements were performed on a Micromass Sector 54 multi-collector thermal ionization mass spectrometer

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295 (TIMS). The TIMS analyses utilized a single i on-counting Daly multiplier in peak jumping mode. Both U and Th isotopes ar e measured on the ion-counting Daly multiplier with abundance sensitivity in the range of 20 ppb at one mass distance in the mass range of U and Th, requiring ve ry little background correction, even for samples with large 232Th content. Multiplier dark noise is approximately 0.12 counts per second. 233U/236U ratio (1.0046) was used for fractionation correction for U analyses. Th fractionation in TIMS is negligible. A CRM145 U isotope standard was meas ured with every batch obtaining the conventionally accepted 234U value of -37.09 0.23 ‰ (n=82). 234U= ([234U/238U sample/ 234U/238U secular equilibrium]-1) x103 where, 234U/238U secular equilibrium is equal to the ratio of t he decay constants of 238U and 234U ( 238/ 234). U and Th procedural blanks were in the range of 5-10 picograms and therefore have no effect on ages. Typical analytical uncerta inties are in the range of 0.2% for U isotope composition, with si milar or somewhat lower precision for Th, depending on the age and size of the sample measured. The ages were corrected for initial 230Th (see Table 6.1for 230Th/232Th ratios used). Linear interpolation between dates was used to create an age model for each sample based on U-series dating results. 7.5.2 Stable Isotope Analysis Oxygen stable isotope ratios (16O and 18O) were measured for 189 calcite samples drilled at discrete 1 mm interval s. Approximately 50 m of calcite was weighed for each sample and reacted with anhydrous phosphoric acid at 70C in individual reaction vessels of a Keil III carbonate-extraction system coupled to a

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296 ThermoFinnigan DeltaPlus XL ma ss spectrometer. Precision (2 ) was monitored by daily analyses of the NBS-19 standard and was within <0.1‰ for both oxygen and carbon. Values are repor ted in standard ‰ notation relative to Vienna Peedee belemnite (V-PDB). 7.6 Results 7.6.1 U/Th Dating Dating of BRC03-03 resulted in two peri ods of growth, from ~4kyr to 5kyr BP during the mid-Holocene and from ~20.5kyr BP to 29.5kyr BP during the Late Pleistocene (also referred to herein as the ‘glacial’ period) (Table 7.1). The difference in coloration of the calcite between the two periods is distinct and clearly delineates a hiatus from 20.5kyr to 5kyr BP (Figure 7.3). This contrast in color is likely due to the slower glacial growth rate allowing an increase in the organic acids and trace elements incorporated into the calcite matrix due to more contact with soil and rock surfaces, as is common during cooler, drier periods (Verheyden 2005). As expected with clean calcite, errors were low with respect to the U/Th ages.

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297 Sample mm from Top238U (ppm)230Th (ppm)230Th/232Th (ppm) 234Ui 234U/238U230Th/238U Uncorrected Age (yr B.P.) Corrected Age (yr B.P. ) 1BRC03-03220.495 0.0020.00020 0.000031695.576 234.19053.1 4.11.052 0.0040.041 0.0014,313 1254313 125 BRC03-03320.487 0.0020.00007 0.000024884.488 1688.53451.8 5.81.051 0.0060.042 0.0014,463 1454,461 145 BRC03-03410.365 0.0030.00012 0.000022210.392 400.22756.8 6.31.056 0.0060.045 0.0014,743 1154,738 115 BRC03-03640.598 0.0020.00033 0.000021382.019 65.03451.6 2.21.051 0.0020.047 0.0024,939 1834,931 183 BRC03-03780.544 0.0010.00844 0.0000257.93 0.03255.7 0.91.055 0.0010.016 0.00015,824 665,088 372 BRC03-03820.405 0.0010.00106 0.000021164.449 18.94454.7 4.21.052 0.0040.186 0.00421,244 53421,078 534 BRC03-031110.446 0.0010.00023 0.000026560.814 588.75849.5 3.11.046 0.0030.211 0.00424,507 46724,482 466 BRC03-031291.023 0.0060.00018 0.0000221424.532 2528.48441.5 3.61.039 0.0030.224 0.00426,548 58126,540 581 BRC03-031460.728 0.0060.00014 0.0000220716.540 2749.14045.1 5.11.042 0.0050.243 0.00429010 61729,001 617 BRC03-031650.516 0.0020.00016 0.0000212588.754 1876.36947.7 4.81.044 0.0040.244 0.00229,033 34829,018 348 BRC03-031890.620 0.0030.00014 0.000013301.469 348.550.8 4.71.047 0.0040.246 0.00529,256 68029,245 680BRC03-03 U/Th DatesAll ages for BRC03-03 corrected using a 230Th/232Th initial ratio of 7.5 x 106 50% ppm. All errors are absolute 2 Table 7.1 U-series dates for BRC03-03.

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298 Figure 7.3 BRC03-03 with dated layers indicated. The clear, clean calcite p ro v ides low-error U/Th dates. The red line delineates the hiatus in growth between the mid-Holocene and Late Pleistocene sections.

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299 7.6.2 Stable Isotope Results Results from this study show cons iderable variability between the growth periods (mid-Holocene vs. Late Plei stocene) in the range of both the 18O and 13C values. During the Holocene period, 18O values ranged from -2.9 ‰ to -4.3‰ and 13C values ranged from -8.7‰ to -11. 1‰ (Figure 7.4). In contrast, the Pleistocene 18O values (-1.6‰ to -3.4‰) and 13C values (-4.7‰ to -10‰) have much greater range and variability (F igure 7.5). Major is otopic depletion of both 18O and 13C occur during the glacial period around 24 kyr BP, reaching -3.4‰ and -10‰, respectively. Several smal ler isotopic excursions towards both depleted and enriched values of both st able isotopes occur during both growth periods and are discussed below.

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300 Figure 7.4 BRC03-03 mid-Holocene 18 O and 1 3 C data.

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301 7.7 Discussion This location is ideal to study the mu ltiple influences on climate in Florida during a peak glacial period, due to its proximity to both t he Gulf of Mexico (GOM) and North Atlantic Ocean, which bot h play significant roles in glacialinterglacial cycles. Studies by va n Beynen et al. (2007a, 2007b, 2008) and Chapter 6 previously illustrated the co mplexity of teleconnection mechanisms acting upon Florida’s climate, and it c an be assumed these likely also affected the region during the span of BRC 03-03’s growth, though with reduced intensities. However, during periods of such major environmental change Figure 7.4 BRC03-03 Late Pleistocene (glacial) 18 O and 1 3 C data.

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302 temperature and source water compos ition must also be considered when interpreting the isotopic record from BRC03-03. 7.7.1 Oxygen Isotope Interpretation The difference in the average speleothem 18O values between the midHolocene (-3.6‰) and glacial period (-2.7‰) can be attributed to changes in the isotopic composition of the source water, controlled to some degree by temperature, from which the precipitation feeding the speleothem is derived (Figure 7.6) (Dorale et al. 1992). Ba sed on the difference in the average 18O values between the mid-Holocene and glacia l period, using the relationship of 0.24‰/ 1C (Friedman and O’Neil 1977), the te mperature during the last glacial would have been ~4C cooler than during the mid-Holocene, and approximately 8C cooler than modern ti mes (based on the average 18O value from BRC03-02 in Chapter 6). For the lowlatitudes, this estimate is within the approximated ranges of other terrestrial proxy records (Wang et al. 2001), but differs slightly from ice core estimates t hat suggest up to a ~15C di fference for higher latitudes (Blunier et al. 2004).

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303 Figure 7.6 BRC03-03 oxygen isotope comparison. Comparison of BRC03-03 mid-Holocene and Late Pleistocene 18 O data, showing averages for each period. The green line indicates the modern 18O average from the BRC03-02 speleothem discussed in Chapter 6.

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304 During the last glacial peri od, much of the available 16O was stored in the massive ice sheets in Greenland and North America (Bradley 1999). This ice volume effect causes glacial ocean wate r to be isotopically enriched compared to that of the Holocene, when warmer conditi ons contributed to melting of the ice sheets, thus resulting in a reintroduction of the isotopically lighter meltwater into the oceans. This is shown in the 18O values of BRC03-03, which become progressively lighter (mor e negative) from the glacial period to modern times (Figure 7.6), reflecting the increasing cont ribution of isotopically-light meltwater caused by deglaciation. While this accounts for the overall more enriched (positive) 18O values during the glacial period, also significant is the large variability seen in the 18O values during glacial period, and to a lesser extent in the Holocene 18O data (Figure 7.6). These variations are attr ibuted to changes in regional climate teleconnections and the amount effect, henc e the smaller magnitude, short-term shifts in the isotopic record are super imposed over the long-term, isotopicallylower average glacial and mid-Holocene 18O values. I propose the major shifts between the mid-Holocene and glacial 18O values results from the aforementioned ic e volume effect and the calcite-water temperature-dependent fracti onation, and this is suppor ted by the accompanying large shifts in the 13C data (Wang et al. 2001; Holmgren et al. 2003) (Figures 7.4 and 7.5). However, the in ter-period variation in 18O values during the midHolocene and Late Pleistocene is likely c aused by the amount effect, caused by changes in convective storm intensity in both the GOM and North Atlantic Ocean

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305 (see Chapter 6). Under this interp retation, more negative (depleted) 18O values indicate wetter conditions, also likely from warmer temp eratures causing increased evaporation and convection. Additi onal evidence for this explanation is the difference in the average speleothem 18O values between the mid-Holocene and glacial periods, where more negative 18O values characterize the warmer, wetter mid-Holocene; hence, trends toward more negative values in the glacial period also reflect increased pr ecipitation and temperatures. 7.7.2 Carbon Isotope Interpretation Regarding the 13C data (Figure 7.5), the variabi lity in the record is much higher during the glacial period (~5.3‰), which is likely due to more drastic climate extremes causing sh ifts in the abundance of C3 to C4 vegetation due to varying precipitation amounts (Dorale et al. 1992). The close synchronicity of the 13C and 18O records during the glacial period indicate rapid vegetation response to changing climate conditions (Dor ale et al. 1992; Gent y et al. 2003). The mid-Holocene 13C values reflect a more stable climate showing a range of ~2.4‰, which is less than hal f of the range seen in the glacial 13C values, thereby implying wetter condition s characterized by more abundant C3 vegetation during this interglacial period. The 13C values for this period also track the 18O values, but the agreement is not as close as during the glacial period (Figures 7.4 and 7.5). This is likel y attributable to a more muted response of the vegetation during a more stable midHolocene climate, thereby leading to less severe vegetation responses.

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306 7.7.3 Growth Rates Why did BRC03-03 start growing prior to the last glacial maximum for ~10 kyr? According to the U/Th dates, BRC 03-03 deposition started in the glacial period around 30 kyr BP. This is an accept ed time for the occurrence of Heinrich event 3 in multiple records (Schulz et al. 1998; Cacho et al. 1999; Stuiver and Grootes 2000; Hemming et al. 2004), and may be indicative of this event being comparatively wetter than the precedi ng Heinrich events in Florida. One important testament to the difference betw een the climate of the glacial and mid-Holocene period in Florida is the amount of calcite for BRC03-03 (~8 cm/~1kyr) during the Holocene compar ed to ~10 cm over ~10 kyr during the glacial period. This stark difference in growth rates is robust evidence for a warmer, wetter Holocene in the region com pared that of glacia l conditions in the Late Pleistocene. As for the hiatus and subsequent resumption of growth (Figure 7.3), the speleothem ceased growth at t he coldest, driest period at ~20 kyr BP during the last glacial maximum (LGM) (Bluni er et al 2004). It is also possible that lower sea-level contributed to a change in the hydrology of the area and the lower water table altered water flow to the cave and prevented further calcite deposition until the warmer, wetter midHolocene when sea-levels rose again and altered the hydrology such that spel eothem growth occurre d for another 1kyr period from ~5 to 4 kyr BP. 7.7.4 Heinrich Event 2 An abrupt negative shift in 18O around 24 kyr BP (~2‰), occurs at the time of Heinrich Event 2 (H2) (Hemming et al. 2004) (Figure 7.7). This event is

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307 preceded by two distinct, gradual periods of higher 18O (~-1.7‰) punctuated by a less pronounced (wetter) (~-2.7‰) ev ent lasting approximately 1,500 years (Figure 7.7). Dansgaard-Oeschger precursors to Heinrich events, such as the one seen prior to H2 in the BRC03-03 18O record, are found in other records with a cyclicity of ~1,500 years (Bond et al. 1999). These are suggested to be related to rapid changes in temperature caused by solar forcing near Greenland, which generates the calving of icebergs building up to Heinrich events, and likely would affect precipitation amounts in the study area. During the last glacial period, t he Laurentide Ice Sheet (LIS) underwent Figure 7.7 Evidence of H2. The BRC03-03 Late Pleistocene 18 O data clearly showing the more negative excursion of Heinrich event 2 at ~24kyr BP. H# also appears to be present around 30 kyr BP when speleothem deposition began.

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308 several advances and retreats, releasi ng vast amounts of freshwater during melting events (Heinrich events) (Bond and Lotti 1995; Bond et al. 1999). This flux of freshwater would have dischar ged into the paleoMississippi and St. Lawrence Rivers, creating an in flux of isotopically depl eted freshwater into the GOM and North Atlantic, both of which ar e moisture sources for the Florida peninsula. Consequences of this cool fr eshwater would have included a slowing down of the North Atlantic Deep Water (N ADW) formation and possibly stalling of the Gulf Stream, thereby producing relati vely warmer conditions in the GOM and subtropical southeastern United States (Grimm et al. 2006). Warmer conditions would enhance evaporation and convective storm activity; therefore, a shift toward more negative 18O values in BRC03-03 during H2 is likely a product of both isotopically-lighter source wate r and increased precipitation amount. 7.7.5 Proxy Comparisons Comparison of the glacial BRC0 3-03 data to other regional records indicates agreement in the timing (~24 kyr BP) of H2. Pollen analyses from Lake Tulane sediment (Watts and Hansen 2004; Grimm et al. 2006; Huang et al. 2006) show an increase in Pinus during H2, which also supports the evidence of warmer, wetter conditions seen in the BRC03-03 18O (and 13C) data during this period (Figure 7.6). However, the pollen record’s resolution is too low to show the precursor events. A study by Ellw ood and Gose (2006) examining magnetic susceptibility in Hall’s Cave in Texas al so found evidence for mild, wet Heinrich events in the GOM region, further suppor ting the interpretation of the Lake Tulane sediment records and BRC03-03’s oxygen isotopes.

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309 Other records showing agreement in t he timing of H2 from geographically distant locations include Hulu Cave in China (Wang et al. 2001) and the GISP2 (Grootes et al. 1993), GRIP (Blunier et al. 1998), and Vostok (Petit et al. 1999) ice core records, shown in Figure 7.8. Regional paleoclimate Interpretations of these various paleoclimate proxies vary from that of the BRC03-03 18O and 13C data, with Heinrich events (characterized by more negative 18O values in the Hulu, GISP2 and Vostok records) being colder events in the these areas. The slowing of NADW formation would explain t he cooler conditions in these regions, which fits with the warming trends in the GOM (Hill et al. 2006). The GRIP core’s anomalous 18O trend compared to the other ice core records is attributed to local climate effects (Blunier et al. 1998) All of the records clearly show the precursor events building up to the H2 and also give an indication of the timing of H3 and possibly explain the slight del ay of BRC03-03 b eginning deposition during this period (Figure 7.8).

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310 Figure 7.8 BRC03-03 proxy record comparisons. Comparison of the BRC03-03 Late Pleistocene 18O data, clearly showing H2 at ~24kyr BP, to other proxies. From the top: Hula Cave (Wang et al. 2001) reversed; Vostok ice core (Petit et al. 1999) reversed; GRIP ice core (Blunier et al. 1998) reverse; and GISP 2 (Grootes et al. 1993). The blue (cool) to red (warm) gradient lines indicate the interpretation of each record’s proxy data. Blue (wet) to brown (dry) is used for the

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311 7.8 Conclusions Evidence from BRC03-03 18O data indicates a drier, cooler Late Pleistocene climate in Florida, and mu ch warmer, wetter conditions during the mid-Holocene, with up to a ~4C diffe rence in temperature between the two periods and further warming through to modern conditions. Temperature and ice volume effects on the 18O signal of source water for BRC03-03 are likely accountable for the major changes in the is otopic record between these periods, with the amount effect super imposed on both the glacia l and mid-Holocene data, thus accounting for the minor shortterm variations within each period. Corroborating evidence is seen the 13C variability, resulting from major shifts in vegetation between glacial an d interglacial periods. When compared to the data in Chapter 6 from BRC03-02’s 18O values (average -4.7‰), it is interesting to not e the approximate 1‰ gradient of more depleted values from the gl acial periods through to modern conditions, which clearly shows the process of deglaciation an d its effect on Flor ida’s climate. The results from Chapter 6 also indicated the strong role teleconnections have on Florida’s precipitation, with the ITCZ, ENSO/PDO, and the NAO all contributing to rainfall variability. The existence of m illennial and centennial (although no time series analysis was performed) cycles in the BRC03-03 data seems visually evident, and if 18O variability is linked to so lar forcing of teleconnection mechanisms, as proposed in the BRC03-02 record, it would account for these periodicities in the record.

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312 Evidence of H2 is prominent in t he BRC03-03 data, as corroborated by agreement with several other ice core and cave proxies (Grootes et al. 1993; Blunier et al. 1998; Petit et al. 1999; W ang et al. 2001), including those in Florida (Grimm et al. 1993; 2006, H uang et al. 2006) for the la st 50kyr BP. In agreement with the regional records, H2 is characte rized by warmer, wetter conditions in the study area and supports the explanation of a warme r GOM from decreased NADW and subsequent weakening of the Gulf Stream, thereby allowing for increased evaporation and conv ection during this period. Changes in the GOM and North Atlantic sea surface temperat ures may have impacted the position of the ITCZ, which could account for the changes in precipitation. Altogether, the BRC03-03 data clear ly demonstrates the subtropical response to climate variability during the la st glacial period differed from that of northerly latitudes. Linkages betw een Northern and Southern hemisphere feedback mechanisms may account for the anomalous response to H2 in BRC03-03, which is both abruptly synchr onized with other global records in its timing and differs in that it was warm and we t in Florida, compared to the cool and dry condition seen in other regions A higher-resolution sampling of the stable isotopes from BRC03-03 combi ned with trace element and time series analysis may better elucidate the timing and magnitude of Heinrich events, as well as the differences in climate c onditions between the mid-Holocene and Late Pleistocene in Florida. Fluid inclusion ana lysis would also assist in improving the temperature difference estimation between modern and glacial climate conditions in the region.

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313 7.9 Chapter Acknowledgements Special thanks to Victor Poly ak and Yemane Asmerom for dating assistance. Thanks to Ethan Goddard for st able isotope analysis. I also want to credit Limaris Soto for preliminary analysi s of the speleothem data. This study would not have been possible without the ai d of Robert Brooks, Tom Turner, and Lee Florea for assistance with cave access and sample collection. This work was funded by a University of South Fl orida Internal Grant and SWFWMD. 7.10 Chapter References Alley, R.B., Anandakrishnan, S., and Jung, P. 2001. Stochastic resonance in the North Atlantic. Paleoceanography 16(2): 190-198. Arz, H.W., Ptzold, J. and Wefer, G. 1998. Correlated millennial-scale changes in surface hydrography and terrigenous sediment yield inferred from lastglacial marine deposits off northeastern Brazil. Quaternary Research 50: 157-166. Bard, E., Rostek, F., Turon, J.L., and G endreau, S. 2000. Hydrol ogical impact of Heinrich events in the s ubtropical Northeast Atlantic. Science 289: 13211323. Blunier, T., Chappellaz, J., Schwander, J. Dllenbach, A., Stauffer, B., Stocker, T., Raynaud, D., Jouzel, J., Claus en, H.B., Hammer, C.U., and Johnsen, S.J. 1998. Asynchrony of Antarctica and Greenland climate during the last glacial. Nature 394: 739-743. Blunier, T., Schwander, J. Chappellaz, J., Parrenin F., and Barnola, J.M. 2004. What was the surface temperature in central Antarctica during the last glacial maximum? Earth and Planetary Science Letters 218(3-4): 379-388/ Bond, G.C., and Lotti, R. 1995. Iceberg disc harges into the North Atlantic on millennial time scales during the last glaciation. Science 267: 1005-1010.

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314 Bond, G.C., Showers, W., Elliot, M., Ev ans, M., Lotti, R., Hajdas, I., Bonani, G., and Johnson, S. 1999. The North Atlantic ’s 1-2kyr climate rhythm: relation to Heinrich events, Dansgaard-Oe schger cycles, and the Little Ice Age. In : Clarke, P.K., Webb, R.S., and Keigwin L.D. (Eds.), Mechanisms of Global Climate Change at Millennial Time Scales Geophysical Monograph 112, 35-58. Bradley, R.S., 1999. Paleoclimatology: Reconstructing climates of the Quaternary 2nd ed. El Sevier Academic Press: San Diego, 613 p. Cacho, I., Grimalt, J.O., Pelejero, C., C anals, M. Sierro, F.J. Flores, J.A., and Skackleton, N. 1999. Dans gaard-Oeschger and Heinri ch event imprints in Alboran Sea paleotemperatures. Paleoceanography 14(6): 698-705. Clark, P.U., Marshall, S.J., Clarke, G.K.C., Hostetler, S.W., Licciardi, J.M., and Teller, J.T. 2001. Freshwater forc ing of abrupt clim ate change during the last glaciation. Science 293: 283-287. CLIMAP Project Members. 1984. T he last interglacial ocean. Quaternary Research 21: 123-224. Dansgaard, W., Clausen, H.B., Gundestrup, N., Johnsen, S.J., and Rygner,C.1985. Dating and climatic in terpretation of two deep Greenland ice cores. In : C.C. Langway, H. Oeschger and W. Dansgaard (eds) Greenland Ice Core. Geophysics, Geochemistry and the Environment Geophysical Monograph, AGU, Washington, DC: 71–76 p. Dorale, J.A., Gonzalez, L.A., Reagan, M.K., Pickett, D.A., Murrell, M.T., and Baker, R.G. 1992. A high-resolution re cord of Holocene climate change in speleothem calcite from Cold Water Cave, Northeast Iowa. Science 258: 1626-630. Ellwood, B.B., and Gose, W. A. 2006. Heinrich H1 and 8200 yr B.P. climate events recorded in Hall’s Cave, Texas. Geology 34(9): 753-756. Florea, L.J., Vacher, H.L., Donahue, B., and Naar, D. 2007. Quaternary cave levels in peninsular Florida. Quaternary Science Reviews 26:1344-1361. Ford, D.C. and Williams, P.W. 2007. Karst Geomorphology and Hydrology. Wiley : West Sussex, England, 2nd ed., 576 p. Friedman, I., and O’Ne il, J. R. 1977. Compilation of stable isotope fractionation factors of geochemical interest USGS Prof. Paper 440-KK.

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315 Frumkin, A., Carmi, I., G opher, A., Ford, D., Schwarcz, H.P., and Tsuk, T. 1999a. A Holocene millennial-scale climat ic cycle from a speleothem in Nahal Qanah Cave, Israel. The Holocene 9(6): 677-682. Gascoyne, M. 1992. Palaeoclimate determi nation from cave calcite deposits. Quaternary Science Reviews 11: 609-632. Genty, D., Blamart, D., Ouahdi, R., Film our, M., Baker, A., Jouzel, J., and VanExter, S. 2003. Precise dating of D ansgaard-Oeschger clim ate oscillations in Western Europe fr om stalagmite data. Nature 421: 833-837. Grimm, E.C., Jacobson, G.L, Watts, W. A., Hansen, B.C.S., and Maasch, K.A. 1993. A 50,000 year record of climat e oscillations from Florida and its temporal correlation with the Heinrich events. Science 261(5118): 198200. Grimm, E.C., Watts, W.A., Jacobson, G.L., Hansen, B.C.S., Almquist, H.R., and Dieffenbacher-Krall, A.C. 2006. Evidence for warm wet Heinrich events in Florida. Quaternary Research 25: 2197-2211. Grootes, P.M., M. Stuiver, J.W.C. Whit e, S.J. Johnsen, and J. Jouzel.1993. Comparison of oxygen isotope records from the GISP2 and GRIP Greenland ice cores. Nature 366, 552-554. Heinrich, H. 1988. Origin and consequences of cyclic ice rafting in the northeast Atlantic Ocean during the past 130,000 years. Quaternary Research 29: 142-152. Hemming, S.R. 2004. Heinrich events: massi ve late Pleistocene detritus layers of the North Atlantic and t heir global climate imprint. Review of Geophysics 42: RG1005. Hill, H.W., Flower, B.O., Qu inn, T.M., Hollander D.J., and Guilderson, T.P. 2006. Laurentide Ice Sheet meltwater and abr upt climate change during the last glaciation. Paleoceanography 21: PA1006, doi:10. 1029/2005PA001186. Holmgren, K., Lee-Thorp, J.A., Cooper, G.R.J., Lundbald, K., Partridge, T.C., Scott, L., Sithaldeen, R., Talma, A. S., and Tyson, P.D. 2003. Persistent millennial-scale climatic variability over the past 25,000 years in Southern Africa. Quaternary Science Reviews 22: 2311-2326.

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316 Huang, Y., Shuman, B., Wang, Y., Webb, T., Grimm, E.C., and Jacobson, G.L. 2006. Climatic and environmental c ontrols on the variation of C3 and C4 plant abundance in central Flor ida for the past 62,000 years. Palaeogeography, Palaeoclimat ology, Palaeoecology 237: 428-435. Lynch-Stieglitz, J. 2004. Hemispheric asynchrony of abrupt climate change. Science 304: 1919-1920. Masson, V., Vimeux, F., Jouzel, J., Mor gan, V., Delmotte, M., Ciais, P., Hammer, C., Johnsen, S., Lipenkov, V.Y., Mosley-Thompson, E ., Petit, J.R., Steig, E.J., Stievenard, M., and Vaikmae, R. 2000. Holocene climate variability in Antarctica based on 11 ice-core isotopic records. Quaternary Research 54: 348-358. Peck, V.L., Hall, I.R., Zahn, R., Grousset, F., Hemming, S.R., and Scourse, J.D. 2007. The relationship of Heinrich events and their European precursors over the past 60ka BP: a multi-proxy ice-rafted debris provenance study in the North East Atlantic. Quaternary Science Reviews 26: 862-875. Petit, J. R., Jouzel, J., Raynaud, D., Bark ov, N. I., Barnola, J. M., Basile, I., Benders, M., Cappellaz, J., Davis, M., Delaygue, G., Delmotte, M., Kotlyakov, V. M., Legrand, M., Li penkov, V. Y., Lorius, C., Pepin, L., Ritz, C., Saltzman, E., and Stievenard, M. 1999. Climate and atmospheric history of the past 420, 000 years from the Vostok ice core, Antarctica. Nature 399(3): 429-436. Polyak, V.J. and Asmerom, Y. 2001. Late Holocene climate and cultural changes in the Southwestern United States. Science 294: 148-151. Reeder, P. and Brinkmann, R. 1998. Paleoe nvironmental Reconstruction of an Oligocene-Aged Island Remnant in Florida, USA Cave and Karst Science 25: 7-13. Schulz, H., van Rad, U., and Erlenkeus er, H. 1998. Correlation between Arabian Sea and Greenland climate oscillat ions of the past 110,000 years. Nature 393: 54-57. Scott, T.M. 1997. Miocene to Holocene History of Florida. In : Jones, D.S. and Randazzo, A.F., (eds.). The Geology of Florida University Press of Florida: Gainesville, p. 1-12. South East Regional Climate Cent er. Accessed September 2006 at http://cirrus.dnr.state.sc.us/cgi -bin/sercc/cliMAIN.pl?fl1046.

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317 Stoner, J.S., Channell, J.E.T., Hillaire -Marcel, C., and Kissel, C. 2000. Geomagnetic paleointensit y and environmental record from Labrador Sea core MD95-2024: global marine sedim ent and ice core chronostratigraphy for the last 110 kyr. Earth and Planetary Science Letters 183: 161-177. Stuiver, M., and Grootes, P.M. 20 00. GISP2 oxygen isotope ratios. Quaternary Research 53: 277-283. Wang, Y.J., Cheng, H., Edwards, R.L., An, Z.S., Wu, A.Y., Shen, C.C., and Dorale, J.A. 2001. A high-resoluti on absolute-dated late Pleistocene monsoon record from Hulu Cave, China. Science 294: 2345-2348. Watts, W.A., and Hansen, B.C.S. 1994. Pre-Holocene and Holocene pollen records of vegetation hi story from the Florida peni nsula and their climatic implications. Palaeogeography, Palaeoclim atology, Palaeoecology 109: 163-176. Watts, F.C., and Collins, M.E. 2008. Soils of Florida Soil Science Society of America Inc.: Madison, WI, 88pp. Willard, D.A., Bernhardt, C.E., Brooks, G.R., Cronin, T.M., Edgar, T., and Larson, R. 2007. Deglacial climate variabi lity in central Florida, USA. Palaeogeography, Palaeoclimat ology, Palaeoecology 251: 366-382. van Beynen. P.E., Soto, L., Pace-Graczyk, K., 2007a. Paleoclimate reconstruction derived from speleothem strontium and 13C in Central Florida. Quaternary International 187(1): 76-83. van Beynen, P.E., Asmerom, Y., Polyak, V., Soto, L., Polk, J.S., 2007b. Variable intensity of teleconnections during the Late Holocene in Subtropical North America from an isotopic study of speleothem from Florida. Geophysical Research Letters 34: L18703, doi:10:1029/2007GL031046. van Beynen, P.E., Soto, L., Polk, J., 2008. Variable calcite deposition rates as proxy for paleo-precipitation determinat ion as derived from speleothems in Central Florida. Journal of Cave and Karst Studies 70 (1): 1-19. Verheyden, S. 2005. Trace elements in spel eothems: a short re view of the state of the art. Speleogenesis and Evolution of Karst Aquifers 3 (1). Republished from International Journal of Speleology 2004, 33(1/4): 97104.

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318 Chapter 8 Conclusions and Implications When the well is dry, we know the worth of water. -Benjamin Franklin 8.1 Conclusions The overarching question posed in this dissertation was how have perturbations in climate affected tropica l and subtropical karst regions in the past? Ultimately, I addressed this question through a variety of studies presented in the previous chapters that focused on t he main concepts of: (1) the ability of climate change to influence the existence of a past society in a karst setting; (2) the utility of cave sediments for paleoe nvironmental reconstruction, (3) the complexity of understanding mechanisms of climate change affecting the tropics and subtropics, and (4) the sensitivity of subtropical karst proxies to global climate change and their potential to furt her elucidate the linkages between teleconnection mechanisms affecting long-term climate change. The first chapter of this dissertat ion highlights the importance of water scarcity, both from anthropogenic and c limatic causes, which together can potentially culminate in catastrophic societal and environmental consequences.

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319 Chapter 3 presents the results of my research on the past Maya collapse stemming from this very problem, in cluding the possible underlying climate implications using a new method for paleoenvironmental reconstruction. Chapters 4-7 present the resu lts of my research attempting to address this same problem in west-central Florida through reconstructions of both modern and longterm climate change mechanisms to better understand their possible influence on the social and physical aspects of tropi cal and subtropical regions. Below is a critical summary of the results from each chapter. Chapter 3 provides further evidence for t he climatic contribution to Maya collapse through the novel use of fulv ic acid carbon isotopes from cave sediments. This pilot study in Belize, Central America shows the influence of anthropogenic disturbance and climate change on the landscape during the Maya occupation using cave sediment fulvic acid carbon isotopes as a paleoenvironmental proxy. The results conf irm the detrimental effects of climate change on the demise of the Maya in Beliz e, and illustrates the utility of cave sediments as a possible high-resoluti on proxy for climate and environmental change in karst areas lacking other proxies. The low-resolution sampling and lack of further proxy comparisons limit ed the usefulness of this technique, therefore spurring the study presented in Chapter 4. Chapter 4 expands upon the cave sedime nt study in Chapter 3 from Belize by providing additional data confi rming the robustness of high-resolution cave sediment fulvic acid carbon isot ope analysis as a paleoenvironmental proxy in west-central Florida. The Jennings Ca ve carbon isotope record of ~3,000

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320 years shows isotopic changes concurrent with nearby speleothem records of climate change, and close agr eement with speleothem oxygen records in the area indicate precipitation amount to be the primary contro l on past vegetation shifts in Florida. An interesting result from Chapter 4 is the complexity of cave sediment processes in the region based on the result s of the attempted calibration of the modern Vandal Cave sediment core. Alternating layers and consistent carbon isotope values in the core suggest seas onal, episodic precipitation events likely dominate the sediment record, making it difficult to discer n individual precipitation events, and that only subtle changes in climate over the last few decades have likely occurred. Overall, the results s how both the strengths and weaknesses of using cave sediment carbon isotopes as paleoclimate proxies, but point to their usefulness when appropriate locations are selected and thorough analyses are performed to calibrate the data. Further st udy of Florida cave sediments using a modern sediment trap, additional radi ocarbon dates, and corresponding records from other nearby caves cont aining sediment would impr ove the results of this research and possibly more clearly eluc idate how sediments record climate change in Florida. Chapter 5 expanded upon a study conducted by Onac et al. (2008) investigating the isotopic com position of precipitation a nd cave dripwater in westcentral Florida. Results indicate that the amount effect dominates the isotopic composition of the rainfa ll and provide a modern calibration for the interpretation of speleothem isotope studies in the area. The droughty conditions during the

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321 period of collection can be attributed to phasing of atmospheric teleconnections (ENSO and NAO), while synoptic weather data provide further evidence of the amount effect by showing that more intense storms with higher convection heights (characteristic of summer storms) produce higher amount s of isotopically depleted (more negative) rainfall. Additionally, the cave dripwater re sults indicate homogenization of the precipitation in the epikarst, producing a similar annual average 18O value as that of the amount weighted annual average 18O value of precipitation. One result not seen in Chapter 5 was evidenc e of a clear lag time between an intense storm event (Tropical Sto rm Fay) and its isotopic sign ature in the dripwater. Collection of drip rates may have assi sted in delineating a lag time. While Chapter 5 does not conclusively provi de data regarding how teleconnection conditions affect the isotopic condition of precipitation in west-central Florida due to its one year duration, it does present a foundation for interpreting speleothem oxygen isotopes in the area. By collecting dripwater and precip itation data, along with synoptic weather data, for additi onal years in Legend and other nearby caves, a more comprehensive understandi ng of how modern climate change is manifested in dripwater and speleothem ca lcite could be achieved. Also, using a drip rate counter would assist with under standing the hydrology of the epikarst and response time of the drip water to rain events. Chapters 6 and 7 collectively examine Florida’s paleoclimate through the last 30,000 years using speleothem records from Brooksville Ridge Cave and expand on work by van Beynen et al. (2007a, 2007b, 2008). Chapter 6 presents

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322 a high-resolution record of climate change for the last 1500 years, using carbon and oxygen isotopes, trace elements, and time series analysis. The results indicate the amount effect dominates prec ipitation in west-cent ral Florida, thus controlling the speleothem isotopic signal, an d further validating the results from Chapter 5. The speleothem record indi cates the changes in precipitation in response to varying teleconnection infl uences affecting the Gulf of Mexico, clearly highlighting the clim ate of the LIA and MWP in th e region. Specifically, the results demonstrate the complexity of teleconnection influences on Florida’s climate over the long-term, showing t hat Pacific (ENSO and PDO) and Atlantic (NAO and AMO) influences both play major roles in controlling precipitation, and to a surprisingly greater extent, so does t he ITCZ. Collectively, the intensities of these teleconnections and their interactions may be driven by solar forcing, as shown by agreement between the BRC03-02 18O data and solar irradiance over the last 1500 years. Chapter 7 extends the BRC03-02 speleothem record back through the mid-Holocene (~4 to 5 kyr BP) and the Late Pleistocene (~20 to 30 kyr BP), providing snapshot glimpses of how Fl orida’s climate vari ed between glacial and interglacial conditions. In general, it was expected that the climate of the region would vary between these two periods; how ever, the results reveal not only a possible significant difference in temperat ure and precipitation patterns, but also a contrast in the subtropical response to Heinrich event 2, indicating warmer, wetter conditions, compared to more norther ly latitudes where these events are usually seen as colder and drier. This result agrees with the finding of other

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323 studies in the area and shows that larger global scale climate mechanisms affect Florida’s climate in addition to the regi onalized teleconnections affecting it on centennial to multidecadal scales. Additional Uranium-series dating for both speleothems would improve dating control of major climate events, while a more complete cross-spectral analysis of the records com pared to the BRC03-02 data w ould allow for statistical correlations between the data sets to better determine their agreement and the major influential teleconnections over ti me. Collection and analysis of dripwater from the stalactite feeding this sample would also provide a more direct connection between the modern climate change mechanisms and their effect on the carbon and oxygen isotopic values of speleothem calcite in BRC. The BRC03-03 sample would benefit from higher-resolution isotope sampling to better constrain the Heinrich event and a llow for time-series analysis to delineate any major oscillations or periodici ties seen in the isotopic record. Collectively, the results from Chapter s 4-7 show subtropi cal Florida’s past climate is varied and complex, havi ng undergone several abrupt changes since the Late Pleistocene. Furthermore, this di ssertation also presents the ways in which proxy records from cave deposits provide invaluable clues to these past climate changes. Rarely does a single fact or explain the cause of past climate change, therefore underst anding natural climate variabilit y at different temporal and spatial scales is necessary to el ucidate the multiple teleconnection mechanisms affecting climate change.

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324 Through this research, the overar ching question regarding changes in subtropical and tropical c limate change in the past was successfully answered on various levels for both Florida and Be lize using speleothem and cave sediment proxy records. While this study is not spatially comprehensive regarding the subtropics and tropics, Florida’s transitionzone location provides insight on the possible paleoclimatic changes occurring in the past in the region caused by both local and global influences, which also likely affected other subtropical and tropical locations. Additional research using speleothems and sediments from other subtropical and tropical locations would substantially expand to the contribution of this study to understanding past climate changes in these areas. 8.2 Implications The case of the Maya in Belize provides evidence of how climate uncertainties can enhance Malthusian cond itions and lead to population demise, even for what are perceived as advanced ci vilizations. While the current state of technology and knowledge obviously trump that which was available during the time of the Maya, the curr ent global threat of climate change presents more of a challenge than just the regional impacts seen in Central America 1,400 years ago. Understanding the social and physica l implications of climate change is critical in areas like Florida that are vulnerable to drought, flooding, saltwater intrusion, sea level rise, and frequent hurricane strikes. Water is one of the common themes that bind the chapters of this dissertation together. In C hapter 1, I focused on th e importance of climate

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325 change, especially in regard to water resource availability and the modern manifestation of this relationship in west -central Florida, where a water shortage alert from severe drought was recently put into effect (SWFWMD 2009). The results of this dissertation culminates in a plethora of information applicable to better understanding the complexities of futu re climate variability in this region and its potential impacts on water resources. In his book Collapse: How Societies Choose to Fail or Succeed professor of geography Jared Diamond postulated on the complications of researching climate change and society (Diamond 2005, p. 11). When I began this book, I didn’t appreciate those complications, and I navely thought that the book would just be about environmental damage. Eventually, I arrived at a five-point framework of possible contributing factors that I now consider in trying to understand any putative environmental collapse. Four of those sets of factorsenvironmental damage, climate change, hostile neighbors, and friendly trade partnersmay or may not prove significant for a particular society. The fifth set of factorsthe society’s responses to its environmental problemsalways proves significant. Dr. Diamond astutely realized the one vari able that is inherently complicated and unpredictable in conducting climate change research. The controllable variables are the location, region, time scale and methodology, but the unpredictable variables are those of human response to and application of, the data toward mitigating future climate change scenarios. It is my hope that the results from this dissertation will be used to more accurately assess the future implications of climate change in west-central Florida with regard to water resource availability.

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326 Dissemination of this data to policymak ers could help spur the development of more appropriate long-term mitigation strategi es to alleviate the impacts of future climate change on Florida’s unique karst aquifer. While by no means all-inclusive, this dissertation represents pioneering research regarding the use of cave sediments for paleoenvironmental reconstruction and lays a solid foundat ion for understanding the interrelated teleconnections influencing the climate of west-central Florida. The multitude of data presents another piece of the vast c limate change puzzle we currently face. Additionally, it points to the importance of preserving karst features, especially caves, as they may yield the most signi ficant paleoclimate proxies in tropical and subtropical areas where ot her types of paleoclimate pr oxies are often limited. 8.3 Chapter References Diamond, J. 2005. Collapse: How Societies Choose to Fail or Succeed. Viking: New York. 575 p. Onac, B.P., Pace-Graczyk, K., and Atudire i, V. 2008. Stable isotopic study of precipitation and cave drip water in Florida (USA): implications for speleothem-based paleoclimate studies. Isotopes in Environmental and Health Studies 44(2): 149-161. Southwest Florida Water Management Dis trict Website. 2009. Accessed at http://www.swfwmd.state.fl.us/. van Beynen. P.E., Soto, L., Pace-Graczyk, K., 2007a. Paleoclimate reconstruction derived from speleothem strontium and 13C in Central Florida. Quaternary International doi:10:1016/j.quai nt.2007.03.019. van Beynen, P.E., Asmerom, Y., Polyak, V., Soto, L., Polk, J.S., 2007b. Variable intensity of teleconnections during the Late Holocene in Subtropical North America from an isotopic study of speleothem from Florida. Geophysical Research Letters 34: L18703, doi:10:1029/2007GL031046.

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327 van Beynen, P.E., Soto, L., Polk, J., 2008. Variable calcite deposition rates as proxy for paleo-precipitation determinat ion as derived from speleothems in Central Florida. Journal of Cave and Karst Studies 70 (1): 1-19.

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328 Appendix A Jennings Cave Sediment Core Description

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329 Appendix A: (Continued) Depth (cm) Layer Color Description Thickness (mm) Grouping 0 1 DB OM/charcoal 10 1 2 BR Clayey OM/charcoal 3 3 Lt. Tan OM/clay 3 4 DB Dark OM/charcoal 4 2 5 DB Dark OM/charcoal 5 6 PY Fine sand 1 7 DB Dark OM/charcoal 4 3 8 DB OM/charcoal 3 9 PY Fine sand 2 10 DB OM/charcoal 1 11 PY Fine sand 1 12 DB OM/charcoal 2 13 Tan Fine sand 1 4 14 DB Heavy OM/charcoal 5 15 PY2.5Y7/4 Fine sand 0.5 16 BR OM/clayey 0.5 17 BR OM 1 18 DB OM/silty 2 19 PY Fine sand 2 5 20 PY Fine sand 5 21 DB OM/charcoal 4 22 PY Fine sand 1 6 23 PY Fine sand 1 24 DB/OR OM/iron staining 4 25 BR OM/fine sand 5 7 26 PY Fine sand 1 27 BR OM 2 28 PY Fine sand 1 29 DB OM/silty 1 30 PY Fine sand 5 8 31 PY Fine sand 10 9 32 Lt. BR Clayey silt OM 2 33 DB OM/charcoal 3 34 DB OM/clayey/charcoal 5 10 35 DB OM/clayey/charcoal 2 36 Dk. Tan OM/red iron stains 3 37 Lt. Tan mixed OM/sand 2 38 DB OM 3 39 PY Fine sand 2

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330 Appendix A: (Continued) 11 40 DB OM 4 41 PY Fine sand 4 42 DB OM 1 43 PY Fine sand 1 12 44 DB OM/charcoal 2 45 PY Fine sand 7 46 DB OM 1 13 47 DB OM/charcoal 4 48 PY Fine sand 6 14 49 PY Fine sand 1 50 DB Heavy OM/charcoal 9 15 51 DB Heavy OM/charcoal 10 16 52 DB Heavy OM/charcoal 4 53 PY Fine sand 6 17 54 O/BR OM/sand/iron stains 7 55 DB OM/charcoal 3 18 56 DB OM/charcoal 2 57 PY Fine sand 8 19 58 PY Fine sand 4 59 BR OM 1 60 PY Fine sand 5 20 61 PY Fine sand 9 62 DB OM/no charcoal 1 21 63 BR OM/sand mix 9 64 DB OM 1 22 65 BR OM/sand mix 4 66 BR OM/sand mix 6 23 67 PY Fine sand 5 68 DB silty OM 5 24 69 PY Fine sand 4 70 DB OM 1 71 DB Heavy OM/charcoal 5 25 72 PY Fine sand 2 73 BL Heavy OM/Heavy charcoal 8 26 74 BR sand/OM mixed 3 75 PY Fine sand 7 27 76 DB OM/charcoal 3 77 PY Fine sand 3 78 BR silty OM 1 79 PY Fine sand 3 28 80 BR mixed OM/sand 10

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331 Appendix A: (Continued) 29 81 DB Heavy OM/charcoal 5 82 PY Fine sand 5 30 83 PY Fine sand 10 31 84 PY Fine sand/trace OM 10 32 85 PY Fine sand 10 33 86 PY Fine sand 8 87 O/BR clayey OM/ iron stains 2 34 88 O/BR clayey OM/ iron stains 10 35 89 O/BR clayey OM/ iron stains 10 36 90 BR mixed OM/sand 8 91 PY Fine sand w/charcoal 2 37 92 BR mixed OM/sand 1 93 PY Fine sand 2 94 BR mixed OM/sand 7 38 95 LYB OM stained fine sand 1 96 DB Clayey silt OM 2 97 DB OM 7 39 98 DB OM/sand unconsolidated 10 40 99 DB OM/sand unconsolidated 8 100 BR mixed OM/sand 2 41 101 PY Fine sand 8 102 PY Fine sand 2 42 103 PY Fine sand 2 104 DB OM/clayey 6 105 PY Fine sand 2 43 106 PY Fine sand 5 107 DB OM/clayey 5 44 108 DB OM/clayey 7 109 PY Fine sand 3 45 110 BR mixed OM/sand 2 111 PY Fine sand 8 46 112 PY Fine sand 1 113 BL OM/charcoal 4 114 BR mixed OM/sand 5 47 115 DB OM 1 116 PY Coarse sand 9 48 117 PY Fine sand 10 49 118 PY Fine sand 10 50 119 PY Fine sand 1 120 DB Heavy OM/charcoal 4 121 PY Fine sand 1

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332 Appendix A: (Continued)122 DB Heavy OM/charcoal 4 51 123 PY Fine sand 2 124 PY Fine sand 4 125 Lt. Tan sandy OM 1 126 PY Fine sand 3 52 127 PY Fine sand 10 53 128 PY Fine sand 10 54 129 PY Fine sand 8 130 BR mixed OM/sand 2 55 131 PY Fine sand 1 132 DB OM/charcoal 6 133 PY Fine sand 3 56 134 PY Fine sand 2 135 DB OM 6 136 PY Fine sand 1 137 DB OM 1 57 138 PY Fine sand 10 58 139 PY Fine sand 4 140 DB Heavy OM/clayey silt 4 141 O/BR clayey sand/iron stain 2 59 142 O/BR clayey sand/iron stain 10 60 143 PY Fine sand 1 144 Lt. Tan sandy OM 1 145 PY Fine sand 1 146 Lt. Tan sandy OM 1 147 PY Fine sand 6 61 148 PY Fine sand 2 149 DB Heavy OM/charcoal 8 62 150 PY Fine sand 1 151 PY Fine sand 2 152 DB Heavy OM/charcoal 7 63 153 DB Heavy OM/charcoal 9 154 BR mixed OM/sand 1 64 155 BR mixed OM/sand 2 156 Lt. Tan sandy OM 1 157 PY Fine sand 1 158 DB Heavy OM/charcoal 5 159 PY Fine sand 1 65 160 PY Fine sand 6 161 BL Heavy charcoal/OM 2 162 PY Fine sand 2

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333 Appendix A: (Continued) 66 163 PY Fine sand 1 164 BR clayey OM 2 165 BL Heavy charcoal/OM 6 166 PY Fine sand 1 67 167 PY Fine sand 1 168 DB Heavy charcoal/OM 6 169 PY Fine sand 3 68 170 PY Fine sand 4 171 DB OM/clayey silt 6 69 172 DB OM/clayey silt 1 173 PY Fine sand 1 174 DB O clayey OM/iron stains 4 175 PY Fine sand 1 176 DB OM/charcoal 3 70 177 DB OM/charcoal 3 178 PY Fine sand 7 71 179 PY Fine sand 1 180 Lt. Tan mixed OM/sand 3 181 PY Fine sand 6 72 182 PY Fine sand 4 183 DB OM/clayey silt 6 73 184 PY Fine sand 2 185 DB Heavy charcoal/OM 7 186 PY Fine sand 1 74 187 DB Clayey OM/charcoal 10 75 188 DB Clayey OM/charcoal 10 76 189 DB Clayey OM/charcoal 10 77 190 BR mixed OM/sand 10 78 191 PY Fine sand 10 79 192 PY Fine sand 10 80 193 PY Fine sand 7 194 Lt. Tan mixed OM/sand 3 81 195 DB OM 1 196 BR finely laminated sand/OM 9 82 197 DB Charcoal rich clayey silt 4 198 PY Fine sand 6 83 199 PY Fine sand 10 84 200 PY Fine sand 9 201 DB Charcoal rich clayey silt 1 85 202 PY Fine sand 10 86 203 PY Fine sand 8

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334 Appendix A: (Continued)204 DB OM 2 87 205 PY Fine sand 1 206 DB OM/silty 3 207 BR mixed OM/sand 2 208 DB OM 2 209 PY Fine sand 2 88 210 PY Fine sand 4 211 DB OM/charcoal 1 212 PY Fine sand 5 89 213 PY Fine sand 10 90 214 PY Fine sand 1 215 Lt. Tan mixed OM/sand 1 216 PY Fine sand 1 217 Lt. Tan mixed OM/sand 1 218 PY Fine sand 1 219 Lt. Tan mixed OM/sand 2 220 PY Fine sand 3 91 221 DB OM 5 222 DB OM/charcoal 5 92 223 PY Fine sand 5 224 DB OM/silty 1 225 PY Fine sand 4 93 226 PY Fine sand 3 227 DB OM 1 228 PY Fine sand 6 94 229 PY Fine sand 5 230 O BR Clayey silt OM 5 95 231 O BR iron stained sand 10 95 232 O BR iron stained sand 10 97 233 O BR iron stained sand 7 234 DB OM 3 98 235 DB OM 8 236 PY Fine sand 2 99 237 PY Fine sand 5 238 DB OM/charcoal 5 100 239 DB OM/charcoal 2 240 BL Heavy charcoal/OM 3 241 DB OM 5 101 242 DB clayey OM 10 102 243 DB clayey OM 10 103 244 DB clayey OM 10

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335 Appendix A: (Continued) 104 245 Lt. Tan mixed OM/sand 10 105 246 Lt. Tan mixed OM/sand 10 106 247 BR clayey OM 10 107 248 BR clayey OM 10 108 248 Lt. Tan mixed OM/clayey silt 8 249 Lt. Tan mixed OM/sand 2 109 250 BR clayey OM 10 110 251 BR clayey OM 10 Avg layer thickness (mm) 4.42 Color Key DB Dark Brown O/DB Orange/Dark Brown BR Brown O Orange PY Pure Yellow GY Grey Lt. BR Light Brown Lt. Tan Light Tan B/PY Brown/Pure Yellow

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336 Appendix B Jennings Cave Sediment Core Data

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337 Appendix B: (Continued) Depth (cm) Age (cal yr BP) FA 13C Bulk 13C HA 13C 0 0.0 -23.94 -22.82 -23.94 1 121.8 -29.93 -30.29 -23.52 2 168.6 -24.00 -22.36 3 214.7 -26.43 -24.16 -22.96 4 260.2 -29.72 -36.85 -24.03 5 305.0 -27.08 -23.71 -27.18 6 349.1 -23.00 -23.49 -23.02 7 392.6 -24.30 -23.19 8 435.3 -22.25 -23.27 9 477.4 -22.73 -23.64 10 518.8 -21.50 -37.06 -23.72 11 559.5 -27.66 -24.38 -22.44 12 599.5 -23.03 -24.71 -23.30 13 638.9 -24.48 -38.88 -22.24 14 677.5 -21.65 -31.76 -22.42 15 715.5 -22.43 -24.40 -22.50 16 752.7 -23.04 -24.53 -21.77 17 789.3 -34.51 -23.78 -20.97 18 825.2 -28.48 -24.04 -21.33 19 860.5 -33.72 -23.97 -22.46 20 895.0 -30.65 -23.86 -22.35 21 928.9 -30.91 -23.84 -20.93 22 962.1 -28.12 -24.76 -21.48 23 994.6 -28.00 -22.29 24 1026.5 -29.04 -23.59 25 1057.8 -30.66 -39.54 -23.15 26 1088.3 -26.74 -24.62 -22.00 27 1118.3 -27.30 -24.72 -23.03 28 1147.6 -26.80 -24.31 -23.66 29 1176.2 -25.00 -23.73 30 1204.3 -25.50 -22.58 31 1231.7 -25.00 -24.41 32 1258.5 -29.00 -23.77 33 1284.8 -28.42 -23.98 34 1310.4 -29.67 -24.62 -24.31 35 1335.5 -25.00 -25.10 36 1360.0 -32.41 -23.20 -23.04

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338 Appendix B: (Continued) 37 1383.9 -30.00 -22.86 -20.81 38 1407.3 -28.04 -23.35 -24.56 39 1430.2 -27.00 -24.03 -24.36 40 1452.5 -26.70 -37.12 -24.82 41 1474.4 -26.00 -23.06 -23.67 42 1495.7 -24.51 -38.10 -24.60 43 1516.6 -27.42 -23.02 -24.78 44 1537.0 -27.74 -23.33 -23.87 45 1557.0 -22.95 -23.55 -24.57 46 1576.5 -23.80 -23.40 -24.56 47 1595.6 -25.77 -24.09 -24.76 48 1614.3 -21.01 -24.07 -25.41 49 1632.7 -21.40 -24.62 -25.72 50 1650.6 -22.02 -24.76 -23.61 51 1668.2 -23.62 -24.99 52 1685.5 -25.75 -23.81 -24.96 53 1702.5 -24.77 -23.88 -25.92 54 1719.1 -25.91 -12.25 -25.74 55 1735.5 -22.63 -24.39 -23.61 56 1751.7 -23.20 -23.88 -23.77 57 1767.6 -25.89 -24.24 -24.70 58 1783.3 -22.30 -23.78 -24.45 59 1798.8 -22.00 -23.75 -24.33 60 1814.1 -21.40 -23.11 -24.46 61 1829.3 -22.34 -23.67 -23.85 62 1844.4 -23.52 -24.29 -23.89 63 1859.4 -23.39 -24.35 -25.05 64 1874.3 -25.10 -24.27 -25.99 65 1889.1 -24.19 -29.90 -25.50 66 1903.9 -28.28 -24.92 -25.41 67 1918.8 -23.84 -24.65 -24.56 68 1933.6 -24.09 -26.66 -25.64 69 1948.5 -24.23 -24.11 -25.54 70 1963.5 -24.48 -27.72 -24.10 71 1978.6 -27.51 -23.99 -25.57 72 1993.8 -24.28 -24.67 -23.92 73 2009.1 -23.71 -24.17 -18.06 74 2024.7 -24.94 -24.78 -24.54 75 2040.5 -26.84 -18.58

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339 Appendix B: (Continued) 76 2056.5 -23.55 -25.01 -17.73 77 2072.9 -24.92 -24.49 -23.15 78 2089.5 -26.22 -30.18 79 2106.5 -27.34 -24.76 -26.55 80 2123.8 -23.89 -22.89 -25.70 81 2141.6 -23.69 -24.62 -23.43 82 2159.8 -28.58 -24.05 -20.99 83 2178.4 -24.31 -15.87 -26.74 84 2197.6 -24.97 -24.22 -28.30 85 2217.3 -24.19 -19.94 -27.67 86 2237.6 -24.96 -27.27 87 2258.5 -24.93 -17.77 -25.74 88 2280.0 -24.34 -23.13 -24.90 89 2302.3 -26.21 -24.40 -25.72 90 2325.2 -24.34 -23.65 -25.46 91 2348.9 -23.97 -22.16 -24.75 92 2373.4 -23.62 -25.50 -35.65 93 2398.7 -25.52 -27.93 94 2424.9 -24.63 -30.91 -29.17 95 2451.9 -24.59 -25.98 96 2480.0 -24.24 -29.27 97 2509.0 -23.63 -25.03 98 2539.0 -23.64 -24.31 -23.56 99 2570.2 -23.16 -24.81 -24.54 100 2602.4 -23.27 -23.62 -31.46 101 2635.8 -23.69 -23.23 -21.67 102 2670.3 -23.27 -23.89 -14.26 103 2706.1 -23.24 -26.82 -20.88 104 2743.2 -23.09 -23.50 -24.52 105 2781.6 -23.75 -24.48 -24.82 106 2821.4 -24.27 -24.07 -24.70 107 2862.5 -25.13 -23.55 -24.63 108 2905.2 -24.29 -22.42 -26.38 109 2949.3 -24.49 -22.39 -22.39 110 2995.0 -25.13

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340 Appendix C Vandal Cave Sediment Core Description

PAGE 370

341 Appendix C: (Continued) Cal YR Depth (cm) Layer Color Description Thickness (mm) Grouping 2008 1 1 DB OM/charcoal 10 2 2 DB Clayey OM/charcoal 10 3 3 DB OM/charcoal 10 4 4 DB Dark OM/charcoal 5 5 O/DB Sand/orange staining 5 2007 5 6 FY Fine sand 10 6 7 O/DB Sand/orange staining 10 7 8 FY Fine sand 10 8 9 B/PY Sand/orange stainig/charcoal 10 9 10 BR sand/OM mixed 10 2005 10 11 DB OM 10 11 12 DB OM 3 13 Lt. Tan sand/OM mixed 3 14 O/DB Sand/orange staining 4 12 15 PY Fine sand 2 16 DB OM 4 17 Lt. Tan sand/OM mixed 4 13 18 O/DB Sand/orange staining 7 19 DB OM 3 14 20 DB OM 10 2003 15 21 BR sand/OM mixed 2 22 DB OM 8 16 23 DB OM 4 24 PY Fine sand 2 25 DB OM 4 17 26 DB Heavy OM 6 27 PY Fine sand 4 18 28 PY Fine sand 10 19 29 PY Fine Sand 10 20 30 PY Fine sand 10 21 31 PY Fine sand 10 22 32 Lt. BR sand/OM mixed 3 33 DB Heavy OM 4 34 PY Fine sand 3 23 35 GY Grey OM/charcaol/fine silt 10

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342 Appendix C: (Continued) 24 36 GY Grey OM/charcaol/fine silt 10 2002 25 37 DB OM/charcoal 10 26 38 DB OM 10 27 39 DB OM 10 28 40 DB OM 10 29 41 Lt. Tan Fine loamy sand w/OM 10 2000 30 42 Lt. Tan Fine loamy sand w/OM 5 43 DB OM 5 31 44 DB OM/charcoal 10 32 45 DB Clayey OM/charcoal 10 33 46 DB Clayey OM/charcoal 8 47 PY Fine Sand 2 34 48 PY Fine sand 8 49 BR mixed OM/sand 2 35 50 DB Heavy OM/charcoal 10 36 51 DB OM/unconsolidated lg OM 10 37 52 DB OM/unconsolidated lg OM 10 38 53 PY Fine sand 8 54 DB clayey OM 2 39 55 DB clayey OM 10 1991 40 56 BR mixed OM/sand 10 41 57 PY Fine sand 5 58 DB OM 5 42 59 PY Fine sand 10 43 60 PY Fine sand 10 44 61 PY Fine sand 10 45 62 PY Fine sand 8 63 DB OM 2 46 64 PY Fine sand 1 65 PY Fine sand 9 47 66 PY Fine sand 3 67 DB OM 2 68 PY Fine sand 3 69 DB OM 2 48 70 PY Fine sand 10 49 71 PY Fine sand 10 1979 50 72 PY Fine sand 1 73 DB Heavy OM 9 51 74 DB Heavy OM 10

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343 Appendix C: (Continued) 52 75 PY Fine sand 10 53 76 PY Fine sand 10 54 77 PY Fine sand 10 55 78 PY Fine sand 10 56 79 PY Very fine sand 10 57 80 PY Very fine sand 10 58 81 PY Fine sand 10 59 82 PY Fine sand 10 60 83 PY Fine sand 10 61 84 PY Fine sand 5 85 DB OM 5 62 86 DB mixed OM/sand 2 87 DB mixed OM/sand 8 63 88 DB mixed OM/sand 5 89 DB OM 5 64 90 BR mixed OM/sand 10 1971 65 91 BR mixed OM/sand 10 66 92 BR unconsolidate sand/OM 10 67 93 BR unconsolidate sand/OM 10 68 94 BR unconsolidate sand/OM 10 69 95 DB mixed OM/sand 10 70 96 DB mixed OM/sand 5 97 PY Fine sand 5 71 98 DB OM 10 72 99 PY Fine sand 10 73 100 BR mixed OM/sand 10 1964 74 101 DB paleofloor/unconsolidated 10 Avg layer thickness (mm) 7.33

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344 Appendix D Vandal Cave Data

PAGE 374

345 Appendix D: (Continued) Depth (cm)Date 13C 0 2008 -25.49 5 2007 -25.88 10 2005 -26.92 15 2003 -26.40 25 2002 -23.75 30 2000 -25.63 40 1991 -26.73 50 1979 -23.66 65 1971 -25.83 74 1964 -23.86

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346 Appendix E Legend Cave Precipitation Data

PAGE 376

347 Appendix E: (Continued) Date Ringold (cm) Lecanto (cm) Legend RG (cm) Avg (cm) 2007-10-27 0.000 0.000 0.000 2007-10-28 0.004 0.000 0.002 2007-10-29 0.008 0.004 0.006 2007-10-30 0.000 0.004 0.002 2007-10-31 0.004 0.000 0.002 2007-11-01 0.000 0.000 0.000 2007-11-02 0.000 0.000 0.000 2007-11-03 0.000 0.000 0.000 2007-11-04 0.000 0.000 0.000 2007-11-05 0.000 0.000 0.000 2007-11-06 0.000 0.000 0.000 2007-11-07 0.000 0.000 0.000 2007-11-08 0.000 0.000 0.000 2007-11-09 0.000 0.004 0.002 2007-11-10 0.000 0.000 0.000 2007-11-11 0.000 0.000 0.000 2007-11-12 0.000 0.000 0.000 2007-11-13 0.000 0.000 0.000 2007-11-14 0.000 0.000 0.000 2007-11-15 0.000 0.000 0.000 2007-11-16 0.004 0.000 0.002 2007-11-17 0.000 0.000 0.000 2007-11-18 0.000 0.000 0.000 2007-11-19 0.000 0.000 0.000 2007-11-20 0.000 0.000 0.000 2007-11-21 0.000 0.000 0.000 2007-11-22 0.138 0.193 0.165 2007-11-23 0.000 0.000 0.000 2007-11-24 0.000 0.000 0.000 2007-11-25 0.004 0.000 0.002 2007-11-26 0.004 0.004 0.004 2007-11-27 0.000 0.000 0.000 2007-11-28 0.000 0.000 0.000 0.000 2007-11-29 0.000 0.051 1.165 0.406 2007-11-30 0.000 0.004 0.004 0.003 2007-12-01 0.000 0.000 0.000 0.000 2007-12-02 0.000 0.004 0.000 0.001 2007-12-03 0.028 0.000 0.035 0.021

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348 Appendix E: (Continued) 2007-12-04 0.000 0.000 0.000 0.000 2007-12-05 0.000 0.000 0.000 0.000 2007-12-06 0.000 0.000 0.000 0.000 2007-12-07 0.000 0.000 0.000 0.000 2007-12-08 0.000 0.000 0.000 0.000 2007-12-09 0.000 0.000 0.000 0.000 2007-12-10 0.000 0.000 0.000 0.000 2007-12-11 0.000 0.000 0.000 0.000 2007-12-12 0.000 0.000 0.000 0.000 2007-12-13 0.000 0.000 0.000 0.000 2007-12-14 0.000 0.000 0.000 0.000 2007-12-15 0.000 0.004 0.000 0.001 2007-12-16 0.681 0.685 1.339 0.902 2007-12-17 0.000 0.000 0.000 0.000 2007-12-18 0.000 0.000 0.000 0.000 2007-12-19 0.000 0.000 0.000 0.000 2007-12-20 0.000 0.000 0.000 0.000 2007-12-21 0.201 0.138 0.591 0.310 2007-12-22 0.000 0.000 0.004 0.001 2007-12-23 0.004 0.000 0.000 0.001 2007-12-24 0.000 0.000 0.000 0.000 2007-12-25 0.000 0.000 0.000 0.000 2007-12-26 0.000 0.000 0.000 0.000 2007-12-27 0.000 0.000 0.000 0.000 2007-12-28 0.000 0.000 0.000 0.000 2007-12-29 0.000 0.000 0.000 0.000 2007-12-30 0.118 0.004 0.409 0.177 2007-12-31 0.012 0.004 0.087 0.034 2008-01-01 0.051 0.228 0.287 0.189 2008-01-02 0.000 0.000 0.004 0.001 2008-01-03 0.000 0.000 0.000 0.000 2008-01-04 0.000 0.000 0.008 0.003 2008-01-05 0.000 0.000 0.000 2008-01-06 0.000 0.000 0.000 2008-01-07 0.000 0.000 0.000 2008-01-08 0.000 0.000 0.000 2008-01-09 0.000 0.000 0.000 2008-01-10 0.000 0.000 0.000 2008-01-11 0.000 0.000 0.000 2008-01-12 0.000 0.000 0.000 2008-01-13 0.055 0.126 0.091

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349 Appendix E: (Continued) 2008-01-14 0.000 0.000 0.000 2008-01-15 0.000 0.000 0.000 2008-01-16 0.134 0.114 0.124 2008-01-17 0.437 0.232 0.335 2008-01-18 0.000 0.000 0.000 2008-01-19 0.453 0.291 0.372 2008-01-20 0.000 0.000 0.000 2008-01-21 0.000 0.000 0.000 2008-01-22 0.000 0.378 0.189 2008-01-23 0.000 0.236 0.118 2008-01-24 0.000 0.000 0.000 2008-01-25 0.409 0.004 0.207 2008-01-26 0.031 0.031 0.031 2008-01-27 0.016 0.031 0.024 2008-01-28 0.000 0.000 0.000 2008-01-29 0.020 0.000 0.010 2008-01-30 0.000 0.000 0.000 2008-01-31 0.000 0.000 0.000 2008-02-01 0.004 0.004 0.004 2008-02-02 0.004 0.000 0.002 2008-02-03 0.000 0.000 0.000 2008-02-04 0.000 0.000 0.000 2008-02-05 0.000 0.000 0.000 2008-02-06 0.000 0.000 0.000 2008-02-07 0.004 0.083 0.043 2008-02-08 0.000 0.004 0.002 2008-02-09 0.000 0.000 0.000 2008-02-10 0.000 0.000 0.000 2008-02-11 0.000 0.000 0.000 2008-02-12 0.614 0.614 0.614 2008-02-13 0.016 0.020 0.018 2008-02-14 0.000 0.000 0.000 2008-02-15 0.000 0.000 0.000 2008-02-16 0.000 0.000 0.000 2008-02-17 0.000 0.000 0.000 2008-02-18 0.000 0.004 0.002 2008-02-19 0.000 0.004 0.002 2008-02-20 0.000 0.000 0.000 2008-02-21 0.004 0.059 0.031 2008-02-22 0.000 0.008 0.004 2008-02-23 0.280 0.370 0.325

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350 Appendix E: (Continued) 2008-02-24 0.000 0.004 0.002 2008-02-25 0.000 0.000 0.000 2008-02-26 0.146 0.201 0.173 2008-02-27 0.051 0.016 0.031 0.033 2008-02-28 0.000 0.000 0.000 0.000 2008-02-29 0.000 0.000 0.000 0.000 2008-03-01 0.000 0.000 0.000 0.000 2008-03-02 0.000 0.000 0.000 0.000 2008-03-03 0.000 0.000 0.000 0.000 2008-03-04 0.142 0.035 0.291 0.156 2008-03-05 0.004 0.000 0.000 0.001 2008-03-06 0.098 0.079 0.374 0.184 2008-03-07 0.965 1.138 1.630 1.244 2008-03-08 0.000 0.000 0.567 0.189 2008-03-09 0.000 0.000 0.000 0.000 2008-03-10 0.000 0.000 0.000 0.000 2008-03-11 0.000 0.000 0.000 0.000 2008-03-12 0.000 0.000 0.000 0.000 2008-03-13 0.000 0.000 0.000 0.000 2008-03-14 0.094 0.122 0.268 0.161 2008-03-15 0.000 0.004 0.016 0.007 2008-03-16 0.000 0.000 0.000 0.000 2008-03-17 0.000 0.000 0.000 0.000 2008-03-18 0.000 0.000 0.000 0.000 2008-03-19 0.000 0.000 0.000 0.000 2008-03-20 0.189 0.217 0.358 0.255 2008-03-21 0.000 0.000 0.000 0.000 2008-03-22 0.087 0.035 0.126 0.083 2008-03-23 0.055 0.004 0.244 0.101 2008-03-24 0.000 0.000 0.000 0.000 2008-03-25 0.000 0.000 0.000 0.000 2008-03-26 0.000 0.000 0.000 0.000 2008-03-27 0.000 0.000 0.000 0.000 2008-03-28 0.000 0.000 0.024 0.008 2008-03-29 0.000 0.000 0.000 0.000 2008-03-30 0.000 0.000 0.000 0.000 2008-03-31 0.000 0.130 0.000 0.043 2008-04-01 0.000 0.000 0.000 0.000 2008-04-02 0.000 0.000 0.000 0.000 2008-04-03 0.083 0.051 0.228 0.121 2008-04-04 0.004 0.000 0.004 0.003

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351 Appendix E: (Continued) 2008-04-05 0.173 0.386 0.280 2008-04-06 0.394 0.437 0.415 2008-04-07 0.000 0.000 0.000 2008-04-08 0.000 0.000 0.000 2008-04-09 0.000 0.000 0.000 2008-04-10 0.000 0.000 0.000 2008-04-11 0.000 0.000 0.000 2008-04-12 0.000 0.000 0.000 2008-04-13 0.000 0.012 0.006 2008-04-14 0.000 0.000 0.000 2008-04-15 0.000 0.000 0.000 2008-04-16 0.000 0.000 0.000 2008-04-17 0.000 0.000 0.000 2008-04-18 0.000 0.000 0.000 2008-04-19 0.000 0.000 0.000 2008-04-20 0.000 0.004 0.002 2008-04-21 0.000 0.000 0.000 2008-04-22 0.000 0.000 0.000 2008-04-23 0.000 0.000 0.000 2008-04-24 0.000 0.000 0.000 2008-04-25 0.000 0.000 0.000 2008-04-26 0.000 0.000 0.000 2008-04-27 0.000 0.000 0.000 2008-04-28 0.020 0.067 0.043 2008-04-29 0.000 0.000 0.000 2008-04-30 0.000 0.000 0.000 2008-05-01 0.000 0.000 0.000 2008-05-02 0.000 0.000 0.000 2008-05-03 0.000 0.000 0.000 2008-05-04 0.000 0.000 0.000 2008-05-05 0.000 0.000 0.000 2008-05-06 0.000 0.000 0.000 2008-05-07 0.000 0.000 0.000 2008-05-08 0.000 0.000 0.000 2008-05-09 0.000 0.000 0.000 2008-05-10 0.000 0.000 0.000 2008-05-11 0.000 0.000 0.000 2008-05-12 0.000 0.000 0.000 2008-05-13 0.000 0.000 0.000 2008-05-14 0.000 0.000 0.000 2008-05-15 0.000 0.000 0.000

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352 Appendix E: (Continued) 2008-05-16 0.000 0.000 0.000 2008-05-17 0.000 0.000 0.000 2008-05-18 0.016 0.000 0.008 2008-05-19 0.004 0.000 0.002 2008-05-20 0.000 0.000 0.000 2008-05-21 0.000 0.000 0.000 2008-05-22 0.008 0.012 0.010 2008-05-23 0.000 0.004 0.002 2008-05-24 0.000 0.000 0.000 2008-05-25 0.000 0.000 0.000 2008-05-26 0.000 0.000 0.000 2008-05-27 0.000 0.000 0.000 2008-05-28 0.000 0.000 0.000 2008-05-29 0.000 0.000 0.000 2008-05-30 0.000 0.000 0.000 2008-05-31 0.000 0.000 0.000 2008-06-01 0.000 0.000 0.000 2008-06-02 0.000 0.000 0.000 2008-06-03 0.000 0.000 0.000 2008-06-04 0.071 0.000 0.016 0.029 2008-06-05 0.000 0.004 0.091 0.031 2008-06-06 0.000 0.004 0.008 0.004 2008-06-07 0.000 0.000 0.000 0.000 2008-06-08 0.031 0.169 0.311 0.171 2008-06-09 0.035 0.043 0.000 0.026 2008-06-10 0.008 0.142 0.276 0.142 2008-06-11 0.000 0.004 0.264 0.089 2008-06-12 0.315 0.547 0.598 0.487 2008-06-13 0.484 0.169 0.866 0.507 2008-06-14 0.004 0.374 0.008 0.129 2008-06-15 0.114 0.882 0.807 0.601 2008-06-16 0.008 0.035 0.016 0.020 2008-06-17 0.031 0.205 0.016 0.084 2008-06-18 0.280 0.425 0.217 0.307 2008-06-19 0.047 0.008 0.150 0.068 2008-06-20 0.000 0.000 0.000 0.000 2008-06-21 0.169 0.492 0.091 0.251 2008-06-22 0.185 0.224 0.382 0.264 2008-06-23 0.016 0.051 0.008 0.025 2008-06-24 0.004 0.000 0.000 0.001 2008-06-25 0.343 0.512 0.602 0.486

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353 Appendix E: (Continued) 2008-06-26 0.055 0.264 0.762 0.360 2008-06-27 0.004 0.004 0.004 0.004 2008-06-28 0.000 0.000 0.000 0.000 2008-06-29 0.000 0.000 0.000 0.000 2008-06-30 0.000 0.000 0.000 0.000 2008-07-01 0.039 0.000 0.118 0.052 2008-07-02 0.024 0.213 0.028 0.088 2008-07-03 0.008 0.008 0.031 0.016 2008-07-04 0.181 0.102 0.091 0.125 2008-07-05 0.000 0.000 0.000 0.000 2008-07-06 0.059 0.417 0.024 0.167 2008-07-07 0.630 0.224 0.650 0.501 2008-07-08 0.264 0.169 0.827 0.420 2008-07-09 0.000 0.004 0.000 0.001 2008-07-10 0.000 0.063 0.000 0.021 2008-07-11 0.004 0.059 0.866 0.310 2008-07-12 0.169 0.047 0.000 0.108 2008-07-13 0.114 1.098 0.000 0.606 2008-07-14 0.114 0.094 0.000 0.104 2008-07-15 0.024 0.114 0.000 0.069 2008-07-16 0.055 0.268 0.000 0.161 2008-07-17 0.067 0.008 0.000 0.037 2008-07-18 0.000 0.000 0.000 0.000 2008-07-19 0.000 0.000 0.000 0.000 2008-07-20 0.000 0.000 0.000 0.000 2008-07-21 0.000 0.000 0.000 0.000 2008-07-22 0.000 0.000 0.000 0.000 2008-07-23 0.024 0.012 0.000 0.012 2008-07-24 0.000 0.004 0.000 0.001 2008-07-25 0.000 0.016 0.303 0.106 2008-07-26 0.039 0.000 0.551 0.197 2008-07-27 0.114 0.000 0.079 0.064 2008-07-28 0.193 0.000 0.205 0.133 2008-07-29 0.161 0.031 0.433 0.209 2008-07-30 0.220 0.071 0.055 0.115 2008-07-31 1.012 0.150 0.827 0.663 2008-08-01 0.063 0.024 0.248 0.112 2008-08-02 0.024 0.240 0.287 0.184 2008-08-03 0.000 0.000 0.000 0.000 2008-08-04 0.161 0.146 0.000 0.102 2008-08-05 0.000 0.000 0.000 0.000

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354 Appendix E: (Continued) 2008-08-06 0.024 0.000 0.866 0.297 2008-08-07 0.000 0.000 0.000 0.000 2008-08-08 0.000 0.047 0.264 0.104 2008-08-09 0.008 0.004 0.626 0.213 2008-08-10 0.000 0.000 0.000 0.000 2008-08-11 0.000 0.000 0.000 0.000 2008-08-12 0.488 0.189 0.807 0.495 2008-08-13 0.083 0.201 0.417 0.234 2008-08-14 0.476 0.429 1.701 0.869 2008-08-15 0.185 0.016 0.594 0.265 2008-08-16 0.000 0.000 0.000 0.000 2008-08-17 0.043 0.000 0.000 0.014 2008-08-18 0.165 0.004 0.205 0.125 2008-08-19 0.083 0.087 0.311 0.160 2008-08-20 0.004 0.016 0.016 0.012 2008-08-21 0.173 0.295 0.815 0.428 2008-08-22 1.039 2.642 2.866 2.182 2008-08-23 0.516 0.228 1.091 0.612 2008-08-24 0.134 0.343 0.957 0.478 2008-08-25 0.248 0.004 0.496 0.249 2008-08-26 0.000 0.000 0.000 0.000 2008-08-27 0.000 0.000 0.000 0.000 2008-08-28 0.000 0.000 0.000 0.000 2008-08-29 0.000 0.000 0.000 0.000 2008-08-30 0.043 0.287 0.417 0.249 2008-08-31 0.000 0.016 0.000 0.005 2008-09-01 0.000 0.000 0.000 0.000 2008-09-02 0.024 0.024 0.098 0.049 2008-09-03 0.004 0.000 0.000 0.001 2008-09-04 0.000 0.000 0.000 0.000 2008-09-05 0.000 0.000 0.000 0.000 2008-09-06 0.000 0.000 0.000 0.000 2008-09-07 0.000 0.000 0.000 0.000 2008-09-08 0.028 0.008 0.000 0.012 2008-09-09 0.004 0.000 0.000 0.001 2008-09-10 0.134 0.012 0.354 0.167 2008-09-11 0.028 0.000 0.000 0.009 2008-09-12 0.000 0.000 0.000 0.000 2008-09-13 0.000 0.000 0.000 0.000 2008-09-14 0.000 0.000 0.000 0.000 2008-09-15 0.012 0.000 0.012 0.008

PAGE 384

355 Appendix E: (Continued) 2008-09-16 0.000 0.000 0.000 0.000 2008-09-17 0.110 0.000 0.299 0.136 2008-09-18 0.004 0.004 0.012 0.007 2008-09-19 0.000 0.000 0.000 0.000 2008-09-20 0.000 0.000 0.000 0.000 2008-09-21 0.378 0.055 0.555 0.329 2008-09-22 0.008 0.008 0.055 0.024 2008-09-23 0.283 0.004 0.000 0.096 2008-09-24 0.000 0.000 0.000 0.000 2008-09-25 0.000 0.000 0.000 0.000 2008-09-26 0.000 0.000 0.000 0.000 2008-09-27 0.000 0.000 0.000 0.000 2008-09-28 0.000 0.000 0.000 0.000 2008-09-29 0.272 0.000 0.067 0.113 2008-09-30 0.004 0.004 0.016 0.008 2008-10-01 0.000 0.004 0.000 0.001 2008-10-02 0.000 0.000 0.000 0.000 2008-10-03 0.000 0.000 0.012 0.004 2008-10-04 0.000 0.000 0.000 0.000 2008-10-05 0.000 0.000 0.000 0.000 2008-10-06 0.587 0.992 0.000 0.789 2008-10-07 0.004 0.031 0.000 0.018 2008-10-08 0.000 0.000 0.000 0.000 2008-10-09 0.004 0.000 0.000 0.002 2008-10-10 0.000 0.000 0.000 0.000 2008-10-11 0.000 0.000 0.000 0.000 2008-10-12 0.000 0.000 0.000 0.000 2008-10-13 0.004 0.000 0.000 0.002 2008-10-14 0.000 0.000 0.000 0.000 2008-10-15 0.000 0.000 0.000 0.000 2008-10-16 0.000 0.000 0.000 0.000 2008-10-17 0.000 0.000 0.000 0.000 2008-10-18 0.000 0.000 0.000 0.000 2008-10-19 0.000 0.000 0.000 0.000 2008-10-20 0.000 0.000 0.000 0.000 2008-10-21 0.000 0.000 0.000 0.000 2008-10-22 0.000 0.000 0.000 0.000 2008-10-23 0.091 0.067 0.000 0.079 2008-10-24 0.201 0.146 0.000 0.173 2008-10-25 0.028 0.047 0.000 0.037 2008-10-26 0.000 0.000 0.000 0.000

PAGE 385

356 Appendix E: (Continued) 2008-10-27 0.000 0.004 0.000 0.002 2008-10-28 0.000 0.000 0.000 0.000 2008-10-29 0.000 0.000 0.000 0.000 2008-10-30 0.000 0.000 0.000 0.000 2008-10-31 0.000 0.000 0.000 0.000 2008-11-01 0.000 0.000 0.000 0.000 2008-11-02 0.000 0.000 0.000 0.000 2008-11-03 0.000 0.000 0.000 0.000 2008-11-04 0.000 0.000 0.000 0.000 2008-11-05 0.000 0.000 0.000 0.000 2008-11-06 0.000 0.000 0.000 0.000 2008-11-07 0.000 0.000 0.000 0.000

PAGE 386

357 Appendix F Legend Cave Surface and Cave Temperature Data

PAGE 387

358 Appendix F: (Continued) Date Legend Temp C Surface Temp C 10/27/2007 23.24 22.80 10/28/2007 23.24 27.80 10/29/2007 23.24 23.30 10/30/2007 23.24 25.60 10/31/2007 23.24 24.40 11/1/2007 23.24 25.60 11/2/2007 23.24 23.30 11/3/2007 23.24 23.30 11/4/2007 23.24 24.40 11/5/2007 23.24 22.80 11/6/2007 23.24 22.80 11/7/2007 23.24 18.90 11/8/2007 23.24 20.00 11/9/2007 23.24 20.60 11/10/2007 23.24 22.20 11/11/2007 23.24 22.80 11/12/2007 23.24 24.40 11/13/2007 23.24 23.90 11/14/2007 23.24 25.00 11/15/2007 23.24 23.30 11/16/2007 23.24 15.00 11/17/2007 23.24 21.70 11/18/2007 23.24 24.40 11/19/2007 23.24 22.80 11/20/2007 23.24 25.00 11/21/2007 23.24 24.40 11/22/2007 23.24 21.10 11/23/2007 23.24 21.10 11/24/2007 23.24 23.90 11/25/2007 23.24 28.30 11/26/2007 23.24 27.80 11/27/2007 23.24 23.30 11/28/2007 23.24 23.90 11/29/2007 23.24 23.90 11/30/2007 23.24 23.90 12/1/2007 23.24 25.60 12/2/2007 23.24 27.80 12/3/2007 23.24 21.10 12/4/2007 23.24 18.90

PAGE 388

359 Appendix F: (Continued) 12/5/2007 23.24 19.40 12/6/2007 23.24 21.70 12/7/2007 23.24 25.00 12/8/2007 23.24 27.80 12/9/2007 23.24 26.70 12/10/2007 23.24 25.00 12/11/2007 23.24 27.20 12/12/2007 23.24 26.10 12/13/2007 23.24 25.60 12/14/2007 23.24 26.10 12/15/2007 23.24 27.20 12/16/2007 23.24 12.80 12/17/2007 23.24 11.10 12/18/2007 23.24 16.70 12/19/2007 23.24 22.20 12/20/2007 23.24 23.30 12/21/2007 23.24 21.10 12/22/2007 23.24 16.10 12/23/2007 23.24 20.00 12/24/2007 23.24 18.90 12/25/2007 23.24 23.30 12/26/2007 23.24 21.10 12/27/2007 23.24 26.70 12/28/2007 23.24 25.60 12/29/2007 23.24 27.20 12/30/2007 23.24 26.70 12/31/2007 23.24 22.80 1/1/2008 23.24 21.10 1/2/2008 23.24 6.70 1/3/2008 23.24 8.90 1/4/2008 23.24 16.70 1/5/2008 23.24 20.00 1/6/2008 23.24 23.90 1/7/2008 23.24 25.00 1/8/2008 23.24 23.90 1/9/2008 23.24 24.40 1/10/2008 23.24 25.60 1/11/2008 23.24 23.90 1/12/2008 23.24 20.60 1/13/2008 23.24 16.70 1/14/2008 23.24 15.00

PAGE 389

360 Appendix F: (Continued) 1/15/2008 23.24 13.30 1/16/2008 23.24 18.30 1/17/2008 23.24 20.60 1/18/2008 23.24 15.00 1/19/2008 23.24 22.80 1/20/2008 23.24 5.60 1/21/2008 23.24 20.00 1/22/2008 23.24 23.30 1/23/2008 23.24 17.80 1/24/2008 23.24 18.90 1/25/2008 23.24 15.00 1/26/2008 23.24 15.60 1/27/2008 23.24 18.30 1/28/2008 23.24 17.80 1/29/2008 23.24 21.70 1/30/2008 23.24 23.30 1/31/2008 23.24 23.90 2/1/2008 23.24 19.40 2/2/2008 23.24 25.60 2/3/2008 23.2 25.60 2/4/2008 23.2 26.10 2/5/2008 23.2 27.20 2/6/2008 23.2 26.10 2/7/2008 23.2 24.40 2/8/2008 23.2 23.30 2/9/2008 23.2 21.10 2/10/2008 23.2 22.80 2/11/2008 23.2 22.80 2/12/2008 23.2 18.90 2/13/2008 23.2 14.40 2/14/2008 23.2 18.90 2/15/2008 23.2 23.30 2/16/2008 23.2 26.10 2/17/2008 23.2 27.80 2/18/2008 23.2 21.10 2/19/2008 23.2 20.60 2/20/2008 23.2 17.80 2/21/2008 23.2 23.90 2/22/2008 23.24 27.80 2/23/2008 23.24 23.30 2/24/2008 23.24 25.60

PAGE 390

361 Appendix F: (Continued) 2/25/2008 23.24 23.30 2/26/2008 23.24 25.00 2/27/2008 23.24 11.10 2/28/2008 23.24 13.90 2/29/2008 23.24 20.60 3/1/2008 23.24 21.10 3/2/2008 23.24 25.00 3/3/2008 23.24 26.70 3/4/2008 23.24 20.60 3/5/2008 23.24 18.90 3/6/2008 23.24 16.10 3/7/2008 23.24 26.10 3/8/2008 23.24 25.00 3/9/2008 23.24 22.20 3/10/2008 23.24 21.10 3/11/2008 23.24 22.80 3/12/2008 23.24 23.30 3/13/2008 23.24 24.40 3/14/2008 23.24 16.70 3/15/2008 23.24 27.80 3/16/2008 23.24 29.40 3/17/2008 23.24 25.00 3/18/2008 23.24 26.10 3/19/2008 23.24 28.90 3/20/2008 23.24 22.80 3/21/2008 23.24 26.10 3/22/2008 23.24 20.60 3/23/2008 23.24 26.10 3/24/2008 23.24 18.30 3/25/2008 23.24 17.80 3/26/2008 23.24 22.80 3/27/2008 23.24 25.00 3/28/2008 23.24 27.20 3/29/2008 23.24 27.20 3/30/2008 23.24 25.00 3/31/2008 23.24 26.70 4/1/2008 23.24 27.20 4/2/2008 23.24 27.20 4/3/2008 23.24 28.30 4/4/2008 23.47 29.40 4/5/2008 23.43 28.90

PAGE 391

362 Appendix F: (Continued) 4/6/2008 23.30 17.80 4/7/2008 23.30 23.30 4/8/2008 23.18 25.00 4/9/2008 22.90 26.70 4/10/2008 23.15 26.10 4/11/2008 23.30 27.20 4/12/2008 23.30 27.80 4/13/2008 23.30 21.10 4/14/2008 23.30 17.20 4/15/2008 23.30 17.20 4/16/2008 23.30 20.00 4/17/2008 23.30 24.40 4/18/2008 22.98 26.10 4/19/2008 22.90 26.70 4/20/2008 22.90 27.20 4/21/2008 22.91 26.70 4/22/2008 23.08 26.70 4/23/2008 23.15 26.10 4/24/2008 23.22 27.80 4/25/2008 23.10 29.40 4/26/2008 23.30 29.40 4/27/2008 23.32 29.40 4/28/2008 23.16 25.60 4/29/2008 23.14 24.40 4/30/2008 22.93 27.80 5/1/2008 22.90 29.40 5/2/2008 22.97 29.40 5/3/2008 22.94 29.40 5/4/2008 22.98 29.40 5/5/2008 22.99 28.30 5/6/2008 22.99 31.70 5/7/2008 22.99 31.70 5/8/2008 22.99 29.40 5/9/2008 22.99 28.30 5/10/2008 22.94 30.00 5/11/2008 22.91 26.70 5/12/2008 22.92 25.60 5/13/2008 22.92 29.40 5/14/2008 22.94 30.00 5/15/2008 22.95 28.90 5/16/2008 22.96 28.90

PAGE 392

363 Appendix F: (Continued) 5/17/2008 22.95 28.90 5/18/2008 22.99 28.90 5/19/2008 22.99 28.90 5/20/2008 23.01 27.20 5/21/2008 23.01 30.00 5/22/2008 23.01 23.30 5/23/2008 23.01 30.60 5/24/2008 23.01 31.70 5/25/2008 23.01 31.70 5/26/2008 23.00 30.00 5/27/2008 23.01 30.00 5/28/2008 23.01 29.40 5/29/2008 23.00 31.10 5/30/2008 23.01 32.20 5/31/2008 23.01 35.00 6/1/2008 23.01 30.00 6/2/2008 23.05 31.70 6/3/2008 23.33 32.20 6/4/2008 23.07 25.60 6/5/2008 23.29 33.30 6/6/2008 23.41 31.70 6/7/2008 23.43 33.90 6/8/2008 23.43 33.90 6/9/2008 23.43 31.70 6/10/2008 23.43 24.40 6/11/2008 23.43 31.70 6/12/2008 23.46 28.30 6/13/2008 23.43 30.60 6/14/2008 23.43 31.70 6/15/2008 23.43 27.20 6/16/2008 23.43 26.70 6/17/2008 23.43 30.00 6/18/2008 23.46 29.40 6/19/2008 23.43 30.00 6/20/2008 23.43 32.20 6/21/2008 23.43 25.60 6/22/2008 23.43 19.40 6/23/2008 23.43 30.00 6/24/2008 23.42 30.00 6/25/2008 23.43 28.90 6/26/2008 23.43 23.30

PAGE 393

364 Appendix F: (Continued) 6/27/2008 23.43 30.00 6/28/2008 23.43 32.20 6/29/2008 23.43 31.70 6/30/2008 23.43 31.10 7/1/2008 23.43 28.30 7/2/2008 23.43 29.40 7/3/2008 23.43 27.20 7/4/2008 23.43 30.00 7/5/2008 23.43 31.10 7/6/2008 23.43 31.70 7/7/2008 23.43 29.40 7/8/2008 23.42 22.80 7/9/2008 23.43 30.00 7/10/2008 23.41 32.20 7/11/2008 23.41 23.90 7/12/2008 23.47 25.60 7/13/2008 23.46 26.10 7/14/2008 23.46 30.60 7/15/2008 23.44 24.40 7/16/2008 23.44 29.40 7/17/2008 23.44 30.60 7/18/2008 23.44 30.00 7/19/2008 23.44 32.80 7/20/2008 23.44 33.30 7/21/2008 23.44 33.30 7/22/2008 23.44 22.80 7/23/2008 23.44 30.60 7/24/2008 23.44 28.30 7/25/2008 23.44 24.40 7/26/2008 23.44 26.70 7/27/2008 23.44 30.00 7/28/2008 23.44 27.20 7/29/2008 23.44 26.70 7/30/2008 23.44 25.00 7/31/2008 23.44 22.20 8/1/2008 23.44 27.20 8/2/2008 23.44 23.90 8/3/2008 23.44 30.00 8/4/2008 23.44 31.10 8/5/2008 23.44 32.20 8/6/2008 23.44 30.00

PAGE 394

365 Appendix F: (Continued) 8/7/2008 23.44 31.70 8/8/2008 23.44 28.90 8/9/2008 23.44 31.70 8/10/2008 23.44 31.70 8/11/2008 23.44 30.00 8/12/2008 23.45 22.80 8/13/2008 23.44 28.30 8/14/2008 23.44 23.30 8/15/2008 23.43 25.60 8/16/2008 23.44 30.60 8/17/2008 23.44 24.40 8/18/2008 23.44 29.40 8/19/2008 23.40 27.80 8/20/2008 23.26 25.00 8/21/2008 23.25 25.00 8/22/2008 23.34 27.20 8/23/2008 23.35 25.00 8/24/2008 23.35 25.00 8/25/2008 23.35 23.90 8/26/2008 23.35 30.00 8/27/2008 23.35 32.20 8/28/2008 23.35 32.20 8/29/2008 23.36 31.10 8/30/2008 23.35 25.00 8/31/2008 23.35 28.30 9/1/2008 23.35 31.10 9/2/2008 23.40 24.40 9/3/2008 23.35 29.40 9/4/2008 23.36 30.00 9/5/2008 23.36 27.80 9/6/2008 23.36 31.70 9/7/2008 23.46 32.20 9/8/2008 23.49 31.70 9/9/2008 23.49 31.70 9/10/2008 23.50 31.10 9/11/2008 23.50 31.70 9/12/2008 23.45 32.80 9/13/2008 23.46 33.90 9/14/2008 23.51 32.20 9/15/2008 23.51 26.70 9/16/2008 23.44 31.10

PAGE 395

366 Appendix F: (Continued) 9/17/2008 23.48 23.90 9/18/2008 23.46 30.00 9/19/2008 23.51 29.40 9/20/2008 23.50 31.70 9/21/2008 23.50 31.70 9/22/2008 23.50 26.70 9/23/2008 23.50 28.90 9/24/2008 23.51 26.70 9/25/2008 23.49 26.70 9/26/2008 23.46 28.90 9/27/2008 23.47 30.00 9/28/2008 23.47 28.90 9/29/2008 23.45 28.90 9/30/2008 23.48 29.40 10/1/2008 23.48 29.40 10/2/2008 23.49 27.20 10/3/2008 23.43 26.70 10/4/2008 23.46 28.90 10/5/2008 23.47 28.30 10/6/2008 23.46 30.60 10/7/2008 23.46 28.30 10/8/2008 23.41 28.90 10/9/2008 23.47 28.90 10/10/2008 23.47 27.20 10/11/2008 23.48 28.90 10/12/2008 23.47 30.60 10/13/2008 23.48 28.30 10/14/2008 23.48 27.80 10/15/2008 23.46 28.30 10/16/2008 23.48 27.20 10/17/2008 23.49 28.30 10/18/2008 23.48 23.30 10/19/2008 23.47 23.90 10/20/2008 23.47 26.10 10/21/2008 23.46 25.60 10/22/2008 23.46 25.00 10/23/2008 23.46 24.40 10/24/2008 23.46 25.00 10/25/2008 23.47 24.40 10/26/2008 23.45 23.30 10/27/2008 23.46 23.90

PAGE 396

367 Appendix F: (Continued) 10/28/2008 23.46 15.60 10/29/2008 23.42 16.10 10/30/2008 23.42 18.90 10/31/2008 23.41 23.90 11/1/2008 23.44 26.10 11/2/2008 23.40 22.20 11/3/2008 23.39 24.40 11/4/2008 23.39 18.90 11/5/2008 23.34 20.60 11/6/2008 23.37 23.90 11/7/2008 23.38 25.00

PAGE 397

368 Appendix G Legend Cave Isotope Data

PAGE 398

369 Appendix G: (Continued) Week Avg Rain (cm) Rain 18O Rain 2D Cave 18O Cave 2H d-excess 11/2/2007 0.076 -3.04 -18.81 -3.19 -14.97 5.5 11/9/2007 0.013 -3.07 -16.41 -2.84 8.1 11/16/2007 -3.01 -14.39 11/23/2007 1.067 -1.91 -4.23 -3.09 -15.65 11.1 11/30/2007 -3.06 -14.20 12/7/2007 0.144 -0.11 4.58 -3.02 -13.58 5.5 12/14/2007 -3.03 -14.00 12/21/2007 7.823 -4.88 -28.62 -3.09 -15.64 10.4 12/28/2007 -3.22 -7.85 1/4/2008 2.608 -1.58 -9.68 -3.07 -16.08 3.0 1/11/2008 -3.02 -14.85 1/18/2008 3.543 -2.76 -11.21 -3.07 -16.36 10.8 1/25/2008 5.715 -3.44 -17.12 -3.02 -17.74 10.4 2/1/2008 0.445 -0.57 8.96 -3.14 -17.17 13.5 2/8/2008 0.305 -0.57 2.69 -3.00 -17.29 7.2 2/15/2008 4.077 -4.13 -27.25 -3.11 -15.54 5.8 2/22/2008 0.254 -0.29 6.70 -3.15 -17.46 9.0 2/29/2008 3.437 -1.61 -1.87 -3.08 -17.30 11.0 3/7/2008 10.228 -1.90 -2.64 -3.07 -17.12 12.6 3/14/2008 2.261 -4.20 -16.15 -3.02 -17.59 17.5 3/21/2008 1.685 -2.05 -0.98 -2.86 -16.84 15.4 3/28/2008 1.236 -1.29 1.01 -3.08 -16.42 11.3 4/4/2008 1.075 -0.99 1.78 -3.10 -15.90 9.7 4/11/2008 4.483 -4.55 -26.17 -2.99 -17.17 10.2 4/18/2008 -3.02 -16.71 4/25/2008 -3.08 -17.92 5/2/2008 0.279 -0.24 3.15 -3.08 -19.45 5.1 5/9/2008 -3.04 -36.75 5/16/2008 -3.07 -13.40 5/23/2008 0.140 -0.71 -4.19 -3.00 -16.91 1.5 5/30/2008 -3.00 -16.17 6/6/2008 0.415 1.15 18.59 -3.01 -14.48 9.4 6/13/2008 9.169 -2.66 -11.99 -2.98 -17.22 9.3 6/20/2008 7.798 -2.48 -4.47 -3.31 -6.88 15.4 6/27/2008 8.970 -2.69 -12.41 -3.31 -12.53 9.1 7/4/2008 1.812 -1.87 5.06 -3.37 -8.90 20.0 7/11/2008 9.161 -2.40 -1.09 -3.46 -19.30 18.1 7/18/2008 7.010 -4.16 -9.88 -3.48 -7.87 23.4

PAGE 399

370 Appendix G: (Continued) 7/25/2008 0.770 -2.82 -1.93 -3.30 -19.23 20.6 8/1/2008 9.627 -3.55 -15.94 -3.36 -6.78 12.5 8/8/2008 4.428 -3.00 -12.47 -3.45 -10.38 11.5 8/15/2008 13.386 -3.91 -16.70 -3.46 -14.57 14.5 8/22/2008 18.847 -9.12 -59.82 -3.59 -15.01 13.2 8/29/2008 8.636 -4.10 -15.82 -3.54 -11.94 17.0 9/5/2008 1.964 -3.46 -9.17 -3.60 -14.90 18.5 9/12/2008 1.219 -3.24 -13.50 -3.35 -9.63 12.4 9/19/2008 0.974 -2.68 -7.92 -3.38 -9.86 13.5 9/26/2008 2.896 -3.34 -3.22 -3.44 -11.56 23.5 10/3/2008 0.813 -1.70 -12.25 -3.47 -16.10 1.4 10/10/2008 5.220 -7.32 -38.28 -3.33 -10.88 20.3 10/17/2008 -3.24 -14.70 10/24/2008 1.626 -2.93 8.03 -3.49 -12.03 31.5 10/31/2008 -3.23 -12.03 11/7/2008 -3.29 -10.36

PAGE 400

371 Appendix H Legend Cave Surface Weather Data

PAGE 401

372 Appendix H: (Continued) Sunday, October 28, 2007 Saturday, October 27, 2007

PAGE 402

373 Appendix H: (Continued) Monday, October 29,2008

PAGE 403

374 Appendix H: (Continued) Wednesday, October 31, 2007 Tuesday, October 30, 2007

PAGE 404

375 Appendix H: (Continued) Thursday, November 1, 2007 Friday, November 2, 2007

PAGE 405

376 Appendix H: (Continued) October 27, 2007 November 2, 2007 DatePrecipitation (In) Wind Direction PressureComments October 27, 2007TNE (030)1016Cold front over Ft. Myers area (south) October 28, 20070.00NE (040)1017Cold front over south-central Florida October 29, 20070.21NE (060)1018Stationary Front over Tampa Bay October 30, 2007TE (070)1018Stationary Front over Central Florida October 31, 20070.01NE (050)1015Stationary Front over Tampa Bay; TS Noel over Eastern Cuba November 1, 2007TN (010)1012TS Noel in Gulf; unnamed TS in Bahamas November 2, 20070.00NE (030)1012Stationary front southern Florida; Hurricane Noel off LA coast; unnamed hurricane in Atlantic, W of GATotal Precipitation: 0.22

PAGE 406

377 Appendix H: (Continued) Saturday, November 3, 2007 Sunday, November 4, 2007

PAGE 407

378 Appendix H: (Continued) Monday, November 5, 2007 Tuesday, November 6, 2007

PAGE 408

379 Appendix H: (Continued) Wednesday, November 7, 2007 Thursday, November 8, 2007

PAGE 409

380 Appendix H: (Continued) Friday, November 9, 2007

PAGE 410

381 Appendix H: (Continued) November 3, 2007 November 9, 2007 DatePrecipitation (In) Wind Direction PressureComments November 3, 20070.00N (360)1016Stationary Front off S. Florida Coast November 4, 20070.00W (280)1018None November 5, 20070.00E (070)1018High over Florida’s Panhandle November 6, 20070.00W (290)1018Cold front just to the north of Florida November 7, 20070.00N (350)1020Cold front over Ft. Myers November 8, 20070.02sNW (310)1018None November 9, 20070.00N (020)1018High over Florida’s PanhandleTotal Precipitation: 0.02

PAGE 411

382 Appendix H: (Continued) Saturday, November 17, 2007 Sunday, November 18, 2007

PAGE 412

383 Appendix H: (Continued) Monday, November 19, 2007 Tuesday, November 20, 2007

PAGE 413

384 Appendix H: (Continued) Wednesday, November 21, 2007 Thursday, November 22, 2007

PAGE 414

385 Appendix H: (Continued) Friday, November 23, 2007

PAGE 415

386 Appendix H: (Continued) November 17, 2007 November 23, 2007 DatePrecipitation (In) Wind Direction PressureComments November 17, 20070.00NW (300)1020High north of Florida November 18, 20070.00SE (140)1020High off GA’s Atlantic Coast November 19, 20070.00NE (060)1022High over GA November 20, 20070.00E (080)1022None November 21, 20070.01sSE (140)1020High off GA’s Atlantic Coast November 22, 20070.11W (260)1020Rain in Pensacola; Approaching Cold front November 23, 2007TNW (300)1018Cold front South of Tampa Bay AreaTotal Precipitation: 0.12

PAGE 416

387 Appendix H: (Continued) Saturday, December 1, 2007 Sunday, December 2, 2007

PAGE 417

388 Appendix H: (Continued) Monday, December 3, 2007 Tuesday, December 4, 2007

PAGE 418

389 Appendix H: (Continued) Wednesday, December 5, 2007 Thursday, December 6, 2007

PAGE 419

390 Appendix H: (Continued) Friday, December 7, 2007

PAGE 420

391 Appendix H: (Continued) December 1, 2007 December 7, 2007 DatePrecipitation (In) Wind Direction PressureComments December 1, 20070.00S (190)1024None December 2, 20070.00W (280)1024None December 3, 2007TW (260)1020Approaching Cold Front December 4, 20070.00N (360)1018Cold Front over Miami December 5, 20070.00W (250)1012Low off Florida’s Atlantic Coast December 6, 20070.00N (360)1016Cold Front N of Brooksville December 7, 20070.00SE (150)1024NoneTotal Precipitation: T

PAGE 421

392 Appendix H: (Continued) Saturday, December 15, 2007 Sunday, December 16, 2007

PAGE 422

393 Appendix H: (Continued) Monday, December 17, 2008 Tuesday, December 18, 2007

PAGE 423

394 Appendix H: (Continued) Wednesday, December 19, 2007 Thursday, December 20, 2007

PAGE 424

395 Appendix H: (Continued) Friday, December 21, 2007

PAGE 425

396 Appendix H: (Continued) December 15, 2007 December 21, 2007 DatePrecipitation (In) Wind Direction PressureComments December 15, 2007TS (160)1018Rain over North Florida/ South GA December 16, 20073.12W (290)1010Rain in Central and South Florida December 17, 20070.00N (010)1024None December 18, 20070.00E (080)1027None December 19, 20070.00NW (310)1024High off of GA/SC Coast December 20, 20070.00SE (150)1020None December 21, 20070.65W (260)1012Cold Front over Tampa Bay; Low just north of FL; Rain in SW FLTotal Precipitation: 3.77

PAGE 426

397 Appendix H: (Continued) Saturday, December 29, 2007 Sunday, December 30, 2007

PAGE 427

398 Appendix H: (Continued) Monday, December 31, 2007 Tuesday, January 1, 2008

PAGE 428

399 Appendix H: (Continued) Wednesday, January 2, 2008 Thursday, January 3, 2008

PAGE 429

400 Appendix H: (Continued) Friday, January 4, 2008

PAGE 430

401 Appendix H: (Continued) December 29, 2007 January 4, 2008 DatePrecipitation (In) Wind Direction PressureComments December 29, 20070.00SW (240)1020Approaching Cold Front December 30, 20070.04S (160)1018Approaching Cold front with rain December 31, 20070.00E (080)1016Cold Front N of Tampa Bay Area January 1, 20080.08NW (330)1020Cold Front S of Tampa Bay Area January 2, 20080.00W (290)1028None January 3, 20080.00NE (060)1036None January 4, 20080.00NE (050)1036NoneTotal Precipitation: 0.12

PAGE 431

402 Appendix H: (Continued) Saturday, January 12, 2008 Sunday, January 13, 2008

PAGE 432

403 Appendix H: (Continued) Monday, January 14, 2008 Tuesday, January 15, 2008

PAGE 433

404 Appendix H: (Continued) Wednesday, January 16, 2008 Thursday, January 17, 2008

PAGE 434

405 Appendix H: (Continued) Friday, January 18, 2008

PAGE 435

406 Appendix H: (Continued) January 12, 2008 January 18, 2008 DatePrecipitation (In) Wind Direction PressureComments January 12, 20080.04SW (240)1016Cold Front in North Florida January 13, 20080.06W (280)1016Cold Front in North Florida January 14, 20080.00N (350)1020Cold Front just south of Florida January 15, 20080.00NE (030)1020None January 16, 20080.39SE (120)1020Rain in Florida Panhandle January 17, 20080.99SE (140)1016Low by FL Panhandle; Rain in Tampa Bay Area January 18, 2008TN (340)1020Cold Front in South Florida; Rain in Southwest FloridaTotal Precipitation: 1.48

PAGE 436

407 Appendix H: (Continued) Saturday, January 19, 2008 Sunday, January 20, 2008

PAGE 437

408 Appendix H: (Continued) Monday, January 21, 2008 Tuesday, January 22, 2008

PAGE 438

409 Appendix H: (Continued) Wednesday, January 23, 2008 Thursday, January 24, 2008

PAGE 439

410 Appendix H: (Continued) Friday, January 25, 2008

PAGE 440

411 Appendix H: (Continued) January 19, 2008 January 25, 2008 DatePrecipitation (In) Wind DirectionPressureComments January 19, 20080.63W (260)1020Warm Front over Tampa Bay Area; Rain in N Florida Panhandle January 20, 20080.00N (010)1024Cold Front just South of Florida January 21, 20080.00E (080)1032None January 22, 20080.90SE (120)1026Stationary Front off NE Florida January 23, 20080.54W (290)1020Cold Front over N Florida; Rain in Central Florida January 24, 2008TNW (320)1020Cold Front over South Florida January 25, 20080.00NE (050)1026Cold Front South of FloridaTotal Precipitation: 2.07

PAGE 441

412 Appendix H: (Continued) Saturday, January 26, 2008 Sunday, January 27, 2008

PAGE 442

413 Appendix H: (Continued) Monday, January 28, 2008 Tuesday, January 28

PAGE 443

414 Appendix H: (Continued) Wednesday, January 30, 2008 Thursday, January 31, 2008

PAGE 444

415 Appendix H: (Continued) Friday, February 1, 2008

PAGE 445

416 Appendix H: (Continued) January 26, 2008 February 1, 2008 DatePrecipitation (In) Wind DirectionPressureComments January 26, 20080.09NE (050)1024Stationary Front to the W of Florida; Rain over North Florida January 27, 2008TN (010)1020Cold Front over South Florida January 28, 20080.00E (070)1022High West of Florida January 29, 20080.02sSW (220)1020High over Florida January 30, 20080.00SW (230)1016Cold Front over North Florida January 31, 20080.00SE (150)1020Warm Front North of Tampa Bay February 1, 20080.07NW (310)1020Cold Front over North FloridaTotal Precipitation: 0.18

PAGE 446

417 Appendix H: (Continued) Saturday, February 2, 2008 Sunday, February 3, 2008

PAGE 447

418 Appendix H: (Continued) Monday, February 4, 2008 Tuesday, February 5, 2008

PAGE 448

419 Appendix H: (Continued) Wednesday, February 6, 2008 Thursday, February 7, 2008

PAGE 449

420 Appendix H: (Continued) Friday, February 8, 2008

PAGE 450

421 Appendix H: (Continued) February 2, 2008 February 8, 2008 DatePrecipitation (In) Wind Direction PressureComments February 2, 20080.00W (270)1024High over South Carolina February 3, 20080.00W (290)1024None February 4, 20080.00W (270)1022None February 5, 20080.00S (160)1022Cold Front Approaching February 6, 20080.01SW (220)1018Rain in Western Panhandle February 7, 20080.02SW (240)1016Cold Front N of Tampa Bay Area February 8, 2008TN (350)1016Low-Central FloridaTotal Precipitation: 0.03

PAGE 451

422 Appendix H: (Continued) Saturday, February 9, 2008 Sunday, February 10, 2008

PAGE 452

423 Appendix H: (Continued) Monday, February 11, 2008 Tuesday, February 12, 2008

PAGE 453

424 Appendix H: (Continued) Wednesday, February 13, 2008 Thursday, February 14, 2008

PAGE 454

425 Appendix H: (Continued) Friday, February 15, 2008

PAGE 455

426 Appendix H: (Continued) February 9, 2008 February 15, 2008 DatePrecipitation (In) Wind Direction PressureComments February 9, 20080.00W (280)1016Approaching Cold Front February 10, 20080.00N (020)1024High over La; Cold front off E Coast of Florida February 11, 20080.00E (070)1024High over Central FL; Cold Front over N Florida February 12, 20081.14SE (140)1020None February 13, 20080.06W (280)1008Cold Front over panhandle; rain in south Florida February 14, 20080.00NW (310)1020High to the North February 15, 20080.00SE (120)1024Approaching Cold FrontTotal Precipitation: 1.20

PAGE 456

427 Appendix H: (Continued) Saturday, February 16, 2008 Sunday, February 17, 2008

PAGE 457

428 Appendix H: (Continued) Monday, February 18, 2008 Tuesday, February 19, 2008

PAGE 458

429 Appendix H: (Continued) Wednesday, February 20, 2008 Thursday, February 21, 2008

PAGE 459

430 Appendix H: (Continued) Friday, February 22, 2008

PAGE 460

431 Appendix H: (Continued) February 16, 2008 –February 22, 2008 DatePrecipitation (In) Wind Direction PressureComments February 16, 20080.00E (090)1022Approaching Cold Front February 17, 20080.00SE (150)1016Approaching Cold Front February 18, 2008TSW (240)1012Cold Front over N Florida February 19, 20080.00N (360)1024High over La; Cold Front over S. Florida February 20, 20080.00E (080)1024High over Florida; Stationary Front off South Florida Coast February 21, 20080.03SE (150)1020Approaching Cold front with rain February 22, 20080.00SW (240)1016Approaching Stationary FrontTotal Precipitation: 0.03

PAGE 461

432 Appendix H: (Continued) Saturday, February 23, 2008 Sunday, February 24, 2008

PAGE 462

433 Appendix H: (Continued) Monday, February 25, 2008 Tuesday, February 26, 2008

PAGE 463

434 Appendix H: (Continued) Wednesday, February 27, 2008 Thursday, February 28, 2008

PAGE 464

435 Appendix H: (Continued) Friday, February 29, 2008

PAGE 465

436 Appendix H: (Continued) February 23, 2008 –February 29, 2008 DatePrecipitation (In) Wind Direction PressureComments February 23, 20080.25W (270)1016Cold Front of Florida panhandle; rain in NE Florida February 24, 20080.00W (270)1020Cold Front over South-Central FL. February 25, 20080.00W (260)1016None February 26, 20080.39W (280)1012Approaching Cold Front February 27, 20080.13NW (300)1016Cold Front over S. Florida February 28, 20080.00W (280)1024High over Florida Panhandle February 29, 20080.00E (080)1028NoneTotal Precipitation: 0.77

PAGE 466

437 Appendix H: (Continued) Saturday, March 1, 2008 Sunday, March 2, 2008

PAGE 467

438 Appendix H: (Continued) Monday, March 3, 2008 Tuesday, March 4, 2008

PAGE 468

439 Appendix H: (Continued) Wednesday, March 5, 2008 Thursday, March 6, 2008

PAGE 469

440 Appendix H: (Continued) Friday, March 7, 2008

PAGE 470

441 Appendix H: (Continued) March 1, 2008 –March 7, 2008 DatePrecipitation (In) Wind Direction PressureComments March 1, 20080.00NW (310)1024High over NE Florida March 2, 20080.00E (080)1020Approaching Stationary Front March 3, 20080.00SE (120)1022None March 4, 20080.15W (280)1016Approaching cold front with rain March 5, 20080.00W (290)1016Cold Front over South Florida March 6, 20080.38W (260)1016Cold Front over South Florida March 7, 20081.00W (280)1008Low over Florida panhandle; Approaching Stationary front; rain in NE FloridaTotal Precipitation: 1.53

PAGE 471

442 Appendix H: (Continued) Saturday, March 8,2008 Sunday, March 9, 2008

PAGE 472

443 Appendix H: (Continued) Monday, March 10, 2008 Tuesday, March 11, 2008

PAGE 473

444 Appendix H: (Continued) Wednesday, March 12, 2008 Thursday, March 13, 2008

PAGE 474

445 Appendix H: (Continued) Friday, March 14, 2008

PAGE 475

446 Appendix H: (Continued) March 8, 2008 –March 14, 2008 DatePrecipitation (In) Wind Direction PressureComments March 8, 2008TW (280)1014Rain in Central and South Florida March 9, 20080.00NE (040)1024None March 10, 20080.00E (080)1028None March 11, 20080.05W (270)1020Stationary Front off La Coast March 12, 20080.00W (290)1016Cold Front over Ft. Myers March 13, 20080.00W (280)1016Low off Coast of Florida March 14, 20080.30SE (150)1012NoneTotal Precipitation: 0.35

PAGE 476

447 Appendix H: (Continued) Saturday, March 15, 2008 Sunday, March 16, 2008

PAGE 477

448 Appendix H: (Continued) Monday, March 17, 2008 Tuesday, March 18, 2008

PAGE 478

449 Appendix H: (Continued) Wednesday, March 19, 2008 Thursday, March 20, 2008

PAGE 479

450 Appendix H: (Continued) Friday, March 21, 2008

PAGE 480

451 Appendix H: (Continued) March 15, 2008 –March 21, 2008 DatePrecipitation (In) Wind Direction PressureComments March 15, 20080.00SW (220)1012Approaching Cold Front March 16, 20080.00SW (240)1016Cold Front just N of Tampa Bay March 17, 20080.00SE (120)1024Cold Front S of Florida March 18, 20080.00SE (150)1024 None March 19, 20080.00S (160)1016Approaching Low with Rain March 20, 20080.89W (290)1016Cold Front over Central Florida; Rain in Central Florida March 21, 20080.00E (070)1020High N of FloridaTotal Precipitation: 0.89

PAGE 481

452 Appendix H: (Continued) Saturday, March 22, 2008 Sunday, March 23, 2008

PAGE 482

453 Appendix H: (Continued) Monday, March 24, 2008 Tuesday, March 25, 2008

PAGE 483

454 Appendix H: (Continued) Wednesday, March 26, 2008 Thursday, March 27, 2008

PAGE 484

455 Appendix H: (Continued) Friday, March 28, 2008

PAGE 485

456 Appendix H: (Continued) March 22, 2008 –March 28, 2008 DatePrecipitation (In) Wind Direction PressureComments March 22, 20080.36SE (130)1016Stationary Front S of Florida; Approaching Cold Front March 23, 2008TNW (310)1016Cold Front N of Tampa Bay Area March 24, 20080.00NW (300)1018Cold Front just S of Ft. Myers March 25, 20080.00NE (060)1028High over Ga March 26, 20080.00NW (300)1028None March 27, 20080.00W (280)1020Approaching Stationary Front March 28, 20080.00W (290)1016Approaching Cold FrontTotal Precipitation: 0.36

PAGE 486

457 Appendix H: (Continued) Saturday, March 29, 2008 Sunday, March 30, 2008

PAGE 487

458 Appendix H: (Continued) Monday, March 31, 2008 Tuesday, April 1, 2008

PAGE 488

459 Appendix H: (Continued) Wednesday, April 2, 2008 Thursday, April 3, 2008

PAGE 489

460 Appendix H: (Continued) Friday, April 4, 2008

PAGE 490

461 Appendix H: (Continued) March 29, 2008 –April 4, 2008 DatePrecipitation (In) Wind Direction PressureComments March 29, 20080.00NW (300)1020Approaching Cold Front March 30, 20080.00NE (060)1022Stationary Front Over N Florida March 31, 20080.04E (070)1024None April 1, 2008TSE (140)1020Approaching Cold Front April 2, 20080.01SE (140)1020Cold Front just N of Florida April 3, 20080.01NW (310)1022Cold Front just N of Florida April 4, 2008TSE (150)1018 Warm Front N of FloridaTotal Precipitation: 0.06

PAGE 491

462 Appendix H: (Continued) Saturday, April 5, 2008 Sunday, April 6, 2008

PAGE 492

463 Appendix H: (Continued) Monday, April 7, 2008 Tuesday, April 8, 2008

PAGE 493

464 Appendix H: (Continued) Wednesday, April 9, 2008 Thursday, April 10, 2008

PAGE 494

465 Appendix H: (Continued) Friday, April 11, 2008

PAGE 495

466 Appendix H: (Continued) April 5, 2008 –April 11, 2008Total Precipitation: 1.96 DatePrecipitation (In) Wind Direction PressureComments April 5, 20080.38NW (320)1016Low W of Florida; Cold Front Approaching with rain April 6, 20081.58NW (330)1014Cold Front Approaching April 7, 20080.00NE (050)1016Cold Front just N of Florida April 8, 20080.00E (070)1016Rain in the Florida Keys April 9, 20080.00E (080)1020None April 10, 20080.00E (070)1018Stationary Front Approaching April 11, 20080.00W (290)1016Cold Front Approaching

PAGE 496

467 Appendix H: (Continued) Saturday, April 26, 2008 Sun d ay, Apr il 27, 2008

PAGE 497

468 Appendix H: (Continued) Monday, April 28, 2008 Tuesday, April 29, 2008

PAGE 498

469 Appendix H: (Continued) Wednesday, April 30, 2008 Thursday, May 1, 2008

PAGE 499

470 Appendix H: (Continued) Friday, May 2, 2008

PAGE 500

471 Appendix H: (Continued) April 26, 2008 –May 2, 2008Total Precipitation: 0.06 DatePrecipitation (In) Wind Direction PressureComments April 26, 20080.00SE (150)1016Cold Front Approaching April 27, 20080.00W (280)1016Cold Front Approaching April 28, 20080.06W (250)1016Cold Front Approaching; Rain in Panhandle April 29, 20080.00W (290)1016Cold Front S of Florida; Another Cold Front Approaching April 30, 20080.00E (080)1018High over Ga May 1, 20080.00SE (120)1020None May 2, 20080.00SE (130)1020 None

PAGE 501

472 Appendix H: (Continued) Saturday, May 17, 2008 Sunday, May 18, 2008

PAGE 502

473 Appendix H: (Continued) Monday, May 19, 2008 Tuesday, May 20, 2008

PAGE 503

474 Appendix H: (Continued) Wednesday, May 21, 2008 Thursday, May 22, 2008

PAGE 504

475 Appendix H: (Continued) Friday, May 23, 2008

PAGE 505

476 Appendix H: (Continued) May 17, 2008 –May 23, 2008Total Precipitation: 0.98 DatePrecipitation (In) Wind Direction PressureComments May 17, 20080.00W (260)1012Cold Front over Tampa Bay Area May 18, 20080.05W (250)1012Cold Front just S of Tampa Bay May 19, 20080.00W (280)1012Approaching Cold Front May 20, 20080.74W (250)1012None May 21, 20080.00SW (240)1010Approaching Cold Front May 22, 20080.19W (250)1012Approaching Cold Front May 23, 2008T W (270)1012Rain in Panhandle; Approaching cold front

PAGE 506

477 Appendix H: (Continued) Saturday, May 31, 2008 Sunday, June 1, 2008

PAGE 507

478 Appendix H: (Continued) Monday, June 2, 2008 Tuesday, June 3, 2008

PAGE 508

479 Appendix H: (Continued) Wednesday, June 4, 2008 Thursday, June 5, 2008

PAGE 509

480 Appendix H: (Continued) Friday, June 6, 2008

PAGE 510

481 Appendix H: (Continued) May 31, 2008 –June 6, 2008Total Precipitation: T DatePrecipitation (In) Wind Direction PressureComments May 31, 20080.00W (290)1012Rain in Panhandle; Approaching Cold Front June 1, 20080.00W (270)1016High over Florida; Rain in the Keys June 2, 20080.00W (270)1016Approaching Cold Front June 3, 20080.00W (280)1016High E of Florida June 4, 2008TW (260)1016None June 5, 20080.00SE (140)1016Cold Front Approaching June 6, 20080.00E (110)1020Cold Front Approaching

PAGE 511

482 Appendix H: (Continued) Saturday, June 7, 2008 Sunday, June 8, 2008

PAGE 512

483 Appendix H: (Continued) Monday, June 9, 2008 Tuesday, June 10, 2008

PAGE 513

484 Appendix H: (Continued) Wednesday, June 11, 2008 Thursday, June 12, 2008

PAGE 514

485 Appendix H: (Continued) Friday, June 13, 2008

PAGE 515

486 Appendix H: (Continued) June 7, 2008 –June 13, 2008Total Precipitation: 3.30 DatePrecipitation (In) Wind Direction PressureComments June 7, 20080.00E (070)1020None June 8, 20080.31E (080)1020High over Ga June 9, 20080.32SW (240)1016High E of Florida June 10, 20080.38NW (310)1016High E of Florida; Approaching Cold Front June 11, 20080.00N (350)1016None June 12, 20082.27N (010)1018Approaching Cold Front June 13, 20080.02N (010)1020Approaching Cold Front

PAGE 516

487 Appendix H: (Continued) Saturday, June 14, 2008 Sunday, June 15, 2008

PAGE 517

488 Appendix H: (Continued) Monday, June 16, 2008 Tuesday, June 17, 2008

PAGE 518

489 Appendix H: (Continued) Wednesday, June 18, 2008 Thursday, June 19, 2008

PAGE 519

490 Appendix H: (Continued) Friday, June 20, 2008

PAGE 520

491 Appendix H: (Continued) June 14, 2008 –June 20, 2008Total Precipitation: 0.71 DatePrecipitation (In) Wind Direction PressureComments June 14, 20080.00W (280)1016High off of Ga coast; Approaching Cold Front June 15, 20080.12E (080)1012None June 16, 20080.04W (250)1016Approaching Cold Front June 17, 20080.25W (290)1014Approaching Cold Front June 18, 20080.05W (260)1012Cold Front over N Florida June 19, 20080.25W (280)1012Cold Front just N of Tampa Bay June 20, 20080.00W (270)1016Low over N Florida; Cold Front over Panhandle

PAGE 521

492 Appendix H: (Continued) Saturday, June 21, 2008 Sunday, June 22, 2008

PAGE 522

493 Appendix H: (Continued) Monday, June 23, 2008 Tuesday, June 24, 2008

PAGE 523

494 Appendix H: (Continued) Wednesday, June 25, 2008 Thursday, June 26, 2008

PAGE 524

495 Appendix H: (Continued) Friday, June 27, 2008

PAGE 525

496 Appendix H: (Continued) June 21, 2008 –June 27, 2008Total Precipitation: 2.26 DatePrecipitation (In) Wind Direction PressureComments June 21, 20080.17W (250)1020None June 22, 20080.39W (260)1016Low over Panhandle June 23, 2008TNW (310)1016Approaching Cold Front June 24, 2008TN (010)1020Low E of Florida; Approaching Cold Front June 25, 20081.57NE (040)1024Approaching Stationary Front June 26, 20080.13W (260)1020High E of Florida June 27, 20080.00NW (300)1020High E of Florida

PAGE 526

497 Appendix H: (Continued) Saturday, June 28, 2008 Sunday, June 29, 2008

PAGE 527

498 Appendix H: (Continued) Monday, June 30, 2008 Tuesday, July 1, 2008

PAGE 528

499 Appendix H: (Continued) Wednesday, July 2, 2008 Thursday, July 3, 2008

PAGE 529

500 Appendix H: (Continued) Friday, July 4, 2008

PAGE 530

501 Appendix H: (Continued) June 28, 2008 –July 4, 2008Total Precipitation: 0.02 DatePrecipitation (In) Wind Direction 1020None June 28, 20080.00ESE (120)1020None June 29, 20080.00W (290)1020Approaching Cold Front from NW June 30, 20080.00N (350)1016Cold front over N. FL July 1, 20080.00S (150)1020Stationary cold Front July 2, 20080.02ESE (140)1020Approaching low from NW July 3, 2008TW (290)1020Low NE of Florida July 4, 20080.00W (260)1020None

PAGE 531

502 Appendix H: (Continued) Saturday, July 5, 2008 Sunday, July 6, 2008

PAGE 532

503 Appendix H: (Continued) Monday, July 7, 2008 Tuesday, July 8, 2008

PAGE 533

504 Appendix H: (Continued) Wednesday, July 9, 2008 Thursday, July 10, 2008

PAGE 534

505 Appendix H: (Continued) Friday, July 11, 2008

PAGE 535

506 Appendix H: (Continued) July 5, 2008 –July 11, 2008Total Precipitation: 5.51 DatePrecipitation (In) Wind Direction PressureComments July 5, 20080.00E (110)1020None July 6, 20082.08WSW (220)1016None July 7, 20080.92E (080)1016None July 8, 20081.54ESE (140)1020High over FL July 9, 20080.00S (160)1020High over FL July 10, 20080.00W (270)1020High over FL July 11, 20080.97WSW (200)1020High over FL

PAGE 536

507 Appendix H: (Continued) Saturday, July 12, 2008 Sunday, July 13, 2008

PAGE 537

508 Appendix H: (Continued) Mon d ay, Ju l y 14, 2008 Tuesday, July 15, 2008

PAGE 538

509 Appendix H: (Continued) Wednesday, July 16, 2008 Thursday, July 17, 2008

PAGE 539

510 Appendix H: (Continued) Friday, July 18, 2008

PAGE 540

511 Appendix H: (Continued) July 12, 2008 –July 18, 2008Total Precipitation: 4.15 DatePrecipitation (In) Wind Direction PressureComments July 12, 20081.39W (280)1020High over North Florida July 13, 20080.29WSW (220)1016Low over Florida July 14, 20081.14WNW (320)1016Low pressure ridge over Florida July 15, 20080.25ENE (050)1020Low over Florida July 16, 20081.08ENE (050)1016Low pressure system over FL July 17, 20080.00W (250)1020Low pressure system July 18, 20080.00W (280)1020Low pressure system of FL

PAGE 541

512 Appendix H: (Continued) Saturday, July 19, 2008 Sunday, July 20, 2008

PAGE 542

513 Appendix H: (Continued) Monday, July 21, 2008 Tuesday, July 22, 2008

PAGE 543

514 Appendix H: (Continued) Wednesday, July 23, 2008 Thursday, July 24, 2008

PAGE 544

515 Appendix H: (Continued) Friday, July 25, 2008

PAGE 545

516 Appendix H: (Continued) July 19, 2008 –July 25, 2008Total Precipitation: 1.78 DatePrecipitation (In) Wind Direction PressureComments July 19, 20080.00W (270)1016High over North Florida July 20, 20080.00W (280)1016High over Florida July 21, 20080.00W (280)1016High over Florida July 22, 20081.53S (170)1016No comments July 23, 20080.14ENE (040)1016Low pressure and rain over FL July 24, 20080.04W (280)1016High moving in from NW July 25, 20080.07W (250)1016High over FL

PAGE 546

517 Appendix H: (Continued) Saturday, July 26, 2008 Sunday, July 27, 2008

PAGE 547

518 Appendix H: (Continued) Monday, July 28, 2008 Tuesday, July 29, 2008

PAGE 548

519 Appendix H: (Continued) Wednesday, July 30, 2008 Thursday, July 31, 2008

PAGE 549

520 Appendix H: (Continued) Friday, August 1, 2008

PAGE 550

521 Appendix H: (Continued) July 26, 2008 –August 1, 2008Total Precipitation: 3.91 DatePrecipitation (In) Wind Direction PressureComments July 26, 20080.51W (290)1016Approaching cold front from NW July 27, 20080.30W (290)1016High over Florida, approaching cold front from NW July 28, 20080.00WSW (220)1014Low pressure cold front approaching from NW July 29, 20080.31WSW (230)1014High pressure over FL July 30, 20082.18W (260)1016No comments July 31, 20080.61N (340)1014Low pressure system from NW and rain August 1, 2008TWNW (310)1014No comments

PAGE 551

522 Appendix H: (Continued) Saturday, August 2, 2008 Sunday, August 3, 2008

PAGE 552

523 Appendix H: (Continued) Monday, August 4, 2008 Tuesday, August 5, 2008

PAGE 553

524 Appendix H: (Continued) Wednesday, August 6, 2008 Thursday, August 7, 2008

PAGE 554

525 Appendix H: (Continued) Friday, August 8, 2008

PAGE 555

526 Appendix H: (Continued) August 2, 2008 –August 8, 2008Total Precipitation: 0.64 DatePrecipitation (In) Wind Direction PressureComments August 2, 20080.51W (270)1014Cold front approaching from NW August 3, 20080.00WNW (310)1014Approaching cold front from NW August 4, 20080.00ESE (150)1014Approaching high, TS in GOM August 5, 2008TWNW (330)1016High pressure over FL August 6, 2008TN (360)1016High over FL August 7, 20080.00W (280)1016High in GOM August 8, 20080.13WSW (230)1012Approaching cold front from NW

PAGE 556

527 Appendix H: (Continued) Saturday, August 9, 2008 Sunday, August 10, 2008

PAGE 557

528 Appendix H: (Continued) Monday, August 11, 2008 Tuesday, August 12, 2008

PAGE 558

529 Appendix H: (Continued) We d nes d ay, August 13, 2008 Thursday, August 14, 2008

PAGE 559

530 Appendix H: (Continued) Friday, August 15, 2008

PAGE 560

531 Appendix H: (Continued) August 9, 2008 –August 15, 2008Total Precipitation: 3.75 DatePrecipitation (In) Wind Direction PressureComments August 9, 20080.79W (270)1012Cold front approaching from NW August 10, 20080.00W (280)1014Cold front over FL, high to S August 11, 20080.00NW (260)1014Approaching low from NW August 12, 20080.26W (290)1012Approaching low pressure system and cold front from NW August 13, 20080.16W (280)1012Approaching low pressure system and cold front from NW August 14, 20082.43W (260)1012Low pressure cold front over FL August 15, 20080.11W (280)1016Approaching cold front from NW

PAGE 561

532 Appendix H: (Continued) Saturday, August 16, 2008 Sunday, August 17, 2008

PAGE 562

533 Appendix H: (Continued) Mon d ay, August 18, 2008 Tuesday, August 19, 2008

PAGE 563

534 Appendix H: (Continued) Wednesday, August 20, 2008 Thursday, August 21, 2008

PAGE 564

535 Appendix H: (Continued) Friday, August 22, 2008

PAGE 565

536 Appendix H: (Continued) August 16, 2008 –August 22, 2008Total Precipitation: 1.96 DatePrecipitation (In) Wind Direction PressureComments August 16, 20080.00N (330)1018Cold front approaching from NW, high over FL August 17, 2008TW (290)1014Front approaching from NW August 18, 2008TE (110)1014High in GOM, TS Fay approaching from S August 19, 20080.15ENE (050)1008Low pressure over FL, TS Fay crossing peninsula August 20, 20080.04W (290)1008Low pressure over FL, TS Fay crossing peninsula August 21, 20080.13W (280)1004Low pressure over FL, TS Fay crossing peninsula August 22, 20081.64WSW (240)1004Low pressure over FL, TS Fay crossing peninsula

PAGE 566

537 Appendix H: (Continued) Saturday, August 23, 2008 Sunday, August 24, 2008

PAGE 567

538 Appendix H: (Continued) Monday, August 25, 2008 Tuesday, August 26, 2008

PAGE 568

539 Appendix H: (Continued) Wednesday, August 27, 2008 Thursday, August 28, 2008

PAGE 569

540 Appendix H: (Continued) Friday, August 29, 2008

PAGE 570

541 Appendix H: (Continued) August 23, 2008 –August 29, 2008Total Precipitation: 3.5 DatePrecipitation (In) Wind Direction PressureComments August 23, 20081.63ESE (140)1008TS Fay moving into GOM August 24, 20080.71ESE (130)1014Low pressure over FL August 25, 2008TW (290)1014Low pressure over FL August 26, 20080.45WSW (210)1012Low pressure NW of FL August 27, 20080.00W (270)1012Low pressure over FL August 28, 20080.00ESE (120)1012Low pressure over FL August 29, 20080.71ENE (030)1012Approaching cold front from NW

PAGE 571

542 Appendix H: (Continued) Saturday, August 30, 2008 Sunday, August 31, 2008

PAGE 572

543 Appendix H: (Continued) Monday, September 1, 2008 Tuesday, September 2, 2008

PAGE 573

544 Appendix H: (Continued) Wednesday, September 3, 2008 Thursday, September 4, 2008

PAGE 574

545 Appendix H: (Continued) Friday, September 5, 2008

PAGE 575

546 Appendix H: (Continued) August 30, 2008 –September 5, 2008Total Precipitation: 0.21 DatePrecipitation (In) Wind Direction PressureComments August 30, 20080.21E (070)1012High over FL August 31, 2008TE (090)1012Low over FL, Hurricane Gustav approaching from SW September 1, 20080.00E (090)1012Low over FL, Hurricane Gustav in GOM September 2, 2008TE (060)1012Low pressure NW of FL September 3, 20080.00E (080)1012Low pressure NW of FL September 4, 20080.00E (060)1012Low pressure over FL September 5, 2008TW (280)1000Cold front W of FL, TS Hanna in Atlantic

PAGE 576

547 Appendix H: (Continued) Saturday, September 6, 2008 Sunday, September 7, 2008

PAGE 577

548 Appendix H: (Continued) Monday, September 8, 2008 Tuesday, September 9, 2008

PAGE 578

549 Appendix H: (Continued) Wednesday, September 10, 2008 Thursday, September 11, 2008

PAGE 579

550 Appendix H: (Continued) Friday, September 12, 2008

PAGE 580

551 Appendix H: (Continued) September 6, 2008 –September 12, 2008Total Precipitation: 0.19 DatePrecipitation (In) Wind Direction PressureComments September 6, 20080.00W (260)1014Cold front W of FL, TS Hanna N of FL September 7, 20080.00ENE (060)1016Approaching front from NW September 8, 20080.00E (090)1016Hurricane Ike in GOM September 9, 20080.00E (080)1016Approaching front from NW, Ike in GOM September 10, 2008TE (100)1012Approaching front from NW, Ike over S FL September 11, 20080.19ESE (150)1016Approaching front from NW, Ike in GOM September 12, 20080.00ESE (140)1016Approaching front from NW, Ike in GOM

PAGE 581

552 Appendix H: (Continued) Saturday, September 13, 2008 Sunday, September 14, 2008

PAGE 582

553 Appendix H: (Continued) Monday, September 15, 2008 Tuesday, September 16, 2008

PAGE 583

554 Appendix H: (Continued) Wednesday, September 17, 2008 Thursday, September 18, 2008

PAGE 584

555 Appendix H: (Continued) Friday, September 19, 2008

PAGE 585

556 Appendix H: (Continued) September 13, 2008 –September 19, 2008Total Precipitation: 0.79 DatePrecipitation (In) Wind Direction PressureComments September 13, 20080.00W (280)1016High over FL September 14, 20080.1W (290)1016High over FL September 15, 2008TW (290)1012Approaching cold front from NW September 16, 20080.00WNW (320)1016Cold front from over FL, high to NE September 17, 20080.69WNW (320)1016Cold front from over FL, high to NW, low to NE September 18, 20080.00ENE (040)1016Cold front from over FL, low to NE September 19, 20080.00ENE (050)1016No comments

PAGE 586

557 Appendix H: (Continued) Saturday, September 20, 2008 Sunday, September 21, 2008

PAGE 587

558 Appendix H: (Continued) Mon d ay, Septem b er 22, 2008 Tuesday, September 23, 2008

PAGE 588

559 Appendix H: (Continued) Wednesday, September 24, 2008 Thursday, September 25, 2008

PAGE 589

560 Appendix H: (Continued) Friday, September 26, 2008

PAGE 590

561 Appendix H: (Continued) September 20, 2008 –September 26, 2008Total Precipitation: 0.01 DatePrecipitation (In) Wind Direction PressureComments September 20, 2008TENE (050)1016No comments September 21, 20080.00WNW (300)1016Passing high September 22, 2008TENE (060)1016No comments September 23, 20080.01N (020)1016Low to NE September 24, 20080.00ENE (050)1012Low to NE September 25, 20080.00W (270)1012Low to NE September 26, 20080.00WNW (300)1012Low to N of FL, passing low pressure system

PAGE 591

562 Appendix H: (Continued) Saturday, September 27, 2008 Sunday, September 28, 2008

PAGE 592

563 Appendix H: (Continued) Monday, September 29, 2008 Tuesday, September 30, 2008

PAGE 593

564 Appendix H: (Continued) Wednesday, October 1, 2008 Thursday, October 2, 2008

PAGE 594

565 Appendix H: (Continued) Friday, October 3, 2008

PAGE 595

566 Appendix H: (Continued) September 27, 2008 –October 3, 2008Total Precipitation: T DatePrecipitation (In) Wind Direction PressureComments September 27, 20080.00W (290)1012Low N of FL September 28, 20080.00ENE (040)1016Hurricane Kyle to NE September 29, 20080.00E (080)1012No comments September 30, 2008TW (290)1012Approaching cold front from NW October 1, 20080.00W (270)1012Approaching cold front from NW October 2, 20080.00WNW (310)1008Passing cold front from NW October 3, 20080.00E (070)1016High over N FL

PAGE 596

567 Appendix H: (Continued) Saturday, October 4, 2008 Sunday, October 5, 2008

PAGE 597

568 Appendix H: (Continued) Monday, October 6, 2008 Tuesday, October 7, 2008

PAGE 598

569 Appendix H: (Continued) Wednesday, October 8, 2008 Thursday, October 9, 2008

PAGE 599

570 Appendix H: (Continued) Friday, October 10, 2008

PAGE 600

571 Appendix H: (Continued) October 4, 2008 –October 10, 2008Total Precipitation: 1.16 DatePrecipitation (In) Wind Direction PressureComments October 4, 20080.00E (080)1020High over FL October 5, 2008TE (070)1020No comments October 6, 20080.40E (100)1016No comments October 7, 20080.33E (110)1016Approaching cold front from and WNW October 8, 20080.00W (270)1016Converging cold fronts over FL October 9, 20080.43W (280)1012Low over FL October 10, 20080.00W (270)1016Low over FL

PAGE 601

572 Appendix H: (Continued) Saturday, October 18, 2008 Sunday, October 19, 2008

PAGE 602

573 Appendix H: (Continued) Monday, October 20, 2008 Tuesday, October 21, 2008

PAGE 603

574 Appendix H: (Continued) Wednesday, October 22, 2008 Thursday, October 23, 2008

PAGE 604

575 Appendix H: (Continued) Friday, October 24, 2008

PAGE 605

576 Appendix H: (Continued) October 18, 2008 –October 24, 2008Total Precipitation: 0.03 DatePrecipitation (In) Wind Direction PressureComments October 18, 20080.00W (290)1016Passing cold front from NW October 19, 20080.00ENE (060)1016No comments October 20, 20080.03ENE (060)1020No comments October 21, 2008TENE (040)1020Approaching high from NW October 22, 20080.00E (080)1020Approaching low from NW October 23, 20080.00E (080)1020Low over FL, rain in N FL October 24, 20080.00ESE (150)1012Low over FL, rain in FL

PAGE 606

577 Appendix I Legend Rain Gauge CR10 Program

PAGE 607

578 Appendix I: (Continued) ;{CR10} *Table 1 Program 01: 600.0000 Execution Interval (seconds) 1: Batt Voltage (P10) 1: 1 Loc [ Batt_Volt ] 2: If time is (P92) 1: 0 Mi nutes (Seconds --) into a 2: 1440 Interval (same units as above) 3: 30 Then Do 3: Signature (P19) 1: 2 Loc [ Prog_Sig ] 4: End (P95) 5: Pulse (P3) 1: 1 Reps 2: 1 Pulse Input Channel 3: 2 Swit ch Closure, All Counts 4: 3 Loc [ Rain_in ] 5: .01 Mult 6: 0 Offset 6: Z=X+Y (P33) 1: 4 X Loc [ Tot24 ] 2: 3 Y Loc [ Rain_in ] 3: 4 Z Loc [ Tot24 ] 7: If time is (P92) 1: 0 Mi nutes (Seconds --) into a 2: 1440 Interval (same units as above) 3: 30 Then Do 8: Z=F x 10^n (P30) 1: 0 F 2: 0 n, Exponent of 10 3: 4 Z Loc [ Tot24 ] 9: End (P95) 10: If time is (P92)

PAGE 608

579 Appendix I: (Continued) 1: 0 Mi nutes (Seconds --) into a 2: 60 Interval (same units as above) 3: 10 Se t Output Flag High 11: Set Active Storage Area (P80)^7680 1: 1 Final Storage Area 1 2: 101 Array ID 12: Real Time (P77)^14703 1: 1220 Year,Day,H our/Minute (midnight = 2400) 13: Average (P71)^3597 1: 1 Reps 2: 1 Loc [ Batt_Volt ] 14: Totalize (P72)^23041 1: 1 Reps 2: 3 Loc [ Rain_in ] 15: If time is (P92) 1: 0 Mi nutes (Seconds --) into a 2: 1440 Interval (same units as above) 3: 10 Se t Output Flag High 16: Set Active Storage Area (P80)^1825 1: 1 Final Storage Area 1 2: 102 Array ID 17: Real Time (P77)^17596 1: 1220 Year,Day,H our/Minute (midnight = 2400) 18: Minimum (P74)^9549 1: 1 Reps 2: 0 Value Only 3: 1 Loc [ Batt_Volt ] 19: Sample (P70)^16092 1: 1 Reps 2: 2 Loc [ Prog_Sig ] 20: Sample (P70)^838 1: 1 Reps 2: 4 Loc [ Tot24 ]

PAGE 609

580 Appendix I: (Continued) *Table 2 Program 01: 10.0000 Execution Interval (seconds) 1: Serial Out (P96) 1: 71 Storage Module *Table 3 Subroutines End Program

PAGE 610

581 Appendix J Legend Water Collector Program

PAGE 611

582 Appendix J: (Continued) ;************************* ************************** ******************* ; ; Filename: water. asm ; Date: ; File Version: ; ; Author: ; Company: ; ; ;************************* ************************** ******************* ; ; Files required: ; 16F690.lkr ; ; ;************************* ************************** ******************* ; ; Notes: ; ; ; ; ;************************* ************************** ******************* ; list p=16F690 ; #include errorlevel -302 #include __config (_INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_OFF & _MCLRE_OFF & _CP_OFF & _IESO_OFF & _FCMEN_OFF) ; '__CONFIG' directive is used to embed configuration word within .asm file. ; The lables following the directive are located in the respective .inc file. ; See data sheet for additi onal information on configuration word settings. ;***** VARIABLE DEFINITIONS (examples)

PAGE 612

583 Appendix J: (Continued) ; example of using Shared Un initialized Data Section ;INT_VAR UDATA_SHR 0x70 ;pclath_temp RES 1 ; vari able used for context saving ;************************* ************************** ******************* cblock 0x20 WaitXMin WaitXMinHolder SleepXMin SleepXMinHolder SleepXDay SleepXDayHolder XBottleCount XForwardStep XForwardStepHolder XReverseStep XReverseStepHolder XMainloopHolder XMainloop COUNT125 COUNT20 COUNT60 COUNT24 COUNT4 endc org 0 ;****Setting up the ports and initial conditions**** bsf STATUS,R P0 ;Switch to Bank 1 bcf OSCCON,6 bcf OSCCON,5 ;Sets frequency to 31kHz bsf OSCCON,4 bsf OSCCON,0

PAGE 613

584 Appendix J: (Continued) movlw 0x00 ;0x0000OOOOD movwf TRISB ;Set PortC Inputs/Outputs movlw 0xE0 ;0xIIIOOOOOD movwf TRISC ;Set PortC Inputs/Outputs bcf STATUS,R P0 ;Switch back to Bank 0 movlw 0x80 movwf COUNT125 movlw 0x14 movwf COUNT20 movlw 0x3C movwf COUNT60 movlw 0x18 movwf COUNT24 movlw 0x04 movwf COUNT4 movlw 0x05 ;X (in min) for length of time movwf WaitXMinHolder ;of time water drains movwf WaitXMin ;into bottle movlw 0xAF ;X (in min) for length of time over drain hole before back movwf SleepXMinH older ;over bottle movwf SleepXMin movlw 0x38 ;Repeats Main loop X times before next bottle movwf XMainloopHolder movwf XMainloop movlw 0x08 ;# of bottles movwf XBottleCount ;********************************* ******************************* *************************** ********** ;Steps forward and reverse not required fo r the modified version of the software (micro switch version

PAGE 614

585 Appendix J: (Continued) ;********************************* ******************************* *************************** ********** ;movlw 0x0D ;movwf XForwardStepHolder ;# of steps Forward ;movwf XForwardStep ;**must be .5x(# steps between each bottle) ;movlw 0x0D ;movwf XReverseStepHolder ;# of steps Reverse ;movwf XReverseStep ;**must be .5x(# steps between each bottle) ;movlw 0x01 ;X (in day) for length of time(1=nodays 2-8 =desired -1 ;movwf SleepXDayHol der ;of time remaining in long sleepif 0, will sleep for 255 days ;movwf SleepXDay ;prior to start of a new cycle Startup call StartUpInitialization Main call HoleWaitTimer call ReverseMovement call SleepWaitTimer call ForwardMovement decfsz XMainloop goto Main movf XMainloopHolder,0 movwf XMainloop ;decfsz SleepXDay,0 ;call SleepDayTimer call ForwardMovement decfsz XBottleCount,1 goto Startup

PAGE 615

586 Appendix J: (Continued) Park goto Park StartUpInitialization call CCW call LoopCheck return ;LoopForward ;call DriverClock ;decfsz XForwardStep,1 ;goto LoopForward ;movf XForwardStepHolder,0 ;movwf XForwardStep ;call CheckBit ;call PowerOff ;return ReverseMovement call CW call LoopCheck ;LoopReverse ;call LoopCheck ;call DriverClock ;decfsz XReverseStep,1 ;goto LoopReverse ;movf XReverseStepHolder,0 ;movwf XReverseStep ;call PowerOff return ForwardMovement call CCW call LoopCheck return LoopCheck call DriverClock call DriverClock call DriverClock call DriverClock call DriverClock CheckBit BTFSC PORTC,5

PAGE 616

587 Appendix J: (Continued) call DriverClock BTFSC PORTC,5 goto CheckBit call PowerOff return DriverClock movlw 0xFF movwf PORTB nop nop nop nop nop nop nop nop movlw 0x00 movwf PORTB call WaitTimerQuarterSec return CW movlw 0x1E movwf PORTC call WaitTimerQuarterSec return CCW movlw 0x1F movwf PORTC call WaitTimerQuarterSec return PowerOff movlw 0x00 movwf PORTC return ;TIMER SUBROUTINES MinTimer

PAGE 617

588 Appendix J: (Continued) MinTimerLoop call WaitTimerQuarterSec decfsz COUNT4,1 goto MinTimerLoop movlw 0x04 movwf COUNT4 decfsz COUNT60,1 ;Delete for second loop goto MinTimerLoop ;Delete for second loop movlw 0x3C ;Delete for second loop movwf COUNT60 ;Delete for second loop return WaitTimerQuarterSec QuarterLoop decfsz COUNT125,1 goto QuarterLoop movlw 0x80 movwf COUNT125 decfsz COUNT20,1 goto QuarterLoop movlw 0x14 movwf COUNT20 return HoleWaitTimer HoleTimerLoop call MinTimer decfsz WaitXMin goto HoleTimerLoop movf WaitXMinHolder,0 movwf WaitXMin return SleepWaitTimer SleepTimerLoop call MinTimer decfsz SleepXMin,1 goto SleepTimerLoop movf SleepXMinHolder,0 movwf SleepXMin return DayTimer

PAGE 618

589 Appendix J: (Continued) DayTimerLoop call MinTimer decfsz COUNT60 goto DayTimerLoop movlw 0x3C movwf COUNT60 decfsz COUNT24 goto DayTimerLoop movlw 0x18 movwf COUNT24 return SleepDayTimer SleepDayLoop call DayTimer decfsz SleepXDay,1 goto SleepDayLoop movf SleepXDayHolder,0 movwf SleepXDay return ;****End of program**** END

PAGE 619

590 Appendix K BRC03-02 Stable Isotope Data

PAGE 620

591 Appendix K: (Continued) Distance from top (m) Distance from top (mm) Age (yr BP) 13C 18O 100 0.1 3.47 -11.00 -4.75 200 0.2 6.94 -11.08 -4.59 300 0.3 10.41 -11.23 -4.62 400 0.4 13.88 -10.67 -4.68 500 0.5 17.35 -10.57 -4.62 600 0.6 20.82 -10.91 -4.64 700 0.7 24.29 -11.07 -4.73 800 0.8 27.76 -10.61 -4.67 900 0.9 31.23 -11.32 -4.66 1000 1 34.7 -11.30 -4.57 1100 1.1 38.17 -10.89 -4.71 1200 1.2 41.64 -11.20 -4.58 1300 1.3 45.11 -11.22 -4.66 1400 1.4 48.58 -11.07 -4.65 1500 1.5 52.05 -11.38 -4.69 1600 1.6 55.52 -11.41 -4.68 1700 1.7 58.99 -11.49 -4.74 1800 1.8 62.46 -11.44 -4.64 1900 1.9 65.93 -11.49 -4.74 2000 2 69.4 -11.48 -4.62 2100 2.1 72.87 -11.42 -4.59 2200 2.2 76.34 -11.72 -4.59 2300 2.3 79.81 -11.78 -4.63 2400 2.4 83.28 -11.94 -4.73 2500 2.5 86.75 -12.01 -4.63 2600 2.6 90.22 -11.83 -4.60 2700 2.7 93.69 -12.04 -4.51 2800 2.8 97.16 -11.92 -4.54 2900 2.9 100.63 -11.98 -4.57 3000 3 104.1 -12.20 -4.55 3100 3.1 107.57 -12.03 -4.56 3200 3.2 111.04 -11.92 -4.44 3300 3.3 114.51 -12.05 -4.52 3400 3.4 117.98 -11.87 -4.52 3500 3.5 121.45 -12.00 -4.44 3600 3.6 124.92 -11.94 -4.67 3700 3.7 128.39 -11.96 -4.48 3800 3.8 131.86 -11.91 -4.56 3900 3.9 135.33 -11.88 -4.52 4000 4 138.8 -11.85 -4.63

PAGE 621

592 Appendix K: (Continued) 4100 4.1 142.27 -11.84 -4.39 4200 4.2 145.74 -11.89 -4.54 4300 4.3 149.21 -11.82 -4.39 4400 4.4 152.68 -11.85 -4.44 4500 4.5 156.15 -11.88 -4.43 4600 4.6 159.62 -11.86 -4.47 4700 4.7 163.09 -11.86 -4.50 4800 4.8 166.56 -11.87 -4.58 4900 4.9 170.03 -11.87 -4.53 5000 5 173.5 -11.85 -4.57 5100 5.1 176.97 -11.81 -4.56 5200 5.2 180.44 -11.69 -4.45 5300 5.3 183.91 -11.67 -4.49 5400 5.4 187.38 -11.60 -4.43 5500 5.5 190.85 -11.64 -4.46 5600 5.6 194.32 -11.62 -4.46 5700 5.7 197.79 -11.70 -4.47 5800 5.8 201.26 -11.79 -4.60 5900 5.9 204.73 -11.78 -4.58 6000 6 208.2 -11.73 -4.39 6100 6.1 211.67 -11.76 -4.41 6200 6.2 215.14 -11.80 -4.50 6300 6.3 218.61 -11.85 -4.60 6400 6.4 222.08 -11.87 -4.86 6500 6.5 225.55 -11.91 -4.72 6600 6.6 229.02 -11.82 -4.78 6700 6.7 232.49 -11.83 -4.83 6800 6.8 235.96 -11.88 -4.83 6900 6.9 239.43 -11.83 -4.72 7000 7 242.9 -11.86 -4.85 7100 7.1 246.37 -11.88 -4.60 7200 7.2 249.84 -11.81 -4.77 7300 7.3 253.31 -11.85 -4.67 7400 7.4 256.78 -11.89 -4.72 7500 7.5 260.25 -11.89 -4.68 7600 7.6 263.72 -12.00 -4.76 7700 7.7 267.19 -11.83 -4.67 7800 7.8 270.66 -11.65 -4.71 7900 7.9 274.13 -11.92 -4.70 8000 8 277.6 -11.81 -4.75 8100 8.1 281.07 -11.89 -4.70 8200 8.2 284.54 -11.67 -4.67 8300 8.3 288.01 -11.60 -4.64

PAGE 622

593 Appendix K: (Continued) 8400 8.4 291.48 -11.50 -4.64 8500 8.5 294.95 -11.45 -4.53 8600 8.6 298.42 -11.44 -4.68 8700 8.7 301.89 -11.44 -4.59 8800 8.8 305.36 -11.53 -4.63 8900 8.9 308.83 -11.53 -4.63 9000 9 312.3 -11.52 -4.56 9100 9.1 315.77 -11.36 -4.47 9200 9.2 319.24 -11.27 -4.40 9300 9.3 322.71 -11.21 -4.32 9400 9.4 326.18 -11.19 -4.61 9500 9.5 329.65 -11.18 -4.41 9600 9.6 333.12 -11.17 -4.25 9700 9.7 336.59 -11.04 -4.09 9800 9.8 340.06 -11.22 -4.29 9900 9.9 343.53 -11.31 -4.21 10000 10 347 -11.33 -4.10 10100 10.1 348.28 -11.17 -4.32 10200 10.2 349.56 -11.27 -4.33 10300 10.3 350.84 -11.25 -4.40 10400 10.4 352.12 -11.37 -4.57 10500 10.5 353.4 -11.24 -4.42 10600 10.6 354.68 -11.36 -4.44 10700 10.7 355.96 -11.57 -4.53 10800 10.8 357.24 -11.43 -4.45 10900 10.9 358.52 -11.70 -4.52 11000 11 359.8 -11.37 -4.41 11100 11.1 361.08 -11.71 -4.79 11200 11.2 362.36 -11.69 -4.46 11300 11.3 363.64 -11.66 -4.45 11400 11.4 364.92 -11.73 -4.32 11500 11.5 366.2 -11.83 -4.51 11600 11.6 367.48 -11.87 -4.57 11700 11.7 368.76 -11.85 -4.49 11800 11.8 370.04 -11.86 -4.51 11900 11.9 371.32 -11.81 -4.36 12000 12 372.6 -11.81 -4.34 12100 12.1 373.88 -11.84 -4.30 12200 12.2 375.16 -11.82 -4.40 12300 12.3 376.44 -11.84 -4.17 12400 12.4 377.72 -11.87 -4.44 12500 12.5 379 -11.84 -4.40 12600 12.6 380.28 -11.89 -4.51

PAGE 623

594 Appendix K: (Continued) 12700 12.7 381.56 -11.80 -4.53 12800 12.8 382.84 -11.79 -4.60 12900 12.9 384.12 -11.73 -4.48 13000 13 385.4 -11.83 -4.43 13100 13.1 386.68 -11.74 -4.39 13200 13.2 387.96 -11.84 -4.41 13300 13.3 389.24 -12.02 -4.59 13400 13.4 390.52 -11.95 -4.37 13500 13.5 391.8 -12.05 -4.49 13600 13.6 393.08 -12.08 -4.38 13700 13.7 394.36 -12.13 -4.41 13800 13.8 395.64 -12.14 -4.45 13900 13.9 396.92 -12.12 -4.44 14000 14 398.2 -12.03 -4.42 14100 14.1 399.48 -11.76 -4.28 14200 14.2 400.76 -11.79 -4.32 14300 14.3 402.04 -11.86 -4.32 14400 14.4 403.32 -11.94 -4.46 14500 14.5 404.6 -11.94 -4.51 14600 14.6 405.88 -12.13 -4.47 14700 14.7 407.16 -12.17 -4.43 14800 14.8 408.44 -12.11 -4.58 14900 14.9 409.72 -12.32 -4.63 15000 15 411 -12.37 -4.70 15100 15.1 412.28 -12.22 -4.36 15200 15.2 413.56 -12.30 -4.51 15300 15.3 414.84 -12.24 -4.64 15400 15.4 416.12 -12.11 -4.62 15500 15.5 417.4 -12.16 -4.58 15600 15.6 418.68 -12.12 -4.67 15700 15.7 419.96 -12.23 -4.76 15800 15.8 421.24 -12.14 -4.54 15900 15.9 422.52 -12.16 -4.68 16000 16 423.8 -12.21 -4.57 16100 16.1 425.08 -12.29 -4.70 16200 16.2 426.36 -12.25 -4.66 16300 16.3 427.64 -12.31 -4.78 16400 16.4 428.92 -12.20 -4.72 16500 16.5 430.2 -12.18 -4.86 16600 16.6 431.48 -12.14 -4.71 16700 16.7 432.76 -12.08 -4.73 16800 16.8 434.04 -12.13 -4.85 16900 16.9 435.32 -12.12 -4.74

PAGE 624

595 Appendix K: (Continued) 17000 17 436.6 -12.08 -4.79 17100 17.1 437.88 -12.13 -4.70 17200 17.2 439.16 -11.95 -4.63 17300 17.3 440.44 -12.06 -4.75 17400 17.4 441.72 -12.17 -4.89 17500 17.5 443 -12.15 -4.88 17600 17.6 444.28 -12.17 -4.84 17700 17.7 445.56 -12.19 -4.92 17800 17.8 446.84 -12.22 -4.87 17900 17.9 448.12 -12.09 -4.83 18000 18 449.4 -12.17 -4.83 18100 18.1 450.68 -12.03 -4.93 18200 18.2 451.96 -12.20 -4.85 18300 18.3 453.24 -12.19 -4.94 18400 18.4 454.52 -12.04 -4.83 18500 18.5 455.8 -11.98 -4.78 18600 18.6 457.08 -11.85 -4.64 18700 18.7 458.36 -11.80 -4.62 18800 18.8 459.64 -11.75 -4.55 18900 18.9 460.92 -11.55 -4.45 19000 19 462.2 -11.40 -4.29 19100 19.1 463.48 -11.69 -4.47 19200 19.2 464.76 -11.38 -4.37 19300 19.3 466.04 -11.43 -4.43 19400 19.4 467.32 -11.72 -4.39 19500 19.5 468.6 -11.63 -4.36 19600 19.6 469.88 -11.82 -4.38 19700 19.7 471.16 -11.91 -4.48 19800 19.8 472.44 -11.97 -4.54 19900 19.9 473.72 -12.15 -4.66 20000 20 475 -11.96 -4.47 20100 20.1 475.23 -11.96 -4.52 20200 20.2 475.46 -12.08 -4.57 20300 20.3 475.69 -12.16 -4.68 20400 20.4 475.92 -12.13 -4.62 20500 20.5 476.15 -12.11 -4.64 20600 20.6 476.38 -12.12 -4.60 20700 20.7 476.61 -12.12 -4.60 20800 20.8 476.84 -12.23 -4.65 20900 20.9 477.07 -12.21 -4.58 21000 21 477.3 -12.14 -4.45 21100 21.1 477.53 -12.15 -4.58 21200 21.2 477.76 -11.98 -4.54

PAGE 625

596 Appendix K: (Continued) 21300 21.3 477.99 -12.07 -4.55 21400 21.4 478.22 -12.00 -4.56 21500 21.5 478.45 -11.92 -4.67 21600 21.6 478.68 -11.87 -4.60 21700 21.7 478.91 -12.04 -4.66 21800 21.8 479.14 -11.92 -4.47 21900 21.9 479.37 -12.02 -4.64 22000 22 479.6 -11.97 -4.62 22100 22.1 479.83 -11.99 -4.61 22200 22.2 480.06 -11.90 -4.52 22300 22.3 480.29 -11.94 -4.51 22400 22.4 480.52 -11.92 -4.52 22500 22.5 480.75 -11.92 -4.48 22600 22.6 480.98 -11.96 -4.48 22700 22.7 481.21 -12.07 -4.60 22800 22.8 481.44 -12.08 -4.52 22900 22.9 481.67 -11.88 -4.56 23000 23 481.9 -12.01 -4.62 23100 23.1 482.13 -12.03 -4.64 23200 23.2 482.36 -11.97 -4.67 23300 23.3 482.59 -11.98 -4.69 23400 23.4 482.82 -12.12 -4.65 23500 23.5 483.05 -12.06 -4.64 23600 23.6 483.28 -12.05 -4.76 23700 23.7 483.51 -12.13 -4.67 23800 23.8 483.74 -12.16 -4.78 23900 23.9 483.97 -12.10 -4.73 24000 24 484.2 -12.13 -4.84 24100 24.1 484.43 -12.08 -4.69 24200 24.2 484.66 -11.97 -4.74 24300 24.3 484.89 -11.94 -4.75 24400 24.4 485.12 -11.92 -4.75 24500 24.5 485.35 -11.85 -4.78 24600 24.6 485.58 -11.86 -4.79 24700 24.7 485.81 -11.89 -4.84 24800 24.8 486.04 -11.94 -4.88 24900 24.9 486.27 -12.10 -4.84 25000 25 486.5 -11.99 -4.88 25100 25.1 486.73 -12.05 -4.93 25200 25.2 486.96 -12.02 -5.00 25300 25.3 487.19 -12.01 -5.10 25400 25.4 487.42 -12.03 -5.09 25500 25.5 487.65 -12.11 -5.16

PAGE 626

597 Appendix K: (Continued) 25600 25.6 487.88 -12.15 -5.06 25700 25.7 488.11 -12.08 -5.01 25800 25.8 488.34 -12.12 -5.05 25900 25.9 488.57 -12.04 -5.03 26000 26 488.8 -12.08 -4.95 26100 26.1 489.03 -12.19 -5.15 26200 26.2 489.26 -12.17 -5.07 26300 26.3 489.49 -12.14 -5.16 26400 26.4 489.72 -12.07 -5.10 26500 26.5 489.95 -12.15 -5.16 26600 26.6 490.18 -12.12 -5.13 26700 26.7 490.41 -12.15 -5.09 26800 26.8 490.64 -12.20 -5.13 26900 26.9 490.87 -12.12 -5.05 27000 27 491.1 -12.17 -4.96 27100 27.1 491.33 -12.10 -4.96 27200 27.2 491.56 -12.13 -4.97 27300 27.3 491.79 -12.04 -4.88 27400 27.4 492.02 -12.05 -4.95 27500 27.5 492.25 -12.01 -4.84 27600 27.6 492.48 -12.07 -4.91 27700 27.7 492.71 -11.93 -4.75 27800 27.8 492.94 -11.88 -4.84 27900 27.9 493.17 -11.80 -4.73 28000 28 493.4 -11.82 -4.75 28100 28.1 493.63 -11.90 -4.66 28200 28.2 493.86 -11.66 -4.64 28300 28.3 494.09 -11.60 -4.56 28400 28.4 494.32 -11.52 -4.49 28500 28.5 494.55 -11.64 -4.60 28600 28.6 494.78 -11.74 -4.57 28700 28.7 495.01 -11.73 -4.53 28800 28.8 495.24 -11.80 -4.59 28900 28.9 495.47 -11.89 -4.60 29000 29 495.7 -11.87 -4.60 29100 29.1 495.93 -11.81 -4.54 29200 29.2 496.16 -11.77 -4.76 29300 29.3 496.39 -11.81 -4.57 29400 29.4 496.62 -11.74 -4.74 29500 29.5 496.85 -11.73 -4.73 29600 29.6 497.08 -11.73 -4.79 29700 29.7 497.31 -11.68 -4.64 29800 29.8 497.54 -11.73 -4.79

PAGE 627

598 Appendix K: (Continued) 29900 29.9 497.77 -11.66 -4.69 30000 30 498 -11.65 -4.80 30100 30.1 498.23 -11.77 -4.66 30200 30.2 498.46 -11.73 -4.83 30300 30.3 498.69 -11.76 -4.80 30400 30.4 498.92 -11.77 -4.92 30500 30.5 499.15 -11.81 -4.93 30600 30.6 499.38 -11.82 -4.94 30700 30.7 499.61 -11.76 -4.85 30800 30.8 499.84 -11.82 -5.00 30900 30.9 500.07 -11.86 -4.87 31000 31 500.3 -11.81 -5.08 31100 31.1 500.53 -11.85 -4.77 31200 31.2 500.76 -11.79 -5.02 31300 31.3 500.99 -11.74 -4.83 31400 31.4 501.22 -11.44 -4.85 31500 31.5 501.45 -11.53 -4.79 31600 31.6 501.68 -11.63 -4.88 31700 31.7 501.91 -11.73 -4.87 31800 31.8 502.14 -11.69 -4.87 31900 31.9 502.37 -11.70 -4.75 32000 32 502.6 -11.78 -4.84 32100 32.1 502.83 -11.74 -4.90 32200 32.2 503.06 -11.76 -4.80 32300 32.3 503.29 -11.77 -4.82 32400 32.4 503.52 -11.71 -4.82 32500 32.5 503.75 -11.67 -4.78 32600 32.6 503.98 -11.66 -4.84 32700 32.7 504.21 -11.64 -4.74 32800 32.8 504.44 -11.58 -4.77 32900 32.9 504.67 -11.60 -4.76 33000 33 504.9 -11.51 -4.74 33100 33.1 505.13 -11.35 -4.71 33200 33.2 505.36 -11.34 -4.72 33300 33.3 505.59 -11.45 -4.73 33400 33.4 505.82 -11.46 -4.66 33500 33.5 506.05 -11.80 -4.85 33600 33.6 506.28 -11.83 -4.83 33700 33.7 506.51 -11.93 -4.94 33800 33.8 506.74 -11.97 -4.91 33900 33.9 506.97 -11.98 -4.97 34000 34 507.2 -11.95 -4.95 34100 34.1 507.43 -11.88 -4.92

PAGE 628

599 Appendix K: (Continued) 34200 34.2 507.66 -12.01 -4.98 34300 34.3 507.89 -12.07 -5.01 34400 34.4 508.12 -12.02 -5.05 34500 34.5 508.35 -11.94 -5.00 34600 34.6 508.58 -11.99 -5.04 34700 34.7 508.81 -11.85 -4.89 34800 34.8 509.04 -11.83 -4.99 34900 34.9 509.27 -11.85 -4.96 35000 35 509.5 -11.80 -4.95 35100 35.1 509.73 -11.79 -4.86 35200 35.2 509.96 -11.76 -4.92 35300 35.3 510.19 -11.87 -4.91 35400 35.4 510.42 -12.05 -5.05 35500 35.5 510.65 -12.16 -5.03 35600 35.6 510.88 -12.03 -4.98 35700 35.7 511.11 -12.14 -4.92 35800 35.8 511.34 -12.17 -5.01 35900 35.9 511.57 -12.16 -5.00 36000 36 511.8 -12.09 -5.00 36100 36.1 512.03 -12.12 -4.93 36200 36.2 512.26 -12.10 -5.00 36300 36.3 512.49 -12.04 -5.04 36400 36.4 512.72 -12.04 -4.96 36500 36.5 512.95 -12.03 -5.08 36600 36.6 513.18 -11.98 -5.00 36700 36.7 513.41 -12.11 -5.00 36800 36.8 513.64 -12.07 -5.04 36900 36.9 513.87 -12.13 -4.99 37000 37 514.1 -12.06 -5.00 37100 37.1 514.33 -11.96 -4.99 37200 37.2 514.56 -11.79 -5.00 37300 37.3 514.79 -11.84 -4.99 37400 37.4 515.02 -11.83 -5.09 37500 37.5 515.25 -11.85 -5.07 37600 37.6 515.48 -11.77 -5.05 37700 37.7 515.71 -11.95 -5.04 37800 37.8 515.94 -11.85 -4.95 37900 37.9 516.17 -11.91 -4.98 38000 38 516.4 -11.89 -5.00 38100 38.1 516.63 -12.00 -4.90 38200 38.2 516.86 -12.00 -4.92 38300 38.3 517.09 -11.95 -4.93 38400 38.4 517.32 -11.86 -4.91

PAGE 629

600 Appendix K: (Continued) 38500 38.5 517.55 -11.87 -4.94 38600 38.6 517.78 -11.94 -4.99 38700 38.7 518.01 -11.89 -4.81 38800 38.8 518.24 -11.88 -4.78 38900 38.9 518.47 -11.89 -4.93 39000 39 518.7 -11.91 -4.86 39100 39.1 518.93 -11.88 -4.85 39200 39.2 519.16 -11.85 -4.92 39300 39.3 519.39 -11.89 -4.88 39400 39.4 519.62 -11.80 -4.83 39500 39.5 519.85 -11.75 -4.81 39600 39.6 520.08 -11.71 -4.74 39700 39.7 520.31 -11.55 -4.88 39800 39.8 520.54 -11.36 -4.75 39900 39.9 520.77 -11.66 -4.82 40000 40 521 -11.61 -4.78 40100 40.1 521.23 -11.77 -4.80 40200 40.2 521.46 -11.79 -4.93 40300 40.3 521.69 -12.05 -4.99 40400 40.4 521.92 -11.86 -5.11 40500 40.5 522.15 -12.12 -5.10 40600 40.6 522.38 -12.17 -5.19 40700 40.7 522.61 -12.09 -5.10 40800 40.8 522.84 -11.98 -5.14 40900 40.9 523.07 -11.24 -5.19 41000 41 524 -11.99 -5.02 41100 41.1 525.34 -11.92 -4.97 41200 41.2 526.68 -11.90 -5.05 41300 41.3 528.02 -11.98 -5.11 41400 41.4 529.36 -11.87 -5.02 41500 41.5 530.7 -11.97 -4.92 41600 41.6 532.04 -11.95 -4.92 41700 41.7 533.38 -12.01 -5.00 41800 41.8 534.72 -12.04 -5.03 41900 41.9 536.06 -12.05 -5.05 42000 42 537.4 -12.08 -4.90 42100 42.1 538.74 -12.03 -4.90 42200 42.2 540.08 -12.02 -4.89 42300 42.3 541.42 -12.01 -4.82 42400 42.4 542.76 -12.06 -4.78 42500 42.5 544.1 -12.02 -4.80 42600 42.6 545.44 -11.95 -4.65 42700 42.7 546.78 -11.73 -4.60

PAGE 630

601 Appendix K: (Continued) 42800 42.8 548.12 -12.10 -4.69 42900 42.9 549.46 -12.38 -4.48 43000 43 550.8 -12.20 -4.67 43100 43.1 552.14 -11.99 -4.59 43200 43.2 553.48 -12.10 -4.61 43300 43.3 554.82 -12.08 -4.53 43400 43.4 556.16 -12.18 -4.76 43500 43.5 557.5 -12.28 -4.67 43600 43.6 558.84 -12.22 -4.71 43700 43.7 560.18 -12.17 -4.79 43800 43.8 561.52 -12.20 -4.73 43900 43.9 562.86 -12.08 -4.72 44000 44 564.2 -12.14 -4.61 44100 44.1 565.54 -12.11 -4.79 44200 44.2 566.88 -12.07 -4.61 44300 44.3 568.22 -12.17 -4.76 44400 44.4 569.56 -12.06 -4.60 44500 44.5 570.9 -12.13 -4.80 44600 44.6 572.24 -12.07 -4.71 44700 44.7 573.58 -12.05 -4.67 44800 44.8 574.92 -12.11 -4.48 44900 44.9 576.26 -12.07 -4.44 45000 45 577.6 -12.07 -4.57 45100 45.1 578.94 -12.10 -4.51 45200 45.2 580.28 -12.01 -4.42 45300 45.3 581.62 -12.02 -4.38 45400 45.4 582.96 -12.07 -4.44 45500 45.5 584.3 -12.07 -4.48 45600 45.6 585.64 -12.07 -4.53 45700 45.7 586.98 -12.17 -4.63 45800 45.8 588.32 -12.13 -4.80 45900 45.9 589.66 -12.05 -4.57 46000 46 591 -12.04 -4.72 46100 46.1 592.34 -12.25 -4.68 46200 46.2 593.68 -12.10 -4.72 46300 46.3 595.02 -12.12 -4.73 46400 46.4 596.36 -12.14 -4.90 46500 46.5 597.7 -12.20 -5.00 46600 46.6 599.04 -12.17 -4.80 46700 46.7 600.38 -12.13 -4.81 46800 46.8 601.72 -12.04 -4.73 46900 46.9 603.06 -12.22 -4.84 47000 47 604.4 -11.95 -4.62

PAGE 631

602 Appendix K: (Continued) 47100 47.1 605.74 -12.16 -4.84 47200 47.2 607.08 -12.05 -4.68 47300 47.3 608.42 -12.10 -4.68 47400 47.4 609.76 -12.05 -4.82 47500 47.5 611.1 -12.10 -4.70 47600 47.6 612.44 -12.04 -4.93 47700 47.7 613.78 -12.10 -4.86 47800 47.8 615.12 -12.09 -4.67 47900 47.9 616.46 -12.11 -4.76 48000 48 617.8 -12.12 -4.75 48100 48.1 619.14 -12.15 -4.79 48200 48.2 620.48 -12.11 -4.81 48300 48.3 621.82 -12.10 -4.76 48400 48.4 623.16 -12.15 -4.66 48500 48.5 624.5 -12.14 -4.80 48600 48.6 625.84 -12.15 -4.72 48700 48.7 627.18 -12.16 -4.70 48800 48.8 628.52 -12.17 -4.81 48900 48.9 629.86 -12.07 -4.63 49000 49 631.2 -12.09 -4.74 49100 49.1 632.54 -12.17 -4.65 49200 49.2 633.88 -12.08 -4.73 49300 49.3 635.22 -12.01 -4.78 49400 49.4 636.56 -12.14 -4.82 49500 49.5 637.9 -12.09 -4.67 49600 49.6 639.24 -12.06 -4.69 49700 49.7 640.58 -12.07 -4.61 49800 49.8 641.92 -12.11 -4.76 49900 49.9 643.26 -12.20 -4.66 50000 50 644.6 -12.25 -4.67 50100 50.1 645.94 -12.21 -4.59 50200 50.2 647.28 -12.10 -4.56 50300 50.3 648.62 -12.02 -4.61 50400 50.4 649.96 -11.98 -4.39 50500 50.5 651.3 -12.02 -4.47 50600 50.6 652.64 -12.13 -4.43 50700 50.7 653.98 -11.94 -4.53 50800 50.8 655.32 -11.97 -4.52 50900 50.9 656.66 -11.94 -4.47 51000 51 658 -11.96 -4.54 51100 51.1 659.34 -12.09 -4.51 51200 51.2 660.68 -11.98 -4.65 51300 51.3 662.02 -11.96 -4.57

PAGE 632

603 Appendix K: (Continued) 51400 51.4 663.36 -12.07 -4.58 51500 51.5 664.7 -11.91 -4.49 51600 51.6 666.04 -11.82 -4.57 51700 51.7 667.38 -12.03 -4.66 51800 51.8 668.72 -12.00 -4.57 51900 51.9 670.06 -11.90 -4.62 52000 52 671.4 -11.95 -4.62 52100 52.1 672.74 -12.13 -4.73 52200 52.2 674.08 -12.02 -4.65 52300 52.3 675.42 -12.02 -4.76 52400 52.4 676.76 -12.07 -4.55 52500 52.5 678.1 -12.19 -4.63 52600 52.6 679.44 -12.16 -4.93 52700 52.7 680.78 -11.97 -4.62 52800 52.8 682.12 -12.01 -4.73 52900 52.9 683.46 -11.95 -4.65 53000 53 684.8 -12.09 -4.82 53100 53.1 686.14 -12.09 -4.74 53200 53.2 687.48 -12.06 -4.93 53300 53.3 688.82 -12.11 -4.92 53400 53.4 690.16 -12.05 -4.86 53500 53.5 691.5 -12.14 -4.82 53600 53.6 692.84 -12.06 -4.94 53700 53.7 694.18 -12.09 -4.92 53800 53.8 695.52 -11.99 -4.89 53900 53.9 696.86 -11.96 -4.77 54000 54 698.2 -12.06 -4.73 54100 54.1 699.54 -12.04 -4.84 54200 54.2 700.88 -12.13 -4.86 54300 54.3 702.22 -12.11 -4.84 54400 54.4 703.56 -12.01 -4.75 54500 54.5 704.9 -12.13 -4.84 54600 54.6 706.24 -12.16 -4.81 54700 54.7 707.58 -12.18 -4.68 54800 54.8 708.92 -12.05 -4.84 54900 54.9 710.26 -12.09 -4.87 55000 55 711.6 -12.23 -4.89 55100 55.1 712.94 -12.14 -4.87 55200 55.2 714.28 -12.17 -4.95 55300 55.3 715.62 -12.12 -4.74 55400 55.4 716.96 -12.13 -4.69 55500 55.5 718.3 -12.24 -4.91 55600 55.6 719.64 -12.17 -4.84

PAGE 633

604 Appendix K: (Continued) 55700 55.7 720.98 -12.25 -4.85 55800 55.8 722.32 -12.32 -4.87 55900 55.9 723.66 -12.19 -4.68 56000 56 725 -12.17 -4.73 56100 56.1 726.34 -12.25 -4.67 56200 56.2 727.68 -12.19 -4.51 56300 56.3 729.02 -12.12 -4.50 56400 56.4 730.36 -12.29 -4.76 56500 56.5 731.7 -12.17 -4.60 56600 56.6 733.04 -12.19 -4.57 56700 56.7 734.38 -12.32 -4.84 56800 56.8 735.72 -12.20 -4.70 56900 56.9 737.06 -12.32 -4.74 57000 57 738.4 -12.28 -4.78 57100 57.1 739.74 -12.31 -4.70 57200 57.2 741.08 -12.20 -4.53 57300 57.3 742.42 -12.26 -4.67 57400 57.4 743.76 -12.19 -4.69 57500 57.5 745.1 -12.25 -4.80 57600 57.6 746.44 -12.24 -4.90 57700 57.7 747.78 -12.38 -4.85 57800 57.8 749.12 -12.28 -4.76 57900 57.9 750.46 -12.14 -4.73 58000 58 751.8 -12.22 -4.80 58100 58.1 753.14 -12.23 -4.64 58200 58.2 754.48 -12.24 -4.82 58300 58.3 755.82 -12.17 -4.74 58400 58.4 757.16 -12.15 -4.78 58500 58.5 758.5 -12.27 -4.76 58600 58.6 759.84 -12.20 -4.79 58700 58.7 761.18 -12.24 -4.88 58800 58.8 762.52 -12.16 -4.87 58900 58.9 763.86 -12.12 -4.71 59000 59 765.2 -12.05 -4.78 59100 59.1 766.54 -12.15 -4.59 59200 59.2 767.88 -12.06 -4.68 59300 59.3 769.22 -12.08 -4.74 59400 59.4 770.56 -12.05 -4.63 59500 59.5 771.9 -12.19 -4.66 59600 59.6 773.24 -12.19 -4.61 59700 59.7 774.58 -12.23 -4.52 59800 59.8 775.92 -12.19 -4.57 59900 59.9 777.26 -12.08 -4.71

PAGE 634

605 Appendix K: (Continued) 60000 60 778.6 -12.06 -4.44 60100 60.1 779.94 -12.02 -4.39 60200 60.2 781.28 -12.01 -4.48 60300 60.3 782.62 -12.23 -4.56 60400 60.4 783.96 -12.09 -4.62 60500 60.5 785.3 -12.05 -4.57 60600 60.6 786.64 -12.09 -4.47 60700 60.7 787.98 -12.05 -4.51 60800 60.8 789.32 -12.09 -4.57 60900 60.9 790.66 -12.02 -4.46 61000 61 792 -11.98 -4.43 61100 61.1 793.34 -12.01 -4.39 61200 61.2 794.68 -12.00 -4.41 61300 61.3 796.02 -11.99 -4.45 61400 61.4 797.36 -12.04 -4.64 61500 61.5 798.7 -12.06 -4.41 61600 61.6 800.04 -12.09 -4.48 61700 61.7 801.38 -12.07 -4.58 61800 61.8 802.72 -12.08 -4.65 61900 61.9 804.06 -11.98 -4.57 62000 62 805 -12.09 -4.55 62100 62.1 806.95 -12.05 -4.63 62200 62.2 808.9 -11.93 -4.54 62300 62.3 810.85 -11.98 -4.66 62400 62.4 812.8 -11.93 -4.63 62500 62.5 814.75 -11.99 -4.56 62600 62.6 816.7 -12.03 -4.57 62700 62.7 818.65 -12.01 -4.61 62800 62.8 820.6 -11.94 -4.62 62900 62.9 822.55 -11.96 -4.67 63000 63 824.5 -11.96 -4.71 63100 63.1 826.45 -11.95 -4.59 63200 63.2 828.4 -11.89 -4.63 63300 63.3 830.35 -11.95 -4.81 63400 63.4 832.3 -11.89 -4.58 63500 63.5 834.25 -11.94 -4.66 63600 63.6 836.2 -11.97 -4.87 63700 63.7 838.15 -12.00 -4.65 63800 63.8 840.1 -11.89 -4.67 63900 63.9 842.05 -12.00 -4.52 64000 64 844 -11.99 -4.50 64100 64.1 845.95 -11.97 -4.44 64200 64.2 847.9 -12.00 -4.43

PAGE 635

606 Appendix K: (Continued) 64300 64.3 849.85 -12.01 -4.46 64400 64.4 851.8 -11.94 -4.40 64500 64.5 853.75 -12.07 -4.47 64600 64.6 855.7 -12.06 -4.53 64700 64.7 857.65 -12.04 -4.54 64800 64.8 859.6 -12.05 -4.58 64900 64.9 861.55 -12.14 -4.65 65000 65 863.5 -12.00 -4.62 65100 65.1 865.45 -11.98 -4.53 65200 65.2 867.4 -12.10 -4.74 65300 65.3 869.35 -11.99 -4.82 65400 65.4 871.3 -12.10 -4.71 65500 65.5 873.25 -12.14 -4.69 65600 65.6 875.2 -12.08 -4.75 65700 65.7 877.15 -12.11 -4.90 65800 65.8 879.1 -12.19 -4.87 65900 65.9 881.05 -12.17 -4.85 66000 66 883 -12.04 -4.79 66100 66.1 884.95 -12.18 -4.78 66200 66.2 886.9 -12.02 -4.90 66300 66.3 888.85 -12.04 -4.91 66400 66.4 890.8 -11.41 -4.72 66500 66.5 892.75 -11.98 -4.93 66600 66.6 894.7 -12.02 -4.94 66700 66.7 896.65 -11.94 -4.96 66800 66.8 898.6 -11.83 -5.07 66900 66.9 900.55 -11.95 -5.13 67000 67 902.5 -11.92 -5.24 67100 67.1 904.45 -12.05 -5.03 67200 67.2 906.4 -11.89 -5.21 67300 67.3 908.35 -12.18 -5.21 67400 67.4 910.3 -12.02 -5.25 67500 67.5 912.25 -12.03 -5.46 67600 67.6 914.2 -12.02 -5.40 67700 67.7 916.15 -12.05 -5.38 67800 67.8 918.1 -11.97 -5.42 67900 67.9 920.05 -11.90 -5.43 68000 68 922 -11.96 -5.38 68100 68.1 923.95 -12.12 -5.49 68200 68.2 925.9 -12.07 -5.14 68300 68.3 927.85 -12.12 -5.13 68400 68.4 929.8 -12.07 -5.29 68500 68.5 931.75 -11.95 -5.08

PAGE 636

607 Appendix K: (Continued) 68600 68.6 933.7 -11.91 -5.32 68700 68.7 935.65 -11.99 -5.11 68800 68.8 937.6 -11.95 -5.00 68900 68.9 939.55 -11.81 -4.89 69000 69 941.5 -12.05 -5.09 69100 69.1 943.45 -11.84 -4.92 69200 69.2 945.4 -11.81 -4.80 69300 69.3 947.35 -11.82 -5.08 69400 69.4 949.3 -11.97 -4.83 69500 69.5 951.25 -11.87 -5.05 69600 69.6 953.2 -11.88 -5.15 69700 69.7 955.15 -11.82 -5.08 69800 69.8 957.1 -11.83 -5.00 69900 69.9 959.05 -11.80 -4.87 70000 70 961 -11.79 -4.91 70100 70.1 962.95 -11.95 -5.02 70200 70.2 964.9 -11.78 -4.91 70300 70.3 966.85 -11.72 -4.76 70400 70.4 968.8 -11.78 -4.91 70500 70.5 970.75 -11.87 -4.92 70600 70.6 972.7 -11.96 -4.97 70700 70.7 974.65 -11.83 -4.91 70800 70.8 976.6 -11.85 -5.04 70900 70.9 978.55 -11.87 -5.01 71000 71 980.5 -11.75 -4.91 71100 71.1 982.45 -11.92 -5.03 71200 71.2 984.4 -11.52 -4.85 71300 71.3 986.35 -11.63 -4.77 71400 71.4 988.3 -11.53 -4.82 71500 71.5 990.25 -11.59 -4.88 71600 71.6 992.2 -11.64 -4.89 71700 71.7 994.15 -11.67 -4.92 71800 71.8 996.1 -11.67 -4.97 71900 71.9 998.05 -11.77 -4.93 72000 72 1000 -11.83 -4.98 72100 72.1 1001.95 -11.76 -5.05 72200 72.2 1003.9 -11.87 -5.09 72300 72.3 1005.85 -11.92 -5.14 72400 72.4 1007.8 -11.89 -5.15 72500 72.5 1009.75 -11.92 -5.20 72600 72.6 1011.7 -11.90 -5.22 72700 72.7 1013.65 -11.78 -5.15 72800 72.8 1015.6 -11.90 -5.35

PAGE 637

608 Appendix K: (Continued) 72900 72.9 1017.55 -11.87 -5.34 73000 73 1019.5 -11.78 -5.21 73100 73.1 1021.45 -11.86 -5.11 73200 73.2 1023.4 -11.87 -5.29 73300 73.3 1025.35 -12.01 -5.42 73400 73.4 1027.3 -12.10 -5.42 73500 73.5 1029.25 -12.07 -5.31 73600 73.6 1031.2 -12.08 -5.42 73700 73.7 1033.15 -12.05 -5.46 73800 73.8 1035.1 -12.10 -5.36 73900 73.9 1037.05 -12.10 -5.13 74000 74 1039 -12.12 -5.19 74100 74.1 1040.95 -12.13 -5.21 74200 74.2 1042.9 -12.08 -5.20 74300 74.3 1044.85 -12.04 -5.10 74400 74.4 1046.8 -12.04 -5.11 74500 74.5 1048.75 -11.93 -5.07 74600 74.6 1050.7 -11.96 -5.03 74700 74.7 1052.65 -11.83 -5.08 74800 74.8 1054.6 -11.98 -5.23 74900 74.9 1056.55 -11.96 -5.29 75000 75 1058.5 -11.93 -5.24 75100 75.1 1060.45 -12.03 -5.21 75200 75.2 1062.4 -12.01 -5.21 75300 75.3 1064.35 -11.96 -5.37 75400 75.4 1066.3 -11.99 -5.24 75500 75.5 1068.25 -11.99 -5.29 75600 75.6 1070.2 -11.86 -5.17 75700 75.7 1072.15 -11.90 -5.12 75800 75.8 1074.1 -11.83 -5.20 75900 75.9 1076.05 -11.98 -5.17 76000 76 1078 -11.84 -5.17 76100 76.1 1079.95 -11.95 -5.24 76200 76.2 1081.9 -11.92 -5.21 76300 76.3 1083.85 -11.98 -4.98 76400 76.4 1085.8 -11.93 -4.97 76500 76.5 1087.75 -11.98 -4.92 76600 76.6 1089.7 -11.96 -4.82 76700 76.7 1091.65 -11.98 -4.79 76800 76.8 1093.6 -12.03 -4.85 76900 76.9 1095.55 -11.97 -4.84 77000 77 1097.5 -11.81 -4.70 77100 77.1 1099.45 -11.98 -4.91

PAGE 638

609 Appendix K: (Continued) 77200 77.2 1101.4 -11.86 -4.74 77300 77.3 1103.35 -11.88 -4.81 77400 77.4 1105.3 -11.86 -4.68 77500 77.5 1107.25 -11.75 -4.63 77600 77.6 1109.2 -11.73 -4.62 77700 77.7 1111.15 -11.44 -4.63 77800 77.8 1113.1 -11.75 -4.73 77900 77.9 1115.05 -11.76 -4.43 78000 78 1117 -11.78 -4.74 78100 78.1 1118.95 -11.83 -4.60 78200 78.2 1120.9 -11.86 -4.78 78300 78.3 1122.85 -11.84 -4.58 78400 78.4 1124.8 -11.75 -4.49 78500 78.5 1126.75 -11.81 -4.53 78600 78.6 1128.7 -11.97 -4.83 78700 78.7 1130.65 -11.82 -4.51 78800 78.8 1132.6 -12.06 -4.57 78900 78.9 1134.55 -11.90 -4.55 79000 79 1136.5 -11.87 -4.70 79100 79.1 1138.45 -11.80 -4.55 79200 79.2 1140.4 -11.66 -4.54 79300 79.3 1142.35 -11.65 -4.55 79400 79.4 1144.3 -11.69 -4.55 79500 79.5 1146.25 -11.64 -4.56 79600 79.6 1148.2 -11.73 -4.46 79700 79.7 1150.15 -11.72 -4.59 79800 79.8 1152.1 -11.74 -4.54 79900 79.9 1154.05 -11.85 -4.69 80000 80 1156 -11.99 -4.65 80100 80.1 1157.95 -11.94 -4.65 80200 80.2 1159.9 -11.95 -4.63 80300 80.3 1161.85 -11.93 -4.64 80400 80.4 1163.8 -12.08 -4.63 80500 80.5 1165.75 -12.06 -4.71 80600 80.6 1167.7 -11.95 -4.53 80700 80.7 1169.65 -12.10 -4.70 80800 80.8 1171.6 -12.12 -4.69 80900 80.9 1173.55 -12.09 -4.68 81000 81 1175.5 -12.14 -4.52 81100 81.1 1177.45 -12.19 -4.60 81200 81.2 1179.4 -12.21 -4.54 81300 81.3 1181.35 -12.18 -4.66 81400 81.4 1183.3 -12.23 -4.62

PAGE 639

610 Appendix K: (Continued) 81500 81.5 1185.25 -12.29 -4.68 81600 81.6 1187.2 -12.17 -4.61 81700 81.7 1189.15 -12.18 -4.74 81800 81.8 1191.1 -12.28 -4.64 81900 81.9 1193.05 -12.20 -4.70 82000 82 1195 -12.28 -4.75 82100 82.1 1196.95 -12.30 -4.82 82200 82.2 1198.9 -12.34 -5.00 82300 82.3 1200.85 -12.47 -4.90 82400 82.4 1202.8 -12.42 -5.02 82500 82.5 1204.75 -12.34 -5.01 82600 82.6 1206.7 -12.36 -4.91 82700 82.7 1208.65 -12.27 -4.99 82800 82.8 1210.6 -12.40 -5.01 82900 82.9 1212.55 -12.32 -5.09 83000 83 1214.5 -12.30 -5.03 83100 83.1 1216.45 -12.54 -5.08 83200 83.2 1218.4 -12.35 -5.09 83300 83.3 1220.35 -12.35 -5.14 83400 83.4 1222.3 -12.31 -5.04 83500 83.5 1224.25 -12.23 -5.03 83600 83.6 1226.2 -12.35 -4.99 83700 83.7 1228.15 -12.23 -4.92 83800 83.8 1230.1 -12.24 -4.76 83900 83.9 1232.05 -12.28 -4.90 84000 84 1236 -12.29 -4.87 84100 84.1 1236.88 -12.36 -5.05 84200 84.2 1237.76 -12.22 -4.86 84300 84.3 1238.64 -12.30 -4.94 84400 84.4 1239.52 -12.23 -4.81 84500 84.5 1240.4 -12.18 -4.75 84600 84.6 1241.28 -12.26 -4.86 84700 84.7 1242.16 -12.15 -4.69 84800 84.8 1243.04 -12.32 -4.81 84900 84.9 1243.92 -12.27 -4.84 85000 85 1244.8 -12.17 -4.79 85100 85.1 1245.68 -12.36 -4.77 85200 85.2 1246.56 -12.24 -4.94 85300 85.3 1247.44 -12.38 -4.74 85400 85.4 1248.32 -12.23 -4.84 85500 85.5 1249.2 -12.20 -4.76 85600 85.6 1250.08 -12.31 -4.78 85700 85.7 1250.96 -12.29 -4.92

PAGE 640

611 Appendix K: (Continued) 85800 85.8 1251.84 -12.20 -4.85 85900 85.9 1252.72 -12.20 -4.85 86000 86 1253.6 -12.17 -4.76 86100 86.1 1254.48 -12.18 -4.95 86200 86.2 1255.36 -12.20 -4.81 86300 86.3 1256.24 -12.13 -4.93 86400 86.4 1257.12 -12.19 -4.88 86500 86.5 1258 -12.13 -4.87 86600 86.6 1258.88 -12.17 -4.81 86700 86.7 1259.76 -11.99 -4.84 86800 86.8 1260.64 -12.15 -4.90 86900 86.9 1261.52 -12.19 -4.88 87000 87 1262.4 -12.18 -4.81 87100 87.1 1263.28 -12.27 -4.87 87200 87.2 1264.16 -12.07 -4.81 87300 87.3 1265.04 -12.22 -4.71 87400 87.4 1265.92 -12.09 -4.79 87500 87.5 1266.8 -12.08 -4.82 87600 87.6 1267.68 -12.14 -4.85 87700 87.7 1268.56 -12.13 -4.78 87800 87.8 1269.44 -12.09 -4.80 87900 87.9 1270.32 -12.06 -4.85 88000 88 1271.2 -12.10 -4.85 88100 88.1 1272.08 -12.06 -4.88 88200 88.2 1272.96 -12.11 -4.85 88300 88.3 1273.84 -12.24 -5.09 88400 88.4 1274.72 -12.23 -4.94 88500 88.5 1275.6 -12.19 -4.97 88600 88.6 1276.48 -12.12 -5.04 88700 88.7 1277.36 -12.20 -5.03 88800 88.8 1278.24 -12.16 -4.96 88900 88.9 1279.12 -12.18 -5.08 89000 89 1280 -12.23 -5.01 89100 89.1 1280.88 -12.31 -5.00 89200 89.2 1281.76 -12.18 -4.96 89300 89.3 1282.64 -12.20 -5.07 89400 89.4 1283.52 -12.20 -5.06 89500 89.5 1284.4 -12.12 -5.02 89600 89.6 1285.28 -12.10 -4.90 89700 89.7 1286.16 -12.23 -4.95 89800 89.8 1287.04 -12.09 -4.96 89900 89.9 1287.92 -12.02 -4.98 90000 90 1288.8 -12.24 -4.97

PAGE 641

612 Appendix K: (Continued) 90100 90.1 1289.68 -12.26 -4.88 90200 90.2 1290.56 -12.08 -4.89 90300 90.3 1291.44 -12.12 -4.97 90400 90.4 1292.32 -12.02 -4.85 90500 90.5 1293.2 -12.10 -4.95 90600 90.6 1294.08 -12.03 -4.84 90700 90.7 1294.96 -11.97 -4.85 90800 90.8 1295.84 -12.04 -4.71 90900 90.9 1296.72 -11.99 -4.89 91000 91 1297.6 -12.05 -4.75 91100 91.1 1298.48 -12.03 -4.80 91200 91.2 1299.36 -12.02 -4.76 91300 91.3 1300.24 -11.96 -4.87 91400 91.4 1301.12 -11.85 -4.81 91500 91.5 1302 -11.91 -4.88 91600 91.6 1302.88 -11.97 -4.90 91700 91.7 1303.76 -11.89 -4.79 91800 91.8 1304.64 -11.86 -4.94 91900 91.9 1305.52 -11.76 -4.89 92000 92 1306.4 -11.78 -4.61 92100 92.1 1307.28 -11.73 -4.80 92200 92.2 1308.16 -11.55 -4.78 92300 92.3 1309.04 -11.59 -4.70 92400 92.4 1309.92 -11.85 -4.78 92500 92.5 1310.8 -11.50 -4.77 92600 92.6 1311.68 -11.45 -4.74 92700 92.7 1312.56 -11.65 -4.81 92800 92.8 1313.44 -11.53 -4.71 92900 92.9 1314.32 -11.61 -4.75 93000 93 1315.2 -11.90 -4.65 93100 93.1 1316.08 -11.83 -4.67 93200 93.2 1316.96 -11.95 -4.58 93300 93.3 1317.84 -11.74 -4.54 93400 93.4 1318.72 -11.83 -4.69 93500 93.5 1319.6 -12.02 -4.60 93600 93.6 1320.48 -11.85 -4.83 93700 93.7 1321.36 -11.71 -4.75 93800 93.8 1322.24 -11.73 -4.75 93900 93.9 1323.12 -11.69 -4.76 94000 94 1324 -11.75 -4.68 94100 94.1 1324.88 -11.65 -4.84 94200 94.2 1325.76 -11.77 -4.40 94300 94.3 1326.64 -11.73 -4.75

PAGE 642

613 Appendix K: (Continued) 94400 94.4 1327.52 -11.69 -4.50 94500 94.5 1328.4 -11.79 -4.57 94600 94.6 1329.28 -11.75 -4.61 94700 94.7 1330.16 -11.71 -4.45 94800 94.8 1331.04 -11.82 -4.48 94900 94.9 1331.92 -11.78 -4.62 95000 95 1332.8 -11.78 -4.59 95100 95.1 1333.68 -11.77 -4.60 95200 95.2 1334.56 -11.68 -4.58 95300 95.3 1335.44 -11.70 -4.47 95400 95.4 1336.32 -11.66 -4.74 95500 95.5 1337.2 -11.75 -4.59 95600 95.6 1338.08 -11.70 -4.54 95700 95.7 1338.96 -11.69 -4.61 95800 95.8 1339.84 -11.77 -4.53 95900 95.9 1340.72 -11.76 -4.61 96000 96 1341.6 -11.72 -4.69 96100 96.1 1342.48 -11.66 -4.57 96200 96.2 1343.36 -11.66 -4.67 96300 96.3 1344.24 -11.73 -4.63 96400 96.4 1345.12 -11.75 -4.59 96500 96.5 1346 -11.67 -4.60 96600 96.6 1346.88 -11.76 -4.57 96700 96.7 1347.76 -11.57 -4.56 96800 96.8 1348.64 -11.53 -4.51 96900 96.9 1349.52 -11.53 -4.49 97000 97 1350.4 -11.57 -4.56 97100 97.1 1351.28 -11.58 -4.45 97200 97.2 1352.16 -11.51 -4.42 97300 97.3 1353.04 -11.60 -4.46 97400 97.4 1353.92 -11.45 -4.43 97500 97.5 1354.8 -11.47 -4.39 97600 97.6 1355.68 -11.54 -4.45 97700 97.7 1356.56 -11.54 -4.43 97800 97.8 1357.44 -11.51 -4.45 97900 97.9 1358.32 -11.53 -4.55 98000 98 1359.2 -11.50 -4.52 98100 98.1 1360.08 -11.45 -4.29 98200 98.2 1360.96 -11.48 -4.46 98300 98.3 1361.84 -11.60 -4.34 98400 98.4 1362.72 -11.39 -4.42 98500 98.5 1363.6 -11.57 -4.43 98600 98.6 1364.48 -11.54 -4.34

PAGE 643

614 Appendix K: (Continued) 98700 98.7 1365.36 -11.54 -4.39 98800 98.8 1366.24 -11.65 -4.37 98900 98.9 1367.12 -11.64 -4.40 99000 99 1368 -11.73 -4.49 99100 99.1 1368.88 -11.55 -4.19 99200 99.2 1369.76 -11.63 -4.37 99300 99.3 1370.64 -12.03 -4.46 99400 99.4 1371.52 -11.52 -4.36 99500 99.5 1372.4 -12.04 -4.69 99600 99.6 1373.28 -11.77 -4.51 99700 99.7 1374.16 -12.01 -4.72 99800 99.8 1375.04 -12.00 -4.73 99900 99.9 1375.92 -12.10 -4.87 100000 100 1377 -11.77 -4.61 100100 100.1 1377.88 -12.09 -4.55 100200 100.2 1378.76 -11.94 -4.65 100300 100.3 1379.64 -11.90 -4.55 100400 100.4 1380.52 -12.15 -4.61 100500 100.5 1381.4 -12.14 -4.59 100600 100.6 1382.28 -12.01 -4.69 100700 100.7 1383.16 -12.04 -4.80 100800 100.8 1384.04 -12.24 -4.70 100900 100.9 1384.92 -12.19 -4.71 101000 101 1385.8 -12.33 -4.90 101100 101.1 1386.68 -12.27 -4.67 101200 101.2 1387.56 -12.15 -4.55 101300 101.3 1388.44 -12.25 -4.84 101400 101.4 1389.32 -12.18 -4.76 101500 101.5 1390.2 -12.26 -4.61 101600 101.6 1391.08 -12.26 -4.82 101700 101.7 1391.96 -12.26 -4.69 101800 101.8 1392.84 -12.27 -4.58 101900 101.9 1393.72 -12.24 -4.55 102000 102 1394.6 -12.15 -4.52 102100 102.1 1395.48 -12.22 -4.44 102200 102.2 1396.36 -12.33 -4.67 102300 102.3 1397.24 -12.25 -4.47 102400 102.4 1398.12 -12.11 -4.55 102500 102.5 1399 -12.30 -4.51 102600 102.6 1399.88 -12.17 -4.54 102700 102.7 1400.76 -12.23 -4.46 102800 102.8 1401.64 -12.17 -4.51 102900 102.9 1402.52 -12.10 -4.52

PAGE 644

615 Appendix K: (Continued) 103000 103 1403.4 -11.94 -4.58 103100 103.1 1404.28 -12.06 -4.60 103200 103.2 1405.16 -12.15 -4.64 103300 103.3 1406.04 -12.00 -4.54 103400 103.4 1406.92 -12.20 -4.49 103500 103.5 1407.8 -12.08 -4.50 103600 103.6 1408.68 -11.97 -4.49 103700 103.7 1409.56 -12.11 -4.43 103800 103.8 1410.44 -12.13 -4.54 103900 103.9 1411.32 -12.09 -4.47 104000 104 1412.2 -12.13 -4.45 104100 104.1 1413.08 -12.14 -4.31 104200 104.2 1413.96 -12.18 -4.35 104300 104.3 1414.84 -12.22 -4.45 104400 104.4 1415.72 -12.17 -4.44 104500 104.5 1416.6 -12.15 -4.42 104600 104.6 1417.48 -12.20 -4.18 104700 104.7 1418.36 -12.07 -4.28 104800 104.8 1419.24 -12.08 -4.34 104900 104.9 1420.12 -12.30 -4.26 105000 105 1421 -12.25 -4.34 105100 105.1 1421.88 -12.27 -4.34 105200 105.2 1422.76 -12.20 -4.32 105300 105.3 1423.64 -12.03 -4.34 105400 105.4 1424.52 -12.28 -4.34 105500 105.5 1425.4 -12.14 -4.31 105600 105.6 1426.28 -12.25 -4.46 105700 105.7 1427.16 -12.24 -4.47 105800 105.8 1428.04 -12.27 -4.40 105900 105.9 1428.92 -12.32 -4.50 106000 106 1429.8 -12.16 -4.33 106100 106.1 1430.68 -12.32 -4.26 106200 106.2 1431.56 -12.47 -4.45 106300 106.3 1432.44 -12.43 -4.19 106400 106.4 1433.32 -12.30 -4.35 106500 106.5 1434.2 -12.33 -4.51 106600 106.6 1435.08 -12.33 -4.32 106700 106.7 1435.96 -12.32 -4.42 106800 106.8 1436.84 -12.32 -4.44 106900 106.9 1437.72 -12.30 -4.28 107000 107 1438.6 -12.46 -4.47 107100 107.1 1439.48 -12.28 -4.46 107200 107.2 1440.36 -12.26 -4.24

PAGE 645

616 Appendix K: (Continued) 107300 107.3 1441.24 -12.27 -4.45 107400 107.4 1442.12 -11.96 -4.59 107500 107.5 1443 -12.20 -4.38 107600 107.6 1443.88 -12.18 -4.30 107700 107.7 1444.76 -12.34 -4.56 107800 107.8 1445.64 -12.26 -4.41 107900 107.9 1446.52 -12.27 -4.52 108000 108 1447.4 -12.30 -4.47 108100 108.1 1448.28 -12.17 -4.38 108200 108.2 1449.16 -12.29 -4.58 108300 108.3 1450.04 -12.28 -4.57 108400 108.4 1450.92 -12.26 -4.62 108500 108.5 1451.8 -12.28 -4.64 108600 108.6 1452.68 -12.19 -4.50 108700 108.7 1453.56 -12.28 -4.68 108800 108.8 1454.44 -12.18 -4.48 108900 108.9 1455.32 -12.15 -4.51 109000 109 1456.2 -12.18 -4.47 109100 109.1 1457.08 -12.06 -4.54 109200 109.2 1457.96 -12.23 -4.54 109300 109.3 1458.84 -12.14 -4.52 109400 109.4 1459.72 -12.14 -4.54 109500 109.5 1460.6 -12.04 -4.61 109600 109.6 1461.48 -12.01 -4.56 109700 109.7 1462.36 -12.05 -4.58 109800 109.8 1463.24 -12.14 -4.63 109900 109.9 1464.12 -12.09 -4.73 110000 110 1465 -12.16 -4.72 110100 110.1 1465.88 -12.21 -4.81 110200 110.2 1466.76 -12.17 -4.84 110300 110.3 1467.64 -12.15 -4.89 110400 110.4 1468.52 -12.15 -4.94 110500 110.5 1469.4 -12.20 -4.91 110600 110.6 1470.28 -12.12 -4.87 110700 110.7 1471.16 -12.08 -4.87 110800 110.8 1472.04 -12.11 -4.80 110900 110.9 1472.92 -12.04 -4.86 111000 111 1473.8 -12.15 -4.75 111100 111.1 1474.68 -12.01 -4.88 111200 111.2 1475.56 -12.11 -4.85 111300 111.3 1476.44 -11.74 -4.85 111400 111.4 1477.32 -12.18 -4.75 111500 111.5 1478.2 -12.08 -4.74

PAGE 646

617 Appendix K: (Continued) 111600 111.6 1479.08 -12.12 -4.71 111700 111.7 1479.96 -12.08 -4.67 111800 111.8 1480.84 -12.12 -4.70 111900 111.9 1481.72 -11.97 -4.66 112000 112 1482.6 -12.11 -4.70 112100 112.1 1483.48 -12.12 -4.79 112200 112.2 1484.36 -11.84 -4.69 112300 112.3 1485.24 -11.79 -4.72 112400 112.4 1486.12 -11.96 -4.82 112500 112.5 1487 -11.70 -4.79 112600 112.6 1487.88 -11.84 -4.80 112700 112.7 1488.76 -11.85 -4.79 112800 112.8 1489.64 -11.95 -4.64 112900 112.9 1490.52 -11.81 -4.84 113000 113 1491.4 -11.74 -4.71 113100 113.1 1492.28 -11.85 -4.69 113200 113.2 1493.16 -11.79 -4.57 113300 113.3 1494.04 -11.78 -4.65 113400 113.4 1494.92 -11.69 -4.57 113500 113.5 1495.8 -11.85 -4.62 113600 113.6 1496.68 -11.95 -4.50 113700 113.7 1497.56 -12.09 -4.49 113800 113.8 1498.44 -11.79 -4.56 113900 113.9 1499.32 -11.75 -4.57 114000 114 1500.2 -11.76 -4.54 114100 114.1 1501.08 -11.83 -4.52 114200 114.2 1501.96 -11.88 -4.49 114300 114.3 1502.84 -11.69 -4.60 114400 114.4 1503.72 -11.86 -4.52 114500 114.5 1504.6 -11.81 -4.49 114600 114.6 1505.48 -11.87 -4.56 114700 114.7 1506.36 -11.81 -4.62 114800 114.8 1507.24 -11.99 -4.54 114900 114.9 1508.12 -11.65 -4.49 115000 115 1509 -11.82 -4.62 115100 115.1 1509.88 -11.77 -4.61 115200 115.2 1510.76 -11.94 -4.50 115300 115.3 1511.64 -11.97 -4.58 115400 115.4 1512.52 -11.96 -4.62 115500 115.5 1513.4 -11.83 -4.50 115600 115.6 1514.28 -11.96 -4.50 115700 115.7 1515.16 -11.89 -4.69 115800 115.8 1516.04 -11.78 -4.47

PAGE 647

618 Appendix K: (Continued) 115900 115.9 1516.92 -11.92 -4.31 116000 116 1517.8 -11.88 -4.48 116100 116.1 1518.68 -11.86 -4.48 116200 116.2 1519.56 -11.92 -4.44 116300 116.3 1520.44 -12.00 -4.60 116400 116.4 1521.32 -12.00 -4.48 116500 116.5 1522.2 -11.94 -4.60 116600 116.6 1523.08 -12.04 -4.39 116700 116.7 1523.96 -11.97 -4.21 116800 116.8 1524.84 -11.73 -4.22 116900 116.9 1525.72 -11.80 -4.31 117000 117 1526.6 -11.82 -4.30 117100 117.1 1527.48 -11.78 -4.35 117200 117.2 1528.36 -11.73 -4.28 117300 117.3 1529.24 -11.79 -4.30 117400 117.4 1530.12 -11.73 -4.23 117500 117.5 1531 -11.82 -4.23 117600 117.6 1531.88 -11.79 -4.17 117700 117.7 1532.76 -11.81 -4.19 117800 117.8 1533.64 -11.93 -4.14 117900 117.9 1534.52 -11.91 -4.16 118000 118 1535.4 -12.06 -4.35 118100 118.1 1536.28 -11.98 -4.25 118200 118.2 1537.16 -12.06 -4.25 118300 118.3 1538.04 -12.00 -4.28 118400 118.4 1538.92 -12.09 -4.33 118500 118.5 1539.8 -12.03 -4.29 118600 118.6 1540.68 -11.85 -4.26 118700 118.7 1541.56 -11.99 -4.54 118800 118.8 1542.44 -11.91 -4.32 118900 118.9 1543.32 -11.92 -4.44 119000 119 1544.2 -12.01 -4.45 119100 119.1 1545.08 -12.03 -4.33 119200 119.2 1545.96 -12.03 -4.18 119300 119.3 1546.84 -11.99 -4.33 119400 119.4 1547.72 -11.98 -4.20 119500 119.5 1548.6 -11.87 -4.24 119600 119.6 1549.48 -11.93 -4.24 119700 119.7 1550.36 -11.89 -4.19 119800 119.8 1551.24 -11.68 -4.18 119900 119.9 1552.12 -11.65 -4.26 120000 120 1553 -11.55 -4.13

PAGE 648

619 Appendix L BRC03-02 Trace Element Data

PAGE 649

620 Appendix L: (Continued) Distance from Top (mm) Age (yr BP) Mg-Ca44 Sr-Ca44 Ba-Ca44 1 34.7 9.15 8.16 2.45 2 69.4 8.67 7.88 2.16 3 104.1 9.89 5.12 2.32 4 138.8 10.27 6.33 2.35 5 173.5 10.17 6.09 2.03 6 208.2 9.31 7.61 1.89 7 242.9 8.72 6.98 1.82 8 277.6 9.63 6.74 2.12 9 312.3 10.25 5.39 1.15 10 347 9.37 6.52 1.67 11 359.8 9.64 6.65 2.10 12 372.6 10.00 9.25 3.06 13 385.4 9.48 8.39 2.90 14 398.2 8.93 9.09 2.59 15 411 8.92 7.83 2.05 16 423.8 9.40 8.69 2.72 17 436.6 8.79 6.77 1.62 18 449.4 8.76 8.48 2.70 19 462.2 9.28 7.02 2.18 20 475 9.41 8.59 2.88 21 477.3 8.56 10.12 3.46 22 479.6 9.29 6.86 2.14 23 481.9 9.42 7.39 2.46 24 484.2 9.01 7.81 2.69 25 486.5 9.49 7.22 2.35 26 488.8 9.48 7.97 2.62 27 491.1 9.96 7.42 2.18 28 493.4 10.06 6.91 2.18 29 495.7 10.19 6.71 2.14 30 498 9.73 6.49 2.04 31 500.3 9.65 6.31 1.80 32 502.6 9.96 8.13 2.81 33 504.9 8.91 8.83 3.38 34 507.2 9.95 8.50 3.23 35 509.5 10.24 6.20 1.93 36 511.8 9.55 6.52 2.32 37 514.1 10.26 7.54 2.40 38 516.4 9.72 6.66 2.20 39 518.7 10.25 5.42 1.57 40 521 10.36 7.09 2.32 41 524 9.76 6.96 2.35

PAGE 650

621 Appendix L: (Continued) 42 537.4 8.42 6.93 2.34 43 550.8 8.58 6.77 2.27 44 564.2 8.72 5.74 2.06 45 577.6 8.14 5.09 1.38 46 591 9.37 7.43 2.45 47 604.4 9.56 7.16 2.34 48 617.8 9.07 7.48 2.74 49 631.2 9.04 7.70 2.96 50 644.6 8.70 8.08 2.98 51 658 8.07 6.48 2.39 52 671.4 7.85 7.03 2.47 53 684.8 8.38 6.96 3.03 54 698.2 8.93 5.79 1.92 55 711.6 8.09 4.95 1.57 56 725 7.86 4.09 1.27 57 738.4 7.95 4.42 1.36 58 751.8 8.41 5.71 1.81 59 765.2 8.55 6.37 2.42 60 778.6 8.45 7.02 2.69 61 792 8.53 5.98 2.28 62 805 8.95 6.43 2.32 63 824.5 9.02 6.59 2.63 64 844 9.06 4.97 1.18 65 863.5 8.85 5.60 1.74 66 883 9.17 6.17 2.36 67 902.5 8.45 5.90 1.97 68 922 8.97 6.00 2.10 69 941.5 9.17 6.21 1.89 70 961 8.56 5.38 1.78 71 980.5 8.58 6.46 2.31 72 1000 9.42 7.58 2.56 73 1019.5 8.65 7.29 2.60 74 1039 7.74 8.25 3.32 75 1058.5 8.87 7.97 2.96 76 1078 8.31 8.42 3.28 77 1097.5 7.98 7.56 3.11 78 1117 8.83 6.63 2.26 79 1136.5 9.00 7.45 2.90 80 1156 9.17 6.13 2.06 81 1175.5 9.56 6.63 2.15 82 1195 8.46 6.91 2.83 83 1214.5 8.31 7.01 2.90 84 1236 8.62 5.85 2.20

PAGE 651

622 Appendix L: (Continued) 85 1244.8 8.85 7.21 2.72 86 1253.6 8.89 7.25 2.72 87 1262.4 8.95 8.01 3.11 88 1271.2 8.33 7.49 2.92 89 1280 8.33 7.56 2.70 90 1288.8 9.38 6.38 2.47 91 1297.6 8.64 6.80 2.84 92 1306.4 8.41 6.81 2.59 93 1315.2 9.41 5.06 1.74 94 1324 9.14 5.88 2.19 95 1332.8 8.89 6.66 2.29 96 1341.6 9.27 6.31 2.15 97 1350.4 9.03 7.68 3.02 98 1359.2 8.26 6.34 2.28 99 1368 8.81 6.74 2.48 100 1377 8.30 5.72 2.03 101 1385.8 8.07 6.79 2.51 102 1394.6 7.59 5.95 1.95 103 1403.4 8.65 6.12 2.41 104 1412.2 9.40 5.45 1.60 105 1421 8.17 3.97 1.22 106 1429.8 7.30 3.55 1.25 107 1438.6 8.16 3.98 1.40 108 1447.4 8.25 4.45 1.46 109 1456.2 8.35 4.56 1.53 110 1465 8.19 5.61 2.27 111 1473.8 8.23 5.44 2.25 112 1482.6 8.16 5.06 1.99 113 1491.4 7.89 4.06 1.51 114 1500.2 8.44 5.04 1.82 115 1509 9.16 4.54 1.50 116 1517.8 8.74 5.24 2.09 117 1526.6 7.03 6.06 0.96 118 1535.4 8.73 5.99 2.66 119 1544.2 8.56 6.17 2.70 120 1553 8.69 2.86 1.00

PAGE 652

623 Appendix M BRC03-03 Stable Isotope Data

PAGE 653

624 Appendix M: (Continued) Dist from top (mm) Age (years BP) 13C 18O 0 3983 -10.48 -3.76 1 3998 -10.4 -3.68 2 4013 -10.63 -3.64 3 4028 -10.86 -3.43 4 4043 -9.88 -3.54 5 4058 -10.3 -3.72 6 4073 -10.29 -3.77 7 4088 -10.12 -3.62 8 4103 -10.2 -3.4 9 4118 -9.23 -3.63 10 4133 -9.01 -3.25 11 4148 -9.89 -3.35 12 4163 -10.13 -3.13 13 4178 -9.95 -3.12 14 4193 -10.02 -3.24 15 4208 -9.99 -3.33 16 4223 -9.68 -3.33 17 4238 -9.37 -3.63 18 4253 -9.91 -4.08 19 4268 -10.03 -4.17 20 4283 -9.76 -3.63 21 4298 -9.64 -3.65 22 4313 -10 -3.65 23 4328 -9.86 -3.67 24 4343 -9.33 -3.42 25 4358 -10.82 -3.66 26 4373 -11.11 -4.08 27 4388 -11 -3.88 28 4403 -11.03 -3.95 29 4418 -10.18 -3.74 30 4433 -10.21 -3.75 31 4448 -10.78 -3.98 32 4463 -10.28 -3.78 33 4494 -10.7 -3.74 34 4525 -10.54 -3.9 35 4556 -9.22 -3.34 36 4587 -10.47 -3.53 37 4618 -10.08 -3.81

PAGE 654

625 Appendix M: (Continued) 38 4649 -10.65 -4.05 39 4680 -10.6 -3.86 40 4711 -10.53 -3.53 41 4743 -9.74 -3.2 42 4751.5 -9.64 -3.58 43 4760 -10.1 -3.42 44 4768.5 -9.95 -3.49 45 4777 -9.75 -3.5 46 4785.5 -8.97 -3.15 47 4794 -9.06 -3.04 48 4802.5 -9.28 -3.57 49 4811 -8.71 -3.22 50 4819.5 -9.17 -3.51 51 4828 -9.02 -3.37 52 4836.5 -9.01 -3.38 53 4845 -10.02 -3.77 54 4853.5 -10.53 -3.79 55 4862 -10.42 -3.64 56 4870.5 -10.6 -3.7 57 4879 -10.66 -3.76 58 4887.5 -10.67 -3.76 59 4896 -10.33 -3.72 60 4904.5 -10.23 -3.49 61 4913 -9.55 -3.47 62 4921.5 -9.58 -3.31 63 4930 -10.57 -3.52 64 4939 -10.75 -3.55 65 4949.62 -10.59 -2.91 66 4960.24 -10.84 -3.6 67 4970.86 -10.6 -3.52 68 4981.48 -10.68 -3.91 69 4992.1 -11.1 -4.36 70 5002.72 -10.13 -3.77 71 5013.34 -10.39 -3.17 73 5023.96 -10.16 -3.75 74 5034.58 -10.56 -4.07 75 5045.2 -10.42 -3.73 76 5055.82 -10.34 -3.24 77 5066.44 -10.52 -3.86 78 5088 -10.07 -3.21

PAGE 655

626 Appendix M: (Continued) 79 20725.89 -8.7 -3.17 80 20843.26 -8.49 -2.56 81 20960.63 -6.55 -1.95 82 21078 -5.85 -2.04 83 21195.37 -6.84 -2.58 84 21312.74 -7.16 -2.68 85 21430.11 -6.24 -2.39 86 21547.48 -6.14 -2.3 87 21664.85 -6.88 -2.47 88 21782.22 -7.96 -2.89 89 21899.59 -8.6 -3.26 90 22016.96 -7.98 -2.91 91 22134.33 -9.37 -2.91 92 22251.7 -8.04 -3.26 93 22369.07 -9.07 -2.65 94 22486.44 -8.87 -2.8 95 22603.81 -9.31 -2.76 96 22721.18 -9.32 -3.17 97 22838.55 -9.05 -2.66 98 22955.92 -9.3 -2.51 99 23073.29 -9.12 -2.59 100 23190.66 -8.86 -2.44 101 23308.03 -9.13 -2.45 102 23425.4 -9.11 -2.26 103 23542.77 -9.09 -2.32 104 23660.14 -9.2 -2.59 105 23777.51 -9.19 -2.6 106 23894.88 -9.93 -3.31 107 24012.25 -10.01 -3.42 108 24129.62 -9.93 -3.34 109 24246.99 -9.85 -3.28 110 24364.36 -9.15 -2.87 111 24482 -7.95 -2.16 112 24596.3 -7.71 -2.08 113 24710.6 -7.4 -1.85 114 24824.9 -6.83 -1.79 116 24939.2 -8.58 -2.85 117 25053.5 -7.38 -2.5 118 25167.8 -5.27 -1.69 119 25282.1 -4.75 -1.72 120 25396.4 -5.34 -1.86

PAGE 656

627 Appendix M: (Continued) 121 25510.7 -5.24 -1.89 122 25625 -6.34 -2.24 123 25739.3 -6.9 -2.73 124 25853.6 -7.03 -2.53 125 25967.9 -7.32 -2.92 126 26082.2 -7.01 -2.19 127 26196.5 -7.78 -2.48 128 26310.8 -6.86 -2.07 129 26540 -8.64 -2.77 130 26684.76 -9.17 -2.34 131 26829.52 -9.35 -2.69 132 26974.28 -8.16 -2.58 133 27119.04 -8.18 -2.56 134 27263.8 -7.33 -2.33 135 27408.56 -7.41 -2.37 136 27553.32 -8.43 -2.63 137 27698.08 -8.2 -2.54 138 27842.84 -8.22 -2.53 139 27987.6 -6.9 -2.72 140 28132.36 -7.67 -2.81 141 28277.12 -7.24 -2.75 142 28421.88 -8.42 -2.8 143 28566.64 -8.04 -2.7 144 28711.4 -8.3 -3 145 28856.16 -8.47 -3.24 146 29001 -8.29 -3.09 147 29001.9 -8.48 -3.29 148 29002.8 -8.15 -3.01 149 29003.7 -8.38 -3.03 150 29004.6 -8.21 -2.93 151 29005.5 -8.34 -3.09 152 29006.4 -7.84 -2.77 153 29007.3 -8.15 -3.02 154 29008.2 -7.81 -2.73 155 29009.1 -7.86 -2.82 156 29010 -8.18 -3.01 157 29010.9 -7.94 -2.63 158 29011.8 -7.97 -2.65 159 29012.7 -8 -2.75 160 29013.6 -7.98 -2.6 161 29014.5 -7.96 -2.94

PAGE 657

628 Appendix M: (Continued) 162 29015.4 -7.52 -2.58 163 29016.3 -7.52 -2.52 164 29017.2 -7.52 -2.72 165 29018 -7.64 -2.95 166 29027.46 -7.09 -2.95 167 29036.92 -7.34 -3.45 168 29046.38 -7.28 -3.05 169 29055.84 -6.91 -2.75 170 29065.3 -7.27 -2.93 171 29074.76 -7.24 -2.79 172 29084.22 -7.23 -2.84 173 29093.68 -7.18 -2.71 174 29103.14 -7.84 -3.44 175 29112.6 -7.31 -2.79 176 29122.06 -7.58 -2.87 177 29131.52 -7.5 -2.89 178 29140.98 -7.93 -3.11 179 29150.44 -8.01 -3.23 180 29159.9 -7.94 -3.09 181 29169.36 -7.94 -2.97 182 29178.82 -8.3 -3.25 183 29188.28 -8.48 -3.39 184 29197.74 -8.6 -3.07 185 29207.2 -8.23 -3.27 186 29216.66 -7.73 -2.85 187 29226.12 -6.37 -2.26 188 29235.58 -6.79 -2.59 189 29245 -6.9 -2.72

PAGE 658

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Polk, Jason Samuel.
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Proxy records of climate change in subtropical and tropical karst environments
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by Jason Samuel Polk.
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[Tampa, Fla] :
b University of South Florida,
2009.
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Dissertation (Ph.D.)--University of South Florida, 2009.
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Text (Electronic dissertation) in PDF format.
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Mode of access: World Wide Web.
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Advisor: Philip van Beynen, Ph.D.
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ABSTRACT: Understanding the paleoclimate of a region is important, especially when trying to determine the extent of natural climate variability within the context of anthropogenic impacts. Recent anomalous periods of climate change in the Late Holocene, including the Little Ice Age and Medieval Warm Period, could possibly repeat in the future, having significant worldwide consequences. This holds especially true for tropical and subtropical karst environments, where limited paleoclimate proxies provide minimal data regarding past climate change. An investigation into past climate change in Belize using fulvic acids from cave sediments shows periods of drought during the collapse of the Maya society around 1400 years ago. Comparison of changes in the carbon isotope data from the fulvic acids agree with speleothem records, but more closely reflect changes in the vegetation above the cave, showing Maya population decline through waning agriculture.Further investigation of using fulvic and other organics acids are examined from cave sediments in Florida. The data show fulvic acid carbon isotopes are the most robust recorders of climate change, agreeing with several nearby speleothem O and C records from west-central Florida. A more detailed record of climate change in Florida through a calibration study of precipitation and cave dripwater oxygen and hydrogen isotopes revealed that the amount effect dominates rainfall in west-central Florida. Homogenization of epikarst dripwater gives average O values representative of the annual amount-weighted average of precipitation O for the area, suggesting speleothem isotope records reflect changes in rainfall amount. Examination of two speleothems from west-central Florida show complex teleconnection and solar forcing mechanisms responsible for past climate changes.A high-resolution stable isotope, trace element, and time series analysis study for the last 1500 years shows variability during the LIA and MWP, pointing to a combined influence of Pacific and Atlantic teleconnection mechanisms, especially the ITCZ, NAO and PDO, being responsible for precipitation variability. Long-term reconstruction of the mid-Holocene and Late Pleistocene from another speleothem reveals differences in temperature and precipitation between glacial and interglacial conditions in Florida. Climate proxies from the tropics and subtropics provide additional clues to global climate change crucial to understanding future water availability.
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Paleoclimate
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Florida
Stable isotopes
Holocene
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Dissertations, Academic
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