Coastal wetland surface elevation changes : salt marsh and mangrove systems, Tampa Bay, Florida

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Coastal wetland surface elevation changes : salt marsh and mangrove systems, Tampa Bay, Florida

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Title:
Coastal wetland surface elevation changes : salt marsh and mangrove systems, Tampa Bay, Florida
Creator:
Nawrocki, Kerri
Place of Publication:
Tampa, Florida
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University of South Florida
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English
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ix, 122 leaves : ill. (some col.) ; 29 cm.

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Sedimentation and deposition -- Florida -- Tampa Bay ( lcsh )
Salt marshes -- Florida -- Tampa Bay ( lcsh )
Mangrove swamps -- Florida -- Tampa Bay ( lcsh )
Dissertations, Academic -- Geology -- Masters -- USF ( FTS )

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General Note:
Thesis (M.A.)--University of South Florida, 2001. Includes bibliographical references (leaves 83-87).

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University of South Florida
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Universtity of South Florida
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All applicable rights reserved by the source institution and holding location.
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028871239 ( ALEPH )
50728213 ( OCLC )
F51-00160 ( USFLDC DOI )
f51.160 ( USFLDC Handle )

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COASTAL WETLAND SURF ACE ELEVATION CHANGES: SALT MARSH AND MANGROVE SYSTEMS, TAMP A BAY, FLORIDA by KERR! NAWROCKI A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science Department of Geology College of Arts and Sciences University of South Florida December 2001 Major Professor : Eric Oches, Ph. D.

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Examining Committee: Office of Graduate Studies University of South Florida Tampa, Florida CERTIFICATE OF APPROVAL This is to certifY that the thesis of KERRI NAWROCKI in the graduate degree program of Geology was approved on August 17, 2001 for the Master of Science degree Major Professor : Eric A. Oches, Ph.D Member: Albert C.

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Acknowledgements I would like to thank Rick Oches my major professor, and other committee members, Skip Davis and AI Hine, for their expertise, assistance, and patience. This project in its form wouldn't have occurred without Ellen Raabe ofUSGS Center for Coastal Geology in St. Petersburg FL, who was heavily involved in the site selection and formatting of the project, and offered guidance on several occasions. USGS Center for Coastal Geology also provided funding for the SET devices and radiometric dating analyses, compensation for field work, and assistance in installation of equipment. Randy Runnels of Florida Department of Environmental Protection, Coastal and Aquatic Preserves division, aided in the site selection by providing use of his knowledge and boat, as well as permitting two of the site locations on DEP land. The other site was located on Hillsborough County Parks and Recreation Land and I would like to thank them for their permission and assistance Much appreciation goes to people who helped in the field work: Rick Oches, Ginger Tiling James Funderburk, and especially Matt Moore and Chuck Nawrocki. Gulf Coast Association of Geological Societies, Sigma xi Scientific Organization, and the USF Department of Geology provided additional funding, and my thanks goes to them as well. I would like to thank my friends and family, especially my husband, for all their support, moral and otherwise. Finally I would like to express my sincere gratitude to Rick Oches, who was always available to me ( ok, when not out of the country) and provided exactly the right level of support to promote encouragement and enable independence.

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List of Tables List of Figures Abstract Introduction Site Description Objectives Significance of Study Table of Contents Regional Environmental Setting Sea Level Trends Coastal Surface Elevation Changes Previous Work Central West Coast of Florida Coastal Wetland Sedimentation Studies in Other Regions Methods Coastal Wetland Sedimentation Coastal Wetland Surface Elevation Sedimentation Sediment Traps Marker Horizon Sediment Cores Lead-210 and Cesium-137 Dating Surface Elevation Others SET Sediment Pins Piezometers Tidal Gauge Statistics Frequency of Sampling Present Sedimentation Traps iii iv V11 1 3 8 10 11 12 13 15 15 15 16 16 16 19 19 19 20 21 21 22 22 25 25 25 2 6 28 28 30 30

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Marker Horizon 32 Historical Sedimentation 36 Short Sediment Cores 36 Radiometric Dating (Lead-210) 41 Surface Elevation 49 SET-Intensive Surface Elevation Data 49 Spring Cycle 49 Neap Cycle 49 Daily Neap to Spring December 52 Daily Neap to Spring-May 53 SET-Monthly Surfuce Elevation Data 56 Upper Tampa Bay Monthly Surface Elevation 58 Little Manatee River Monthly Surfuce Elevation 59 Mariposa Key Monthly Surface Elevation 59 63 Seasonal Pattern 64 Differences Between Sites 64 Subsurface Patterns 67 Upper Tampa Bay 67 Little Manatee River 67 Mariposa Key 68 Relationship Between Surface Elevation and Sediment Accretion 72 Seasonal Pattern in Subsidence/Production 73 Future Projections and Conclusions 78 Future Projections 78 Conclusions 80 References 83 Appendices 88 Appendix I : Field Monitoring-SET 89 Appendix II: SET Error Measurements 109 Appendix III : Multi-Data 110 Appendix IV: Sedimentation Data 114 Appendix V: Sediment Cores 116 Appendix VI: Lead-210 Analysis 119 Appendix VII: Calculations for Sea Level Rise to 2100 122 11

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List of Tables Table la Table depicting sedimentation rates using traps. 31 Table lb. Table depicting sediment accumulation above marker horizon. 31 Table 2a Lead-210 analysis for Upper Tampa Bay core showing sedimentation rates for past 130 years. 42 Table 2b. Lead-210 analysis for Little Manatee core showing sedimentation rates for past 150+ years 43 Table 2c. Lead-21 0 analysis for Mariposa Key core showing sedimentation rates for past 150+ years. 43 Table 3 Statistical correlation results using non-parametric Spearman's Rank correlation test. 50 Table 4 Kruskal Wallis statistical results, testing for significant differences between surface elevations within each site. 52 Table 5 Table comparing sedimentation and elevation change recorded in various studies. 74 ll1

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List of Figures Figure 1. Map showing study area, indicating the locations of the three sites. 4 Figure2a Location of northern most site in Upper Tampa Bay Regional park: salt marsh. 5 Figure 2b. Aerial photograph of Upper Tampa Bay area obtained from USGS Orthoquad photographs, 8m resolution. 5 Figure 3a Map showing location of Site #2: Little Manatee River salt marsh. 6 Figure 3b. Aerial photograph of Little Manatee River and site location obtained from USGS Orthoquads, 8m resolution. 6 Figure4a Map showing location of southern most site on Mariposa Key: mangrove mangal 7 Figure4b. Aerial photograph of Mariposa Key obtained from USGS Orthoquads 8m resolution. 7 Figure 5a Photograph of SET device at Little Manatee River site. 23 Figure 5b. Diagram of Surface Elevation Table (SET). 24 Figure 6. Map showing location of study sites, in relation to NOAA tidal gauges. 27 Figure 7a Figure depicting Upper Tampa Bay core, showing schematic of organic content, mud content and description with depth. 38 Figure 7b. Figure depicting Little Manatee core, showing schematic of organic content, mud content and description with depth. 39 Figure 7c. Figure depicting Mariposa Key core showing schematic of organic matter mud content and description with depth. 40 iv

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Figure 8a. Excess or unsupported Lead210 activity (red) and Cesium 137 activity (green) versus depth for Upper Tampa Bay core. 44 Figure 8b. Excess or unsupported Lead-210 activity (red) and Cesium-137 activity (green) versus depth for Little Manatee core. 45 Figure 8c. Excess or unsupported Lead-210 activity (red) and Cesium-137 activity (green) versus depth for Mariposa Key core. 46 Figure 9a Bi-hourly measurements taken during November spring tidal cycle at Upper Tampa Bay. 51 Figure 9b. Bi-hourly measurements taken during March neap tidal cycle at Upper Tampa Bay. 51 Figure lOa Daily measurements taken over December neap to spring lunar cycle at Upper Tampa Bay 55 Figure lOb. Daily measurements taken over May neap to spring lunar cycle at Upper Tampa Bay. 55 Figure lla. Monthly measurements at Upper Tampa Bay. 57 Figure lib. Monthly measurements taken at Little Manatee. 57 Figure llc. Monthly measurements taken at Mariposa Key. 58 Figure 12a Monthly SET medians and Pin values plotted over time for Upper Tampa Bay. 62 Figure 12b. Monthly SET medians and Pin values plotted over time for Little Manatee. 62 Figure 13a. Two-Dimensional depiction of surface and subsurface processes and relationship to change in net elevation at Upper Tampa Bay for October to May period 69 Figure 13b Two-Dimensional depiction of surface and subsurface processes and relationship to change in net elevation at Little Manatee for October to May period. 70 v

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Figure 13c. Two-Dimensional depiction of surface and subsurface processes and relationship to change in net elevation at Mariposa Key for October to May period Figure 14 Chart depicting predicted sediment accumulation for year 2100 at Upper Tampa Bay, Little Manatee River, and Mariposa Key (based on past) compared with probable sea level rise for the same period V l 71 79

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COASTAL WETLAND SURF ACE ELEVATION CHANGES : SALT MARSH AND MANGROVE SYSTEMS, TAMPA BAY, FLORIDA by KERR! NAWROCKI An Abstract of a thesis submitted in partial fulfillm e nt of the requirements for the degree of Master of Science Department of Geology College o f Arts and Sciences University of South Florida December 2001 Major Profe ssor : E ri c O ches Ph. D Vll

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Surface elevation of coastal wetlands can be altered through a variety of processes These include sediment accretion, underground biomass production, subsidence, compaction, and erosion. These processes regulate the stability of salt marsh and mangrove mangal surface elevations with respect to sea level. Three coastal wetlands within Tampa Bay, Florida, have been monitored for surface elevation changes using a combination of techniques, including the surface elevation table (SET) Though this method has been utilized in other United States southeast coastal regions, measurements have previously been obtained on a quarterly or semi-annual basis In this study sampling ranging from hourly to monthly has been carried out to understand short-term surface variability in coastal wetlands in response to and seasonal fluctuations. The winter season appeared to be a critical period of sediment delivery to the wetlands combined with subsidence, and spring was an erosional season coupled with subsurface gain. The pattern observed in the monthly SET data corresponded closely among the three sites, suggesting a similar forcing mechanism. Based on statistical correlation, short-term surface variability appears to be related to tidal forcing and associated groundwater fluctuation. Our results suggest that the passage of a cold front, tidal stage, or seasonal changes may effectively alter the surface elevation on the order of 1-2cm from the "norm". Short-term surface fluctuation as a result of these influences occurs on the same scale of vertical change that has been observed over much longer periods in other coastal settings Therefore without high-frequency sampling, these few centimeters of change might incorrectly be associated with a long-term pattern in this low energy, low sediment microtidal environment. Refinement of the SET measurement technique higher frequency sampling, and accounting for tidal conditions is Vlll

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recommended in order to remove the bias of short-term influences from quarterly measurements which have more commonly been used to characterize coastal wetland surface elevation changes through time These refinements may be necessary for the collection of data representative of long-term trends, rather than a snap-shot of the coastal wetland surface elevation at the time of a single measurement. Abstract Approved : ---------4o'---==----==-=---Major Professor : Eric Oches, Ph.D. Professor Department of Geology Date Approved : -----------lX

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Introduction Coastal wetlands perform several vital functions. Major benefits include providing a buffer from storms and flooding to inland areas, functioning as a ''filter'' for pollutants draining from urban areas, and anchoring the coastline by lessening erosive processes. The organic matter produced in coastal wetlands and estuaries provide the base of the coastal ocean food chain. These coastal vegetated environments also serve as critical wildlife habitat for migratory waterfowl and as a nursery for many marine animals (Chabreck, 1988). Despite these benefits there exists a dichotomy between human activity and environmental conservation. Consistent with the rest of the country, the number of remaining tracts ofFlorida Gulf Coast marshes has declined sharply In fact, over 40% ofTampa Bay's coastal wetlands consisting ofboth mangroves and salt marshes have been lost over the past 100 years (FMRI, 1997). This decrease is a result of developmental pressures agricultural demands and drowning due to a deficit of sediment input relativ e to sea level rise. Stability of coastal wetlands may be assessed by monitoring changes in surface elevation through time. This monitoring can be accomplished by measuring both surface a ccretion and subsurface processe s affecting elevation. A few recent studies of marsh systems in the Gulf Coast and United States South Atlantic regions have indicated that accretion or sediment received by a coastal wetland does not strictly correlate with increased surface elevation (Boumans and Day 1993 ; Childers, et. al., 1993 ; Cahoon, et I

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al, 1995) Although related, it is the elevation of the coastal wetland surfuce, not the amoWlt of sediment it receives, that will be the decisive factor in its continued existence during a period of sea level rise. Sedimentation and erosion are not the only means by which salt marshes are ahered vertically. Several physical processes that result in elevation changes operate in both coastal marsh and mangrove systems. Subsidence and compaction result in vertical changes in the negative direction as a result of dewatering of sediments, fluid withdrawal, compression due to confining pressure of overlying sediment, etc. Positive elevational changes can result from subsurface processes as well UndergroWld production of biomass in the form of roots or rhizomes, or the accumulation of peat, can occur in marshes and mangrove systems resuhing in an increase in elevation. Measuring sedimentation alone, therefore, cannot accoWlt for these numerous processes in coastal wetland systems. Three coastal wetland sites have been selected in greater Tampa Bay for surface elevation and sedimentation monitoring. The Tampa Bay area occupies a unique position as it generally coincides with the freeze boWldary for western Florida and serves as the northern limit for many subtropical flora, including mangroves. As such, the Tampa coastline is a zone of transition between more temperate salt marshes northward and subtropical mangroves southward. Other ongoing and previous studies have characterized wetland processes in salt marsh locations to the north in the Big Bend of Florida and mangrove islands to the south in Rookery Bay (Ladner, et. aL, 2000; Leonard et. al, 1994; Osking, 1985; Cahoon and Lynch, 1997). This study will serve as a link in assessing sedimentation and subsurface dynamics between the two biomes. In addition, the central west coast ofFlorida is a region oflow sediment influx and low 2

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energy. As a resuh of this low input, the survival of coastal marsh systems in association with sea level rise in this region is unclear. The major focus of this study is in quantifying and predicting surface elevation behavior in relation to other variables in an effort to evaluate sustainability, as well as refining the sampling methodology commonly applied in use of the surfuce elevation table device (SEl). The three study sites include two salt marshes (Juncus roemerianus), with dissimilar hydrological settings and differing in degree of connection to land, and a black mangrove (Avicennia germinans) location. Site Description The three site locations included in this study, all in designated conservation lands, were selected to include a more restricted upper-bay location, a mid-bay location, and a southernbay location, which provide a north-south transect (Figure 1 ). lbis transect also incorporates a coastal wetland transition from salt marsh to mangrove mangal. The first northern site is aJuncus roemerianus patch located in Upper Tampa Bay Regional Park (UTB) in Northern Hillsborough County, Florida (Figures 2a and 2b). This site has the greatest degree of connection to inland areas. A second Juncus roemerianus site is on Snake Key, an island located near the mouth of the Little Manatee River (LMR), in the southern portion of Hillsborough County (Figures 3a and 3b). The third site is a mangrove mangal and was selected because it represents a unique environment in which black mangrove (Avicennia germinans) occupies a position normally defmed by Juncus on the edge of a tidal flat with a significant elevation boundary. This southerly site is located on Mariposa Key (MK), a coastal strand in northern Manatee County (Figures 4a 3

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and 4b). The first site is located in Hillsborough County parkland and the second and third sites are located on Florida Department of Environmental Protection property. Figure 1. Map showing study area indicating the locations of the three sites. 4

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... .. .. i:1J ., -:J:illisb..OI.OU gh A V e .. 6 Q -+ Figure 2a. Location of northern most site in Upper Tampa Bay Regional Park: s alt marsh Solid blue indicates water green represent wetlands, and white is land Figure 2b. Aerial photograph of Upper Tampa Bay area obtained from USGS Orthoquad photographs. 8m resolution 5

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Figure 3a. Map showing location of Site # 2 : Little Manatee River salt marsh. Solid blue represents water, green is wetlands and white is land. Figure 3b. Aerial photograph of Little Manatee River and site location obtained from USGS orthoquads, 8m resolution. 6

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Figure 4a. Map showing location of southern most site on Mariposa Key: mangrove mangal. Solid blue represents water green is wetlands and white is land Figure 4b. Aerial photograph ofMariposa Key obtained from USGS orthoquads, 8m resolution. 7

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Objectives The major focus of the objectives involves evaluating short-term surface elevation fluctuations, predicting sustainability of these sites, and refining the surface elevation table measurement technique. Specific objectives of this thesis project include: 1) Establishing surface elevation table (SET) sites within salt marsh (Upper Tampa Bay and Little Manatee) and mangrove (Mariposa Key) communities to monitor surfitce elevation changes over long and short term time scales ranging from hourly to monthly over a nine-month period. Addressing surface elevation changes on these short time scales allows us to determine the minimum necessary temporal sampling interval for surface elevation measurements in order to extract a long-term trend as well as identify mechanisms involved in these short-term fluctuations. 2) Measuring present and historical sedimentation at each site. Present sedimentation is compared with surface elevation and is evaluated relative to seasonal changes Present sedimentation is monitored using sediment traps and sediment marker horizons. Historical sedimentation is assessed through 210Pb and 137Cs radiometric dating methods applied to sediment cores collected at each site Historical sedimentation is used to predict future sedimentation and is addressed relative to predicted sea level rise Data obtained at the three wetland sites should yield information regarding the status and probable trend with respect to growth, maintenance, or destruction of these systems in the future. 3) Relating wetland surface elevation to sedimentation. It is the vertical elevation of the wetland surface that determines sustainability in the face of rising seas. Simply measuring accretion or sedimentation biases the study because it does not accurately 8

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reflect erosion of sediment from the marsh surface, nor subsurface processes. Despite adequate accretion, a wetland affected by subsurfuce processes such as subsidence or compaction could decrease the ability of the wetland system to maintain its elevation. Furthermore, only addressing accretion skews the measurements toward inorganic sedimentation, because marsh systems often produce biomass below the surface, which contributes to elevation (Rooth and Stevenson, 2000; Reed and Cahoon, 1993). Therefore, considering sedimentation together with surface elevation will yield more meaningful results than either process alone in understanding wetland processes and projecting their future in the context of sea level rise. 4) Comparing the above measurements with other data such as tide level, groundwater level, wind speed and barometric pressure obtained at or near each site. Important relationships among various factors, such as groundwater, tidal stage, and meteorological elements affecting these particular sites are also examined to identify forcing factors involved in surface elevation change. 5) Comparing salt marsh and mangrove environments Because one of the study sites is a mangrove mangal, comparative analyses with salt marsh environments will be possible Sedimentation and elevation patterns will be compared between the salt marsh and mangrove environments. In addition, a comparison of both patterns will be made between the mangrove area involved in this study, located in a region of transition from salt marsh to mangrove, with the mangrove studies completed to the south in Rookery Bay (Cahoon and Lynch, 1997). 9

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Significance ofStudy Deciphering the short-term fluctuations and variability in salt marsh accretion is important for several reasons. High frequency monitoring allows for an evaluation of the contribution of different events and processes in adding to and subtracting from marsh elevation. The role of non-cyclic events in marsh maintenance needs to be understood For example, does the passage of a cold front add sediment or remove it from the marsh surface? In addition, the effects of cyclic events on marsh surface processes need to be addressed. How does the marsh respond to seasonal changes, such as rainy versus dry periods, or low Gulf water level versus high Gulf water level periods? Other issues include variations in lunar cycle (neap/spring tides), daily tidal cycle and stage, and groundwater movements. By studying these short-term variations, a better understanding of marsh morphodynamics will be gained. This knowledge can then be applied in predicting long term sustainability As an example, with projected changes in global weather patterns associated with global warming, it is important to know which types of meteorological events contribute to marsh changes In addition, planners can use the information in projecting possible impacts of nearby development on coastal wetlands. For instance, the understanding of the relationship between groundwater flow and marsh surface elevation may yield information relevant to a hypothetical request for the implementation of new groundwater wells in the area. Finally, knowledge gained by examining short-term processes can also be beneficial in coastal wetland restoration and mitigation. 10

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To provide high frequency data, surface elevation tables (SETs) at the Little Manatee River marsh site and the Mariposa Key mangrove site were monitored on a monthly basis. In addition to monthly measurements, the Upper Tampa Bay marsh site (site #1) was monitored on a high-frequency basis involving daily measurements over lunar cycles during late December and May, representing the winter cold front season and early spring prior to the arrival of the summer thunderstorm season. The Upper Tampa Bay site was also monitored every two hours through a tidal cycle to encompass low-high-low tidal regime, during one spring and one neap tidal cycle Regional Environmental Setting The central west coast of Florida is a prime location from which to observe coastal changes associated with rising seas. This region is underlain by a stable limestone platform that is undergoing neither widespread compaction, subsidence, nor glacio isostatic adjustments. Additionally this region is characterized by low energy conditions, low tidal range and low sediment input (Davis, et. al., 1985). As a result of these low energy and sediment inputs it is uncertain whether coastal marsh systems located in this region will be able to keep pace with sea level rise. In the past some marsh systems were able to survive sea level rise by accreting and transgressing inland However the rapid development occurring today in these west-central Florida coastal counties (Hillsborough, Manatee, Pasco) would make such a shift unlikely, if not impossible, because the wetlands would not be able to migrate inland with sea level rise. The study area and adjacent coastline is considered to be a low-energy coast with a very low-gradient ( 1: 1300) carbonate shelf, a mean diurnal tidal range of less than 1m, and low mean annual wave height of less than 0.40m (Davis, 1982). The Tampa Bay 11

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area receives the majority of its 124cm of mean annual precipitation in the form of subtropical afternoon thunderstorms in the summer months. The driest period of the year occurs from October through May (Wooten, 1982). Consequently, the area experiences a slightly higher sea level in the Gulf in August and a low in February (Provost, 1974). The late fall and winter are characterized by the passage of infrequent cold fronts in which the prevailing southeasterly winds shift to the northwest, and wave heights can exceed 1m (Davis, 1982). With the exception of the rare tropical storm or hurricane, these cold fronts are the major energy-systems affecting the coast. For the purposes of this study, late summer/fall is defined as late August through November, as summer thunderstorm season comes to an end; winter is defined as December through March, as this was the interval during which cold fronts were observed; and spring is defined as April through June because late June marks the beginning of thunderstorm season. Sea Level Trends For the last 10,000 years, the earth has been in an interglacial, rising sea level cycle. Although most post-glacial sea level rise occurred prior to approximately 3000 years ago, global sea level is currently rising at a rate of 1.8mm/year, and this rate is expected to increase due to intensified global warming (Titus and Narayanan, 1995). It is unrealistic, however to app ly this rate to a specific coastal area to determine the potential land lost to the sea. Simply applying global sea level values to a particular location does not give an accurate picture as some regions are affected differently due to subsidence, uplift, or the configuration of the adjacent continental shelf. Local sea level rise for St. Petersburg, FL, has been calculated at 2.3mm/year (based on 1990 data) (Titus and Narayanan, 1995). For the year 2100, the most likely (median) rise for the Tampa Bay area is 12

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calculated at 51-61 em, based on a normalized EPA calculation using the more conservative temperature increase of2C by 2100 (Titus and Narayanan, 1995) The high end projection for the Tampa Bay area is 117cm by 2100, and the lowest end is 26cm (Appendix VII). Due to the broad, very low gradient of the west Florida continental shelf and the low elevation of the Tampa Bay area, the potential impacts of this increase could be substantial. Coastal Surface Elevation Changes Over geological time sea level has risen and fallen by over a hundred meters many times (Lowe and Walker, 1984). A salt marsh can represent a transitional stage in a coastal sedimentary succession. As an example an estuary receiving a net accumulation of sediment fills in gradually, grades into a tidal flat, which typically becomes vegetated, and eventually evolves to a salt marsh. At the other extreme salt marshes can represent the initial stage in a transgression (sea level rise) sequence. For instance, a salt marsh with a net deficit of sediment in a time of sea level rise transforms into an estuary, an event that is occurring on the Louisiana coast on human timescales (Reed and Cahoon, 1992 ; Cahoon and Reed, 1995; DeLaune et. al., 1992). Several phys ical processes operate in coastal wetland systems that result in elevation changes. Subsidence and compaction result in subsurface elevation decrease as a result of dewatering of sediments, fluid withdrawal, and compression due to confining pressure of overlying sediment. Erosion is another process contributing to elevation decrease by which surface sediment i s removed from the marsh. Positive elevation changes can result from surface sedimentation and subsurface processes as well. Underground production of biomass in the form of roots and rhizomes or accumulation of peat can occur in 13

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marshes and mangrove systems, resuhing in an elevation gain. Sedimentation measurements alone cannot account for these diverse processes nor produce an elevation budget Although related, it is the elevation of the marsh surface not the amount of sediment a marsh receives that will be the decisive factor in its continued existence in a period of sea level rise. Therefore the methods used in this study include mechanisms to measure both surface elevation and sedimentation. 14

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Previous Work Central West Coast of Florida Coastal wetland sedimentation. The open-marine marsh system on the west coast of Florida north of Tampa Bay has been the subject of several recent studies. Goodbred, et. al. (1998) examined late Holocene sedimentation of the Waccasassa Bay salt marsh system located north of Tampa Bay in the open-marine marsh coast of Florida. They found that this marsh tract moved inland with sea level rise; the marsh migration was largely dependent upon storm-related sediment deposition. Leonard, et al. (1994) linked tidal creek suspended sediment dynamics to marsh deposition in Cedar Creek, Florida. Their results indicated that the majority of sedimentation was inorganic, and that the adjacent marsh is presently keeping pace with sea level rise based solely on measured accretion rates. Hutton (1986) investigated subsurface bedrock dissolution features and the morphological sequence that developed in Big Bend marshes of the Florida Gulf Coast as a result of sea level rise. That sequence consisted of marsh encroachment upon upland tidal creek formation in low areas, followed by hammock flooding and mangrove death Osking (1985) investigated shallow embayments and associated marsh systems along the Big Bend area ofthe Florida Gulf Coast By analyzing cores from the area, he identified six substrate facies and three stages of shelf embayment through time. However, the relationship between accretion and surface elevation was not addressed in these studies. 15

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Studies in Other Regions Coastal wetland sedimentation Bricker-Urso, et al. (1989) measured historical sedimentation rates in cores obtained from Rhode Island salt marshes using Lead-210 radiometric dating. Low marshes were found to be historically accreting 1-112 times greater than present rate of sea level rise, while high marshes accreted at a rate approximately equal to sea level rise. Callaway, et. al. (1997) compared historical sedimentation rates using Cesium-13 7 dating method and organic versus mineral accumulation in four coastal systems throughout the Gulf of Mexico : two marshes in Texas, one in Mississippi, and a mangrove system in the Florida Keys. They concluded that accretion rates at three sites were greater than sea level rise but the fourth, located in Texas, was experiencing an accretion deficit In addition, they concluded that organic matter production is the dominant accretionary component. Kadlec and Robbins (1984) compared historical sedimentation patterns using Cesium-137 and Lead-210 techniques applied to core segments for three coastal wetland sites in Michigan They found that the Lead-210 method was more valuable in dating cores with lower sedimentation rates, because Cesium-137 resolution was poor in areas with lower accretion rates. Finally many researchers have applied artificial marker horizons or sediment traps to the sediment surface in order to measure sedimentation received over a specific time interval on the marsh surface e.g ., Cahoon and Turner, 1989; Letzsch and Frey, 1980; Hutchinson, et. al., 1995. Coastal wetland surface elevation. Pethick (1981) measured salt marsh accretion using surface elevation measurements obtained by standard surveying/leveling techniques at a site in England He found that the age of a marsh, as well as tidal range and 16

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affect the amount of accretion in a marsh. By contrast, in a study of coastal marshes in LouisPenland and Ramsey (1998) found that surveying as a method of determining subsidence yielded ''highly variable" results et. al. (1995) employed both feldspar marker horizons and surface-elevation tables (SET) to compare sediment deposition with vertical elevation change within three different marsh environments in LouisBig Bend Florida, and North Carolina. Each site was monitored bi-annually for two years, and they concluded that positive surfilce elevation change was significantly lower than sedimentation rates at each locale et. al., 1995) Finally, Cahoon and Lynch (1997) measured vertical accretion using a combination of a surfilce-elevation table (SET) and marker horizons in a mangrove forest in Rookery Bay southwest Florida. They determined that short-term elevation measurements rather than long-term accretion measurements were more indicative of potential for submergence because the radiometric dating methods used underestimated and wetland plants are responsive to short term cycles Recent studies of coastal wetland systems in the Gulf Coast and US South Atlantic coastal regions have indicated that accretion or sediment received by a wetland does not strictly correlate with increased surface elevation (Boumans and Day, 1993 ; Childers et. al., 1993; Cahoon, et. al ., 1995). Clearly, the elevation ofthe marsh is an important component in determining the susceptibility to sea level rise In those studies did not involve intensive short-term samplin g Missing from the scientific literature on coastal marsh systems in the Gulf Coast is a study combining high-frequency surface elevation measurements with accretion or sedimentation measurements. It is not currently understood how coastal marshes breathe and fluctuate over the short-term, 17

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and how short-term fluctuations fit into longer-term variability Hutchinson, et. al. (1995) performed short-term sedimentation measurements (daily over some tidal regimes) on a Spartina marsh in South Carolina ; however, accretion was not related to surface elevation. Conversely, Cahoon, et. al. (1995), Cahoon and Lynch (1997), and Childers, et. al. (1993) related sediment accretion to surface elevation in Gulf or South Atlantic coastal marshes, but only longer time periods were addressed, ranging from quarterly to bi-annual sampling. 18

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Methods Methods used in this study include a combination of techniques to address changes in elevation due to accretion, erosion, compaction, and other physical processes. Sedimentation Two methods were used to measure sedimentation over the study period: sediment traps and marker horizons, each having different advantages and disadvantages associated with their use Marker horizons, though very simple and effective in measuring sediment accretion over the study period, have the drawback of being disturbed by active bioturbation. Sediment traps provide an alternative method, but they have the potential for being lost, destroyed by wildlife, or destroyed by storm action. Therefore, both methods were employed in this study in an attempt to calibrate sedimentation measurements. Sediment traps. Sediment traps can measure small sedimentation inputs over shorter timescales than the horizon and enable sampling of the accumulated sediment to determine the composition. The main disadvantage encountered with sediment traps is that the filters tended to degrade easily It is also possible that such a small sampling area can be potentially more biased by redistribution of sediments, as well as possibly serving as an artificial baffle to trap sediments. This method of assessing sedimentation 19

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represents mass deposited per area over time, and represents a maximum estimate of the sedimentation when compared with the marker horizon method. Sedimentation was measured on sediment traps consisting of plexiglass anchored to the marsh surface. Pre-weighed ashless glass fiber fiher papers were attached to a base and an elevated coarse-meshed screen placed over the top to avoid disturbance by fauna. Unfortunately, this method proved unreliable in recovery of the filter papers and resulted in no sediment data being collected using this trap design. Beginning in December, new traps were used modified from Reed's (1989) traps Although some fihers were decomposed, most were recoverable and this design proved more reliable Once collected, the filter papers were dried and weighed, and bulk sediment accumulation was calculated. In addition, organic versus inorganic sedimentation was determined by heating the filter papers to 500C in a muffle furnace for four hours, resulting in combustion of organics. The cooled filter papers were then reweighed, and the difference between the dried post-sedimentation weight and this weight calculated as the organic constituent (Brower, et. al., 1998) (Appendix IV) Marker horizon Artificial marker horizons placed on the sediment surface and periodically cored represent millimeters of accumulation over time. An advantage ofthis method is that it can be more meaningful to compare millimeters of accumulation over time (vertical accretion) when compared with surface elevation rather than mass calculations; however, these accumulated sediments can still be converted to mass/area when cored. This method is more consistently reliable when not contingent upon preservation of filters and does not produce a baffling effect Disadvantages include compaction involved in inserting the cores for measurement and potential bioturbation 20

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effects from wetland organisms. With the marker horizon method, push cores represent a minimum estimate of accumulation, while cryogenic cores represent a maximum estimate; as compaction is not an issue with the latter. To measure specific accretion, a marker horizon consisting of powdered feldspar was laid upon the wetland surface in October near the SET platform at each site (after Cahoon and Turner, 1989). Cores were taken through the marsh surface monthly, and sediment accretion above the marker horizon was measured in mi11imeters. Sediment cores. In addition to cores taken through the marker horizon, short cores of approximately 1m were taken from each site at the beginning of the study period. These cores were then split and sedimentological analyses performed. Stratigraphy was examined on one half of the core, and small sections of the other half were analyzed for grain size distribution and organic content. The purpose of these analyses was to assess historical sedimentation patterns, including shallow subsurface processes such as underground biomass production. Lead-21 0 and Cesium-13 7 dating. Historical sedimentation was measured using radiometric dating f10Pb and 137Cs) performed by United States Geological Survey, Denver, CO, on the top 20cm of 1 meter long cores obtained from the marsh surface (after DeLaune, et. al., 1989). Only the upper portion of each core was used to provide uniform interval coverage of the core given available funds. The suitable time scale that can be assessed using 210Pb, due to its half-life of approximately 22 years, is 1-150 years (Olssen, 1986). 137Cs is incorporated into sediments due to above-ground nuclear weapons testing in the 1960s Peak 137Cs deposition in this area occurred in 1965 (James Budahn, personal communication). 210Pb occurs naturally in the atmosphere as a product 21

PAGE 34

of decay of gaseous 222Rn, and also occurs in sediment as a product of decaying Atmospheric 210pb deposited in sedimentary columns is referred to as unsupported lead, and that derived from decay occurring within the sedimentary column as supported 210pb (French, et. al., 1994; DeLaune, et. al., 1989). The activity of the unsupported 210pb is higher than that of supported 210pb (Holmes, 1998). Both forms are measured, and the supported lead is subtracted from the total lead to yield the unsupported lead value, which is the value that is used in the dating procedure (Olssen, 1986 ; Holmes, 1998). Sections of the cores are dated, and the sediment intervals between dated levels are averaged to yield sediment accumulation per year This method assumes a constant rate of sedimentation and a constant level of210pb through time (Bricker-Urso, et. al., 1989), as well as an absence of significant bioturbation within the sedimentary column. Surface Elevation SET. A trio of surface elevation tables, SET, (note: previously termed sedimentation-erosion table) were employed to measure the change in elevation of the wetland surface through time (Figure 5a). The SET device consists of a stationary platform attached to a 6m shaft that was implanted, via jetting, into the wetland subsurface for the length of the study. A transportable arm containing equally spaced holes along the length of the arm hooks into the permanently installed base for sampling (Figure 5b). The arm is mounted onto perpendicular notches on the platform to enable measurement in four directions The distance to the marsh surface is measured by lowering the pins through holes in the arm until they just touch the wetland substrate. The four locations for measurement around the platform provide replicate samples and 22

PAGE 35

the eight pin measurements are subsamples, which are usually averaged. The confidence error for this device has been calculated at plus/minus 1.5mm (Boumans and Day 1993) The SET devices were installed in a manner consistent with relative summer high tide position on the same day at each site to ensure similar tidal regime. It was possible to observe the same tidal position at each site in one day due to the tidal lag associated with the different settings Absolute elevation of the SET platform was measured by GPS surveying conducted by USGS. Boardwalks were installed at the time of installation of the SET devices to minimize surface disturbance when sampling. Figur e Sa Photograph of SET device at Little Manatee River site. Not e SET measurements are taken from an elevated boardwalk to avoid substrate disturbance. 23

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SET 1 .24m pin (8 total] arm 6m Figure 5b. Diagram of Surface Elevation Table (SET). A version of this device was originally used in tidal flats and was modified by Boumans & Day 1993 for use in coastal wetland applications. The device consists of a permanent base installed to a depth of 6m, with a detachable arm that is mounted for sampling in four perpendicular directions Along the length of the arm, pins are inserted through eight holes to the s ubstrate and the distance measured from arm to substrate 2 4

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Multiple approaches were attempted to provide a greater degree of objectivity in SET measurements than the standard visual method. One technique employed was the use of a resistivity meter. One lead of the meter was placed on the exposed metal top of the pin, and the other placed in the damp substrate The bottom of the pin, also containing exposed was lowered and the meter indicated the exact instant of connection between the pin and the substrate One problem with this method occurred when ponded water remained on the surface-the meter indicated contact before the actual connection of pin to substrate. Finally, a ''foot" for the bottom of the pin was created, measuring approximately 3cm in diameter with holes in the disc to allow for submergence in the case of ponding. This method proved to be beneficial. Not only did the foot serve to distribute the measurement over a greater area than the point of the pin, but also provided an objective means of identifying contact. Sediment pins. Metal rods approximately I meter in length, were inserted through a hole in a thin aluminum sheet to a depth of 40-50cm, so that the sheet remained on the surface. The distance from the sheet to the top of the rod was measured upon installation. With each sampling, the distance is again measured and the difference between the current measurement and the previous is potentially equivalent to elevation change in the upper layers of the sediment column, providing an accompaniment to the SET device (Cahoon and Lynch, 1997) Oth e rs Piezometers Piezometers were installed near the SET devices to enable measuring both the vertical level and salinity o f the groundwater. As is well known, the water table fluctuates frequently and the interface between fresh and salt-water below ground is not 2 5

PAGE 38

a fixed point. Both can affect vertical changes in marsh elevation (DeLaune, et. al., 1989). Tidal gauge. No tidal gauge was readily available at any of the study locations However, National Oceanic and Atmospheric Administration (NOAA) tidal gauges located within the Tampa Bay area were used and interpolated to assess tidal cycle or stage at the time of field measurements (Figure 6). A NOAA tidal station located at Old Port Tampa was used for the Upper Tampa Bay site, an interpolation between a tidal station located at St. Petersburg and one located at Port Manatee was used in determining tidal stage for the Little Manatee River site, and the Port Manatee tidal station was used for obtaining the Mariposa Key tidal data In addition, a primitive tidal gauge in the form of a pipe inserted in the substrate surrounded by a plastic casing marked with depth measurements, was installed at the Upper Tampa Bay site to correlate diurnal SET measurements taken through hi-hourly tidal cycles with tidal stage. 26

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Tide Gauge. Figure 6. Map showing location of study sites in relation to NOAA tidal gauges. 27

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Statistics. The raw SET data were not normally distributed, hence parametric statistics could not be employed. Therefore, non-parametric statistics were used. The median, rather than the mean, elevation at each site for each sampling period was used in this analysis. Kruskal Wallis tests, a non-parametric version of a one-way ANOV A, were applied to the raw SET data to compare differences between sampling events within the same site Kruskal Wallis compares the medians of different ''populations", and if two or more are different, the null hypothesis of no differences is rejected (Sheskin, 1997; Davis, 1986). Data were grouped by season within each site, and intensive data were compared only within each intensive frequency interval. In addition, non-parametric correlation methods were performed. Spearman's Rank Correlations (after Davis, 1986) were used to analyze the likelihood of a relationship between two variables, namely the surface elevation measurements and other factors such as tidal stage, well level, barometric pressure, and wind speed. Least squares regression analyses were performed to compare 210Pb chronology and historical sedimentation rates Frequency of sampling. The sampling regime encompassed nine months (August/September to May) and involved sampling over various tidal lunar cycles and seasons. SET measurements for neap and spring tidal cycles were compared, as well as seasonal cycles to include daily weekly and monthly components. A core through the marker horizon was obtained at each site, and accretion above the marker was measured. To assess seasonal variations a cryogenic core encompassing the periods from October to February and February to May, was taken at each site. Sedimentation accumulated on sediment traps was measured monthly and seasonally (periods as above for the marker horizon). Sediment pins were measured monthly and 28

PAGE 41

seasonally as well as for the length of the study period at all three sites. Depth to water table and salinity of groundwater was measured in the on-site piezometers each time a SET measurement was completed at each site. 29

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Present Sedimentation Traps Due to design difficulties, (see Methods section), the first successfully recovered sediment traps were installed on December 1. Therefore, the initial trap data begin in early winter. Traps were planted and recovered at varying time intervals, yet no real seasonal pattern emerged from the trap data. Based on trap data, Mariposa Key showed the highest mean sedimentation rate, at 0.03g/cm2/month, with Little Manatee and Upper Tampa Bay averaging 0.024g/cm2/month (Table 1a). Percent organic content was lowest at Upper Tampa Bay, with a mean of27% organic matter, and highest at Little Manatee, with a mean of 51% organic content of sediment recovered. Compared to other coastal wetland research using sediment traps, sedimentation rates determined in this study are in the middle of the range observed elsewhere. In a study in Juncus marshes on the open coast in the Big Bend area ofFlorida, Leonard, et. al., (1995) recorded much higher sedimentation rates using sediment traps than was found in this study. However, their sites were located either adjacent to a creek levee, a direct source of nourishment, or 10m away from the creeks. There were no tidal creeks near any of the sites in this study. Conversely, Hutchinson, et. al., (1995) found much lower sedimentation rates than this study using traps deployed in a Spartina marsh located in South Carolina This lower rate may be related to seasonal differences or location within the tidal regime. 30

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Table 1a Table depicting sedimentation rates using traps. Note the close correspondence of mean values among sites. T. Sd" R rap e zmentatzon ates Upper Tampa Bay Little Manatee Mariposa Key Period Rate Period Rate Period Rate (g /cm2/mo.) (g/cm2/mo.) (g/cm2/mo.) 1211 to 2/2 0.03 12/ 1 to 2/2 0 02 1211 to 2 / 2 0.10? 12/22 to 5 /15 0.034 2 / 2 to 5 1 5 0.023 1211 to 515 0.05 12/2 2 to 3 / 3 0.015 2/2 to 515 0.016 12/ 20 to 2 / 2 0 015 2/2 to 3 /3 0.01 2 / 2 to 5/5 0.016 12/2 0 to 2 / 2 0.025 4 / 10 to 5 1 5 0.03 2 / 2 to 3/5 0.021 2 /2 to 4113 0.03 3/5 to 4 /13 0.02 2 / 2 to 3/5 0.021 4 /13 to 5 / 5 0 05 4113 to 5 1 5 0.04 MEAN : 0.024 marsh 0 .024 marsh 0.03 mangrove Table 1 b Table depicting sediment accumulation above marker horizon. Periods showing lower values than previous indicate removal of sediment as one horizon laid down in October at each site. Marker Hori zo n Sedimentation Rat es Upper Tampa Little Manatee Mariposa Key Bay Period Total, mm Mass* Total, mm Mass* Total, mm Mass* Rate/mo. Rate/mo Rate/mo. Oct. to Feb. 23mm NIA 14mm N I A 13mm NIA 4mos. 5.75mm 3.5mm 3.25mm Oct. to April 10mm 0.022 4mm 0.012 3mm 0.013 6mos. 1.67mm 0.67mm O.Smm Oct. to May 6mm 0.01 < 1mm N / A < lmm N I A 7 mos. 0.86mm N / A N I A _L. *Note: Mass rates calculated based on grams/em / mo. 3 1

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Marker Horizon The feldspar marker horizon was placed at all three locations in October. Due to difficulties with the cryogenic coring device, the first core was taken in February, four months later. Because the cyrogenic coring device does not provide any way to retain the sediment, mass nor organic content was not measured. The mean vertical sediment accumulation measured for all months above the horizon for Upper Tampa Bay was 5.75mm/mo; Little Manatee, 3.5mm/mo; and Mariposa Key, 3.25mm/mo during this four-month period. Total accumulation during this period was 23mm for Upper Tampa Bay, 14mm for Little Manatee, and 13mm for Mariposa Key (Table lb). Due to continued problems with the cryogenic coring device, clear plastic push cores were driven through the horizon and vertical accumulation measured for the latter portion (October to May) of the study period. In addition, accumulated sediment above the horizon was collected from these cores in order to measure mass accumulation and organic content. Plastic push cores were taken in April, six months after the marker horizon was placed. Upper Tampa Bay had accumulated I Omm of sediment above the horizon, with a mean of 1.67mm/mo; Little Manatee had accumulated 4mm, with a mean of0.67rnmlmo; and Mariposa Key had 3mm, with a mean of0.5mm/mo (Table lb). Mass per area was also calculated, giving 0.022g/cm2/mo for Upper Tampa Bay with 18% organic matter; 0 012g/cm2/mo for Little Manatee with 39% organic matter; and 0.013g/cm2/mo with 32% organics for Mariposa Key. The non-organic matter was reworked mineral matter, likely originating mainly offshore. Final push cores were obtained in May, seven months after marker horizon application. Accumulation above the horizon for Upper Tampa Bay totaled 6mm, with a 32

PAGE 45

mean of 0.86mm/mo Little Manatee and Mariposa Key each showed accumulation of less than I mm, and accumulated sediment samples were unobtainable. Mass accumulation for Upper Tampa Bay was calculated at O.Olg/cm2/mo with 17% organic matter. Note that between the three coring events at each site, accumulated sediment above the horizon bad decreased, indicating erosion or removal of sediment from the wetland surface. Despite the discrepancy related to compaction between the two coring applications, it actually appeared to be minimal, because little compaction was observed in the push cores. Winter accumulation appeared to be much higher than that measured in other studies. Cahoon and Turner (1989), using an artificial marker horizon on a Spartina marsh in Mississippi, found accretion ranging from 0.2mm/mo or 1.6mm total for the period January through July and 6.9mm total or 1 15mm/mo for the interval June through December These values are consistent with the amount accumulated over the October to May interval in this study. Considering a 6-month interval of sediment accumulation using the marker horizon (October to April) values in this study would appear to range from 3 (Mariposa Key) to 1 Omm (Upper Tampa Bay) (Table 1 b). This is consistent with results found in a Maryland marsh over a six-month period ( 4-6mm) (Rooth and Stevenson, 2000) as well as by Cahoon and Lynch (1997) in a mangrove location in southwest Florida ( 4mm/6 months and 6mm/yr) Cahoon, et. al (1995) found a slightly lower accretion rate (2 2mm/6 months) in a St. Marks marsh, Big Bend of Florida. Even though differences occur based on mass calculations between the two sedimentation methods the sedimentation rates observed at Upper Tampa Bay are consistent between the two methods In addition, the general relationship of organic 33

PAGE 46

accumulation was constant between the methods at all three locations Greatest deposition occurred at all three sites during winter (October to February) This finding is most likely a result of winter cold front passage which in the absence of significant summer tropical storms, provide the most energy to the area. Whereas tidal water level is generally lower in winter, the increase in storm activity coupled with high winds and waves apparently compensates for the reduced duration of inundation. Although Hutchinson, et. al., (1995) and Leonard, et. al. (1995) found a summer-dominated sedimentation pattern, Leonard, et. al. (1995) did find increased accumulation during winter storm passage. In addition, winter storms are usually accompanied by light if any, rain ; thereby limiting erosion. Conversely summer storms involve heavy rains which likely correspond with erosive conditions Others have also found that winter storms can be a significant source of sediment accumulation for coastal marshes (e. g Reed, 1989) After winter erosion appeared to dominate in spring as evidenced by removal of previousl y accumulated sediment above the horizon. There were no individual meteorological events occurring during spring to explain the erosional process The removal of sediment from the surface is possibly related to one of three things. First peak detrital flow (litterfall) in mangroves (Dawes 1981) and wrack formation (litterfall) in salt marshes (Dawes, 1981) would likely have occurred in the fall or winter which would hav e been a source of the organic constituents of the sediment In a study c omparing litter production in mangroves in southwest Florida, peak litterfall was observed in September/ October ( Twilley et. al 1986 ). It is possible erosion was occurring all along-but enough litter was present in the winter to counteract the effects. 3 4

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In addition, it has been shown that salt marsh species can incorporate their dead plant .matter into the sediment substrate (Rooth and Stevenson, 2000). It is likely that by spring, the incorporation of the previous autumn detrital/litter fall would have already occurred, thereby removing a source of replenishment Second, the tide level started to rebound at all locations in spring from the winter low. It is possible that increased inundation associated with increased tidal levels served to remove winter storm-deposited material from the surface during ebbing conditions. Finally with the possible exception ofUpper Tampa Bay, the groundwater level began to increase in spring as well. Others have noted that increased groundwater flow has been linked to net export of sediments from coastal wetlands (Coultas, 1997). 35

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Historical Sedimentation Short Sediment Cores Sediment cores, ranging in length from 4lcm to 66cm were obtained at each site. The cores were sectioned, described, and sedimentological analyses performed (Appendix V) These results indicate highest levels of mud (silt+ clay) at the surface at all three sites generally decreasing with depth in these sandy cores. These values range from 29-37% mud content at the surface to 5% at the base (Figures 7a-7c) Mariposa Key the mangrove location, contained the highest percentage of fine-grained sediment throughout the core. Consistent with the accumulated sedimentation data, surficial organic content was highest at Little Manatee (50%) followed by Mariposa Key (46%), and Upper Tampa Bay (19%). Organic content generally decreased with depth. However, the Upper Tampa Bay core contained an organic spike of28% (highest in the entire core) at approximately 18cm depth, and Little Manatee contained an organic reduction within a distinct sandy layer from 38 to 44cm depth, with a sharp boundary at the 44cm mark. Both Mariposa Key and Upper Tampa Bay cores decrease in organic content near the base to 5% or less but this did not occur in the Little Manatee core Based on cored versus recovered sediment thickness core compaction was determined to be 22% in Upper Tampa Bay, 30% in Little Manat ee and 32% in t he Mariposa Key core. Data shown in figures 5a-5c are not corrected for compaction. 36

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The low percentage of organic content at the bottom of the Mariposa Key and Upper Tampa Bay cores suggests that the base of the wetland was reached These coastal wetlands originated on sandy substrates and likely formed due to a slow increase in sea level resulting in a tidal regime sufficient to support wetland plants. The base of the Little Manatee wetland was not as indicated by the high level of organic content throughout the core. The organic spike found in the Upper Tampa Bay core suggests either a period of higher productivity or organic matter that is rapidly deposited ; and therefore, reduced decomposition. It is possible that the location of the site within this community experienced a shift in vegetation composition to one that is more productive, such as mangrove Alternatively, and more likely based on the Lead-210 analysis which follows this area experienced a period of rapid sedimentation after this organic laye r was produced and allowed for more preservation of the organic matter. The sandwiched sandy layer observed in the Little Manatee core is interpreted as a storm deposit This is indicated by the gradual boundary above, and the sharp boundary below this deposit 37

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w 00 '0 0 .. ,' 1111 : 0 tL ilu. .. ., I''":" tfft f. ,.,, '## .' : , II# ., ''tot" _,, .... ... :.If( 0 j o '<. o I o I 1 lo o ;.1 Upper Tampa Bay Core em Organic Content Mud Content Deoth em 0 I I I I 0 to 3 5 I I I I 3 to 10 10 I I I. I 10 to 13 15 I I I I 13 to 20 20 20 to 41 25 Descriotion 10YR 2/1, black highly organic, large and fine root material 10YR 4/3 brown sandy patches In 10YR 3 / 2 very dk g ray brown organic base; very fibrous w ith fine root materlal dark organic stained band of 10YR 3/1 very dk gray, very fibrous with root material lighter In color 10YR 4/2 dk gray brown sandy organic mix with small plant root matter sandy pale brown base 1 OYR 6 / 3 w ith 50% organic mottling of very dk g ray 10YR 3/1; Infrequent root m a tter I 30 le le 35 Key to Symbols I I HH I r--1 Sand Organic Root matter material 40 I I I I I I I I I I I I I -1 45 0 % Organic 60 0 % Mud 60 50 Figure 7a. Figure depicting U pper Tampa Bay core, showing schematic of organic content, mud content and description with depth.

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lN '-0 Sketch ## 1#1 ,K-## # # ## ,K-Ill ## ,K-1#1 ## # ;K. ## Ill ,K 1#1 ## ## ## II# /< il# Hi ## /<#1 /< 1#1 #I II# em Little Manatee River Core Organic Content Mud Content 0 5 10 15 20 25 30 35 40 45 50 55 60 65 I I I I I I I I I I I I I I 0 % Organi c 60 o % Mud 60 Depth. em Descrjptjon 0 to 23 monotone dk brown 1 OYR 2 / 1 ( black) very f ibrous organic peat; high water content and heavy root matter 23 to 36 s lightly lighter 1 OYR 2/2 very dk brown; still fibrous and highly organic by sl ightly less OM, less root matter, high water content 36 to 44 d istin ct sandy layer 1 OYR 5/3 brown w / dk red gray mottling 2 5 YR 3/1 very root matter; sharp boundary at 44cm 44 to 50 > 70% organic very dk brown 1 OYR 2/2 with sandy patches 2.5YR 3/1 dk red gray with fine root matter 50 to 65 -homogenous, black 1 OYR 2/1 w/ h igh water content and very fine-gra ined organic matter and root materi al Key to Symbols 0!_0 [LJ F igure 7b. Figure depicting Little Manatee core, showing Sand Organi c Root matter materi a l schematic of organic content, mud content, and description with depth.

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0 I# ## 1#1 I# x ' .. #II ,. em #II ## I# #II 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Mariposa Key Core Organic Content Mud Content Depth. em Description 0 to 3 reddish black 2 .5YR 2 5 / 1 rich and h igh organi c content, very fibrous 3 to 26 very dk g ray 10YR 3/1, still fibrous large plant roots 26 to 49 s lightl y lighter 1 OYR 3 / 2 sandy/ s ilty texture w/ high organic matter and fibers 49 to 66 o rganic sandy dk gray brown layer 10YR 3 / 2 w/ patches of light gray 10YR 7 / 1 and light root matter Key to Symbols ifiiil# I I I I I I I I 1 1 1 1 1 I Sand Organ i c Root o %Organic 60 o %Mud 60 matter mater i al Figure 7c. Figure depicting Mariposa Key core, showing schematic of organic matter mud content and description with depth

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Radiometric Dating (Lead-210) Sedimentation rates based on Lead-210 analyses on cores collected from each site are summarized in Tables 2a-2c. Little Manatee and Mariposa Key showed fairly consistent sedimentation rates over the past 150 years. Mariposa averaged 0 15 cm/yr, with a range of 0.11-0.24 ern/yr. For the last 30 years, sedimentation has accumulated at 0.13 em/yr. Mean sedimentation rate for Little Manatee for the past 150 years was 0.16 cm/yr, with a range of 0.08-0.25 em/yr. Sedimentation has averaged 0.19 cm/yr for the past 30 years. Upper Tampa Bay showed a higher sedimentation rate overall with more variability. Upper Tampa Bay sedimentation showed a high peak for approximately a one year period in 1925 at 2 em/yr. Excluding this outlier value, sedimentation averaged 0.20 cm/yr for the past 100 years, with a range of0. 07-0.40 em/yr. Over the last thirty years sedimentation has slowed to 0.07 cm/yr at Upper Tampa Bay (Tables 2a-2c), (Appendix VI). Historical and projected future sedimentation rates were calculated using 210Pb chronology, anchored with 137Cs (Figures 8a-8c) lnitial210Pb rates were established by anchoring the date of 137Cs maxima values at approximately 1965 (James Budahn, personal communication). This 210Pb rate is then assumed to be constant throughout the core, requiring fairly constant atmospheric deposition of210pb. Further assumptions important to the accuracy of this method include that the deposited 210Pb is retained within the wetland sediments and that the system is closed with respect to the introduction of"new" 210Pb, such as could occur with the introduction of eroding sediments from elsewhere. In addition, 210Pb and 137Cs are presumed to not have been significantly disturbed within the sediment column by bioturbation or migration (Bricker-41

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Urso et. al ., 1989 ; Cundy and Croudace, 1995) The closed system and migration re q uirements may have been vio l ated to some d egree in this case There is some indication via 137Cs distributions that some migration did occur because values surrounding the peak are slightly higher than expected In addition, discrepancies between R.adium-226 and Lead-214/Bismuth-214 suggest a 'recent" introduction of Uranium into the system (Budahn, personal communication). As such, there are some questions about the validity of the historica l se d imentation results, but some reassurance is provided in the general agreement between the results at each site. Table 2a. Lead-210 analysis for Upper Tampa Bay core showing sedimentation rates for past 130 years Deposition span represents the interval during which the entire 2cm of each slice accumulated, while the year represents the average age or midpoint of the whole 2cm sample. Note high value around 7 5 years ago Error ranges from 3% near top of the core to 15% at the bottom. Analysis performed by Jim Budahn, USGS, Denver, co D epth, e m r, .... ;. t' ,, .t'"' 1 0 069 5 .. .. ,.,:. 5.5 0 364 ..... 0 133 13 2 00 .. 15: 7.5 0 267 17 27 0 074 19 '30 0 067 42

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Table 2b. Lead-210 analysis for Little Manatee core showing sedimentation rates for past 150+ years. Deposition span represents the interval during which the entire 2cm of each slice accumulated, while the year represents the average age or midpoint of the whole 2cm sample Error ranges from 2% near the top of the core to 28% at the very bottom. Analysis performed by Jim Budahn, USGS, Denver, CO. em ... cm.Jyr 1 0 222 3 'o :ni 5 0.229 7 .. ,.' '0 .222. 9 0 125 11\' 13 0 250 15 17 "' .i9 .. Table 2c. Lead 210 analysis for Mariposa Key core showing sedimentation rates for past 150+ years Deposition span represents the interval during which the entire 2cm of each slice accumulated, while the year represents the average age or midpoint of the whole 2cm sample. Error ranges from 3% near the top of the core to 6% near the bottom. Analysis performed by Jim Budahn, USGS, Denver, CO. 1 3 5 10 0.200 7 : 9 15 0 133 11 13 15 1-5 17 19 43

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0 4 E 8 (,) .c a Cl) 0 12 16 0 + 0 Upper Tampa Bay Radiometric Profile + Unsupported Lead-210, dpm/g 2 4 6 R2 = 0 .93 + 0 2 0 4 0 6 Cesium-137, dpm/g 8 Cesium peak 0 8 Figure 8a. Excess or unsupported Lead-21 0 activity (red) and Cesium-13 7 activity (green) versus depth for Upper Tampa Bay core. Lead-21 0 activity is fit with a linear regression. Cesium peak is shown at approximately year 1965 and serves as the base for anchoring Lead-21 0 dates (Jim Budahn USGS) 44

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0 0 4 E 8 u .c -c.. Q) c 12 16 0 Little Manatee Radiometric Profile + Unsupported Lead-210, dpm/g 4 8 12 R2 = 0.84 + 0.2 0.4 0.6 0.8 Cesium-137, dpm/g 16 ... Cesium peak 1 Figure 8b. Excess or unsupported Lead-210 activity (red) and Cesium-137 activity (green) versus depth for Little Manatee core. Lead-21 0 activity is fit with a linear regression. Cesium peak is shown at approximately year 1965 and serves as the base for anchoring Lead-21 0 dates (Jim Budahn, USGS) 45

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0 0 4 E 8 (,) i .!1 12 16 + 0 0.1 Mariposa Key Radiometric Profile + Unsupported Lead 210, dprnlg 2 4 6 + R2 = 0 .87 0 2 0 3 0.4 Cesium-137, dprnlg 8 Cesium peak 0.5 Figure 8c. Excess or W1Supported Lead-210 activity (red) and Cesium-137 activity (green) versus depth for Mariposa Key core Lead-21 0 activity is fit with a linear regression Cesium peak is shown at approximately year 1965 and serves as the base for anchoring Lead-210 dates (Jim Budahn USGS) 46

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Mean sedimentation rates calculated using 210pb and 137Cs chronology indicate values ranging from 0.15 to 0.20 cm/yr for the three sites over the past 100 years. Average sedimentation rates at Little Manatee and Mariposa Key over the past 1 00 years match closely (0.15 +/-O.lcm/yr); however, the variations through time do not seem to correspond, with the exception of a minor increase in the 1960s at both sites (Table 2b, 2c). This increase is also seen in Upper Tampa Bay (Table 2a). Widespread development was beginning in the area about this time, and this sedimentation increase may be the result of inland erosion related to land-clearing, or bay and river dredging associated with boat traffic. Despite this observation, the lack of significant impact from major development on sedimentation rates over the past 100 years, especially at Little Manatee and Mariposa Key, indicates that human activity has had little effect on sedimentation rates in the area. Overall, sedimentation rates at Upper Tampa Bay are higher and more variable than the other two sites. This observation may reflect the location of this site as more inland, connected to a greater degree to land processes; and therefore, influenced to a greater degree by land disturbances in the form of clearing for development and agriculture. One final interesting result is the large peak in sedimentation rates for approximately one year around 1925 at Upper Tampa Bay (Table 2a). Three major hurricanes passed through the area around that time-a direct Tampa strike in 1921 with a storm surge of 10.5ft, and two others in 1926 and 1928, which initially struck south Florida, but moved across the peninsula near Tampa maintaining significant energy (Williams and Duedall 1997). It is highly likely that this high rate of sedimentation at Upper Tampa Bay is a result of one of these hurricanes. Although no evidence was observed in the sedimentation rates at the 47

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other sites during the same time period, the effects at Upper Tampa Bay would have been intensified due to its position at the restricted upper portion of a bay within Tampa Bay. This intensification at upper bay locations occurs as a result of focusing effects of energy within the bay In addition, similar evidence at the other two sites may have been distorted by bioturbation. Studies conducted by De Laune, et. al. ( 1989) in Louisiana coastal wetlands using 210Pb indicate rates ranging from 0.40 to 0.60 cm/yr mainly inorganic sediments over the past forty years. Despite the submergence problem associated with subsiding Louisiana wetlands, that region would be expected to have a greater sedimentation rate than Tampa Bay, because the Mississippi River and its distributaries transport a large amount of sediment 210Pb analyses conducted in Rhode Island salt marshes indicate accretion rates of approximately 0.25 cm/yr in the high marsh area studied for the past 80 years (Bricker Urso et. al., 1989), which is slightly higher than found in this study. Radiometric analyses in the form of210Pb and 137Cs chronologies express sedimentation rates ranging from 0.27 cm/yr (Florida Keys) to 0 62 crn/yr (Texas) in four coastal wetlands distributed around the Gulf of Mexico (Callaway et. al. 1997). These values are much higher than rate s calculated in this study ; however other than the lower end range found in the Florida Keys, the sediments were mainly inorganic and the sites in Texas and Mississippi are located in higher sediment input areas than Tampa Bay Rivers draining into e s tuaries on the Florida peninsula contain little sediment when compared to higher discharge areas in the western Gulf of Mexico 48

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Surface Elevation SET--Intensive Surface Elevation Data Intensive surface elevation data were collected at the Upper Tampa Bay location to investigate marsh surface elevation changes on time scales ranging from hours to days. Four intensive cycles were monitored to include two daily neap to spring lunar cycles, and one neap and one spring tidal cycle, involving hi-hourly measurements. Spring cycle Surface elevations were collected every two hours through the daylight portion of a spring tidal cycle in November. The maximum surface elevation change during this cycle was 0.6cm. The maximum tidal range was 46cm, and the water table elevation fluctuated 53cm during the cycle. Although no statistical correlations were indicated (Table 3), low tide was encountered around 1:30pm, when the surface elevation showed the lowest level, and the groundwater level was also the lowest of the study interval (Figure 9a). In addition, Kruskal Wallis statistical tests showed no significant surface elevation differences between measurements during this cycle (Table 4). Neap cycle. Surface elevations were collected every two hours through the daylight portion of a neap tidal cycle in March. Changes were very slight during this cycle (Figure 9b ). Maximum surface elevation change was 0.3cm. The maximum tidal change was 20cm, and groundwater fluctuated by only 4cm during the tidal cycle. Note that the NOAA tidal gauge was inoperable during this data collection, so an in-situ tidal monitor was used. Again, no statistical correlations were found between surface elevation and 49

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tidal level, groundwater level, barometric pressure nor wind speed (Table 3) Kruskal Wallis statistical tests indicated no significant difference in surface elevations between measurements during this cycle (Table 4) As mentioned above very little change occurred during this cycle in any of the measured parameters. Table 3 Statistical correlation results using non-parametric Spearman's Rank correlation test Variables tested included SET vs. Tide, Groundwater, Wind Speed, Barometric Pressure, and Wind Direction. Significance tested at 95% confidence level. Statistical Correlations Sampling Interval Site Significant Relation Monthly Upper Tampa Bay SET vs Groundwater Negative Monthly Little Manatee SET vs. Groundwater Positive Monthly Mariposa Key SET vs. Groundwater Negative Bihourly Spring Upper Tampa Bay None Daily Neap to Spring Upper Tampa Bay None December Bihourly Neap Upper Tampa Bay None Daily Neap to Spring-Upper Tampa Bay None Ma In comparing the neap versus spring cycles it must be noted that these were monitored during different seasons; therefore seasonal effects may be incorporated. In general, during the neap cycle the surface elevation was slightly elevated compared to spring. In addition, the groundwater level was much lower during the neap cycle Neap tide is associated with minimum tidal range--lower high tide and higher low tide--because the sun and moon are out of phase thereby weakening the effective gravitational pull of both Conversely spring tide is associated with maximum tidal range--highest high tide and lowest low tide--when the sun and moon are in phase 50

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E 29 5 0 c 2 9 "' :c 28 5 -r----------'-'-"'-><--"="<-'-'<-L-----,--=---------------------+ Q) .... Q) UJ 2 7 5 -t----'----="""-........ __ ---j 9: 4 0am 11/11/00 11: 25am 11/11/00 1 : 30p m 11/11100 Time 3 : 30pm 11/111 00 5 : 30pm 11111/00 1 000 0 500 E a; > 0 00 0 Q) ...J ... Q) .... -0 500 "' 1 000 Figure 9a. Bi-hourly measurements taken during November spring tidal cycle at Upper Tampa Bay. Axis on left, calibrated with mean sea level, represents the median in em, of all32 SET measurements taken each sampling Axis on right represents level of both tide (from NOAA tide gauge) and groundwater (from in-situ well) in meters 30 0 600 0 500 29 5 0.4 0 0 E 0.300 E 0 29 c 0.200 a; .!!! 0 100 > "C 28 5 Q) Q) _. 0 000 ... Q) 1--0 100 .... 28 "' w UJ -0. 200 27 5 -0 300 ----0.400 27 -0 500 10:20 am 12 : 20 p m 2 : 15pm 4 : 15pm 3/3/01 3/3/01 Time 3/3/01 3/3/01 Figure 9b. Bi-hourly measurements taken during March neap tidal cycle at Upper Tampa Bay Axis on left ca l ibrated with mean sea level represents the median of all 32 SET measurements in em, taken each sampling Axis on right represents l evel of both tide (in situ gauge) and groundwater (from in-situ well) in meters. Note that tide level was measured with in situ gauge as NOAA gauge previously u sed was inoperable. 5 1

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Table 4. Kruskal Wallis statistical results, testing for significant differences between surface elevations within each site. Significances tested at the 95% confidence level within each interval. Kruskal Wallis Tests Interval UTB LMR MK Fall No difference No difference No difference Winter Difference Difference No difference Spring No difference Difference No difference Total Period No difference Difference Difference Daily Neap to Spring-Dec. No difference Bihourly Spring No difference Bihourly Neap No difference Daily Neap to Spring May No difference enabling maximum gravitational pull. Accordingly, in comparing the two cycles over a daily tidal range, the surface elevation change observed was greater during the spring bihourly measurements than during the neap. Tide level and groundwater level also showed the greatest range during spring versus neap, and it is assumed that the surface elevation changes reflect the fluctuation of tide and groundwater, although seasonal effects could have played a role as well. Although not found to be statistically significant, the scale of change observed over a day during the spring cycle was on the order of 6mm-the amount of fluctuation that might be expected in this type of low energy setting on a seasonal or semi-annual scale. Daily neap to spring-December Measurements were collected daily from the start ofthe neap lunar cycle to the beginning of the spring lunar cycle. Measurements were collected consistently during low tidal conditions. Maximum surface elevation change during this interval was 0.4cm, with tidal level variation (under low tide conditions) of 84cm, and groundwater fluctuation of 11 em (Figure 1 Oa). No statistical relationships were found among surface elevation and other variables (Table 3). This relationship is 52

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visually apparent as well Kruskal Wallis statistical tests revealed no significant differences between surface elevation measurements during this sampling interval (Table 4). Daily neap to spring-May. Measurements were collected as described above for the similar interval in December. Maximum surface elevation change was measured at O .lcm. Maximum recorded tidal change (under low tide conditions) during sampling was 2lcm, and groundwater fluctuated by 43cm (Figure lOb). Although groundwater fluctuation was very little change was observed in surface elevation and tidal level. no statistical correlations were found {Table 3). Kruskal Wallis tests revealed no significant differences between surface elevation measurements during this sampling interval {Table 4). In comparing the two neap to spring cycles there was less apparent change in the May interval than the December interval. In addition, surface elevation was higher during the December interval than May, which is consistent with the monthly SET data. Again, the results ofKruskal Wallis tests indicate no significant difference within each cycle, but the scale of change was on the orderofO.lcm (May) and 0 .4cm (December) W.inter was found to be the more variable and dynamic season based on the monthly data-thereby this finding is consistent with that pattern. The scale of change during the December interval might be consistent with change on a seasonal or semi-annual scale in this type of low energy environment It should be noted that in some of the previous intensive cycles the measurements indicate groundwater level fluctuated more than tidal level. Clearly this is not an expected result. This observation is likely a manifestation of timing errors involved in 53

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the sampling. First there is a time lag in groundwater fluctuation following tidal fluctuation. For instance, the full tidal range was probably not captured on the hi-hourly cycles, yet the peak in groundwater fluctuation was captured due to the lag. Second, most of the tidal levels are not obtained in-situ, but from NOAA tidal gauges a distance away, and there is an inherent timing uncertainty associated with this process 54

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3 0 E 2 9.5 u c 2 9 Ia :g 28.5 :::!iE t28 w UJ 27 5 27 ............_ .......... u-------t...t-12/1 8 / 00 12/ 1 9/00 ::::::-...... -------.....___ -,o'" ,_. _""J.. 12/20 /00 12/21/0 0 Date ...... S E T Median ..Ac --......... -It-r---:. Well Level 12/2 2/00 12/2 3 / 00 0 8 0 6 E 0 .4 a; 0.2 > 0 0 ... -0 2 .s Ia 0 .4 3: 0 6 0 8 F i gure 1 Oa. D aily measurements take n over December n e ap to s p ring l u nar cycle a t U pper Tamp a Bay. Left axis, cal ibrate d wit h mean sea l evel, represen t s t he median of32 SET m easuremen t s in e m taken each samp l ing. The axis o n the right represents the level ofboth t ide (NOAA gauge) an d groun d water (in situ well) in meters. 3 0 29. 5 E u 29 c Ia :c 2 8. 5 Cll :::!iE t28 w UJ 27. 5 27 T i de Level** ___. :==--::: Median W e ll Level .. --1 0 :2 0 a m 12:20p m 2 :15p m 3/3/0 1 3/3/01 T ime 3/3/01 4 :15p m 3/3/0 1 0 6 0 0 0 5 0 0 0.400 0.300 E 0.20 0 a; 0 100 > Cll ...J 0 .000 ... Cll -0 .100 Ia -0 .200 3: 0 .300 -0.400 -0 .500 Figure 1 Ob. Daily measureme n ts taken over May neap to spr ing lunar cycle at Upper Tampa B ay Le ft axis, cal ibrate d wi t h mean sea level represents t h e m edian of32 SET measurements in em t ake n each sampling. T h e axis on the right represents the leve l of both t i d e (N9AA gau ge) an d groundwate r (in situ well) in meters. 55

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SET--Monthly Surface Elevation Data Monthly surface elevation measurements, along with groundwater and tidal level, were collected during low tide conditions at all three sites from late August through May. It should be emphasized, as with the daily neap to spring cycles, conducting sampling during "exact" low tide was not feasible; therefore, measurements were taken within an hour or so of low tide for any given sampling. During the nine-month interval, the general pattern of surface elevational changes corresponded well at all three locations (Figures 11 a-ll c). In general, surface elevation was low during late summer and fall, increased during the winter season, especially at Little Manatee and Mariposa Key, and began to decrease in spring All three sites showed a surface elevation increase during the late September sampling, which corresponds to the lowest barometric pressure during and in the days preceding the sampling, of the study interval. A large peak in elevation at Little Manatee and Mariposa Key, and a small peak at Upper Tampa Bay were observed on December 1 Statistical correlations were performed comparing surface elevation with other variables, including tide level groundwater level, barometric pressure, wind speed, and wind direction. The only significant statistical correlation found occurred between surface elevation and groundwater level at all three sites (Table 3). A more detailed explanation of the significance of this correlation will be addressed in Chapter 8 Subsurface Patterns. 56

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30 0 8 29.5 SET Median 0 6 0 4 E 29 u r: E 0 2 Qj Cll :s 28. 5 Cll > 0 0 Cll ..1 ::i ...... w 28 (/) Tide Level .. Cll 0 2 .. Cll 3: 27. 5 Welllevel -0.4 -0 6 27 -0 8 8 /26/00 9 /25/00 10/23/00 12/1 /00 12/21/00 2 /2/01 3 / 3 /01 4 / 11 /01 5 /18/01 Date Figure 11a Monthly measurements at Upper Tampa Bay. Values plotted on left axis are SET medians in em, of all32 measurements taken each sampling. The axis on the right represents the level ofboth tide (NOAA gauge) and groundwater (in-situ wt:ll) in meters. Surveying conducted by USGS determined the elevation of the top of the SET platform at 68.16cm above mean sea level ; measurements are therefore reported with respe c t to mean sea level. Well Level 12 5 -0. 9 9/1/00 9/24/00 10/22/00 12/1/00 12/20/00 2/2/0 1 3/5/01 4/13/01 5/5/01 Date Figure 11 b. Monthly measurements taken at Little Manatee Values plotted on left axis are SET medians in em, of all 32 measurements taken each sampling. The axis on the right represents the level ofboth tide (NOAA gauge) and groundwater (in-situ well) in meters Surveying conducted by USGS determined the top of the SET platform at 53.34cm above mean sea level; measurements are therefore reported with respect to mean sea level. 57

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Date 9/1 /00 9/24/00 10/22 /00 12/1 /00 12/20/00 2/2/01 3/5/01 4/13/01 5/5/01 52 0 9 0 7 52. 5 0 5 E (,) 53 c "' :s 53. 5 Q) :iE 154 w en 0 3 E a; 0 1 > Q) ...J -0.1 ... .e -0 3 "' -0 5 54. 5 -0 7 Well Level 55 -0 9 Figure 11c. Monthly measurements taken at Mariposa Key. Values plotted on left axis are SET medians, in em, of all32 measurements taken each sampling. The axis on the right represents the level of both tide (NOAA gauge) and groundwater (in-situ well) in meters. Note that since this site was not surveyed relative to mean sea level SET axis has been inverted to visually represent surface elevation. Upper Tampa Bay monthly surface elevation Maximum change in surface elevation during the study period at Upper Tampa Bay was 1cm. The maximum elevation was recorded on 12/1100 and the lowest was during the late August sampling. As mentioned previously, all monthly measurements were taken during low tide conditions; however, there is some error involved and sampling was not always conducted at the exact lowest tide level. Maximum tidal change recorded (variation in low tide conditions) was 59cm, with a minimum occurring in December and a maximum in August. Maximum groundwater table fluctuation during the interval was 1 OOcm, with a low in May and high in August (Figure 11 a). An inverse relationship between groundwater and surface elevation was found at this location (Table 3). Kruskal Wallis tests were performed to test for significant differences in surface elevations within each season. These results 58

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indicate no difference within late summer/fall measurements, no difference within spring measurements but a significant difference within winter measurements (Table 4). In addition, Kruskal Wallis tests were performed to analyze the significance of change in swface elevation measurements taken at the final sampling in May, from the initial measurements taken in late August These results indicate no significant difference in swface elevation change over the study interval at Upper Tampa Bay (Table 4) Little Manatee River monthly surface elevation Maximum change in surface elevation during the study period at Little Manatee was 1.85cm. The maximum elevation was recorded on 12/1/00 and the minimum on 9/1100 Maximum tidal change recorded, again all in low tide conditions, was 64cm, with a minimum in December and maximum in October. Maximum recorded groundwater table fluctuation during the study period was 70cm, with a low in F ebruary and a high in October (Figure lib). A direct relationship was indicated between groundwater and surface elevation (Table 3). Kruskal Wallis tests indicate no significant surface elevation differences within late summer / fall, but s ignificant differences within both winter and spring seasons (Table 4). In addition, K.ruskal Wallis tests conducted on final swface elevation measurements compared to initial values suggest a significant change over the study interval in surface elevation at Little Manatee (Table 4). Mariposa K e y monthly surface elevation. Maximum change in s urface elevation during the study period at Mariposa Key was 1.5cm The maximum elevation was recorded on 12 /1100 and the minimum on 9 / 1 / 00 Maximum tidal change recorded in low tide conditions was 87cm, with the minimum in December and the maximum in October. Maximum recorded groundwater table fluctuation during the study period was 68cm, 5 9

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with a low in February, and high in September and October (Figure llc). An inverse relationship was found between groundwater and surface elevation (Table 3). Kruskal Wallis tests indicate no significant elevational differences within any season tested: late winter, nor spring (Table 4). However, Kruskal Wallis tests conducted on final surface elevation measurements compared to initial suggest a significant change over the study interval in surface elevation at Mariposa Key (Table 4). Sediment Pins Sediment pins were installed to a depth of 40-50cm at each site in the beginning of the study period to measure elevation changes in the upper sediment layers as a complement to the SET device. However, after the first sampling event, the pin at Mariposa Key unexplainably disappeared from the site. Therefore, there is no pin record at that site. Maximum variation in pin values at Upper Tampa Bay was less than lcm. Pin values correlated well with SET values for most of winter and spring; however, during the fall period uppermost and lower subsurface columns appeared to be moving in opposite directions (Figure 12a) Maximum variation in pin values at Little Manatee was 1 em and did not correspond well with SET values, especially during the fall season (Figure 12b). Sediment pins that remained at Upper Tampa Bay and Little Manatee showed much less variation than surface elevation obtained via the SET device. When interpreting the sediment pin results, it must be remembered that it consists of just one measurement and is not taken as precisely so will be less reliable than the surface elevation table. In addition, the pins were inserted into the sediment surface to a depth of between 40-50cm. Biomass below the surface in Juncus species has been found to be concentrated in the 60

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upper 20 or so em (Good, et. al., 1982). It is assumed that changes in the pin elevation should relate more to changes in the upper layers of sediment (Cahoon and Lynch, 1997); and therefore most likely reflect changes in below-ground biomass 61

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30 45 29 5 45. 5 E 29 46 (..) E c (..) ns oi :c 28. 5 46.5 :::l Q) iii :E > f-c: w 28 47 0:: t/) 27. 5 47. 5 27 48 8/26/00 9/25/00 10/23/00 12/1100 12/21/00 2/2/01 3/3/01 4/11/01 5/18/01 Date Figure l2a. Monthly SET medians and Pin values plotted over time for Upper Tampa Bay. Values plotted on left axis are SET medians ofall32 measurements taken for each sampling, representing surface elevation. Values on right axis are distance from the top of the pin installed at the site; higher numbers indicate a more depressed surface. 15. 5 15 E 14. 5 (..) c: "C 14 Q) ::2 ..... w 13. 5 en 13 12. 5 ,...--------------------------,52 9 P i n Values 52 8 52 7 E (..) 52.6 oi :::l co 52 5 > c: a: 52.4 52 3 +---.----,---,.-------r---r------r-----.----r---+ 52 .2 9/1/00 10/22/00 12/20/00 3/5/01 5/5/01 Date Figure l2b. SET medians and Pin values plotted over time for Little Manatee. Values plotted on left axis are SET medians ofa1132 measurements taken for each sam pling representing surface elevation. Values on right axis are distance from the top of the pin installed at the site; higher numbers indicate a more depressed surface. 62

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SET and pin measurements did not correlate well at either site in the fall Beginning in December; however, the trends indicated by the two methods matched closely at Upper Tampa Bay and somewhat less at Little Manatee. Caution should be observed at making too many assumptions with a device ''floating" in the upper half-meter of the sediment, but this would imply that prior to winter, subsurface biomass production or decomposition processes were not much of a factor in net change and in spring and possibly winter, subsurface production/decomposition processes were more active. Monthly Swface Elevation Scale of Change Maximum seasonal surface elevation changes determined using the SET device occurred on the scale of 1-2cm, an amount of change greater than or equal to changes expected in the course of a year or two. A mangrove study conducted in southwest Florida using SET measurements bi-annually revealed surface elevation changes over a year in the range of0.1-0. 4cm, depending on location (Cahoon and Lynch, 1997). Spartina and Phragmit e s marshes studied in Maryland showed changes over a six-month period ranging from 0 .24-0.95cm (Rooth and Stevenson, 2000) Childers et. al. (1993) observed surface elevation changes in three Spartina marshes along the mid-Atlantic over the course of a year ranging from nearly zero to just over 1 em. Surface elevation measurements conducted in Juncus coastal wetlands located in North Carolina and Big Bend area of Florida revealed changes on the order of 0 14-0.32cm over a two year period (Cahoon, et. al., 1995). Studies performed by Florida Geological Survey (FGS) in the Big Bend area of Florida over a five-year period from 1995 to 2000 indicate surface elevat ion changes on the order of 0 1-0 7cm over the five years. These FGS sites selected to compare with this study include St. Marks National Wildlife Refuge, Aucilla River, 63

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and Ochlockonee River, as they are Juncus marshes located in settings comparable to this study (Raabe, personal communication), (Ladner et. al., 2000). Seasonal Pattern Results of this study indicate a net increase in surfuce elevation during winter The cycle begins in late summer/early fall with a sharp increase in early winter followed by a more gradual decrease into spring. This pattern is fairly consistent among all three sites In the study by Cahoon, et. al. (1995) reporting on measurements in Big Bend Juncus marshes, the authors report an elevation increase in summer, coupled with a decrease in winter. While this is true, a close inspection of their graphical representation reveals that the surface elevation actually starts to increase in early summer and peaks in late fall/early winter (Nov./Dec ), which could show some consistency with the results found in this study However, a true comparison is difficult because this study lacks summer measurements to assess the commencement of elevation increases. Conversely, Childers, et. al., (1993) found no consistent seasonal patterns in their study along the mid-Atlantic except for the year 1991 during which summer and fall values were lower and significantly different from the rest of the year The five-year study conducted by FGS in Florida's Big Bend indicated lower net surface elevations in winter or spring (Ladner, et. al. 2000) Differences Between Sites The greatest amount of elevation change was observed at the Little Manatee site followed by Mariposa Key. This pattern follows the trend ofboth in-situ organic content observed in the long cores, and the organic content observed in the accumulated sediment during this study period. Little Manatee consistently showed the highest organic content 64

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throughout the sediment core and in the observed sedimentation, followed by Mariposa Key, and finally Upper Tampa Bay. Other studies have indicated that the process of coastal wetland surface fluctuation is a function of organic content (Cahoon, et. al., 1995; Knott, et. al., 1987). Therefore, the greater potential for elevation change would be expected in the settings with higher organic content, as was observed in this study. Little Manatee salt marsh and Mariposa Key mangrove sites are located in different hydrologic settings, but in close proximity. The surface elevation and sedimentation patterns, both present and historical, correspond closely between these two sites despite the different vegetation present within these two communities This correspondence suggests a large-scale forcing mechanism, i.e., meteorological or hydrological, affecting elevation processes at these sites Further, this close correspondence would suggest that location or distance between wetland sites is more important in predicting response than vegetation type. The Kruskal Wallis tests employed for significance of total elevation changes at all three sites revealed that although significant differences were observed during the winter period in surface elevations at Upper Tampa Bay overall comparisons between initial and final measurements show no significant change (Table 4). This implies that Upper Tampa Bay is relatively stable in its elevation trend based on the limited amount of time observed during this study. These non-parametric ANOVA statistics also indicate that Little Manatee experienced more frequent significant elevation changes, within both winter and spring seasons, as well as between initial and final readings The difference in elevation between the beginning and end indicates an increase of approximately 1 em at Little Manatee Finally, while statistical tests indicated no significant elevation changes 65

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within any season at Mariposa Key there were differences between seasons, because initial and final measurements were significantly different (Table 4), also showing a net increase of approximately lcm. However, although net changes were observed at these two sites, it should be noted that this may be a part of an annual cycle The summer season in this region would potentially be more erosional due to the intensity of the precipitation with summer thunderstorms Without summer data to confirm the status of the surface through all the seasons an overall trend should not be inferred 66

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Subsurface Patterns Upper Tampa Bay From the period of October to February, net surface elevation increased by 0 4cm. At the same time, sediment accumulation measured 2.3cm. The discrepancy between the two values amounts to 1.9cm, indicating 1.9cm of subsidence. From the interval of February to April, net surface elevation remained the same, while sediment thickness above the marker horizon measured l.Ocm. This decrease of sediment compared to the prior indicates removal of 1.3cm sometime between February and April, and a corresponding 1.3cm of subsurface increase. From the period April to May, net surface elevation decreased by 0.3cm, while sediment accumulation measured 0 6cm, indicating removal of an additional 0.4cm between April and May. The discrepancy between surface elevation and sedimentation during this period amounts to 0 5cm, resulting in a O .lcm subsurface gain (Figure 13a) Little Manatee River During the period of October to February, Little Manatee experienced a net surface elevation gain of l.lcm, while sediment accumulation for the same period measured 1.4cm. The discrepancy between the two values amounts to 0 3cm, indicating 0.3cm of subsidence During the period ofFebruary to April, net surface elevation decreased by 0.3cm, while sediment thickness above the marker measured 0 4cm, indicating a removal of l.Ocm of sediment between February and April. The difference between surface 67

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elevation and sedimentation values indicates a subsurface gain of0.7cm. For the April to May interval, net surface elevation decreased by 0 1 em, while sediment thickness measured less than 0 1 em, indicating removal of an additional 0.3cm during this period. Subsurface expansion equates to 0 2cm to explain the divergence (Figure 13b). Mariposa Key During the period of October to February, the site located at Mariposa Key showed a net surface elevation gain of0.3cm, while sediment accumulation for the same period measured 1.3cm, a divergence ofl.Ocm in the form of subsidence between the two values For the February to April interval, net surface elevation decreased by 0.2cm, while sediment thickness above the marker measured 0.3cm, indicating a removal of 0 7cm of sediment from the surface between February and April These changes suggest a subsurface gain of0.8cm between February and April. Finally for the period April to May, a gain in net surface elevation of 0 2cm was recorded, while sediment thickness measured less than 0.1cm during this period indicating a removal of0. 2cm of sediment from April to May. These net values indicate a subsurface gain of0. 4cm between April and May (Figure 13c ) 68

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0\ '\0 Net elevation at end of period Net elevat i on at start of period Surface sed i ment gain or loss Subsurface gain or loss em 2 5 2 0 1 5 1 0 0 5 0 -0. 5 -1.0 -1. 5 -2.0 -1. 9 -2. 5 October to February T2 T1 +1. 3 -1. 3 S urfa ce Loss : 1 3 Subsurface Gain : 1 3 Net Elev Change : 0 0 February to April T2 T1 +0 1 T 1 -0 4 Surface Loss : 0 4 Subsurface Gain : 0 1 Net El ev Cha nge : -0 3 April to May T2 Fig ure 13a. Three-dimensional depiction of surface and s ubsurface processe s and relationship to change in net elevation at Upper Tampa Bay for October to May period. Black horizontal line indicates net elevation at start of period, yellow horizontal line indicates net elevation at end of that same period. Note that the "zero" position on the scale is arbitrary and is s et with respect to elevation measured in October. Surface gain or loss occurs as a result of sediment accumulation or erosio n and subsurface gain as swelli ng or biom ass production while subsurface l oss refers to co mpaction or subsidence.

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-.....) 0 Net elevation at end of period Net elevation at start of period Surface sediment gain or loss Subsurface gain or loss em 2.5 2 0 1 5 1 0 0.5 0 -0. 5 -1. 0 -1. 5 -2.0 2 5 +1.4 -0 3 Surface Gain : 1.4 Subsurface Loss: 0 .3 Net Elev Change: + 1 1 October to February T2 T1 +0 7 -1. 0 Surface Loss : 1 .0 Subsurface Gain: 0 7 Net Elev. Change: -0. February to April T1 T2 +0 2 -0 3 Surface Loss: 0 3 Subsurface Gain: 0 2 Net Elev Change: -0.1 April to May T1 T2 Figure 13b. Three dimensional depiction of surface and subsurface processes and relationship to changes in net elevation at Little Manatee for October to May period. Black horizontal line indicates net elevation at start of period, yellow horizontal line indicates net elevation at end of that same period. Note that the "zero" position on the scale is arbitrary and is set with respect to elevation measured in October. Surface gain or loss occurs as a result of sediment accumulation or erosion, and subsurface gain as swelling or biomass production while subsurface loss refers to compaction or subsidence.

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-.] Net elevation at end of period Net elevation at start o f period Surface sediment gain or loss Subsurface gain or loss em 2.5 2.0 1.5 1.0 0.5 0 -0 5 -1. 0 -1.5 -2.0 -2.5 +1.3 -1.0 Surface Gain: 1 3 Subsurface Loss : 1.0 Net Elev Change: +0 3 October to February T2 T1 +0. 8 -1.0 Surface Loss : 1 0 Subsurface Gain : 0 8 Net E l ev Change : -0 Feb ruary to April T1 T2 +0. 4 -0.2 Surface Loss: 0.2 Subsurface Gain : 0.4 Net E lev. Change : +0.2 April to May T2 T1 Figure 13c. Three dimensional depiction of surface and subsurface processes and relationship to change in net elevation at Mariposa Key for October to May period. Black horizontal line indicates net elevation at start of period y ellow horizontal line indicates net elevation at end of that same period Note that the "zero" position on the scale is arbitrary and is set with respect to elevation measured in October. Surface gain or l oss occurs as a result of sediment accumulation or erosion and subsurface gain as swelling or biomass production, while subsurface loss refers to compaction or subsidence.

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Relationship Between Surface Elevation and Sediment Accretion Although the SET measurements indicate that the highest surfuce elevations occurred during winter at all three locations in this study, when compared with the vertical accretion data for the same period to reveal subsurface change, winter actually coincides with the most subsidence or compaction. This is revealed when determining the difference in elevation changes and sedimentation received (Figures 13a-13c ). Conversely, although spring coincided with a decrease in elevation, when coupled with a lower sedimentation rate it actually equates to underground swelling or production. All three sites experienced subsidence coupled with sediment accretion over the winter interval (October to February), resulting in a net increase in elevation, and swelling or belowground accumulation coupled with erosion in spring (February to April and April to May), resulting in a net decrease in elevation (Figures 13a-13c) Removing the surface component from the elevation measurements reveals subsurface changes on the order of 0.3-1.9cm subsidence over a six-month period in these Tampa Bay coastal wetland sites. The mangrove site studied by Cahoon and Lynch, (1997) found much smaller fluctuations-a disparity between elevation and sedimentation of0.4-0.6cm in the form of subsidence over a period of one to two years Cahoon, et. al., (1995) found subsidence over a two year period of only 0 .4cm at their North Carolina Juncus location with the greatest subsidence in winter, and l.Ocm subsidence in the Big Bend location in Florida, with the greatest subsidence in spring. In Maryland salt marsh locations, 0.3cm subsidence and O.l-0.3cm below-ground accumulation was recorded for the same six-month period including winter and spring seasons depending on location (Rooth and Stevenson, 2000). Two of the three Juncus 72

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marsh locations monitored by Florida Geological Survey indicate subsidence in winter months of the years analyzed-1995, 1996 1997 The Aucilla River location showed subsidence in winter despite also being a time of relatively high sediment accumulation. Less subsidence was observed in spring, followed by positive elevation in summer. Data from St. Mark's National Wildlife Refuge did not indicate a definite pattern at the two stations analyzed other than winter was a time of subsidence. Ochlockonee station 2 was not considered because accretion data were not consistently measured during the year in question, but data from station 2 suggest opposite results: subsurface gain in winter and decrease in spring and summer (Ladner et. al. 2000). Comparing net elevation with sediment accretion for the same period to estimate subsurface elevation changes for this data set show a range of0.5-1.7cm subsurface fluctuation over a six-month period for these FGS Big Bend Juncus locations (Ladner et. al. 2000), (fable 5) Seasonal Pattern in Subsidence / Production As discussed above previously although maximum surface elevation coincided with winter this season also experienced maximum subsidence There are a few probable explanations for this seasonal subsidence, involving cold front passage decreased groundwater level, and subsurface biomass changes. First, several cold fronts passed through the area over the winter period and the after-effects ofthese fronts in the form of strong northwest winds and high waves were encountered during a few of the sampling events Others have noted that cold front or storm passage can cause compression of the substrate (Cahoon, et. al., 1995) Despite the fact that these systems are generally low pressure fronts, the highest barometric pressures during the study were encountered 73

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Table 5 Table comparing sedimentation and elevation change recorded in various studies. Other Results Study : Sedfmentation, ;:Time em .. . Etevatioq, ,, .it. '' ;r .. em ,j.-;,.-, Cahoon, et. al., 1995 0.89 FL -0.14 1.03 2 yrs Juncus (NC and FL) 0 .77NC 0.32 subsidence 0.45 2 yrs. subsidence Rooth and Stevenson 0.40 Phragmites 0.62 0.22 expansion 6mos. 2000 (MD) 0 .56 0 24 0.32 6mos. Spartina subsidence Childers et. al., 1993 No data 0-1 No data 1 yr Spartina (midAtlantic) Cahoon and Lynch, 0 60 0.37 0.23 2 5 1997 subsidence yrs Mangrove basin (FL) Leonard et. al ., 1995 1.2 tol.8 No data No data I yr. Juncu s (FL) Ladner et. al., 2000 0 15 to 0 98 -0.4 to -0.7 0.55 to 1.7 6mos. Juncus (FL) Au cilia subsidence -0.8 to 0 6 0.6 subsidence 5 mos. -0.2 to -0 3 to 0 9 St.Marks expansion This study 0 3 to 1.0 0.4 to 0 8 0 3 to 1.9 6mos. subsidence during the winter season It is also possible that the higher pressures may have caused compression of the substrate. Statistical correlations performed on total surface elevation change indicate an inverse relationship with the groundwater table level at Upper Tampa Bay and Mariposa Key. However as mentioned previously when the surface processes are removed from the total elevation to reveal only the subsurface component, the subsurface pattern is exactly opposite the total elevation pattern. This means when assessing the relationship 74

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between groundwater and the subsurface contribution to elevation, the opposite relationship from the correlation is implied. Therefore, the subsurface component of elevation at Upper Tampa Bay and Mariposa Key has a direct relationship with groundwater level. Conversely, the subsurfilce component of elevation at Little Manatee has an inverse relationship with groundwater level. This latter relationship does not coincide with the other two locations, most likely because of the vastly different hydrologic setting Groundwater within a site located on a river island would likely experience less tidal forcing of groundwater due to the riverine influence Maximum subsidence occurred at all three sites during October to February. This period corresponds to the largest decrease in and overall lowest sustained tide and groundwater levels and likely is the result of decreased subsurfilce water storage. This removal of water from the column may have resulted in a compressional effect because water previously held in pockets drained, reducing sediment volume Others have found similar surface elevation changes related to water storage. Cahoon and Lynch (1997) found that during the six-month interval they termed "low flood", referring to tidal regime, surfilce elevation decreased. Conversely, during the interval termed "high flood", surfilce elevation increased in the southwest Florida mangroves. An infiltration analysis performed in salt marshes of New England indicates the process of soil matrix compression due to loss of water from drainage or evapotransporation, and expansion upon infiltration (Hemond, et. al., 1984). Additionally, an investigation into salt marsh water storage mechanisms also conducted in New England revealed sediment "swelling" due to dilation with infiltration (Nuttle, et. al., 1990). One factor to take into consideration in these last two comparison is that New England wetlands tend to have 75

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higher organic matter than Florida, which could affect the degree of compression or dilation. In this study elevation collected from February to May shows a subsurface increase that could correspond to swelling due to a rebound in groundwater and tidal levels. Finally, there may be a subsurface biomass process that is associated with seasonal changes responsible for the observed subsurface elevation changes. It has been observed that above-ground and below-ground production respond differently to environmental parameters (Good, et. al, 1982). In a North Carolina study comparing above-and belowground biomass of sah marsh species, Bellis and Gaither (1985) found that below-ground biomass (mostly roots and rhizomes) was an order of magnitude greater than above in all cases, and that Juncus exhibited below-ground minimums in July and February, with peaks in October and April/May. It is possible that October to February in these Florida locations corresponds to a minimum biomass interval-or an interval of greatest decomposition. Conversely, spring may correspond to a peak in biomass, as suggested in the North Carolina study for April/May which would be consistent with the observations in this study. It is important to remember that correlations do not necessarily imply cause and effect, and that there may be a separate factor acting on both. Finally, both groundwater level and biomass may be coupled in subsurface effects. It is entirely possible that the period of minimum below-ground biomass corresponds to certain seasonal groundwater conditions and both act together to affect surface elevation in that respect. In any case, based on the observed groundwater fluctuation, the statistical correlation found between 76

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groundwater and elevation, and lack of significant biomass found in the cores, the groundwater-elevation connection is most likely. 77

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Future Projections and Conclusions Future Projections By taking the mean sedimentation rate over the past I 00-150 years, the projected sediment accumulation by the year 2100 can be calculated for the sites. Sediment accumulation by the year 2100 amounts to 15 (Mariposa Key) to 20 em (Upper Tampa Bay) These values are all less than the lowest projection of26cm of sea level rise for the Tampa Bay area by 2100, using EPA's normalized sea level projection calculator (Figure 14). Even if the current rate of sea level rise did not change from the present value of 2.3mm/yr at St Petersburg, FL, the accumulated 23cm of sea level rise by the year 2100 is still greater than the projected sedimentation rates for these coastal wetlands based on the past 100 years of accumulation. However, these calculations of past and future sedimentation ignore a major component in wetland sustainability-surface elevation Nine-month values of surface elevation collected at these sites indicate significant increases at Little Manatee and Mariposa Key of1cm---more than the measured sedimentation (of October to May) In addition, it is unclear what effect a certain plateau of sea level may have on sediment accumulation, subsidence, or subsurface production It is possible these surface and subsurface factors may vary with sea level rise. Other studies have indicated that increasing the duration of inundation ofthe wetland surface, to a point, leads to greater sediment deposition (Good et. al., 1982; Cahoon and Reed 1995) Finally, this study as well as others (Cahoon and Lynch, 1997 ; Hemond, et al ., 1984; Nuttle, et. al., 1990), indicates positive subsurface elevation change with increased 78

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water (groundwater/tide) level at Upper Tampa Bay and Mariposa Key. Therefore it is not possible to accurately predict the fate at this time ofthese coastal wetlands in a rising sea scenario More long-term surface elevation studies are needed to evaluate longer periods of surface elevation fluctuation, especially because results of this study suggest that shorter term fluctuations are smoothed in the longer period cu UTB LMR Predicted sediment accumulation MK Figure 14. Chart depicting predicted sediment accumulation for year 2100 at Upper Tampa Bay Little Manatee River and Maripo s a Key (based on past) compared with probable sea level rise for the same period. 79

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Conclusions 1) A full annual cycle was not monitored in this study; therefore, conclusions about dominant seasons for sedimentation can not be fully addressed. However, data collected from late summer through spring suggest winter as a critical period for sediment delivery and spring as an erosional period for the coastal wetlands in the area. 2) Although not statistically significant, total elevation changes observed on the order of a daily tidal cycle peaked at 6mm.. This amount of change has been observed in other studies over the course of six months (Rooth and Stevenson, 2000) to two years (Cahoon, et. al., 1995) Therefore, when taking regular surface elevation measurements over the long term in an attempt to extract a trend, measurements should be taken in a consistent manner with respect to daily tide. 3) Seasonal net surface elevation changes in this setting occurred on a scale of change greater than or equal to that which occurred over longer time periods-! to 2 5 years-in other studies (Cahoon, et. al., 1995; Rooth and Stevenson, 2000; Childers, et. al., 1993; Cahoon and Lynch, 1997; Ladner, 2000). These comparisons suggest either this setting is more dynamic, or that over longer periods, greater short term fluctuations are smoothed out. Given the low energy and low sediment input environment of these sites, the latter argument has a stronger case. 4) Consistent with sedimentation, total surface elevation measurements indicate an increased elevation in winter, followed by a gradual decrease in spring. Despite this observation, the sites also experienced the greatest subsidence in winter, followed by subsurface increase in spring. The pattern of subsidence and subsurface increase are 80

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most likely be related to seasonal changes in water storage in the form of dilation/compaction related to tidal forcing (as indicated by statistical correlation). 5) Despite the varied local settings of the three sites within Greater Tampa Bay--a southern open-bay mangrove a southern river mouth salt marsh and a northern restricted upper bay sah marsh---the general sedimentation and surface elevation patterns correspond well. Note that it is the proximity, not the classification of salt marsh or mangrove mangal, that appeared to correlate to similar response, as evidenced by the closer agreement between Little Manatee and Mariposa Key. This correspondence among all three sites signifies similar large-scale mechanisms operating on the sites possibly in the form of meteorological forcing mechanisms and/or seasonal water and biomass patterns 6) Historical sedimentation rates indicate little impact from human development over the long term in the past 100 years. Despite this positive finding, applying historical rates for the next 100 years indicates a rate less than the lowest end projected sea level rise for the region and subsequent wetland drowning However, it has been shown that sedimentation and surface elevation are not coupled Therefore caution should be observed in predicting the future sustainability of these coastal wetlands in relation to rising seas. Longer term surface elevation measurements are necessary to determine realistic trends. 7) The SET data collected for the nine-month period suggest an annual cyclical with increasing surface elevations in winter, and decreasing in summer Based on an observed fluctuation of 1-2 em in elevation during the study period, it is recommended that SET measurements be taken consistently and more frequently than 81

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quarterly or biannually as in previous studies. Clearly, anomalous weather conditions should be avoided, and data collection should be performed within a consistent tidal stage. The SET data collected in this study indicate a monthly minimum sampling interval to avoid bias and obtain measurements representative of long term surfuce elevational trends. 82

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References Bellis, V J. and AC. Gaither. 1985 ''Seasonality of Aboveground and Belowground Biomass for Six Salt Marsh Plant Species". The Journal of the Elisha Mitchell Scientific Society 101(2): 95-109 Boumans, R.M.J and J.W. Day, Jr. 1993. "High Precision Measurements of Sediment Elevation in a Shallow Coastal Area Using a Sedimentation-Erosion Table". Estuaries 16 (2) : 375-380. Bricker-Urso, S.; Nixon, S.W.; Cochran, J.K. ; Hirschberg, D.J. and C Hunt. 1989. "Accretion Rates and Sediment Accumulation in Rhode Island Salt Marshes ." Estuaries 12( 4): 300-317. Brower, J.E.; Zar, J. and C. von Ende. 1998 Field and Laboratory Methods for General Ecology, Fourth ed McGraw Hill: Boston. pp. Budahn, J.R. 2001. Personal communication. Employee ofUnited States Geological Survey, Denver CO Cahoon, D.R.; Reed, D.J. and J. Day Jr. 1995. ''Estimating Shallow Subsidence in Microtidal Salt Marshes of the Southeastern United States : Kaye and Barghoom Revisited". Marine Geology 128 : 1-9. Cahoon, D.R. and J.C. Lynch. 1997 'Vertical Accretion and Shallow Subsidence in a Mangrove Forest of Southwestern Florida, USA" Mangroves and Salt marshes 1: 173-186. Cahoon, D.R and D.J Reed. 1995. 'Relationships Among Marsh Surface Topography, Hydroperiod, and Soil Accretion in a Deteriorating Louisiana Salt Marsh" Journal ofCoastal Research 11: 357-369. Cahoon, D R. and R.E. Turner 1989 Accretion and Canal Impacts in a Rapidly Subsiding Wetland: Feldspar Marker Horizon Technique". Estuaries 12(4): 260-268. Callaway J.C.; DeLaune, R.D and W H. Patrick, Jr. 1997. ''Sediment Accretion Rates from Four Coastal Wetlands Along the Gulf ofMexico". Journal of Coastal Research 13(1): 181-191. 83

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Chabreck, RA 1988 Coastal Marshes. University of Minnesota Press: Minneapolis. pp. 138 Childers, D.L.; Sklar, F.; Drake, B. and T. Jordan. 1993. "Seasonal Measurements of Sediment Elevation in Three Mid-Atlantic Estuaries". Journal of Coastal Research 9(4): 986-1003. Coultas, C.L. 1997. "Soils", Chapter 3, in: Ecology and Management of Tidal Marshes : A Mode/from the Gulf of Mexico. St. Lucie Press: Delray Beach, FL pp. 355. Cundy, AB. and I.W. Croudace. 1995. "Sedimentary and Geochemical Variations in a Salt Marsh/Mud Flat Environment from the Mesotidal Hamble Estuary, Southern England". Marine Chemistry 51: 115-132. Davis, J C. 1973. Statistics and Data Analysis in Geology. John Wiley and Sons: New York. pp. 550. Davis, J.C. 1986. Statistics and Data Analysis in Geology. 200 ed John Wiley and Sons : New York. pp. 646 Davis, RA.; Hine, A.C., and D. Belknap, eds. 1985. Geology of the Barrier Island and Marsh-Dominated Coasts West-Central Florida. University of South Florida, Tampa, FL. pp. 119 Davis, RA 1982. "Coastal Morphodynamics of the Tampa Bay Area with Emphasis on the Barrier Island System", in : Proceedings : Tampa Bay Area Scientific Information Symposium Report No. 65 Florida Sea Grant College Dawes, C.J 1981. Marine Botany. John Wiley & Sons: New York. pp. 628. DeLaune, RD. ; Whitcomb, J.; Patrick, Jr., W H.; Pardue, J. and S R Pezeshki 1989. "Accretion and Canal Impacts in a Rapidly Subsiding Wetland: 137CS and 210PB Techniques". Estuaries 12 (4): 247-259. DeLaune RD.; Patrick, Jr., W.H .; and C.J. Smith. 1992. "Marsh Aggradation and Sediment Distribution along Rapidly Submerging Louisiana Gulf Coast". Environmental Geology and Water Sciences (20): 57-64. FMRI, Florida Marine Research Institute, Department of Environmental Protection. 1997. "Florida's Mangroves: Walking Trees" Public Information Brochure. French, P.W. ; Allen, J R.L and P G Appleby 1994. '"10Lead Dating ofModem Period Salt marsh Deposit from the Severn Estuary (Southwest Britain) and its Implications". Marine Geology 118 : 327-334. 84

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Frey, R. W and P.B. Basan. 1985. "Coastal Salt Marshes", Ch 4, in: Davis, R.A. (ed.) Coastal Sedimentary Environments. 2od ed. Springer-Verlag : New Y orlc pp. 716. Good, R.E. ; Good, N.F.; and B.R. Frasco 1982. A Review of Primary Production and Decomposition Dynamics of the Belowground Marsh Component", in: Estuarine Comparisons Academic Press: New York. pp. 709. Goodbred, Jr., S.L.; Wright, E.E. and A.C Hine 1998. ''Sea-Level Change and Storm Surge Deposition in a Late Holocene Florida Salt Marsh" Journal of Sedimentary Research 68(2): 240-252. Hemond, H.F. and J.L. Fifield. 1982 ''Subsurface Flow in Salt Marsh Peat: A Model and Field Study''. Limnological Oceanography 27(1): 126-136 Hemond, H.F.; Nuttle, W K.; Burke, R.; and Stolzenbach, K. 1984 ''Surface Infiltration in Salt Marshes: Theory, Measurement, and Biogeochemical Implications". Water Resources Research 20(5): 591-600. Hoffinan, J.S ; Keyes, D. and J Titus. 1983. ''Projecting Future Sea Level Rise : Methodology, Estimates to the Year 2100, and Research Needs" US EPA document 230-09-007, Office ofPolicy and Resource Management. pp. 121. Holmes, C.W. 1998 ''Short-Lived Isotopic Chronometers-A Means ofMeasuring Decadal Sedimentary Dynamics" United States Geological Survey Fact Sheet FS-073-98, Department oflnterior. Hutchinson, S E ; Sklar, F and C. Roberts 1995. Short-Term Sediment Dynamics in a Southeastern U.S.A Spartina Marsh". Journal of Coastal Research 11(2) : 370-380. Hutton, J G 1986. "Bedrock Control, Sedimentation and Holocene Evolution ofthe Marsh Archipelago Coast West-Central Florida". Masters Thesis, University of South Florida, St. Petersburg, FL. pp. 154. Kadlec H.H. and J A. Robbins 1984. Sedimentation and Sediment Accretion in Michigan Coastal Wetlands". Chemical Geology 44: 119-150 Knott, J.F.; Nuttle W.K.; and H.F. Hemond. 1987 "Hydrologic Parameters ofSalt Marsh Peat". Hydrological Processes 1 : 211-220. Ladner, J.; Hoenstine, R; Dabous, A.; Harrington, D.; and Cross B. 2000 Coastal Wetlands Study 2000: Tenth Annual Report to United States Geological Survey Unpublished data, Florida Geological Survey: Tallahassee. 85

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Leonard, L.A; Hine, AC. and M Luther 1995 ''Surficial Sediment Transport and Deposition Process in a Juncus roemerianus Marsh, West Central Florida". Journal ofCoastal Research 11(2): 322 -336. Letzsch, W.S. and R. W Frey. 1980 ''Deposition and Erosion in a Holocene Salt Marsh, Sapelo Island, Georgia" Journal of Sedimentary Petrology 50(2): 529-542 Lowe J J. and M J.C. Walker 1984 Reconstructing Quaternary Environments 200 ed Longman Group: Essex, England pp. 446 Nuttle, W.K.; Hemond, H F.; and Stol.zenbach, K. 1990. ''Mechanisms of Water Storage in Salt Marsh Sediments: The Importance ofDilation". Hydrological Process 4 : 1-13 Olssen, I.U 1986 "Radiometric Dating Ch. 14, in: Handbook of Holocene Paleoecology and Paleohydrology John Wiley and Sons Ltd. pp. 869. Osking E B. 1985. 'Sedimentation Controls and Resulting Geomorphology of Microtidal, Low Energy, Freshwater-Influenced ShelfEmbayments West-Central Florida". Masters' Thesis, University of South Florida, St. Petersburg FL. pp. 185. Penland, S and K.E. Ramsey. 1988. ''Relative Sea Level Rise in Louisiana and the Gulf ofMexico: 1908-1988 Journal ofCoastal Research 6 : 323-342. Pethick, J S. 1981. ''Long Term Accretion Rates on Tidal Salt Marshes". Journal of Sedimentary Petrology 51(2): 571-577 Provost, M W 1974. "Mean High Water Mark and Use of Tidelands in Florida". Florida Scientist 36: 50-66 Raabe E. 2000-2001. Personal communication regarding this study and its relation to FGS study conducted in Big Bend United States Geological Survey, Center for Coastal Geology St. Petersburg FL. Reed, D J 1989. "Patterns of Sediment Deposition in Subsiding Coastal Salt Marshes : The Role ofWinter Storms". Estuaries 12(4): 222 227. Reed, D J. and D.R. Cahoon. 1992. "The Relationship Between Marsh Surface Topography, Hydroperiod, and Growth of Spartina altemiflora in a Deteriorating Louisiana Salt Marsh. Journal of Coastal Res earch 8 : 77-87 Sheskin D.J. 1997. Handbook of Parametric and Non-Parametric Statistical Procedures. CRC Press : Boca Raton pp. 719 86

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Titus J.G. and V K. Narayanan. 1995. ''The Probability of Sea Level Rise". US EPA document 230-R-95 008, Office of Policy Planning and Evaluation. pp. 186. Twilley R ; Lugo, A and C Patterson-Zucca 1986 "Litter Production and Turnover in Basin Mangrove Forests in Southwest Florida". Ecology 67(3) : 670-683 Williams J. and I. Duedall. 1997 Florida Hurricanes and Tropical Storms. University Press ofFlorida: Tampa pp. 146. Wooten, G.R Jr. 1982. "The Meteorology of Tampa Bay", in: Proceedings : Tampa Bay Area Scientific Information Symposium. Report No. 65 Florida Sea Grant College. Wright E.E. 1995. ''Sedimentation and Stratigraphy of the Suwannee River Marsh Coastline". Dissertation, University of South Florida, St. Petersburg, FL. pp. 254. 87

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Appendices 88

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Appendix 1: Field Monitoring-SET Upper Tampa Bay (UTB), Site #1 Orientations measured: A, C G E Date: 8/26/00 7 :30am Pin# A c 2 38.9 3 40. 8 39.6 4 40.45 41.2 5 39.45 40.8 6 39.5 41.55 7 39.35 42.4 8 39. 2 41 9 39.85 41.8 10 41.25 G 38.9 39. 5 39.6 37.5 38.3 37 37.45 38. 15 E 39.1 39.7 41.5 39.35 40.45 41.7 40.7 38.8 Mean: 39. 6875 41.2 38.3 40. 1625 Median: Site Mean: 39. 8375 std dev. 1.3599099 sem 0 2404004 Date : 9 / 25/00 8 : 30am ern Pin# A c G E 2 38. 5 no data no data 39.2 3 40 40.2 39 40. 6 4 40.1 40.8 37.9 38.5 5 39 8 40.5 37 6 39.4 6 39 41 38 8 40.5 7 40.3 40 37 9 40 6 8 39.1 41.3 38 1 39 9 39 40 9 38.1 41.2 10 38 8 41.9 37 7 no data Mean: 39. 4 40. 825 38 1375 39. 875 Median: Site Mean: 39.559375 std dev. 1.1768844 sem 0.2080457 Date: 10/ 9 / 00 Sam em Pin# A c G E 2 37.3 no data 38.4 38. 6 3 39.1 39 1 39.3 39.6 4 40.8 40.7 38.2 37 5 40 41.8 38 41.2 6 39.2 41.1 38.5 40.6 7 41.5 42 38 39 8 39.4 40.8 37.7 42.4 9 39.9 41.8 38. 4 41.5 10 no data 42.4 no data no data Mean: 39.65 41.2125 38.3125 39. 9875 Median: Site Mean: 39 790625 std dev. 1.5689239 sem 0.2773492 89 39. 6 39.2 39.4

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A ppen dix 1: (Continued) UTB Date: 10123/00 8 :25am Measmements, em Pin# A c G E 2 39 39.3 39.2 3 39.1 4 0. 9 39. 6 39.5 4 39.2 40 38.8 39.6 5 40. 1 41.7 3 8 .2 41 6 39 41 39.1 40.8 7 40.3 41.3 37.8 40. 2 8 39.2 41.7 37 6 39. 6 9 40.2 41.3 38 9 43 1 0 41.3 Mean: 39.5125 41.15 38.6625 40.3625 Median: 39.6 Site Mean : 39. 921875 std d ev. 1.2252016 sem 0.2165871 Date: 12/1/00 3:12pm Measurements, em Pin # A c G E 2 39.1 39.8 37.7 38.4 3 38.6 40.2 37.6 37.6 4 39.3 4 0 .35 37.5 38.8 5 39.2 40. 2 37.2 38.4 6 39.3 40.2 37.3 38 1 7 38.8 40.8 36.9 37 8 8 38.9 40. 2 36.6 38.5 9 39.1 40.4 36 8 38 6 10 Mean: 39.0375 40.26 8 75 37.2 38.275 Median : 38.6 Site Mean : 39.69 s t d dev. 1.1821494 sem 0.2089765 Date: 12/21/00 8:50am Measurements, em P in# A c G E 2 38.7 39.8 39 38 8 3 38.7 41.2 39.2 39 4 39.5 40.8 37.6 38.9 5 39.3 41.7 37 7 38.5 6 39. 3 41.6 37.3 38 2 7 39.4 41.9 37. 1 38.3 8 39. 2 41.5 37 6 39.3 9 39. 7 41.5 3 7 39. 9 10 Mean : 39.225 41.25 37.8125 38.8625 Median: 39.2 Site Meao: 39 2875 std dev 1.400633 5 sem 0.2475994 90

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Appendix I: (Contin u ed) UTB Date: 212/01 2:00pm Measurements, em Pin # A c G E 2 39 39. 8 38.3 38.8 3 38.7 41 39.2 38.6 4 39.6 40 9 38.1 38 8 5 39.4 40. 9 37.5 38 9 6 39.7 40.6 37.7 38.7 7 39.5 40.3 37 4 39.7 8 39 .. 6 40. 7 37 39 7 9 39.7 41.5 37. 1 1 0 Mean: 39.4 40. 7125 37.7875 39.028571 Median: 392 Site Mean: 39.232143 std d ev. 1.1895874 sem 02102913 Date : 3 / 3 / 01 0:20am Measurements em Pin# A c G E 2 38.7 40.5 38.2 38.4 3 38.1 41.1 38 6 39. 4 4 38 41 38 2 39 2 5 39 41.7 37.8 39.3 6 38.5 41.7 37 7 39 7 39.6 42.2 37.4 39 1 8 39.8 42. 2 37. 6 39. 9 9 39.9 41.9 38.1 40.5 10 Mean: 38.95 41.5375 37.95 39.35 Median: 39 Site Mean : 39. 446875 std d ev. 1.4515808 sem 0 2566056 Date: 4 /11101 1:15pm Measurements em Pin# A c G E 2 39.5 40.1 382 38 2 3 38.5 40.7 39.1 39 .21 4 39.2 41.1 38.2 39.4 5 39.3 41.4 38 38 9 6 39.2 41.5 37.7 38.3 7 39. 7 41.4 37.4 38.9 8 39.4 41.6 36.7 40.4 9 39.9 41. 5 37.4 40 6 1 0 Mean: 39. 3375 41.1625 37 8375 39. 23875 Median: 39.21 Site Mean: 39.394063 std dev. 1.3525957 sem 0 .23 91074 9 1

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Appendix 1 : (Continued) UTB Date: 5/18/01 9:45am Measurements em Pin# A c G E 2 39.4 402 38 7 38.4 3 39. 6 41.1 392 39.3 4 39. 6 41.5 38.5 39. 5 5 39.8 41.4 38 3 39.3 6 39 2 41.7 382 39 7 39 9 41.4 37 5 39 8 39.5 41.6 37.1 40.2 9 40. 2 41.5 37 40.4 10 Mean: 39.65 41.3 38 0625 39.3875 Median: 3 9.5 Site Meao: 39. 6 std dev 1.2954013 sem 0 2289968 92

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Appendix I : (Continued) Field Monitoring-SET UTB Intensive Monitoring (UTB-IN1) Intensive monitoring : Spring Tidal Cycle Upper Tampa Bay, Site #l Orientations measured: A, C, G, E Date: 11/11/00 9 : 40am P in# A c G 2 40.4 39.8 3 40.3 42 5 40 4 40.5 41.7 40.9 5 39 9 40.8 38 5 6 40 1 42.2 39 6 7 40 6 41.7 39.3 8 40 7 42.7 38 7 9 39 42 .15 38.2 10 E 39.7 40.5 40 9 43 38.8 41.8 4 2.3 Mean: 40 1875 41.9643 39.375 41 Median: Site Mean: 40 6317 std dev. 1.32188 sem 0 23368 Upper Tampa Bay, Site #l Orientations measured: A, C, G, E Date: 11/11100 11 : 25am em Pin# A c G E 2 41 42.6 40 8 40 8 3 40 8 42 7 40 1 40 2 4 41 41.6 39.8 40.4 5 40 6 42 .2 40 42.4 6 40.5 43 39.6 40.3 7 41.3 42.3 39.6 41.2 8 40 8 42 8 39 43.3 9 40.5 43.2 39.2 43.8 10 Mean: 40 8125 42.55 39.7625 41.55 Median: Site Mean: 41.16875 std dev 1.29576 sem 0 22906 93 40.5 40.8

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Appendix 1: (Continued) UTB-INT Upper Tampa Bay, Site #1 Orientations measured: A, C, G, E Date: 11/11100 1:30pm Measurements, em Pin# A c G 2 41 42 41.2 3 40.8 41.8 412 4 41 41.2 40.8 5 41 42 40.6 6 40. 8 42.4 40.5 7 41.3 41.3 40.4 8 40.5 43.2 41.4 9 41.1 42.4 42.4 10 E 39.8 39.7 40.4 41.2 39.8 41.2 40.7 44.6 Mean: 40.9375 42.0375 41.0625 40.925 Median: 41.1 Site Mean: 41.24063 std dev. 1.00285 sem 0.17728 Upper Tampa Bay, Site #1 Orientations measured: A, C, G, E Date: 11111/00 3 : 30pm Measurements, em Pin# A c G 2 40.6 40.4 3 40.9 42.7 40.6 4 41.5 41.7 40.6 5 41.2 41.5 39.4 6 41.7 42 39.8 7 41.45 41.5 39.7 8 41.2 43 38.8 9 41 42 40.3 10 Mean: 41.19375 42.0571 39.95 E 41 39.2 40.8 41.2 39.8 40.5 42 42.4 40.8625 Median: Site Mean: 41.01585 std dev. 1.01214 sem 0 17892 94 41

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Appendix 1: (Continued) UTB-INT Upper Tampa Bay, Site #1 Orientations measured: A, C, G, E Date : 11/ 11/00 5:30pm Measurements em Pin# A c G E 2 41 42.4 40.2 40.8 3 41.7 41 39.8 39.6 4 41.7 41.2 40 39.7 5 41.6 422 39.2 40 6 40.9 41.9 38.5 39.5 7 42 42 38 9 40 8 8 412 42 4 39.3 42.5 9 42.9 422 40.4 41.9 10 Mean: 41.625 41.9125 39.5375 40.6 Median: 41 Site Mean: 40 91875 std dev. 1.20092 sem 0 2123 Daily Neap to Spring Upper Tampa Bay, Site #1 Orientations measured: A, C, G, E Date: 12/18 /00 3:00pm Measurements, em Pin # A c G E 2 38 7 39. 1 38.2 38.5 3 38.7 40.5 37.8 38.5 4 39.3 40.2 37 38 9 5 39 40.4 37.1 38.8 6 38 9 41 37 38 7 7 39 40.4 36.9 38.7 8 39 41.1 36. 8 38 8 9 39.2 40.5 37.4 39 1 10 Mean : 38.975 40.4 37 275 38.75 Median: 38.8 Site Mean: 38.85 std dev. 1.19353 sem 0.21099 95

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Appendix 1: (Continued) UTB-INT Upper Tampa Bay, Site #l Orientations measured: A, C, G, E Date : 12/19/00 2:30pm Measurements, em Pin# A c G 2 39 39.6 38 3 38.8 40.2 38.7 4 39.2 40.2 38.1 5 39.1 41.8 36. 7 6 39 41.2 37.4 7 39.2 41.7 37 8 38.9 40 : 7 37 9 39 2 40 37.4 10 Mean: 39. 05 40.675 37.5375 E 38.5 38.6 38.8 38 6 37.8 38.4 38. 8 38.7 38.525 Median: Site Mean: 38 94688 std dev. 1.27051 sem 0 .22 46 Upper Tampa Bay, Site #l Orientations measured: A, C, G, E Date: 12 / 2 1/ 00 8:50am Measurements, cm Pin# A c G E 2 38.7 39.8 39 38.8 3 38.7 41.2 39.2 39 4 39.5 40.8 37. 6 38 9 5 39.3 41.7 37.7 3 8 5 6 39.3 41.6 37.3 38.2 7 39.4 41.9 37 1 38.3 8 39 2 41.5 37 6 39.3 9 39.7 41.5 3 7 39.9 10 Mean: 39.225 41.25 37.8125 38.8625 Median: Site Mean: 3 9.2875 std dev 1.40063 sem 0.2476 96 38.8 39.2

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Appendix I: (Continued) UTB-INT Upper Tampa Bay, Site #l Orientations measured: A, C G, E Date: 12/22/00 9:00am Measurements, em Pin# A c G 2 38.8 402 38.8 3 39 41 38.9 4 39.7 40.8 38.3 5 39.2 41.7 37.3 6 39.2 41.7 37. 6 7 39.4 42 37. 2 8 39.3. 40.7 37.7 9 39. 6 40.8 37. 2 10 Mean: 39. 275 41.1125 37.875 E 38.7 38. 6 39.1 38. 7 37. 8 38.2 38 6 40.3 38.75 Median: Site Mean: 39.25313 std dev. 1.33682 sem 0.23632 Upper Tampa Bay, Site #l Orientations measured: A, C, G, E Date : 12/23/00 !0:09am Measurements, em Pin# A c G 2 39 1 41 38 E 3 39 41.1 39.1 38.7 4 39.9 41 38.5 38.9 5 39.5 41.7 37 6 38 6 6 39.5 41.6 38 382 7 39.8 41.8 37 38 8 39.7 41.5 36.9 37.8 9 40.2 41.5 37.5 38.8 10 39.6 Mean: 39.5875 41.4 37. 825 Site Mean: 39.34688 std dev. 1.45314 38.575 Median: sem 0 25688 97 39 39.1

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Appendix I: (Continued) UTB-INT Upper Tampa Bay, Site #1 Orientations measured: A, C, G, E Date: 2/21/01 3:40pm High Tide Measurements, em Pin# A c G 2 38.5 39.8 38 .7 E 3 38 40.8 38 8 38.6 4 37.6 40.9 38.2 38.5 s 38. 8 41.4 37.5 39 6 382 41.2 37.6 38.5 7 39.4 41.6 36.6 38.3 8 39. 5 41.2 36.6 38.1 9 39.4 41 37 39.3 10 39.8 Mean: 38 675 40.9875 37.625 Site Mean: 39. 0125 std dev 1.40661 38.7625 Median: 38.7 sem 0 24866 Bihourly Tidal Cycle: Neap Upper Tampa Bay, Site #1 Orientations measured: A, C, G, E Date: 3 /3/ 01 !0:20am Measurements, em Pin# A c G 2 38.7 40.5 38.2 E 3 38.1 41.1 38.6 38.4 4 38 41 38.2 39.4 s 39 41.7 37.8 39.2 6 38.5 41.7 37.7 39.3 7 39.6 42.2 37.4 39 8 39.8 42.2 37.6 39.1 9 39.9 41.9 38.1 39.9 10 40 5 Mean: 38.95 41.5375 37.95 Site Mean: 39.44688 std dev. 1.45158 39.35 Median: 39.1 sem 0.25661 98

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Appendix 1: (Continued) UTB-INT Upper Tampa Bay, Site #1 Orientations measured: A, C, G, E Date: 3/3/01 12:15pm Pin# A c G 2 38.8 40.2 38.5 3 38.2 40.8 38.5 4 38.1 41.4 38.7 5 38.8 42.1 38 8 6 39.1 41.5 37 7 7 39 8 42 37.4 8 40.2 42 37.5 9 40 41.6 38 1 10 Mean: 39 125 41.45 38.15 E 38.5 39.3 38 8 38 9 38.6 38.8 40 1 40.2 39.15 Median: Site Mean: 39.46875 std dev. 1.38923 sem 0 24558 Upper Tampa Bay, Site #1 Orientations measured: A, C, G, E Date : 3 / 3/01 2:15pm cnn Pin# A c G 2 39 3 38.2 4 38 5 39 6 39 7 8 9 10 39.3 39.7 39.7 40.2 38 41.2 38.7 41.8 38.1 41.7 37 9 41.3 37.4 41.9 36 6 41.7 37 1 41.5 37.3 Mean: 38.9875 41.4125 37 6375 E 38.5 39 1 37.5 38 6 38.2 38 6 39.2 40.4 38.8 Site Mean: 39.2 std dev. 1.53959 38 7625 Median: 39 sem 0 27216 99

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Appendix I: (Continued) UTB-INT Upper Tampa Bay, Site #1 Orientations measured: A. C, G, E Date: 3/3/01 4 : 15pm Measurements, em Pin# A c G 2 39. 1 40.2 38.1 3 38.6 41.1 39. 6 4 38.1 40 7 38.1 5 39 41.5 38 6 39 41.2 37. 8 7 39.4 41.8 37 8 39.7 41.6 36.9 9 40 41.2 37. 7 10 Mean: 39.1125 41.1625 37.9 E 38.8 39.1 39.4 39.4 39.2 39 40 38.8 39.2125 Median: Site Mean: 39.34688 std dev. 1.32006 sem 0 .233 36 DAD.. Y NEAP TO SPRING: MAY Upper Tampa Bay, Site #1 Orientations measured: A, C, G, E Date: 5/15/01 8:55am Measurements, em Pin# A c G 2 39.6 40.1 38.7 3 39.5 41 39.5 4 39.6 41.2 38.4 5 39. 8 41.3 38.3 6 39.4 41 38 7 40.1 41.1 37 9 8 39.8 41.4 37.4 9 40 41.5 37 10 Mean: 39.725 41.075 38.15 Site Mean: 39.54688 std dev. 1.18457 E 38.9 39.2 39.4 39 38.6 38.8 39.6 40.4 39.2375 Median: sem 0.20941 100 39. 1 39.5

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Appendix 1: (Continued) U1B-INT Upper Tampa Bay, Site #1 Orientations measured: A, C, G, E Date: 5 / 16/01 9 : 10am Measurements em Pin# A c G E 2 39.4 40.2 38.6 38 9 3 39 5 41.2 39.2 39.2 4 39.5 41.4 38.3 39.4 5 39.6 41.6 38.2 39 1 6 39.3 41.4 38.3 38 6 7 40 41.5 37 6 38 7 8 39.6 41.6 37 1 39 7 9 39.7 41.3 37 39.5 10 Mean: 39.575 41.275 38.0375 39 1375 Median: 39.4 Site Mean: 39 50625 std dev. 1.27278 sem 0 225 Upper Tampa Bay, Site #1 Orientations measured: A C G, E Date: 5 / 17 /01 9:30am Measurements, em Pin# A c G 2 39.6 39.4 39.5 E 3 41.1 39.6 38.4 38.9 4 40.3 39 6 37 8 38.1 5 40.5 39.9 38 37 5 6 40.9 39.4 38.1 36 9 7 41 39.5 36 36 8 8 40. 1 39 7 36 6 36.8 9 40 39 9 36.7 37.3 10 37 9 Mean: 40.4375 39 625 37.6375 Site Mean: 38.80625 std dev. 1.458 37.525 Median: 39.4 sem 0 257 7 4 101

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Appendix 1 : (Continued) U1B-INT Upper Tampa Bay, Site #I Orientations measured: A, C, G, E Date : 5 / 18 /01 9:45am Measurements, em Pin# A c G 2 39.4 40 2 38.7 3 39.6 41.1 39.2 4 39.6 41.5 38.5 5 39 8 41.4 38. 3 6 392 41.7 38.2 7 39 9 41.4 37.5 8 39.5 41.6 37.1 9 40 2 41.5 37 10 E 38.4 39.3 39.5 39.3 39 39 40.2 40.4 Mean: 39 65 41.3 38 0625 39. 3875 Median: Site Mean: 3 9 600 std dev. 1.2954 sem Upper Tampa Bay, Site #I Orientations measured: A, C, G, E Date: 5 / 20 / 01 10:30am Measur e m e nts, em Pin# A c G E 2 39 5 40.2 38 7 39.2 3 39.4 41.2 39.2 39.3 4 3 9 7 41.7 38 8 39.4 5 3 9 8 41.8 38.5 39.2 6 39.3 41.4 3 8 38 9 7 40 41.8 37 6 38 6 8 39.8 41.9 37.3 39 8 9 40 41 37 1 40 9 10 Mean: 39.6875 41.375 38 15 39.4125 Site Mean: 39.65625 std dev. 1.30184 sem 102 0 229 Median: 0.23014 39 5 39.4

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Appendix 1: (Continued) Field Monitoring-SET Little Manatee River (LMR), Site #2 Orientations: B, H, F, D Date : 9/1100 12:30pm Measurements, em Pin# B H F D 2 38.1 38.3 39 39.55 3 41.6 39.05 39 .6 39.2 4 41.25 41.4 40.3 40.4 5 43 40.6 40.3 40.7 6 39.85 41.2 40.75 43.9 7 43.35 38 40.14 41.2 8 41.6 38 8 42.2 41.3 9 40.5 40.25 42 41 10 no data no data no data no data Mean: 41.15625 39.7 40.53625 40. 90625 Median: 40.25 Site Mean: 40.574688 std dev 1.4465598 sem 0.2557181 Date: 9/24/00 6:35pm Measurements, em Pin# B H F D 2 38.4 no data 38 2 37 H no data due to adverse 3 39.9 no data 39.3 40 environmental conditions 4 40.3 no data 40.1 40.6 5 39.2 no data 40 2 39 6 37.2 no data 38.5 39.5 7 37.9 no data 41.2 40.5 8 40.1 no data 41.5 43.9 9 39.8 no data 41.2 45 10 no data no data no data no data Mean: 39.1 no data 40. 025 40 6875 Median: 39.9 Site Mean: 39.9375 std dev 1.8384333 sem 0.3752686 Date: 10 /22/00 4 : 40pm Measurements, em Pin# B H F D 2 38.1 39 8 39 .8 40 3 39.8 39.7 39.1 38.6 4 40.2 40.3 40.5 39 5 5 39.8 40.7 40.2 41 6 39.1 39.1 43.2 39 7 7 42 40.8 42.3 40.4 8 44.7 38 6 42.4 44.2 9 39.9 40.5 43.3 42.7 10 no data no data no data no data Mean: 40.45 39.9375 41.35 40.7625 Median: 40.2 Site Mean: 40.625 std dev 1.648264 sem 0.2913747 103

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Appendix 1: (Co n tinued) LMR Date: 12/1100 !2:02pm Measurements, em Pin# B H F D 2 37.2 37.2 37.9 37 7 3 3 8 .2 37.6 38.4 38.1 4 38.2 38.6 39.5 39 5 392 38.05 40 3 8 .8 6 39.3 37.3 38.5 39.4 7 38.8 3 7 7 39.6 38.2 8 38.4 37.3 39. 8 39.8 9 39 37.2 39.6 40.8 10 Mean : 38.5375 37. 61875 39. 1 625 38.975 Median: 3 8 .4 Sit e Mean: 38.573438 std dev 0.9478315 sem 0.1675545 Date: 12120/00 11 :40am Measurements, em Pin# B H F D 2 37.3 37.1 38.8 37.8 3 37.3 37.7 39.2 38.4 4 38.2 38.2 40.1 39.3 5 39.1 38 39.2 40 6 39 38 I 40.3 39.5 7 38.6 37.2 39.4 39.2 8 39 37.3 39.7 41.4 9 38 7 36.9 39.8 40.8 1 0 Mean: 38.4 37.5625 39. 5625 39.55 Median: 38.8 Site Mean: 38.76875 std dev 1.1323505 sem 0.2001732 Date: 2/2/01 II :05am Measurements em P in# 8 H F D 2 38 36.4 38.6 38.2 3 37.6 38.1 38.7 38.5 4 39.1 39 40.1 39.5 5 39.7 38.9 40. 7 39.6 6 40 38.4 39.3 39.4 7 39.2 37 7 39.6 39.5 8 39.6 37.4 40.1 41 9 38.9 37.3 40.2 40.8 10 Mean: 39.0125 37.9 39.6625 3 9.5625 Median : 39.I Site Mean: 39.034375 std dev 1.0852707 sem 0.1918506 104

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Appendix 1: (Continued) LMR Date : 3 / 5 /01 3 : 55pm Pin# B H F D 2 37.3 37.3 39.4 38.1 3 37 6 38.2 40 3 37.9 4 39.6 39.5 41.9 39.5 5 39 7 39 40 9 39 6 6 39 1 38.5 40.3 39.7 7 39 37.3 40.1 40 8 39.6 37.8 40 8 42.2 9 39 6 37.1 40.6 41.9 10 Mean: 38 9375 38 0875 40.5375 39.8625 Median: 39.5 Site Mean: 39.35625 std dev 1.3874873 sem 0.2452754 Date : 4 / 13/01 3 : 15pm Pin# B H F D 2 38 37. 1 37.8 38.4 3 37 9 38 1 39. 1 38.5 4 39.4 39 2 39 9 39. 9 5 40 1 38.6 40 .2 39 6 6 39 8 38 5 40 2 40 7 39.5 37.3 39 7 39.8 8 40.3 37.6 39 2 42.3 9 41.4 36.7 40 1 42.3 10 Mean: 39.55 37 8875 39 525 40.1 Median: 39.4 Site Mean: 39 .2 65625 std dev 1.3530394 sem 0.2391858 Date : 5 / 5/01 11 :OOam Pin# B H F D 2 37.5 37.6 38 5 38.5 3 37 9 38.4 39.4 38 6 4 39.6 39 8 40.5 39 9 5 39.9 38.9 40.3 39.5 6 40 38 7 39 6 39 8 7 39.6 37.7 40 1 38 1 8 3 9.7 38 39.5 41.9 9 39.3 37.3 40 41.8 10 Mean: 39.1875 38.3 39. 7 375 39. 7625 Median: 39.5 Site Mean : 39. 2 46875 std dev 1.1302:2.53 sem .. 0 1997975 105

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Appendix 1: (Continued) Field Monitoring--SET Mariposa Key (MK), Site #3 Orientations measured : A, C E, H Date: 9 / 1/00 9:00am Measurements, em Pin# A c E H 2 54 7 53.2 56 3 56.5 55.15 53.3 53.2 4 55.4 55.3 52.9 52.3 5 55 6 55 6 52.4 54.5 6 55 85 55.4 51.9 54. 6 7 57 54.7 52 54 8 56. 3 55 85 50. 6 53 .95 9 57.25 55 9 50 2 53 2 10 58. 2 Mean: 56.5125 55.325 52 0625 53. 96875 Median: Site Mean: 54.467188 std dev 1.9120842 sem 0.3380119 Date: 9 /24/00 4:34pm Measurements, em Pin# A c G E 2 54.5 54.45 53.6 53.9 3 55.3 54.5 52.8 52.4 4 54 7 55.2 53.3 51.5 5 55 5 55.8 52 9 52.4 6 55.85 55.2 52.9 51.5 7 55 9 55.75 51.9 50 8 8 56.3 56 52.4 50.8 9 56.7 55.8 52.2 51.3 10 no data no data no data no data Mean: 55.59375 55.3375 52.75 51.825 Median: Site Mean: 53. 876563 std dev 1.8032222 sem 0.3187677 Date: 10122100 1:28pm Measurements, em Pin# A c G E 2 54.8 55 1 54. 2 3 55 55.2 54.4 54.5 4 55.8 55.2 54.1 53 1 5 57.2 55.3 54.2 52.7 6 56.9 55.9 53.7 53 7 57.2 56.5 53 9 52.2 8 57 8 55.5 53.3 52 9 5 7 8 55.4 53 1 51.8 10 52.5 Mean: 56.5625 55.5125 53.65 52.9375 Median: Site Mean: 54 665625 54 033333 std dev 1.6853466 sem 106 54 7 53 9 54 5 0.29793

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Appendix 1: (Continued) :MK Date : 12/1/00 9:30am Measurements, em Pin# A c G E 2 53.7 53 .2 54 52.4 3 54.7 54. 8 53.4 51.6 4 53 8 54 52 8 51 5 55.7 53.8 53 50.4 6 55 8 53 2 53 51.1 7 56 54.7 52.75 49 6 8 56.4 54 1 52 9 49.5 9 56.2 54.6 52.2 49 10 Mean: 55 2875 54.05 53 00625 50.575 Median: 532 Site Mean: 52.54375 std dev 1.6815697 sem 0.2972623 Date : 12/20/00 9:40am Measurements, em Pin# A c G E 2 55 53.8 53.2 52.4 3 54.9 54.5 52.8 52.3 4 55.3 53.4 53.5 51.9 5 55 7 55 2 53.2 51 6 56.3 53.9 52.9 50.9 7 56.3 54.4 52.3 50.6 8 56.2 55 1 52.4 50.4 9 56.4 54 3 52 49.5 10 Mean: 55.7625 54.325 52 7875 51.125 Median: 53.4 Site Mean: 52 .7 45833 std dev 1.5134123 sem 0.267536 Date : 2/2/01 9:15am Measurements, em Pin# A c G E 2 57 54 .4 53.6 52 3 3 55.6 55 53. 5 51.8 4 56.2 54.4 53.9 51.7 5 56.4 55.1 54 2 51 6 57.1 54.8 53.4 50. 8 7 56.8 54.7 52.7 49.9 8 57.4 55 2 52 6 49.6 9 56.8 54.5 52 3 49 10 Mean: 56.6625 54.7625 53.275 50.7625 Median: 542 Site Mean: 52.933333 std dev 1.8513606 sem 0.3272774 107

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Appendix 1: (Continued) MK Date: 3 / 5 / 01 2 : 10pm Measurements, em Pin# A c G E 2 55.7 54.4 53 52.7 3 55 8 54.5 52 9 52.4 4 56.2 54.9 54 52 5 56.8 54.8 53.9 51.4 6 57.3 54.8 52.8 50.9 7 57.4 54.5 52.8 502 8 57.3 55.5 53 50 9 56.8 54.7 52 49. 7 10 Mean: 56. 6625 54.7625 53 05 51.1625 Median: 54 Site Mean: 52.991667 std dev 1.6777098 sem 0.29658 Date: 4 /13/ 01 1:15pm Measurements, em Pin# A c G E 2 55.6 54.2 54.4 52.4 3 55.3 54 8 53 9 51.7 4 56.3 54.4 54.8 51.6 5 56.6 54.7 54 51.4 6 57.1 55.2 53.5 50 5 7 57.1 54.8 53 5 50 2 8 57.4 55 53.2 50 9 57.6 54.7 52 8 49. 2 10 Mean: 56.625 54.725 53 .7 625 50 875 Median: 54.4 Site Mean: 53.1 2 0833 std dev 1.8158671 sem 0.3 2 1003 Date: 5 / 5 / 01 9 : 00am Measurements, em Pin# A c G E 2 54. 2 54.4 53. 8 52.7 3 54. 7 54.9 53.6 52 2 4 55.5 54 8 53.3 52 5 56 55 .2 54 1 51.6 6 56.1 55 54.5 5 0.8 7 56.5 55.4 53.4 50 8 5 7.4 5 4.9 53.1 50.3 9 57 54 6 5 2 49. 7 10 Mean: 5 5 925 5 4 9 53.4 75 51.1625 Median: 5 4 .2 Site Mean: 53.17916 7 std dev 1.7 4 7 539 7 sem 0 .3 089 2 4 3 108

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Appendix II: SET Error Measurements visual method, em UTB 11111100 10 :30am Orientation B-open ground Mean, each pin Std Dev 2 40.7 40.56 40.8 41 412 40.852 02520317 3 40.5 40. 7 40.4 40 41 40.52 0.3701351 4 402 40 39.8 40.4 402 40.12 02280351 s 39 9 40.4 40.6 40. 7 40.8 40.48 0.3563706 6 41.4 41.5 41.2 40.9 41 41.2 0.254951 7 41.4 41 42 41.1 41.2 41.34 0 3974921 8 42 422 41.8 41.3 40.8 41.62 0 5674504 9 41.4 41.3 40.8 40.3 39.9 40.74 0 6426508 Mean, per arm set 40. 9375 40.9575 40. 925 40. 713 40.763 40.859 0.1129104 Total Mean 40.859 Total Std Dev. 0 600819 SEM 0 094998 UTB 11111100 Orientation F-juncus Mean, each pin Std Dev 2 40.6 40.4 40. 6 40.3 40. 6 40.5 0.1414214 3 39.9 40.5 40.2 40.6 40. 8 40.4 0.3535534 4 40.7 40.6 40.4 41 39.5 40.44 0.5683 309 s 40.4 39.5 39. 2 40 40.2 39.86 0.497996 6 39.6 3 9.3 40.3 39.2 39.2 3 9.52 0.4658326 7 40.3 38.6 41 41.3 39.2 40. 08 1.1562872 8 41 40.4 39. 7 40. 6 39.6 40.26 0.598331 9 39.7 41.4 41 40.2 40.4 40.54 0.669328 Mean, per arm set 40.275 40.0875 40.3 40. 4 39.938 40.2 0.185194 2 Total Mean 40.2 Total Std Dev. 0.65633 SEM 0.103775 UTB 12121100 using foot made by USGS Orientation F-juncus Mean, each pin Std Dev 2 38.3 38.3 3 8 .2 38.3 38.2 38.26 0.0547723 3 38 2 38. 2 38. 2 3 8 4 38.3 38.26 0.0894427 4 38.25 38. 2 3 8 37.9 38.4 38.15 0 .2 s 37 1 37.4 37.4 37.6 37.5 37. 4 0.1870829 6 37.6 37.4 3 7.3 37. 8 37 9 37. 6 0.254951 7 37.2 37.1 37.5 38 38 37.56 0.427785 8 37.1 37.2 37. 1 37. 7 37. 8 37.38 0.3420526 9 Mean, per arm set 37.67857 37. 6857 37. 6714 37.957 38.014 37. 80142857 0 1695131 Total Mean 37.80143 Total Std Dev. 0 .443994 SEM 0.07020 2 109

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Appendix ill: Multi-Data Upper Tampa Bay Multi-Data Field Data and NOAA Data* em m m ppt em m/s degree mb Wind Wind Date SET Median Tide Level* Well Level Saliuity Pin Speed* Direction* BP* 8/26 / 00 28.56 0 685 0.3467 26.8 45. 7 1.07 72 1015 9/25/00 28. 96 0 646 26 46 0 16 1012 7 10/23/00 28 .56 0 638 -0 1833 11.1 45.8 1.69 17 1023 12/1/ 00 29.56 0.419 -0.4833 24 5 46.5 0 81 60 1022.3 12/ 21/00 28.96 0.162 -0.5233 46.4 0.89 20 1023.8 2 / 2 / 01 28.96 0.155 -0.5233 23.4 46.4 0.27 134 1020 3/3 / 01 29.16 0 6 -0.3733 46 2.24 184 1011.4 4 / 11/01 28.95 0 771 -0 5233 24. 8 46.3 2.41 159 10 1 7 7 5 / 18/01 28 66 0.499 -0 6533 46 5 0 299 1017 6 /30/01 28 .26 0 827 -0 0733 46.5 3 .3 139 1019 7 8 / 1 1/ 01 28.46 0 532 0 2467 9 7 46. 5 4 262 1018.4 10 / 1/01 28.16 0.319 0 0857 19 7 46.5 3 40 1 016 Note : Raw SET levels have been corrected relative to mean sea level. 110

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Appendix ill: (Continued) Little Manatee River Multi-Data Field Data and NOAA Data* em m m ppt em degree mls mb Wind Wind Date SET Median Tid e Level* Well Level Salinity Pin Direction* Speed* BP* 9/1/00 13.09 0.552 -0 099 26.8 52.7 151 0.85 1016.3 9/24/00 13 .44 0 108 27.6 52 8 300 1.56 1012.5 10/22/00 13.14 0.169 -0.043 27 8 52.4 95 1.79 1022.8 12/1100 14.94 0 03 -0.639 27 52.4 60 0.67 1021.7 12/20/00 14.54 -0 .018 -0.539 27 8 52.5 8 3.58 1023 2 2/2/01 14.24 0239 -0 739 27.3 52.4 155 1.07 10192 3 / 5 / 01 13.84 0.258 -0.529 27.6 52.5 306 4 02 1018 .2 4 /13/01 13.94 0 709 -0. 569 27 52.6 160 1.34 1022 5 / 5 / 01 13.84 0 523 -0.319 52.5 62 2.24 1017 617/01 13.84 0.642 0 .2 41 145 22 1018 7 / 30/01 13.94 0 043 -0 044 26. 1 256 3.8 1019.1 9/24 /01 14.34 0.436 0 031 11.1 219 3.8 1012.3 Note: Raw SET values have been corrected relative to mean sea level. 111

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Appendix III: (Continued) Upper Tampa Bay Intensive Multi-Data Field Data and NOAA Data* em m em m em m/s degree mb Wind Wind Description Date Time SET Median Tide Level* In-Situ Tide Well Level Pin Speed* Direction* BP* Extra 10/ 9 / 00 8:00am 28.76 0.155 no data 45.5 16 1018.1 Bihourly Spring cycle 11/11100 9:40am 27.66 0.322 0.127 45.6 1.8 58 1016.8 11111/ 00 11 : 25am 27 36 0.5 0.877 45 3.7 26 1015 7 11111100 1:30pm 27 06 0 736 -0.333 45. 5 2.1 351 1013 8 11/11/ 00 3 : 30pm 27.16 0.653 -0.403 45 7 3 1 326 1012 9 11/11/ 00 5:30pm 27.16 0.504 -0.403 45 7 2.7 309 1013 5 Daily Neap to Spring 12/18/00 29.36 0.102 -0 583 46 0.45 69 1024.4 (water levels obtained 12/19 / 00 29.36 0.187 -0.583 46 2.41 322 1017.5 from McKay gauge) 12/21/ 00 28.96 0.215 -0.523 46.4 0.89 18 1023 9 12/ 22 / 00 29.16 0 098 -0 633 46.4 0 19 1021.1 ...... 12/23/ 00 29.06 -0 553 ...... -0.234 46 1.61 44 1024.1 N Bihourly-Neap Cycle 3 / 3/0 I 1 0 :2 0am 29. 06 0.585 0 .33 -0.373 46 8.3 190 1011.7 !2:20pm 29.36 0.698 0.4 -0.393 46. 3 8.7 201 1011 2:15pm 29.16 0.726 0.438 -0.413 46.4 9 3 195 1010.2 4:15pm 29.06 0.829 0.53 -0.403 46.1 8.9 196 1009.6 Daily Neap to Spring 5/15 /01 28.66 0.527 -0.223 46.5 1.07 135 1018 1 5 / 16/01 28.76 0 585 -0 .383 46.5 0.85 263 1014 8 5 / 17/01 28.76 0.585 -0.603 46 5 0 250 1014 3 5/18/01 28.7 0.547 -0 .653 46.5 0 299 1017 5 / 20/01 28.76 0.635 -0.563 46.5 0 257 1014 6 Note : Raw SET values have been corrected with respect to mean sea leveL

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Appendix ill: (Continued) Mariposa Key Multi-Data Field Data and NOAA Data* em m m ppt m/s degree mb Wind Wind Date SET Median T ide Level* WeULevel Salinity Speed* Direction* BP* 9 /1100 54 7 0.347 -0 .08 41.1 0 05 130 1015.4 9/24 /00 53 9 0 074 42.2 0.36 342 1014.6 10/2 2 /00 54 5 0.324 -0 .08 43. 9 0 .89 99 1022 9 12/ 1/00 53. 2 0.03 -0 53 0 1 3 80 1021 12120/00 53.4 -0.04 -0 .61 46.7 4 .2 340 1022 2/2 /01 54.2 0 235 -0 76 20.5 0 05 88 1019 3 / 5 / 01 54 0. 2 4 0.55 47. 8 2 95 309 1017.2 4 /13/ 01 54.4 0.613 -0.62 47. 8 2.01 174 10 2 2 5 / 5 / 01 54 2 0 375 -0 16 21.5 1.79 40 1017 617/ 01 54. 2 0 .469 -0 .07 2 8 135 1017 8 7/30/01 54.4 0 021 -0 .13 47.8 2.4 102 1019 9 9 /24/ 01 53.8 0 295 -0 .27 2 2 1 5 2 207 1013 7 113

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....... ....... Appendix IV: Sedimentation Data Sediment Trap Data weights in grams Trap area = 63.62 sq em UTB filter sed onl y g/sq em Placed Pre: Post: After LOI: R etrieved: Mass/area %organic A-12 / 1 0.4265 1.3997 0 9654 2/2/01 0.06 31.03 B-12 / 1 0.4279 filter gone unrecoverable C-12 / 22 0.4314 filter gone unrecoverable D-12 / 22 0.4307 4.3108 3.2759 5115/01 0.17 24.01 E-12 / 22 0.4355 filter gone-unrecoverable F-12 / 22 0.4391 0.633 0.4273 3 / 3 / 0 I 0 03 32.50 G-2/2 0.4346 0.2813 0 2243 3 / 3 /01 0 .01 20.26 H-3/ 3 0.4339 filter gone-unrecoverable 1-3/ 3 0.4325 filter gone-unrecoverable J-4 /10 0.4262 0 7944 0.5792 5115/01 0.03 27.09 K-4 /10 0.4256 filter gone-unrecoverable -MK se d only g/sq em Placed Pre: Post: After LOI: Retrieved : Mass/area % organic A-12 / 1 0.4221 4 5201 2 9336 2 / 2 /01 0.21 35.10 B-12 / 1 0.4179 5 585 3.2604 5 1 5 101 0 26 41.62 C-12 / 20 0.4386 0.5401 0.3803 2 / 2 /01 0 03 29.59 D-12 / 20 0 4357 1.1307 0.7704 2 / 2 /01 0 05 31.87 E-2 / 2 0.4415 1.358 0.7081 4113/01 0 .06 47.86 F 2 / 2 0.4289 0.4075 0.2837 3 / 5 /01 0.02 30 38 G-3/ 5 0.4294 filter gone-unrecoverable H-4 /13 0.4292 0.8286 0.3477 5 1 5 101 0 04 58 .04 LMR sed only g/sq em Placed Pre: Post: After LOI: Retrieved : Mass /area % organic A-12/1 0.4252 0.608 0.3429 2 / 2 /01 0.04 43.60 B-12 / 1 0.4265 filter gone-unrecoverable C-2 / 2 0.4297 1.2281 0 5968 5 / 5 /01 0 07 51.40 D-2/2 0.4355 0.7837 0.3273 5 / 5 /01 0 05 58.24 E-2 / 2 0.4332 0.8523 0.4146 5 / 5 /01 0.05 51.36 F -2 / 2 0.4346 0.3975 0.2148 3 / 5 /01 0.02 45 96 G-3/ 5 0.4298 0.2958 0.1191 4 /13/01 0.02 59.74 H-4 /13 0.4316 0.852 0.4334 5 / 5 /01 0.05 49 .13

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Appendix IV: (Continued) Marker Horizon D ata F eldspar Accumulati o n Data Obtained with Core UTB LMR MK P laced ON: 1 0 / 9 / 00 10122/00 10/22100 Date Cored : 2/2/01 2119 / 01 2119/01 with cryogenic corer Time Accumulatio n : (mm) 4 mo 4 mo. 4 mo 23 14 13 with p l astic push cores: Date Cored: 4 / 11/0 1 4 /13/01 4 /13/ 01 Time 6mo. 6mo. 6mo Accumulation : 10 4 3 mm dry weight 3.0751 1.7074 1.832 PostLOI 2.5134 1 0451 12371 %organic 18.3 38 8 32.5 Date Cored : 5 / 1 6 / 01 5 / 5 /01 5 / 5 /01 Time 7mo. 7mo. 7mo. Accumulation : 6 < 1mm < 1mm mm dry weight 1.6879 N / A N / A PostLOI 1.4059 %organic 1 6.7 N / A N / A 115 area=23.76 sq em UTB LMR MK mass/ area 0.129423 0.0718603 0 077104 glsq cm/mo 0 021571 0 0119767 0 012851 0 07104 g/sq cm/mo 0.010149

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--0\ Appendix V : Sediment Cores Upper Tampa Bay weight in grams UTB Organic Content Grain Size Anal ysis Depth empty Pre LOI Post LOI Pre Wt Post Wt LOI gram ;% Organi< Pre Wt. Wt. Post Wt. Thn: % Sand % S ilt/Cl a y em 0 to 3 18.419 21.2413 20.6991 2 822 2 2798 0.5422 3tol0(5) 21.738 24.869 24.5021 3.1312 2 7643 0.3669 1 0 to 1 3 18.268 25 1959 24 5 1 76 6 9278 6.2495 0.6783 13 to 20 (1: 19 785 22.5757 21.7859 2 .7 908 2.001 0 7898 20 to 41 (21 1 7.509 24.2302 23 9 546 6 7216 6.446 0.2756 20 to 4 1 (3 : 16.277 27.0277 26. 797 10 75 10.52 0 2307 Description: Dept h em 0 to 3 1 OYR 2/ highly orga n ic, la r ge and fin e root material 19 2.84 1.8 1.04 63 12 12.28 11.5 0 78 94 10 8.44 7.52 0.92 89 28 15.26 14 22 1.04 93 4 22. 72 21.5 1.22 95 29. 02 27.72 1.3 95 3 to 1 0 10 to 13 13 to 20 20 to 41 l OYR 4/3 brown sandy patches in l OYR 3 / 2 very dk gray brown organic bas e ; very fibrous w/ fine root material dark organic stai ned band of 10YR 3 / 1 very dk gray, very fibrous with root ma t eria l lighter in color I OYR 4/2 dk gray brown sandy organic mix with small plant root matte r sandy pa l e brown base l OYR 6/3 with 50% organic mott l ing of very dk gray 1 OYR 3/ 1 ; i n fre qu ent root ma tter 37 6 11 7 5

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...... ...... -....l Appendix V: (Continued) Little Manatee Sediment Core weight in grams Organic Content Grain Size Analysis LMR Depth empty Pre LOI Post LOI Pre Wt Po st Wt LOI, g rams %Organic Pre Wt. Wt. Post Wt. Thru % Sand % Silt / Clay em 0 to 23 (10) 19. 7849 21.4783 20. 6235 1 6934 0 8386 0 8548 50 4 8 3.4 23 to 36 (25) 21.7378 24.2689 23 .5 482 2 5311 1.8104 0 7207 28 7.64 5 94 36to44( 38 ) 18. 2681 24.5997 23.9858 6.3316 5.7177 0 6139 10 13.6 8 13.06 44 18.4193 22 1594 21.9384 3 7401 3 5191 0 221 8 .62 8 2 44 to 50 (49) 17.5086 22 076 21.0611 4 5674 3.5525 1.0149 22 13. 74 12. 72 50to65(60) 17.1121 22 7621 21.9327 5 65 4 8206 0.8294 1 5 11.46 10 6 Description : Depth em 0 to 23 monotone dk brown 1 OYR 211 (black), very fibrou s organic peat, high water content and heavy root matter 1.4 71 1.7 78 0.62 95 0.42 95 1.02 93 0.86 92 23 to 36 36 to 44 44 to 50 50 to 65 slightly lighter 1 OYR 2/2 very dk brown ; still fibrous and highly organic but slightly les s OM, less root matter, high water content distinct s andy la yer 10YR 5 / 3 brown with dk red gray mottling 2 .5YR 3 /1, very little root matter; sharp boundary at 44cm > 70% organic very dk brown 10YR2 / 2 with s andy patche s 2.5YR 3 / 1 dk red gray with fine root matter homogenou s, black I OYR 2 / 1 with high water content and very fine-grained organic matter and root material 29 22 5 7 8

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-OQ Appendix V: (Continued) Mariposa Key Sediment Core weight in gram s MK Organic Content Depth empty Pre LOI Post LOI Pre Wt Post Wt LOI %Organic em 0 to 3 21.5447 23 1245 22.3947 1 5798 0 85 0.7298 3 to 26 (10) 18. 4193 20 9693 20.4891 2 55 2 0698 0.4802 3 to 26 ( 1 8) 17. 5086 21.0038 20.368 3.4952 2 8594 0.6358 3 to 26 (25) 18. 2681 21.8662 21.3472 3.5981 3 0791 0 519 26 to 49 (32) 19. 7849 23 .63 23 2053 3 8451 3.4204 0.4247 26to49(46) 17.1121 23.0089 22 5188 5 8968 5.4067 0.4901 49 to 66 (60) 21.7378 26. 7691 26.4884 5 0313 4 7506 0 2807 Description: more s ilty than othe r two cores Depth em 0 to 3 3 to 26 reddish black 2 5YR 2 5/1 very r i ch and high organic content very fibrous very dk gray 1 OYR 3 /1, still fibrou s large plant roots 46 18 11 6 Pre Wt. 0 98 5.88 12.44 5 36 12.18 9 .32 16. 3 slightly lighter I OYR 3 / 2, sandy /s ilty texture with heavy organic matter and fibrous Wt. Post 0 .64 4.62 10.86 4.18 9.54 8.46 15. 55 26 to 49 49 to 66 organic sandy dk gray brown layer I OYR 3 / 2 with patche s of light gray I OYR 7 / I and light root matter Grain Size Analysis Wt. Thru %Sand %Silt/Clay 0.34 65 35 1.26 79 1.58 87 13 1.18 78 2.64 78 22 0 86 91 0 75 95 5

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Appendix VI: Lead -21 0 Analysis Upper Tampa Bay depth (em) 210Pb %Error 214Pb 214Bi "U" excess 137Cs Calculated 'ctual I 7 98 3 1.65 1.47 1.56 6.42 0.47 7 0 6 .76 3 6 .26 4 1.05 0.91 0.98 5.28 0 55 5.5 5.4 5 6.31 4 1.55 1.66 1.61 4.71 0 .77 5.2 5.2 7 4.79 5 1.65 1.38 1.52 3.28 0.43 3.9 4 0 9 3.49 7 1.48 1.14 1.31 2.18 0.27 2.4 2.5 11 2 .83 9 1.17 1.08 1.13 1.71 0 .23 1.6 1.6 13 2.63 10 1.09 1.33 1.21 1.42 0.24 1.5 1.7 15 2.40 10 1.03 1.34 1.19 1.22 0 18 1.5 1.6 17 1.95 13 1.35 1.58 1.47 0.49 0 .20 1.0 0 9 19 1.65 15 1.04 1.33 1.19 0.47 0 12 0 8 0 9 + /0 25 0 .15 0 10 0 .02 ..... ..... \0 All values in dpm/g analysis performed and spread s heet prepared by Jim Budahn, USGS Denver, CO

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Appendix VI: (Continued) Little Manatee River depth (em) 210Pb %Error 214Pb 214Bi "U" excess 137Cs Calculated Actual 1 15. 89 2 1.69 1.40 1.55 14.35 0.71 14. 3 14.35 3 10.24 2 1.25 1.13 1.61 9.05 0 75 9 1 9 05 5 6 99 4 1.17 1.26 2.00 5 78 0.77 5.7 5.78 7 6.72 4 1.39 1.32 2 .14 5.37 0 95 5 3 5 37 9 4 63 5 1.37 1.13 2 63 3.38 0 .56 3 3 3 38 ll 2 .81 9 0 93 0 .71 3 .51 1.99 0 .13 2.0 1.99 13 2.47 10 1.08 0 78 3.99 1.54 < 0.04 1.5 1.54 15 2 05 12 0 86 0 86 4 64 1.19 0 10 1.2 1.19 17 1.44 17 1.04 0 93 6.44 0.46 < 0.04 0.5 0.46 19 0 89 28 0.95 0.85 9.96 0.01 < 0.03 0 0 -0.01 +/0.25 N 0.15 0 10 0.03 0 All values in dpm / g ca l culation s a nd s pread s he e t pr e pared by Jim Budahn, USGS Denver CO

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A p pen d ix VI : (Cont i nued) Mariposa Key d epth (em) 210Pb %Error 2 14Pb 214Bi "U" excess 137Cs Ca l culated o\ctu al I 9 88 3 2 08 2 .10 2 .24 7.79 0 .38 17. 2 7 8 5 3 10.2 2 2 2.38 2 08 2.30 7.99 0. 5 0 9.4 9 32 5 8.70 3 2 45 2 34 2.55 6.31 0 .36 6 9 7 .03 7 7.48 3 2 90 2.90 3.05 4 58 0 25 5 1 5.25 9 5 98 4 4 16 3 89 4 08 1.96 0 .24 2.8 2 8 1 11 5.41 5 3 98 3.66 4.09 1.59 0 .13 2.0 2.41 13 6 .21 4 5 83 5.44 5.10 0.58 0 12 1.7 1.73 1 5 4.44 6 4 31 4 .31 4 75 0.13 0.04 0.8 0.86 17 5 .50 5 4 .91 4.80 4 75 0.65 0.08 0 6 1.48 19 5.45 5 5.21 4 82 4 87 0.44 < 0 03 0 0 1.21 +I--0 .2 5 0 .15 0 .10 0 02 N All values in dpm/g c alculations perfonned and spread s heet prepared by Jim Budahn, USGS, Denver CO

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Appendix VII: Calculations for Sea Level Rise to 2100 Cumulative Probability Sea Level Rise Projections for St. Petersburg, FL Calculated based on EPA data, Titus & Narayanan (1995) Cumulative Percentage 2025 2050 10 5 75 11.5 20 6. 75 1 4.5 30 8 78 17 5 40 9.75 19. 5 50 10. 75 21.5 60 11.75 24 5 70 13. 75 2 6 5 80 14. 75 29.5 90 17 75 34 5 95 19. 75 38 5 97.5 22 75 42 5 99 24 75 49 5 Formnla : local (t) =normalized (t) + (t-1990) x trend local (t) = rise in sea level by year tat a part i cular location 2075 17. 25 23 25 2125 31.25 34.25 37.25 41.25 46.25 54. 25 60.25 67 25 1425 2100 24 33 39 43 51 56 59 67 78 87 1 01 115 normalized (t) = conservative estimate for global sea level rise at year t, in which historic component of greenhouse contr i but i on has been removed trend = CWTent rate of sea level rise at a particular location 1 2 2


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