A 1400-year multi-proxy record of climate variability from the northern Gulf of Mexico

Citation
A 1400-year multi-proxy record of climate variability from the northern Gulf of Mexico

Material Information

Title:
A 1400-year multi-proxy record of climate variability from the northern Gulf of Mexico
Creator:
Richey, Julie N
Place of Publication:
[Tampa, Fla]
Publisher:
University of South Florida
Publication Date:
Language:
English

Subjects

Subjects / Keywords:
Little Ice Age
Medieval warm period
Foraminifera
Climate change
Holocene
Dissertations, Academic -- Marine Science -- Masters -- USF ( lcsh )
Genre:
bibliography ( marcgt )
theses ( marcgt )
non-fiction ( marcgt )

Notes

Abstract:
ABSTRACT: A continuous, decadal-scale resolution multi-proxy record of climate variability over the past 1400 years in the northern Gulf of Mexico (GOM) was constructed from a box core recovered in the Pigmy Basin. Proxies include paired analyses of Mg/Ca and oxygen isotopes in the white variety of the planktic foraminifer Globigerinoides ruber and relative abundance variations of G. sacculifer in the foraminifer assemblages. Two multi-decadal intervals of sustained high Mg/Ca values indicate GOM sea-surface temperatures (SSTs) were as warm or warmer than near-modern conditions between 1000 and 1400 yrs BP. Foraminiferal Mg/Ca values during the coolest interval of the Little Ice Age (ca. 250 yrs BP) indicate that SST was 2 - 2.5 degrees Celcius below modern SST. Four minima in the Mg/Ca record between 900 and 250 yrs BP correspond with the Maunder, Spörer, Wolf and Oort sunspot minima, suggesting a link between solar insolation and SST variability in the GOM. An abrupt shift recorded in both the oxygen isotopic ratio of calcite and relative abundance of G. sacculifer occurs ~600 yrs BP. The shift in the Pigmy Basin record corresponds with a shift in the sea-salt-sodium (ssNa) record from the GISP2 ice core, linking changes in high-latitude atmospheric circulation with the subtropical Atlantic Ocean.
Thesis:
Thesis (M.S.)--University of South Florida, 2007.
Bibliography:
Includes bibliographical references.
System Details:
System requirements: World Wide Web browser and PDF reader.
System Details:
Mode of access: World Wide Web.
General Note:
Title from PDF of title page.
General Note:
Document formatted into pages; contains 60 pages.
Statement of Responsibility:
by Julie N. Richey.

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Source Institution:
University of South Florida Library
Holding Location:
University of South Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
001913697 ( ALEPH )
174145325 ( OCLC )
E14-SFE0001950 ( USFLDC DOI )
e14.1950 ( USFLDC Handle )

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Book

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A 1400-year multi-proxy record of climate variability from the northern Gulf of Mexico
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ABSTRACT: A continuous, decadal-scale resolution multi-proxy record of climate variability over the past 1400 years in the northern Gulf of Mexico (GOM) was constructed from a box core recovered in the Pigmy Basin. Proxies include paired analyses of Mg/Ca and oxygen isotopes in the white variety of the planktic foraminifer Globigerinoides ruber and relative abundance variations of G. sacculifer in the foraminifer assemblages. Two multi-decadal intervals of sustained high Mg/Ca values indicate GOM sea-surface temperatures (SSTs) were as warm or warmer than near-modern conditions between 1000 and 1400 yrs BP. Foraminiferal Mg/Ca values during the coolest interval of the Little Ice Age (ca. 250 yrs BP) indicate that SST was 2 2.5 degrees Celcius below modern SST. Four minima in the Mg/Ca record between 900 and 250 yrs BP correspond with the Maunder, Sprer, Wolf and Oort sunspot minima, suggesting a link between solar insolation and SST variability in the GOM. An abrupt shift recorded in both the oxygen isotopic ratio of calcite and relative abundance of G. sacculifer occurs ~600 yrs BP. The shift in the Pigmy Basin record corresponds with a shift in the sea-salt-sodium (ssNa) record from the GISP2 ice core, linking changes in high-latitude atmospheric circulation with the subtropical Atlantic Ocean.
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Little Ice Age.
Medieval warm period.
Foraminifera.
Climate change.
Holocene.
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A 1400 Y e a r M ul t i P r oxy R e c or d O f C l i m a t e V a r i a bi l i t y F r om T he N or t he r n G ul f O f M e xi c o by J ul i e N R i c he y A t he s i s s ubm i t t e d i n pa r t i a l f ul f i l l m e nt of t he r e qui r e m e nt s f or t he de g r e e of M a s t e r of S c i e nc e C ol l e ge of M a r i ne S c i e nc e U ni ve r s i t y of S ou t h F l o r i da M a j or P r of e s s or : B e nj a m i n P F l ow e r P h. D D a vi d J H ol l a nde r P h D T e r r a nc e M Q ui nn P h. D R i c ha r d Z P oor e P h D D a t e of A ppr ova l : A pr i l 10, 2007 K e yw or ds : l i t t l e i c e a ge m e di e va l w a r m pe r i od f o r a m i ni f e r a c l i m a t e c ha nge hol oc e ne C opyr i ght 2007 J ul i e R i c he y

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i T A B L E O F C O N T E N T S L I S T O F T A B L E S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i i L I S T O F F I G U R E S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i i i A B S T R A C T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i v C H A P T E R O N E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 I N T R O D U C T I O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 G e ogr a phi c S e t t i ng . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 M E T H O D S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 M g/ C a A na l ys i s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 S S T E qua t i ons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 P I G M Y B A S I N S S T R E C O R D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 I m pl i c a t i ons f or L a t e H ol oc e ne C l i m a t e E xt r e m e s . . . . . . . . . . . . . . . . . . 8 O X Y G E N I S O T O P E A N D F A U N A L R E C O R D S . . . . . . . . . . . . . . . . . . . . . . 10 L i nks t o H i gh L a t i t ude C i r c ul a t i on . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 C O N C L U S I O N S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 C H A P T E R T W O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 I N T R O D U C T I O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 B a c kgr ound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 M E T H O D S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 R E S U L T S A N D D I S S C U S S I O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 C a r bon i s ot ope s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 O xyge n I s ot ope s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 M g/ C a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 N o s i z e r e l a t i ons hi p i n w hi t e G r ube r ? . . . . . . . . . . . . . . . . . . . . . . . . . 23 C O N C L U S I O N S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 R E F E R E N C E S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 A P P E N D I C E S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 A ppe ndi x I : D a t a t a bl e f or w hi t e G r ube r . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 A ppe ndi x I I : D a t a t a bl e f or pi nk G r ube r . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 A ppe ndi x I I I : F a una l da t a ( % a bunda nc e ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 A ppe ndi x I V : S e a s ur f a c e s a l i ni t y e s t i m a t e s . . . . . . . . . . . . . . . . . . . . . . . . . . 59

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i i L I S T O F T A B L E S T a bl e 1 C or e t op M g/ C a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 T a bl e 2 T he or e t i c a l c a l c ul a t i ons of 1 8 O s e a w a t e r a nd S S T . . . . . . . . . . . . . . . . . . . . . . 25

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i i i L I S T O F F I G U R E S F i gur e 1 M a p of t he G ul f of M e xi c o . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 F i gur e 2 A ge m ode l f or c or e P B B C 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 F i gur e 3 T i m e s e r i e s o f [ A l ] [ F e ] a nd [ M n] i n c or e P B B C 1 . . . . . . . . . . . . . . . . 28 F i gur e 4 S c a t t e r pl ot o f [ A l ] [ F e ] a nd [ M n] ve r s us M g/ C a . . . . . . . . . . . . . . . . . 29 F i gur e 5 C om pa r i s on of c a l c ul a t e d S S T us i ng di f f e r e nt c a l i br a t i on e qua t i ons . . . 30 F i gur e 6 M g/ C a de r i ve d S S T R e c or d a nd N or t he r n H e m i s phe r e r e c ons t r uc t i on . 31 F i gur e 7 O ve r pl ot of r a w M g/ C a r e c or d f r om w hi t e a nd pi n k G r ube r . . . . . . . . 32 F i gur e 8 P i gm y B a s i n % G s ac c ul i f e r 1 8 O c a l c i t e a nd G I S P 2 s s N a . . . . . . . . . . . . 33 F i gur e 9 C a l c ul a t e d 1 8 O s e a w a t e r . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 F i gur e 10 C om pa r i s on of 1 8 O s e a w a t e r w i t h % a bunda nc e G r ube r ( w hi t e ) . . . . . . . 35 F i gur e 11 M ode l of G ul f of M e xi c o s a l i ni t y dur i ng t he m ont h of A p r i l . . . . . . . . . 36 F i gur e 12 S i z e f r a c t i on ve r s us 1 3 C f or w hi t e a nd pi nk G r ube r . . . . . . . . . . . . . . 37 F i gur e 13 G r ube r 1 3 C r e c or d ( pi nk a nd w hi t e ) . . . . . . . . . . . . . . . . . . . . . . . . . . 38 F i gur e 14 S i z e F r a c t i on ve r s us 1 8 O f or w hi t e a nd p i nk G r ube r . . . . . . . . . . . . . . 39 F i gur e 15 S i z e f r a c t i on ve r s us M g/ C a f or G r ube r ( pi nk) . . . . . . . . . . . . . . . . . . . 40 F i gur e 16 S i z e f r a c t i on ve r s us M g/ C a f or G r ube r ( w hi t e ) . . . . . . . . . . . . . . . . . . 41

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i v A 1400 Y e a r M ul t i P r oxy R e c or d of C l i m a t e V a r i a bi l i t y F r om t he N o r t he r n G ul f o f M e xi c o J ul i e N R i c he y A B S T R A C T A c ont i nuous de c a da l s c a l e r e s ol ut i on m ul t i pr ox y r e c or d o f c l i m a t e va r i a bi l i t y ove r t he pa s t 1400 ye a r s i n t he nor t he r n G ul f of M e xi c o ( G O M ) w a s c ons t r uc t e d f r om a box c or e r e c ove r e d i n t he P i gm y B a s i n. P r oxi e s i n c l ude pa i r e d a na l ys e s of M g/ C a a nd 1 8 O i n t he w hi t e va r i e t y of t he pl a nkt i c f or a m i ni f e r G l obi ge r i noi de s r ube r a nd r e l a t i ve a bunda nc e va r i a t i ons of G s ac c ul i f e r i n t he f or a m i ni f e r a s s e m bl a ge s T w o m ul t i de c a da l i nt e r va l s of s us t a i ne d hi gh M g/ C a va l ue s i ndi c a t e G O M s e a s ur f a c e t e m pe r a t ur e s ( S S T s ) w e r e a s w a r m or w a r m e r t ha n ne a r m ode r n c ondi t i ons be t w e e n 1000 a nd 1400 y r s B P F or a m i ni f e r a l M g/ C a va l ue s dur i ng t he c ool e s t i n t e r va l of t he L i t t l e I c e A ge ( c a 250 y r s B P ) i ndi c a t e t ha t S S T w a s 2 2. 5 C be l ow m ode r n S S T F our m i ni m a i n t he M g/ C a r e c or d be t w e e n 900 a nd 250 yr s B P c or r e s pond w i t h t he M a unde r S pr e r W ol f a nd O o r t s uns pot m i ni m a s ugge s t i ng a l i nk be t w e e n s ol a r i n s ol a t i on a nd S S T va r i a bi l i t y i n t he G O M A n a br up t s hi f t r e c or de d i n bot h 1 8 O c a l c i t e a nd r e l a t i ve a bunda nc e of G s ac c ul i f e r oc c ur s ~ 600 yr s B P T he s hi f t i n t he P i gm y B a s i n r e c or d c or r e s ponds w i t h a s hi f t i n t he s e a s a l t s odi um ( s s N a ) r e c or d f r om t he G I S P 2 i c e c or e l i nki ng c ha nge s i n hi gh l a t i t ude a t m os phe r i c c i r c ul a t i on w i t h t he s ubt r opi c a l A t l a nt i c O c e a n

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1 C H A P T E R 1 I N T R O D U C T I O N E s t a bl i s hi ng t he ge ogr a phi c pa t t e r n a nd m a gni t ude of na t u r a l c l i m a t e va r i a bi l i t y i n t he l a t e H ol oc e ne i s i m por t a nt f o r a nt i c i pa t i ng a nd unde r s t a ndi ng t he l i ke l y pa t t e r n s of f ut ur e c l i m a t e c ha nge A num be r of de t a i l e d c l i m a t e r e c or ds s pa nni ng t he l a s t 1 t o 2 t hous a nd ye a r s ( ky) de m ons t r a t e t ha t c l i m a t e o f t h e l a t e H ol oc e ne c ont a i ns hi gh a m pl i t ude va r i a bi l i t y R e gi ona l pa t t e r ns a nd i ndi v i dua l r e c or ds dur i ng r e c e nt c ol d a nd w a r m e xt r e m e c l i m a t e s t a t e s know n r e s pe c t i ve l y a s t he L i t t l e I c e A ge ( L I A ) a nd t he M e di e va l W a r m P e r i od ( M W P ) a r e c om pl e x a nd h i ghl y va r i a bl e C ool i ng/ w a r m i ng i n one r e gi on m a y be a s s oc i a t e d w i t h w a r m i ng/ c ool i n g or no c ha nge i n a not he r r e gi on a nd i ndi vi dua l pr oxy r e c or ds m a y r e pr e s e nt l oc a l c l i m a t e phe nom e na a nd a r e not ne c e s s a r i l y r e pr e s e nt a t i ve of he m i s phe r i c pa t t e r ns ( e g s e e s um m a r y i n C r ow l e y a nd L ow e r y, 2000 ) H e m i s phe r i c t e m pe r a t ur e r e c ons t r uc t i ons ( e g M a nn a nd J one s 2003 ) t ha t a r e ba s e d on a l a r ge num be r of t e m pe r a t ur e s e ns i t i ve p r oxy r e c or ds w i t h va r i a bl e s pa t i a l a nd t e m por a l r e s ol ut i on r e s ul t i n a r e c or d i n w hi c h va r i a bi l i t y ove r t he pa s t 1000 ye a r s pr i o r t o 1900 A D i s s ubdue d ( 0. 5 C ) T he r e s ul t i ng l o w a m pl i t ude r e c ons t r uc t i on c ont r a s t s w i t h s e ve r a l i ndi vi dua l m a r i ne r e c or ds t ha t i ndi c a t e c e nt e nni a l s c a l e S S T os c i l l a t i ons of 2 3 C oc c ur r e d du r i ng t he l a s t 1000 2000 ye a r s ( i e K e i gw i n 1996; L und a nd C ur r y 2005; W a t a na be e t a l 2001 N e w t on e t a l 2006 ) T r e e r i ng a nd m ul t i p r oxy r e c ons t r uc t i ons de s i gne d t o c a pt ur e m ul t i c e nt e nni a l s c a l e va r i a bi l i t y ( e g. E s pe r e t a l

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2 2002; M obe r g e t a l 2005) a l s o s ugge s t t ha t t he a m pl i t ude of na t ur a l c l i m a t e va r i a bi l i t y ove r t he pa s t 1000 ye a r s i s l a r ge r t ha n 0 5 C T hu s t he r e i s c onf l i c t i ng e vi de nc e on t he a m pl i t ude of l a t e H ol oc e ne de c a da l t o c e nt ur y s c a l e c l i m a t e va r i a bi l i t y R e s ol vi ng t he s e di s c r e pa nc i e s r e qui r e s t he c ont i nue d de ve l opm e nt of qua l i t y h i gh r e s ol ut i on l a t e H ol oc e ne c l i m a t e r e c or ds G e ogr aphi c Se t t i ng and R e gi onal C l i m at ol ogy H e r e w e pr e s e nt a c ont i nuous de c a da l s c a l e r e s ol ut i on m a r i ne r e c or d f r om t he P i gm y B a s i n ( F i g 1 ) l oc a t e d on t he c ont i ne nt a l s l ope i n t he no r t he r n G ul f o f M e xi c o ( G O M ) ( 27 11 61 N 91 24 54 W w a t e r de pt h 22 59 m ) T he i nt r a s l ope ba s i ns of t he T e xa s L oui s i a na S l ope i n t he nor t h c e nt r a l G O M a r e f or m e d by t he f a ul t i ng a s s oc i a t e d w i t h a c t i ve s a l t di a pi r i s m T he P i gm y B a s i n i s de f i ne d a s a bl oc ke d c a nyon i nt r a s l ope ba s i n, f or m e d by a n upw a r d m ovi ng s a l t di a pi r bl o c ki ng a f or m e r s ubm a r i ne c a nyon ( B oum a a nd C ol e m a n, 1986 ) D e pos i t i on i n t he P i gm y B a s i n i s pr i m a r i l y he m i pe l a gi c a nd t hus i t s hi gh s e di m e nt a t i on r a t e ( 43 c m / ky) a l l ow s f or hi gh r e s ol ut i on s t udi e s i n t he l a t e H ol oc e ne T he i n f l ux of c ont i ne nt a l m a t e r i a l vi a t he M i s s i s s i ppi R i ve r m a ke s i t a n i de a l s e t t i ng f or r e c or di ng not onl y s e a s ur f a c e va r i a bi l i t y but a l s o hyd r ol ogi c c ha nge s ove r t he N or t h A m e r i c a n c ont i ne nt D ur i ng t he bo r e a l s um m e r ( J ul y, A ugus t S e pt e m b e r ) t he W e s t e r n H e m i s phe r e W a r m P ool ( W H W P ) e xt e nds i nt o t he G O M w i t h s e a s ur f a c e t e m pe r a t ur e ( S S T ) e xc e e di ng 28. 5 o C t h r oughout T he W H W P w hi c h e xt e nds f r om t he e a s t e r n N or t h P a c i f i c O c e a n t hr ough t he G O M a nd C a r i bbe a n a n d i nt o t he t r opi c a l A t l a nt i c i s t he dom i na nt he a t s our c e f o r t he W e s t e r n H e m i s phe r e e xt r a t r opi c s dur i ng t he s um m e r a nd i s

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3 t he pr i m a r y m oi s t ur e s our c e d r i vi ng t he N or t h A m e r i c a n M ons oon ( W a ng a nd E n f i e l d, 2002) T he G O M i s c l os e l y l i nke d t o t he C a r i bbe a n a nd t r opi c a l A t l a nt i c vi a t he L oop C ur r e nt w hi c h i s a s ur f a c e oc e a n c ur r e nt t ha t br i n gs w a r m w a t e r s f r o m t he C a r i bbe a n S e a t hr ough t he Y uc a t a n S t r a i t i nt o t he G O M be f o r e e xi t i ng t h r ough t he F l or i da S t r a i t s t o be i nc or por a t e d i nt o t he G ul f S t r e a m T he G O M i s a s i gni f i c a nt s our c e of m oi s t ur e t o t he N or t h A m e r i c a n c ont i ne nt a nd t hus s t udi e s of hydr ol og i c va r i a bi l i t y dur i ng t h e l a t e H ol oc e ne a r e r e l e va nt t o pr e di c t i ng f ut u r e c ha nge s i n N or t h A m e r i c a n p r e c i pi t a t i on. T he G O M r e gi on ha s one o f t he hi ghe s t r a t e s of e va por a t i on m i nus p r e c i pi t a t i o n ( E P ) i n t he N or t h A t l a nt i c ba s i n. T he m e a n a nnua l E P r a t e i s 150 175 c m / y r a nd r a t e s a r e hi ghe s t i n t he w i nt e r a nd s pr i ng w he n t he y r e a c h 225 250 c m / yr ( S c hm i t t e t a l 19 89) T he ne t e va por a t i on i n t he G O M C a r i bbe a n r e gi on c a n be a t t r i but e d t o t he t r a de w i n ds w hi c h or i gi na t e i n t he r e gi on of s ubt r opi c a l hi gh a nd p r ogr e s s t ow a r d t he e qua t or H i ghe r s e a l e ve l pr e s s ur e ( S L P ) i n t he s ubt r opi c a l A t l a nt i c l e a ds t o hi ghe r t r a de w i nd i nt e ns i t y, w hi c h i s pos i t i ve l y c or r e l a t e d w i t h i nc r e a s e d ne t e va por a t i on i n t he w e s t e r n s ubt r opi c a l A t l a nt i c ( G i a nni ni e t a l 2000) T hi s s ugge s t s a s t r ong l i nk be t w e e n a t m os phe r i c c i r c ul a t i on a nd hyd r ol ogi c va r i a bi l i t y i n t he G O M M E T H O D S A ge c ont r ol f o r P i gm y B a s i n box c o r e P B B C 1 i s ba s e d on 7 A M S 1 4 C da t e s ( F i g. 2 ) R a w r a di oc a r bon da t e s w e r e c onve r t e d t o c a l e nda r ye a r s us i ng t he C A L I B 5 0 P r ogr a m w i t h a 400 ye a r r e s e r voi r c or r e c t i on ( S t u i ve r e t a l 1998 ) C a l i br a t e d a ge s w e r e pl ot t e d a ga i ns t c or e de pt h, a nd a l e a s t s qua r e s r e gr e s s i on ( R 2 = 0. 995) i ndi c a t e s a l i ne a r

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4 s e di m e nt a t i on r a t e of 43 c m / ky ( w i t hi n t he e r r or s o f t he c a l i br a t e d da t e s ) a nd a c o r e t op a ge of 0 y r s B P T hus w e i nf e r t ha t t he d a t a f r om t he younge s t s a m pl e s i n our r e c or d r e pr e s e nt ne a r m ode r n c ondi t i ons or a n a ve r a ge o f t he l a s t 30 50 ye a r s T he a ge m ode l w i t h a s a m pl i ng i nt e r va l of 0. 5 c m r e s ul t s i n a n a ve r a ge s a m pl e r e s ol ut i on of 12 ye a r s t hr oughout t he r e c or d. S e di m e nt s a m pl e s w e r e pr oc e s s e d f or f a una l i s ot o pi c a nd e l e m e nt a l a na l ys e s us i ng s t a nda r d pr oc e dur e s ( P oor e e t a l 2004) T h e r e l a t i ve a bunda nc e of G l obi ge r i noi de s s ac c ul i f e r i n t he pl a nkt i c f or a m i ni f e r a s s e m bl a ge f or e a c h s a m pl e w a s de t e r m i ne d f r om f a una l c e ns us c ou nt s of ~ 300 s pe c i m e ns i n t he > 150 m s i z e f r a c t i on. O xyge n i s ot ope a nd e l e m e nt a l a na l ys i s w a s pe r f or m e d on 40 80 pool e d G l obi ge r i noi de s r ube r ( w hi t e va r i e t y) f r om t he 250 300 m s i z e f r a c t i on of e a c h s a m pl e T he r e s t r i c t e d 250 200 m s i z e f r a c t i on w a s us e d f or ge oc he m i c a l a na l ys e s be c a us e s t udi e s ha ve i ndi c a t e d t ha t t he r e i s a r e l a t i ons hi p be t w e e n f or a m i ni f e r a l t e s t s i z e a nd i s ot opi c a nd e l e m e nt a l r a t i os O xyge n i s ot ope r a t i os w e r e m e a s ur e d on a T he r m o F i nni ga n D e l t a P l us X L l i ght s t a bl e i s ot ope r a t i o m a s s s pe c t r om e t e r ( S I R M S ) a t t he C ol l e ge of M a r i ne S c i e nc e U ni ve r s i t y of S out h F l or i da ( C M S U S F ) T he 1 8 O c a l c i t e i s r e por t e d on t he V P D B s c a l e ba s e d on t he N B S 19 s t a nda r d A ve r a ge pr e c i s i on f or 1 8 O c a l c i t e i s 0. 09 ba s e d on r e pl i c a t i on of 15 % of t he s a m pl e s ( n= 20 r e pl i c a t e s ) E l e m e nt a l a na l ys e s w e r e pe r f or m e d on a P e r k i n E l m e r O pt i m a 4300 dua l vi e w i nduc t i ve l y c oupl e d pl a s m a opt i c a l e m i s s i on s pe c t r om e t e r ( I C P O E S ) a t t he C M S U S F A ve r a ge pr e c i s i on f o r M g/ C a va l ue s i s 0. 16 m m ol / m ol ba s e d on 40 % dupl i c a t e a nd t r i p l i c a t e s a m pl e s ( n= 45 r e pl i c a t e d s a m pl e s ) T hi s c or r e s ponds t o 0 4 C

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5 M g/ C a A nal y s i s I n pr e pa r a t i on f or e l e m e nt a l a na l ys i s s a m pl e s und e r w e nt a r i go r ous c l e a ni ng pr oc e s s a c c or di ng t o t he pr oc e dur e of B a r ke r e t a l ( 2003) T he m a j or s t e ps i nc l ude t he m e c ha ni c a l r e m ova l of c l a y m i ne r a l s oxi da t i on o f or ga ni c m a t t e r a nd a c i d l e a c hi ng t o r e m ove a ds or be d m e t a l s F e a nd A l c onc e nt r a t i on s a r e m e a s ur e d s i m ul t a ne ous l y w i t h M g a nd C a a nd c a n be us e d a s i ndi c a t or s of t he pr e s e nc e of s i l i c a t e c ont a m i na t i on. C l a y m i ne r a l s m a ke up a s i gni f i c a nt por t i on of G O M s e di m e nt s a nd t he s e m i ne r a l s a r e c om pos e d of 1 10% M g by w e i ght ( B a r ke r e t a l 2 003) T he r e f or e i ne f f e c t i ve r e m ova l of c l a y m i ne r a l s du r i ng t he c l e a ni ng pr oc e s s c oul d r e s ul t i n a r t i f i c i a l l y hi gh M g/ C a I n F i gur e 3 [ A l ] [ F e ] a nd [ M n] a r e p l ot t e d i n a t i m e s e r i e s w i t h M g/ C a t o ve r i f y t h a t M g/ C a doe s not c ova r y w i t h s i l i c a t e c ont a m i na nt s T o f ur t he r i l l us t r a t e t h i s poi nt A l F e a nd M n c onc e nt r a t i ons a r e pl ot t e d a ga i ns t M g/ C a i n a s c a t t e r di a gr a m ( F i g 4 ) R 2 va l ue s a r e < 0. 2 i ndi c a t i ng t ha t t he r e i s no s i gni f i c a nt r e l a t i ons hi p b e t w e e n s i l i c a t e c ont a m i na nt s a nd M g/ C a A n a ddi t i ona l r e duc t i ve s t e p out l i ne d i n t he C d/ C a c l e a ni ng pr oc e dur e f r om B oyl e a nd K e i gw i n ( 1985 ) i s us e d i n s om e s t udi e s ( i e L und a nd C ur r y 2006 ) t o r e m ove M n F e oxi de s f r om di a ge ne t i c ove r gr ow t h but w a s de t e r m i ne d t o be unne c e s s a r y f or M g/ C a a na l ys i s by B a r ke r e t a l ( 2003 ) P e na e t a l ( 2005) f ound t ha t M g/ C a i s r e duc e d by 7 36% a f t e r t he r e duc t i ve c l e a ni ng s t e p, but ha ve not s how n c onc l us i ve l y t ha t t hi s i s due e xc l us i ve l y t o r e m ova l of hi gh M g m a t e r i a l w i t hi n t h e di a ge ne t i c ove r g r ow t h pha s e s F i gur e 3 i l l us t r a t e s t ha t t he oc c ur r e nc e of e l e va t e d M n c onc e nt r a t i ons doe s not c oi nc i de w i t h hi gh M g/ C a S a m pl e s f r om t he t op 10 c m o f c or e P B B C 1 ha ve M n c onc e nt r a t i ons c l os e t o z e r o, s ugge s t i ng t ha t di a ge ne t i c pr oc e s s e s ha ve not oc c ur r e d i n t he younge s t pa r t

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6 of t he c or e A r e duc t i ve c l e a ni ng s t e p m a y a r t i f i c i a l l y l ow e r t he M g/ C a of t he c or e t op s a m pl e s r e l a t i ve t o t hos e dow n c or e s a m pl e s t ha t c ont a i n M n oxi de ove r gr ow t h SST E quat i ons W e de t e r m i ne d a m e a n M g/ C a c or e t op va l ue of 4. 43 m m ol / m ol ( 0 03) f or t he P i gm y B a s i n f r om a na l ys e s of 0 0 5 c m s a m pl e s f r om t hr e e s ub c or e s of P B B C 1 ( T a bl e 1) C onve r t i ng M g/ C a t o a n S S T e s t i m a t e i s no t s t r a i ght f or w a r d be c a us e t he r e a r e s i gni f i c a nt di f f e r e nc e s be t w e e n e xi s t i ng c a l i br a t i on e qua t i ons us e d t o de r i ve S S T e s t i m a t e s f r om M g/ C a F or e xa m pl e t he P i gm y B a s i n c or e t op M g/ C a va l ue of 4. 43 m m ol / m ol r e s ul t s i n a t e m pe r a t u r e e s t i m a t e of 25. 4 C us i ng t he G r ube r e qua t i on of A na nd e t a l ( 2003) a nd 27. 2 C us i ng t he e qua t i o n of D e ke ns e t a l ( 2002) H ow e ve r bot h e qua t i ons yi e l d t e m pe r a t u r e r e c or ds w i t h i de n t i c a l a m pl i t ude s be c a us e t he y us e t he s a m e e xpone nt i a l c ons t a nt of 0. 09 F i gur e 5 s how s a c om pa r i s on of t he S S T r e c or d us i ng t he A na nd e t a l ( 2003) a nd D e ke ns e t a l ( 2 002) c a l i br a t i on e qua t i ons a nd i l l us t r a t e s t he e f f e c t of c ha ngi ng t he e xpone nt i a l a nd pr e e xpone nt i a l c ons t a nt i n t he e qua t i on. W e c hos e t o c a l c ul a t e S S T us i ng t he G r ube r s pe c i f i c e qua t i on w i t h a f i xe d e xpone nt i a l c ons t a nt f r om A na nd e t a l ( 2003) [ ( M g/ C a = 0. 449 *e xp( 0. 09*S S T ) ] be c a us e i t yi e l ds a c or e t op S S T va l ue of 25 4 C e qui va l e nt t o t he m ode r n a nnua l a ve r a ge f o r t he G O M ( L e vi t us 2003 ) D ue t o t he l a c k of a c a l i br a t i on e qua t i on s pe c i f i c t o t he G O M C a r i bbe a n r e gi on, a s w e l l a s t he di s c r e pa nc y i n a bs ol ut e S S T va l ue s be t w e e n c a l i br a t i on e qua t i ons w e f oc us on c om pa r i s on o f t he P B B C 1 r e c or d t o P i gm y B a s i n c or e t op M g/ C a a nd hi ghl i ght t he a m pl i t ude of t e m pe r a t ur e c ha nge but not t he a bs ol ut e S S T e s t i m a t e s

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7 P I G M Y B A S I N S S T R E C O R D S e a s ona l f l ux da t a f r om t he S a r ga s s o S e a i ndi c a t e t ha t t he w hi t e va r i e t y of G r ube r i s a bunda nt i n s ur f a c e w a t e r s t hr oughout t he ye a r ( D e us e r e t a l 1987) t he r e f o r e w e f ol l ow p r e vi ous w or k ( F l ow e r e t a l 2004 L oD i c o e t a l 2006 ) a nd i nt e r pr e t va r i a t i on i n M g/ C a of G r ube r ( w hi t e va r i e t y ) a s a p r oxy f o r m e a n a nnua l S S T T he m a i n f e a t ur e s of t he M g/ C a r e c or d f r o m P B B C 1 ( F i g. 6a ) i nc l ude t w o m ul t i de c a da l i nt e r va l s of s us t a i ne d hi gh M g/ C a ( > 4. 4 m m ol / m ol ) be t w e e n 1000 a nd 1400 y r s B P t ha t a r e s e pa r a t e d by a m ul t i de c a da l i nt e r va l of l ow e r M g/ C a A > 0 4 m m o l / m ol s hi f t t o l ow e r m e a n M g/ C a oc c ur r e d a t a bout 1000 yr s B P a nd l ow e r but va r i a bl e m e a n M g/ C a ( m e a n= 3. 8 m m ol / m o l ) oc c ur r e d be t w e e n 900 a nd 300 yr s B P A f t e r 250 yr s B P m e a n M g/ C a i nc r e a s e d by 0. 4 m m ol / m o l t ow a r ds t he c or e t op va l ue of 4. 4 m m ol / m o l I n F i gur e 7 t he M g/ C a of t he pi nk va r i e t y of G r ube r i s pl ot t e d w i t h t he w hi t e G r ube r M g/ C a c ur ve t o i l l us t r a t e t ha t t he s a m e pa t t e r n a nd a m pl i t ude of va r i a bi l i t y i s obs e r ve d i n a di f f e r e nt va r i e t y o f G r ube r T he t ot a l a m pl i t ude of va r i a bi l i t y i n m e a n M g/ C a ( ~ 1. 4 m m ol / m ol ) i ndi c a t e s a t e m pe r a t ur e r a nge o f ~ 3 C f r om t he m a xi m a be t w e e n 1000 a nd 1400 yr s B P t o t he S S T m i ni m a oc c ur r i ng be t w e e n 900 a nd 300 yr s B P T he s us t a i ne d m ul t i de c a da l l ong i nt e r va l s of hi gh M g/ C a be t w e e n 1000 a nd 1400 yr s B P a r e a t t he be gi nni ng o f t he t i m e r a nge a s s oc i a t e d w i t h t he M W P ( c a 800 t o 1200 y r s B P ; B r oe c ke r 2001) T he m e a n M g/ C a i n t he P i gm y ba s i n r e c or d f r om 1000 1400 yr s B P e xc e e ds t he c or e t op va l ue by ~ 0. 4 m m ol / m ol w hi l e 11 i ndi vi dua l m e a s ur e m e nt s e xc e e d t he c or e t op va l ue by > 0 6 m m ol / m ol T hus our da t a pr ovi de e vi de nc e f or m e a n a nnua l S S T i n t he nor t he r n G ul f of M e xi c o a s w a r m or w a r m e r t ha n ne a r m ode r n S S T dur i ng t he e a r l y pa r t o f t he M W P

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8 M i ni m a i n M g/ C a de f i ne d by i nt e r va l s l a s t i ng > 50 ye a r s i n w hi c h t he M g/ C a i s m or e t ha n 0 6 m m o l / m ol l ow e r t ha n t he c or e t op v a l ue ( > 1. 5 C c ool e r ) a r e pr e s e nt a t ~ 850 yr s B P 700 y r s B P 450 yr s B P a nd 250 yr s B P T he youn ge s t t hr e e m i ni m a f a l l w i t hi n t he a ge r a nge a s s oc i a t e d w i t h t he L I A ( C r o w l e y a nd L ow e r y 2000 ) S i x i ndi vi dua l M g/ C a m e a s ur e m e nt s be t w e e n 850 a nd 250 yr s B P a r e m or e t ha n 1 m m ol / m ol l ow e r t ha n t he c or e t op va l ue i ndi c a t i ng t ha t S S T i n t he nor t he r n G O M w a s a s m uc h a s 2. 0 t o 2. 5 C c ool e r t ha n ne a r m ode r n S S T du r i ng s e ve r a l i nt e r va l s of t he L I A T he f ou r M g/ C a m i ni m a c oi nc i de w i t h t he O or t W ol f S p r e r a nd M a unde r M i ni m a i n t he s uns pot r e c or d r e s pe c t i ve l y. T hus i t i s l i ke l y t ha t t he va r i a bi l i t y i n t he P i gm y B a s i n S S T r e c or d i s l i nke d t o c e nt e nni a l s c a l e va r i a b i l i t y i n s ol a r i ns ol a t i on. I m pl i c at i ons f or l at e H ol oc e ne c l i m at e e x t r e m e s T he m a gni t ude o f c ool i ng i ndi c a t e d by P i gm y B a s i n M g/ C a dur i ng c ol d e xt r e m e s of t he L I A ne a r 250 a nd 450 y r B P i s ~ 2. 0 2 5 C w hi c h c oi nc i de s ge ne r a l l y w i t h t he c ol d i nt e r va l s of t he L I A c e nt e r e d a t 1800 A D a nd 1 600 A D ( C r ow l e y a nd L ow e r y, 2000) O xyge n i s ot opi c a nd M g/ C a t e m pe r a t ur e e s t i m a t e s f r om c or a l r e c or ds f r o m P ue r t o R i c o i ndi c a t e a L I A c ool i ng o f 1 5 C c a 1800 A D a nd 2 C c a 1700 A D ( W i nt e r e t a l 2000; W a t a na be e t a l 2001) S r / C a t e m pe r a t ur e e s t i m a t e s f r om B e r m uda c or a l c a 1850 A D i ndi c a t e a c ool i ng of a t l e a s t 1. 0 C ( G oodki n e t a l 2005) S S T e s t i m a t e s ba s e d on 1 8 O i n t he pl a nkt oni c f or a m i ni f e r G r ube r ( w hi t e ) f r o m t he S a r ga s s o S e a s ugge s t a c ool i ng of ~ 1 2 C 300 400 yr B P ( K e i gw i n 1996) T hus t he ~ 2. 0 2. 5 C L I A c ool i ng de r i ve d f r om t he P i gm y B a s i n i s c ons i s t e nt w i t h publ i s he d L I A c ool i ng e s t i m a t e s f r om t he C a r i bbe a n a nd s ubt r opi c a l w e s t e r n A t l a nt i c

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9 L und a nd C ur r y ( 2006) ob t a i ne d 4 M g/ C a S S T r e c or ds f r om t he D r y T o r t uga s a nd t he G r e a t B a ha m a B a nk i n t he s ubt r opi c a l w e s t e r n A t l a nt i c t ha t e a c h s how ve r y di f f e r e nt pa t t e r ns of va r i a bi l i t y ove r t he pa s t ~ 1400 yr H ow e ve r a l l 4 r e c or ds i ndi c a t e S S T dur i ng pa r t s of t he L I A w a s on t he o r de r of 1 0 C c ool e r t ha n m ode r n. I n a ddi t i on, G r e a t B a ha m a B a nk c or e 125 M C i ndi c a t e s S S T c a 1200 1300 yr B P w a s s i m i l a r t o m ode r n S S T N e w t on e t a l ( 2006) de ve l ope d s ub de c a da l r e s ol ut i on M g/ C a S S T r e c or d f r om t he w e s t e r n t r opi c a l P a c i f i c t ha t e xhi bi t s a n a m pl i t ude of S S T va r i a bi l i t y ove r t he pa s t 1500 ye a r s t ha t i s s i m i l a r t o t ha t of t he P i gm y B a s i n S S T r e c or d T e m pe r a t ur e m a xi m a c a 1000 yr B P a r e s i m i l a r t o m ode r n S S T a nd t e m pe r a t ur e m i ni m a du r i ng t he L I A w e r e 1 0 C t o 1. 5 C be l ow m ode r n. T hus t he ne a r m ode r n or s l i ght l y w a r m e r t ha n m ode r n P i gm y B a s i n S S T e s t i m a t e s c a 1000 yr B P a r e s up por t e d i n pa r t by publ i s he d e s t i m a t e s f r om t he s ubt r opi c a l w e s t e r n A t l a nt i c T he P i gm y B a s i n M g/ C a r e c or d i s c om pa r e d i n F i gur e 6 t o a R e gi ona l C ur ve S t a nda r di z a t i on ( R C S ) c l i m a t e r e c ons t r uc t i on de r i ve d f r om t r e e r i ng r e c or ds a t 14 s i t e s i n t he N or t he r n H e m i s phe r e ( E s pe r e t a l 2002 ) T he R C S r e c or d i s de ve l ope d f r om m i d t o hi gh l a t i t ude ( 30 70 N ) a nd h i gh e l e va t i on s i t e s i n t he N or t he r n H e m i s phe r e W e c hos e t o c om pa r e our r e c or d t o t he E s pe r e t a l ( 2002 ) r e c ons t r uc t i on be c a us e t he y ut i l i z e d s t a t i s t i c a l t e c hni que s t ha t pr e s e r ve m ul t i c e nt e nni a l c l i m a t e va r i a bi l i t y a f t e r t he da t a a r e pr oc e s s e d. T he P i gm y B a s i n M g/ C a r e c or d a nd t he R C S c l i m a t e r e c ons t r uc t i on s how s i m i l a r pa t t e r ns of va r i a bi l i t y F o r e xa m pl e bot h i n di c a t e m a xi m um c ool i ng c a 200 a nd 400 yr B P B ot h r e c or ds c ont a i n a m ul t i de c a da l w a r m i nt e r va l c a 1000 y r B P i ndi c a t i ng t e m pe r a t ur e a s w a r m o r w a r m e r t ha n ne a r m ode r n t e m pe r a t ur e R e s ul t s of B l a c km a n T uke y c r os s s pe c t r a l a na l ys i s be t w e e n t he 2 r e c or d s i ndi c a t e a s i gni f i c a nt c ohe r e nc e ( a t

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10 t he 95% s i gni f i c a nc e l e ve l ) a t pe r i ods > 200 yr T h e s i m i l a r i t y o f t he P i gm y B a s i n M g/ C a a nd R C S r e c or ds i ndi c a t e s a l i nka ge be t w e e n e xt r a t r opi c a l c ont i ne nt a l t e m pe r a t u r e va r i a bi l i t y a nd no r t he r n G ul f o f M e xi c o S S T on m ul t i c e nt e nni a l t i m e s c a l e s S m a l l di f f e r e nc e s i n t he t i m i ng o f c l i m a t e e xt r e m e s be t w e e n t he t w o r e c or ds f a l l w i t h i n t he e r r or s of t he i nd e pe nde nt a ge m ode l s O X Y G E N I S O T O P I C A N D F A U N A L R E C O R D S T he r e l a t i ve a bunda nc e o f G l obi ge r i noi de s s ac c ul i f e r i n t he pl a nkt i c f or a m i ni f e r a s s e m bl a ge s a nd t he 1 8 O of G r ube r f r om c or e P B B C 1 a r e pl ot t e d w i t h t he s e a s a l t s odi um ( s s N a ) r e c or d f r om t he G I S P 2 I c e c o r e i n F i gur e 8. G l obi ge r i noi de s s ac c ul i f e r ( F i g. 8a ) i s a bunda nt i n t he C a r i bbe a n a nd va r i a t i o ns i n t he G s ac c ul i f e r a bunda nc e i n t he nor t he r n G O M s e di m e nt s a r e r e l a t e d t o t he i nf l ux of C a r i bbe a n s ur f a c e w a t e r s i nt o t he G O M a nd t he a ve r a ge pos i t i on of t he I T C Z ( P oo r e e t a l 2004 ) T he m os t p r om i ne nt f e a t ur e i n t he G s ac c ul i f e r r e c or d i s a n a b r upt s hi f t t o l ow e r r e l a t i ve a bunda nc e a t 600 yr s B P I nt e r pr e t a t i on o f t he 1 8 O r e c or d i s c om pl i c a t e d be c a us e t he 1 8 O i s i nf l ue nc e d by c ha nge s i n S S T a nd t he i s ot opi c c om pos i t i on of s e a w a t e r T he m a j or f e a t ur e of t he m e a n 1 8 O G r ube r r e c or d ( F i g 8b) i s a r a pi d s hi f t t o m o r e pos i t i ve va l ue s a t a bout 600 yr s B P P r i or t o 600 yr s B P t he m e a n r e c or d i s f a i r l y s t a bl e w i t h t he e xc e pt i on of a de c a da l s c a l e e xc ur s i on t o m or e pos i t i ve va l ue s c a 1050 A D A f t e r t he s hi f t a t 600 yr s B P t he 1 8 O r e c or d c ont a i ns s e ve r a l w e l l de f i ne d os c i l l a t i ons t ha t c ul m i na t e i n a t r e nd t o m o r e ne ga t i ve va l ue s ove r t he l a s t 100 ye a r s

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11 P a i r e d M g/ C a a nd 1 8 O m e a s ur e m e nt s c a n be us e d t o c a l c ul a t e s e a w a t e r 1 8 O ( 1 8 O s e a w a t e r ) T he 1 8 O s e a w a t e r m a y t he n be i nt e r pr e t e d i n t e r m s o f s a l i ni t y va r i a t i ons ( s e e A ppe ndi x I V f o r di s c us s i on of s a l i ni t y c a l c ul a t i ons ) G i ve n t he unr e s ol ve d unc e r t a i nt i e s i n t he a bs ol ut e M g/ C a S S T e s t i m a t e s t h a t a r e us e d a s a n i nput i nt o t he e qua t i on f or de r i vi ng 1 8 O s e a w a t e r w e p r e s e nt t he P B B C 1 1 8 O s e a w a t e r c ur ve ( F i g. 9 ) he r e t o i l l us t r a t e m a j or t r e nds i n 1 8 O s e a w a t e r va r i a bi l i t y but do no t a t t a c h s i gni f i c a nc e t o m i nor f l uc t ua t i ons or a bs ol ut e num e r i c a l 1 8 O s e a w a t e r T he m a j or f e a t u r e s of t he 1 8 O s e a w a t e r c ur ve i nc l ude t w o m a xi m a c e nt e r e d ne a r 500 a nd 1050 yr s B P T he ol de r e xc ur s i on c oi nc i de s w i t h t he s us t a i ne d i nt e r va l of hi gh S S T c e nt e r e d a t 1050 y r s B P ( s e e F i g 6 ) a s w e l l a s a m ul t i de c a da l e xc ur s i on of hi ghe r 1 8 O c a l c i t e ( s e e F i g. 8 ) T he younge r e xc ur s i on c oi nc i de s w i t h t he m e a n s hi f t obs e r ve d i n bot h t he G s ac c ul i f e r a nd 1 8 O c a l c i t e r e c or ds ( s e e F i g. 8 ) T he 1 8 O s e a w a t e r r e c or d a l s o c ova r i e s i nve r s e l y w i t h t he % a bunda nc e of G r ube r ( w hi t e ) i n c or e P B B C 1, w i t h t he t w o m a xi m a i n 1 8 O s e a w a t e r c or r e s pondi ng t o m i ni m a i n t he % a bunda nc e of t he w hi t e va r i e t y of G r ube r ( F i gur e 10 ) T hi s i nve r s e r e l a t i ons hi p be t w e e n 1 8 O s e a w a t e r a nd % a bunda nc e of G r ube r ( w hi t e ) w a s a l s o obs e r ve d i n a m i d H ol o c e ne G O M r e c or d f r om t he O r c a B a s i n ( L odi c o e t a l 2006 ) L i nk s t o hi gh l at i t ude c i r c ul at i on A na l ys i s of a gl a c i oc he m i c a l s e r i e s of m a j or i ons i n a n i c e c or e f r om G r e e nl a nd ( G I S P 2) ha s r e ve a l e d a di s t i nc t s hi f t i n s s N a c onc e nt r a t i ons a t 600 y r B P ( M e e k e r a nd M a ye w s ki 2002) W he n t he m os t r e c e nt 100 ye a r s of t he s s N a s e r i e s i s c om pa r e d t o t he i ns t r um e nt a l r e c or d o f s e a l e ve l pr e s s ur e ( S L P ) i n t he N or t h A t l a nt i c a s t r ong pos i t i ve r e l a t i ons hi p be t w e e n s s N a c onc e nt r a t i on a nd i nt e n s i t y of t he I c e l a ndi c L o w ( I L ) i s

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12 r e ve a l e d ( M e e ke r a nd M a ye w s ki 2002) A m or e pr onounc e d ( de e pe r ) I L r e s ul t s i n i nc r e a s e d w i nt e r w i nds bl ow i ng f r om t he N or t h A t l a nt i c ont o G r e e nl a nd i nc r e a s i ng t he s s N a c ont e nt of t he i c e T hus t he l ong t e r m s s N a r e c or d ( F i g 8c ) i s c ons i de r e d a pr oxy f or va r i a bi l i t y i n t he I L T he s s N a r e c or d c ont a i ns a n a br upt s hi f t i n m e a n v a l ue s a t 600 yr s B P t ha t i s s ync hr onous w i t hi n da t i ng e r r or s w i t h t he a br upt s hi f t s t o l ow e r va l ue s i n t he G s ac c ul i f e r a nd 1 8 O r e c or d f r om P B B C 1. T he s hi f t i n s s N a i s i nt e r pr e t e d a s a n a t m os phe r i c c i r c ul a t i on c ha nge r e s ul t i ng i n a de e p e r I L a nd m o r e i nt e ns e w i nt e r c i r c ul a t i on ove r t he N or t h A t l a nt i c a t t he be gi nni n g of t he L i t t l e I c e A ge ( M e e ke r a nd M a ye w s ki 2002) C r os s s pe c t r a l a na l ys i s ( us i ng t he B l a c km a n T uke y m e t hod) be t w e e n t he P i gm y B a s i n 1 8 O r e c or d a nd t he G I S P 2 s s N a r e c or d i ndi c a t e s i gni f i c a nt c ohe r e nc e ( a t t he 95 % c onf i de nc e l e ve l ) a t pe r i ods > 200 ye a r s T he c l os e c or r e s ponde nc e a t c e nt e nni a l t i m e s c a l e s c oupl e d w i t h t he s ync hr onous m e a n s hi f t obs e r ve d i n b ot h r e c or ds c a 600 yr s B P i ndi c a t e s a l i nk be t w e e n a t m os phe r i c c i r c ul a t i on i n t he N or t h A t l a nt i c a nd t he s ubt r opi c a l A t l a nt i c T he de c r e a s e i n G s ac c ul i f e r a bunda nc e a t 600 yr s B P s ugge s t s a s out hw a r d s hi f t i n t he a ve r a ge pos i t i on of t he I T C Z a nd a r e duc e d i nf l ux of C a r i bbe a n s ur f a c e w a t e r c oi nc i de d w i t h t he i nt e ns i f i c a t i on of t he I L T he c onc ur r e nt s hi f t t o m o r e pos i t i ve 1 8 O s e a w a t e r i s a l s o c ons i s t e nt w i t h a s out hw a r d m i g r a t i on of t he a ve r a ge pos i t i on of t he I T C Z w hi c h w oul d r e s ul t i n r e duc e d s um m e r t r a n s por t of m o i s t ur e i nt o t he G O M r e gi on N o c ha nge i n M g/ C a i s a s s oc i a t e d w i t h t he s hi f t i n t he 1 8 O a nd G s ac c ul i f e r r e c or ds i ndi c a t i ng t ha t t he c ha nge i n r e gi ona l hydr ol ogy c a 600 yr s B P i s no t l i nke d w i t h a m a j or c ha nge i n G O M S S T

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13 O ve r t he i ns t r um e nt a l pe r i od, pos i t i ve s s N a a nom a l i e s a r e hi ghl y c or r e l a t e d w i t h a n i nc r e a s e d S L P g r a di e nt be t w e e n t he I L a nd t he B e r m uda H i gh ( B H ) ( M e e ke r a nd M a ye w s ki 2002) T he i nt e ns i f i c a t i on of w i nt e r t r a de w i nds a s s oc i a t e d w i t h a l a r ge r I L B H gr a di e nt c oul d i nc r e a s e e va por a t i on i n t he t r a d e w i nd be l t t hus pr oduc i ng t he pos i t i ve 1 8 O s e a w a t e r e xc ur s i ons i n t he P i gm y B a s i n r e c or d t ha t c oi nc i de w i t h i nc r e a s e s i n s s N a i n t he G I S P 2 r e c or d c a 600 y r s B P a nd 1050 yr s B P T he s e pos i t i ve 1 8 O s e a w a t e r e xc ur s i ons a r e not l i ke l y t he r e s ul t o f de c r e a s e s i n f r e s hw a t e r i nput f r om t he M i s s i s s i ppi R i ve r F i gur e 11 s how s m ode l e d s e a s ur f a c e s a l i ni t y f or t he G O M i n A pr i l t he m ont h o f m a xi m um M i s s i s s i ppi di s c ha r ge D ur i ng m a xi m u m f r e s hw a t e r i nput t he l ow e r s a l i ni t y pl um e i s c onf i ne d t o t he c oa s t a l a r e a s m ov i ng e a s t w a r d a nd w e s t w a r d a l ong t he s he l f a nd t hus ha s l i t t l e i n f l ue nc e on t he s ur f a c e s a l i ni t y ove r t he P i g m y B a s i n. T he r e f o r e i t i s l i ke l y t ha t t he hydr ol ogi c va r i a bi l i t y ove r t he pa s t 1400 ye a r s i n t he P i gm y B a s i n r e gi on i s be i ng dr i ve n by c ha nge s i n ne t e va por a t i on a nd not M i s s i s s i ppi i nput C O N C L U S I O N S C l os e c or r e s ponde nc e of t he P i gm y B a s i n M g/ C a r e c or d t o t he N H c l i m a t e r e c ons t r uc t i on of E s pe r e t a l ( 2002) de m ons t r a t e s c ohe r e nc e be t w e e n hi gh l a t i t ude t e r r e s t r i a l c l i m a t e a nd s ubt r opi c a l A t l a nt i c S S T R a w M g/ C a dur i ng t w o m u l t i de c a da l i nt e r va l s be t w e e n 1000 a nd 1400 yr s B P s ugge s t S S T w a s a s w a r m o r w a r m e r t ha n ne a r m ode r n S S T a t t ha t t i m e P i gm y B a s i n M g/ C a da t a a l s o s ugge s t S S T c ool i ng dur i ng i nt e r va l s of t he L I A t ha t w a s a t l e a s t 2 C be l ow ne a r m ode r n S S T T he ove r a l l a m pl i t ude of S S T va r i a bi l i t y i n t he P i gm y B a s i n r e c or d dur i n g t he pa s t 1400 ye a r s i s a bout 3 C

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14 75% of t he gl a c i a l i nt e r gl a c i a l S S T di f f e r e nc e e s t i m a t e d i n t he G O M ( F l ow e r e t a l 2004) S S T a nd hydr ol ogi c c ha nge s a r e de c oupl e d on m u l t i de c a da l t o c e nt e nni a l t i m e s c a l e s i n t he G O M T he a br upt s hi f t i n 1 8 O c a l c i t e a nd G s ac c ul i f e r a bunda nc e f r om t he P i gm y B a s i n c a 600 yr s B P c oi nc i de s w i t h a r a pi d c ha nge i n a t m os phe r i c c i r c ul a t i on a s i nf e r r e d f r om t he G I S P 2 s s N a r e c or d f r om M e e ke r a nd M a ye w s ki ( 2002) T he da t a s ugge s t a s t r ong l i nka ge be t w e e n a t m os phe r i c c i r c ul a t i on c ha nge s i n t he hi gh l a t i t ude N or t h A t l a nt i c a nd t he hydr o l ogi c c ha nge s i n s ubt r opi c a l A t l a nt i c a t ~ 600 yr s B P but not w i t h S S T

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15 C H A P T E R 2 I N T R O D U C T I O N T he i nc or por a t i on of m i nor e l e m e nt s a nd s t a bl e i s o t ope s i nt o bi oge ni c c a r bona t e s i s gove r ne d by a nu m be r o f phys i ol ogi c a l a nd e nvi r onm e nt a l pa r a m e t e r s bot h e qui l i br i um a nd non e qui l i br i um W he n ut i l i z i ng e l e m e nt a l a nd i s ot opi c r a t i os i n f or a m i ni f e r a l c a l c i t e f o r t he pu r pos e of pa l e oc e a nogr a phi c r e c ons t r uc t i ons t he goa l i s t o m a xi m i z e t he e nvi r onm e nt a l s i gna l a nd t o m i ni m i z e non e qui l i br i um f r a c t i ona t i on f a c t or s C ont r i but i ng f a c t or s t o non e q ui l i br i um f r a c t i ona t i on i nc l ude m e t a bol i c f r a c t i ona t i on ( B e r ge r e t a l 1978) phot os ynt he s i s a nd r e s pi r a t i on of s ym bi ont s ( S pe r o a nd L e a 1993 ) a nd ki ne t i c e f f e c t s ( M c C onna ughe y, 2003) A s a f or a m i ni f e r gr ow s i t s m e t a bol i c r a t e de pt h ha bi t a t a nd s ym b i ont c ondi t i on c ha nge a nd t hus t he o f f s e t of t e s t ge oc he m i s t r y f r o m e qui l i br i um m a y c ha nge I n t hi s s t udy I t e s t t he hypot he s i s t ha t f or a m i n i f e r a l t e s t s i z e ha s a n e f f e c t upon M g/ C a 3 C a nd 8 O va l ue s by m e a s ur i ng t he i s ot opi c a nd e l e m e nt a l c om pos i t i on of m ul t i pl e s i z e c l a s s e s of t he pi nk a nd w hi t e va r i e t i e s of t he pl a nkt oni c f o r a m i ni f e r G l obi ge r i noi de s r ube r P r e vi ous s t udi e s ha ve s how n non e qui l i br i um f r a c t i ona t i on of c a r bon a nd oxyge n i s ot ope s a s w e l l a s M g/ C a t o be r e l a t e d t o f o r a m i n i f e r a l t e s t s i z e ( B e r ge r e t a l 1978; C ur r y a nd M a t t he w s 1981; E l de r f i e l d e t a l 2002; R a ve l o a nd F a i r ba nks 1995; a nd W i l l i a m s e t a l 1981)

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16 C ur r y a nd M a t t he w s ( 1981) m e a s ur e d 1 3 C a nd 1 8 O i n a s e r i e s of di f f e r e nt s i z e f r a c t i ons of t he w hi t e G r ube r i n c or e t op s a m pl e s f r om t he I ndi a n O c e a n. T he y f ound t ha t t he c a r bon i s ot opi c c om pos i t i on of G r ube r i nc r e a s e d w i t h i nc r e a s i ng s i z e w hi l e t he r e w a s no s i gni f i c a nt c or r e l a t i on be t w e e n t he ox yge n i s ot opi c c om pos i t i on a nd t e s t s i z e E l de r f i e l d e t a l ( 2002) c ond uc t e d a s i m i l a r s t udy i nvol vi ng bot h w hi t e a nd pi nk G r ube r a nd m e a s ur e d M g/ C a i n a ddi t i on t o c a r bon a nd oxyge n i s ot ope s R e s ul t s s ugge s t e d a n i nc r e a s e i n 1 3 C w i t h i nc r e a s i ng t e s t s i z e f or a l l s pe c i e s a na l yz e d. T he i nf l ue nc e of t e s t s i z e on 1 8 O a nd M g/ C a how e ve r w a s l e s s c l e a r T he r e w a s a s l i ght i nc r e a s e i n M g/ C a w i t h s i z e i n w hi t e G r ube r but no r e l a t i ons hi p i n pi nk G r ube r a nd t he r e w a s no s i gni f i c a nt r e l a t i ons hi p be t w e e n t e s t s i z e a nd 1 8 O i n w hi t e or pi nk G r ube r T he m a t e r i a l us e d i n t he E l de r f i e l d e t a l ( 2002 ) s t udy i s of m i d H ol oc e ne a ge a nd t he s a m pl i ng i nt e r va l i s e qui va l e nt t o 800 ye a r s pe r s a m pl e T he y us e d onl y 20 i ndi vi dua l f or a m i n i f e r s pe r m e a s ur e m e nt s o i t i s p os s i bl e t ha t t he i r di f f e r e nt s i z e f r a c t i ons w e r e bi a s e d t ow a r d d i s t i nc t c l i m a t e r e gi m e s w i t hi n t ha t 800 ye a r pe r i od a nd t hus t he va r i a bi l i t y obs e r ve d m a y not r e f l e c t t he t r ue i nf l ue nc e of s i z e on t e s t ge oc he m i s t r y. W i t h t he P i g m y B a s i n m a t e r i a l t he c or e t op m a t e r i a l us e d r e p r e s e nt s onl y a bout 12 ye a r s a nd t hus t h e pos s i bi l i t y o f t he f or a m i ni f e r a r e p r e s e nt i ng di f f e r e nt c l i m a t e e xt r e m e s i s l e s s l i ke l y. B A C K G R O U N D O xyge n i s ot opi c c om pos i t i on i n pl a nkt on i c f o r a m i ni f e r a i s t he m os t w i de l y us e d pr oxy f o r m a ki ng i nf e r e nc e s a bout s e a s ur f a c e t e m pe r a t ur e ( S S T ) a nd s a l i n i t y ( S S S ) i n t he pa l e oc e a nogr a phi c r e c or d. F o r a m i ni f e r a l 8 O be c om e s m or e de pl e t e d w i t h

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17 i nc r e a s i ng t e m pe r a t ur e a nd de c r e a s i ng s a l i ni t y. C a r bon i s ot ope s i n pl a nkt oni c f or a m i ni f e r a a r e m o r e di f f i c ul t t o i nt e r p r e t i n t e r m s of a s i ngl e s e a s ur f a c e pa r a m e t e r T he c a r bon i s ot opi c c om pos i t i on of t he di s s ol ve d i nor g a ni c c a r bon ( D I C ) pool i s f r a c t i ona t e d i n s e a w a t e r by a num be r of e nvi r onm e nt a l p r oc e s s e s i nc l udi ng bi ol ogi c a l pr oduc t i on, m i xi ng of w a t e r m a s s e s a nd e xc ha nge of c a r bon b e t w e e n di f f e r e nt r e s e r voi r s I n a ddi t i on, c a r bon i s f r a c t i ona t e d dur i ng c a l c i f i c a t i on i n bi oge ni c c a r bona t e s a s t he r e s ul t e ndos ym bi ont s m e t a bol i c pr oc e s s e s a nd ki ne t i c e f f e c t s I n a ge ne r a l s e ns e c a r bon i s ot ope s c a n be i nt e r pr e t e d a s a p r oduc t i vi t y p r oxy. W he n pr i m a r y p r oduc t i vi t y i nc r e a s e s t he D I C pool f r om w hi c h t he f or a m i ni f e r c a l c i f i e s be c om e s m or e e nr i c he d i n 3 C T hus i nc r e a s e s i n f or a m i ni f e r a l 3 C i ndi c a t e i nc r e a s e s i n pr i m a r y pr oduc t i vi t y F or a m i ni f e r a l M g/ C a i s us e d a s a pa l e ot e m pe r a t ur e pr oxy. T hi s i s ba s e d on t he pr i nc i pl e t ha t M g 2 + r e pl a c e s C a 2 + i n t he c a l c i t e l a t t i c e a c c or di ng t o a n e xpone nt i a l t e m pe r a t ur e de pe nde nc e ( i e M g/ C a i nc r e a s e s a bout 9% w i t h a 1 C i nc r e a s e i n S S T f r o m A na nd e t a l 2003) D ur i ng t he i no r ga ni c pr e c i pi t a t i on of c a l c i t e M g/ C a i nc r e a s e s by 3% pe r 1 C i nc r e a s e i n t e m pe r a t ur e i ndi c a t i ng a pr e f e r e nc e f or hi gh M g c a l c i t e i n bi oge ni c c a r bona t e s V e r y l i t t l e i s unde r s t ood a bout t he m e c ha ni s m s of e l e m e nt a l f r a c t i ona t i on i n f or a m i ni f e r a l c a l c i f i c a t i on, or how i t m i ght c ha nge a s a f unt i on of t e s t s i z e M E T H O D S F or i s ot opi c a na l ys i s 20 i ndi vi dua l s of bot h t he pi nk a nd w hi t e va r i e t i e s of G r ube r w e r e pi c ke d f r om e a c h s i z e f r a c t i on f r om t he 10 15m m de pt h i n c or e P B B C 1. A 5m m s a m pl e r e pr e s e nt s r oughl y 12 ye a r s of t i m e a nd t he 10 15m m s a m pl e w a s l i ke l y de pos i t e d i n t he l a t t e r ha l f of t he 20 t h c e nt ur y ( s e e e xpl a na t i on on pa ge 4 ) S i z e f r a c t i ons

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18 a na l yz e d f or G r ube r ( pi nk) i nc l ude d 150 212 m 212 250 m 250 300 m 300 355 m a nd 355 425 m S i z e f r a c t i ons a na l yz e d f or G r ube r ( w hi t e ) i nc l ude t he 150 212 m 212 250 m 250 300 m a nd 300 355 m s i z e f r a c t i ons F or M g/ C a t he s a m e s i z e f r a c t i ons w e r e a na l yz e d, but t he e xpe r i m e nt w a s c on duc t e d a t 2 di f f e r e nt de pt hs i n c or e P B B C 1: 20 25m m ( ~ 50 100 yr s B P ) a nd 320 3 25m m ( ~ 800 yr s B P ) R E S U L T S A N D D I S C U S S I O N C ar bon i s ot ope s F i gur e 12 s how s pl ot s o f 3 C a s a f unc t i on of s i z e f or bot h pi nk a nd w hi t e G r ube r T he r e i s a pos i t i ve c or r e l a t i on be t w e e n s i z e a nd c a r bon i s ot opi c c om pos i t i on i n bot h t he pi nk a nd w hi t e G r ube r da t a w i t h R 2 va l ue s of 0. 93 a nd 0 89 r e s pe c t i ve l y. T he s l ope s a r e ne a r l y i de nt i c a l f o r bot h r e gr e s s i ons w i t h t he pi nk va r i e t y be i ng e nr i c he d by 0. 41 pe r m i l r e l a t i v e t o t he w hi t e va r i e t y. T he a ve r a ge di f f e r e nc e be t w e e n t he 1 3 C va l ue s of w hi t e a nd pi nk G r ube r w a s c a l c ul a t e d f or t he 1500 ye a r t i m e s e r i e s ( F i gur e 13) i nd i c a t i ng t ha t p i nk G r ube r i s e nr i c he d by 0. 35 pe r m i l r e l a t i ve t o w hi t e G r ube r t hus i l l us t r a t i ng t ha t t hi s i s ot opi c of f s e t i s c ons i s t e nt t hr ough t i m e T he r e i s a > 1. 0 r a nge be t w e e n t he c a r bon i s ot opi c va l ue s of t he s m a l l e s t ( 150 212 m ) a nd t he l a r ge s t ( > 355 m ) s i z e f r a c t i ons o f bot h pi nk a nd w hi t e G r ube r T hi s r a nge i s e qui va l e nt t o t he e nt i r e r a nge o f va r i a bi l i t y t ha t i s obs e r ve d i n t he 15 00 ye a r t i m e s e r i e s of 3 C da t a ( F i gur e s 13 ) T he r e s ul t s ge ne r a t e d f o r 1 3 C ve r s us s i z e a r e c ons i s t e nt w i t h pr e vi ous s t udi e s ( B e r ge r e t a l 1978; C ur r y a nd M a t t he w s 1981; E l de r f i e l d e t a l 2002; R a ve l o a nd F a i r ba nks 1995) a nd t he p r i nc i pl e s of ki ne t i c f r a c t i on i n s ym bi ont be a r i ng pl a nkt oni c

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19 f or a m i ni f e r a M e t a bol i c pr oc e s s e s pr oduc e C O 2 t ha t i s de pl e t e d i n 1 3 C r e l a t i ve t o D I C i n s e a w a t e r M e t a bol i s m i s hi ghe s t dur i ng e a r l y ont o ge ne t i c s t a ge s ( s m a l l e r s i z e f r a c t i ons ) l e a di ng t o t he i nc or por a t i on of m or e m e t a bol i c C O 2 i nt o f or a m i n i f e r a l c a l c i t e A s t he f or a m gr ow s c a l c i t e pr e c i pi t a t i on c ont i nue s but m e t a bol i s m s l ow s ( B e r ge r e t a l 1978 ) T hus f r a c t i ona t i on due t o m e t a bol i c e f f e c t s i s l ow e s t i n t he l a r ge r s i z e f r a c t i ons T hi s t r e nd i s c l e a r l y i l l us t r a t e d i n F i gur e 12, w he r e t he r e i s a pos i t i ve l i ne a r c or r e l a t i on be t w e e n s i z e a nd 1 3 C P hot os ynt he s i s of di nof l a ge l l a t e s ym bi ont s a l s o c o nt r i but e s t o di s e qui l i br i u m f r a c t i ona t i on of c a r bon i n pl a nkt oni c f or a m i ni f e r a D ur i ng phot os ynt he s i s C O 2 c om pos e d of t he l i ght e r i s ot ope of c a r bon i s pr e f e r e nt i a l l y t a ke n up by t he a l ga l s ym bi ont s T h i s c a r bon i s s ubs e que nt l y pa c ka ge d i nt o l ow m ol e c ul a r w e i ght m e t a bol i t e s t o be ut i l i z e d dur i ng f or a m i ni f e r a l m e t a bol i s m T h i s e f f e c t i s e xpr e s s e d m os t s t r ongl y i n t he s m a l l e r s i z e f r a c t i ons f o r m u l t i pl e r e a s ons A s poi nt e d out i n t he p r e vi ous pa r a gr a ph, m e t a bol i s m i s hi ghe s t i n s m a l l i nd i vi dua l s T he r e f or e m or e pho t os ynt he t i c a l l y f r a c t i ona t e d c a r bon w i l l be i nc o r por a t e d i nt o t he t e s t s of j uve ni l e f o r a m i ni f e r a A ddi t i ona l l y, f or a m i ni f e r a s i nk t h r ough t he w a t e r c ol um n dur i ng t he i r l i f e c yc l e l e a di ng t o de c r e a s e d phot os ynt he t i c a c t i vi t y. T he r e i s a l s o f r a c t i ona t i on a s s oc i a t e d w i t h r e s pi r a t i on, but S pe r o a nd L e a ( 1986) s how t ha t < 1 0% of r e s pi r e d C O 2 i s i nc or por a t e d i nt o t he c a l c i t e s ke l e t on of t he p l a nkt oni c s pe c i e s O r bul i na uni v e r s a M os t c a l c i f i c a t i on oc c ur s dur i ng t he da y w he n phot os ynt he s i s i s m or e a c t i ve t ha n r e s pi r a t i on ( M c C onna ughe y, 2003) I n F i gu r e 12 t he t r e nd l i ne s f o r pi nk a nd w hi t e G r ube r ha ve ne a r l y i de nt i c a l s l ope s but t he r e i s a 0. 4 of f s e t i n t he 1 3 C va l ue s A pos s i bl e c a us e f or t he of f s e t i n

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20 t he i r 1 3 C va l ue s i s di f f e r e nc e i n s e a s ona l di s t r i but i on of w hi t e a nd pi nk G r ube r T he pi nk va r i e t y o f G r ube r i s c onf i ne d t o t he w a r m e s t 6 m ont hs i n t he ye a r w i t h f l uxe s dr oppi ng t o z e r o f r om D e c e m be r t o M a y ( D e us e r e t a l 1987) w hi l e t he m a j o r phyt opl a nkt on bl oom s oc c ur i n t he e a r l y s pr i ng I nc r e a s e d phot os ynt he s i s dur i ng t he e a r l y bl oom m a y l e a ve t he c a r bon pool m o r e e nr i c he d i n t he s um m e r T hi s phe nom e non c oul d a c c ount f or t he 1 3 C va l ue s be i ng 0 4 hi gh e r i n pi nks t ha n i n w h i t e s W hi t e s ha ve a br oa de r s e a s ona l di s t r i but i on, a nd t hus w ou l d not e xhi bi t t he e l e va t e d 1 3 C va l ue s of pi nks T he r e m a y a l s o be s l i ght di f f e r e nc e s i n t he de pt hs of c a l c i f i c a t i on f or t he t w o va r i e t i e s of G r ube r H i gh ph ot os ynt he t i c r a t e s a t t he s ur f a c e c a us e 1 3 C va l ue s t o be hi ghe s t a t t he s ur f a c e a nd de c r e a s e w i t h de pt h i n t h e w a t e r c ol um n. I t i s pos s i bl e t ha t pi nk G r ube r i s c a l c i f yi ng a t a s l i ght l y s ha l l ow e r d e pt h i n t he w a t e r c ol um n O x y ge n i s ot ope s F i gur e 14 i l l us t r a t e s a s i gni f i c a nt ne ga t i ve c or r e l a t i on be t w e e n t he oxyge n i s ot opi c c om pos i t i on of pi nk G r ube r a nd t e s t s i z e w i t h a n R 2 = 0. 92 T he 8 O obs e r ve d i n t he l a r ge s t s i z e c l a s s of pi nk G r ube r i s 0. 6 l ow e r t ha n i n t he s m a l l e s t s i z e c l a s s T hi s i s e qui va l e nt t o a 3 C r a nge i n t e m pe r a t ur e s pa c e T he 1 8 O da t a f or w hi t e G r ube r how e ve r i ndi c a t e no c or r e l a t i on w i t h s i z e I nt e r pr e t a t i on o f da t a ge ne r a t e d f or 1 8 O ve r s us s i z e f r a c t i on ( F i gur e 14 ) i s not a s s t r a i ght f or w a r d a s t he 1 3 C da t a I n t he p i nk G r u be r t he da t a i ndi c a t e a s i gni f i c a nt ne ga t i ve c or r e l a t i on be t w e e n s i z e a nd 1 8 O va l ue T hi s c ont r a di c t s t he s l i ght l y pos i t i ve r e l a t i ons hi p be t w e e n s i z e a nd 1 8 O i n pi nk G r ube r obs e r ve d by E l de r f i e l d e t a l ( 2002) T he s a m pl i ng i nt e r va l f or t ha t s t udy, how e ve r i s ~ 800 ye a r s be t w e e n 4 a nd 5 ky B P T he

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21 c l i m a t e va r i a bi l i t y ove r t ha t 800 ye a r pe r i od i s l a r g e e nough t ha t i t m a y m a s k t he r e a l s i z e 8 O r e l a t i ons hi p w i t hi n a s a m pl e of 20 i ndi v i dua l f or a m i ni f e r a T he 1 8 O da t a ge ne r a t e d f or w hi t e G r ube r s how n o r e l a t i ons hi p t o s i z e f r a c t i on. T hi s i s c onf oundi ng s i nc e t he s a m e c a r bon f r a c t i o na t i on m e c ha ni s m s s e e m t o be a t w or k i n t he t w o va r i e t i e s of G r ube r ba s e d on c ons i de r a t i on of t he 1 3 C da t a T he 0 92 1 8 O va l ue f or t he 212 250 m s a m pl e a ppe a r s t o be a n om a l ous but t he va l ue ha d a hi gh r e pr oduc i bi l i t y. C ur r y a nd M a t t he w s ( 1981) obs e r ve a pos i t i ve r e l a t i ons hi p be t w e e n s i z e a nd 1 8 O i n w hi t e G r ube r w hi l e E l de r f i e l d e t a l ( 2002) obs e r ve a ne ga t i ve r e l a t i ons hi p. C ur r y a nd M a t t he w s ( 1981 ) c or e t op s a m pl e s c om e f r om a r e gi on i n w hi c h t he a nnua l t e m pe r a t ur e r a nge i s > 25 C ( c om pa r e d t o a bout 9 C i n t he G O M ) T he r a nge of c a l c i f i c a t i on t e m pe r a t ur e s w i t hi n a s m a l l s a m pl e s i z e w oul d l i ke l y m a s k a ny t r ue s i z e 1 8 O r e l a t i ons hi p. T a bl e 2 s ho w s t he r e s ul t s of a n e xe r c i s e i n w hi c h t he 1 8 O va l ue s ge ne r a t e d i n t h i s s t udy w e r e us e d t o c a l c ul a t e bot h 1 8 O s e a w a t e r a nd S S T us i ng know n m ode r n va l ue s a s c ons t a nt s i n E qua t i on 1 A m ode r n 1 8 O s e a w a t e r va l ue of 1 1 i s us e d f or t he G O M ( f r om F a i r ba nks e t a l 1992 ) a nd a m ode r n m e a n s um m e r S S T o f 28 0 C i s us e d f or G r ube r ( pi nk) a nd a m ode r n m e a n a nnua l S S T of 25 4 C i s us e d f or G r ube r ( w hi t e ) ( L e vi t us 2003) F or G r ube r ( pi nk) t he 1 8 O da t a f or t he 2 50 300 m s i z e f r a c t i on yi e l ds S S T a nd 1 8 O s e a w a t e r va l ue s t ha t a r e c l os e s t t o pr e di c t e d va l ue s T he pr e di c t e d S S T a nd 1 8 O s e a w a t e r va l ue s w e r e not pr oduc e d f r om a ny of t he s i z e f r a c t i ons f or G r ube r ( w hi t e ) E qua t i on 1: S S T ( C ) = 14. 9 4 8( c s w ) ( f r om B e m i s e t a l 1998 )

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22 M g/ C a T hi s s i z e f r a c t i on e xpe r i m e nt w a s c onduc t e d a t t w o di f f e r e nt c or e de pt hs f or bot h pi nk a nd w hi t e G r ube r t o de t e r m i ne w he t he r t he s i z e M g/ C a r e l a t i ons hi p w a s c ons t a nt t hr ough t i m e a nd w he t he r i t c oul d be r e pl i c a t e d. T he 20 25 m m r e pr e s e nt s a m ode r n pe r i od ( ~ 50 100 yr s B P ) w hi l e t he 320 325m m a ge r e pr e s e nt s a n a ge of 800 yr s B P F i gur e 15 i l l us t r a t e s a s i gni f i c a nt pos i t i ve c or r e l a t i on be t w e e n t e s t s i z e a nd M g/ C a i n pi nk G r ube r a t t w o di f f e r e nt c or e de pt hs T he R 2 va l u e s f or t he 20 25m m a nd 320 325m m de pt hs a r e 0. 68 a nd 0. 86 r e s pe c t i ve l y. T he s l ope s of t he r e gr e s s i on l i ne s a r e i de nt i c a l f or t he t w o di f f e r e nt de pt hs w i t h a n ove r a l l r a nge of 0 8 m m ol / m ol ( 2 C ) be t w e e n t he s m a l l e s t a nd l a r ge s t s i z e c l a s s T he M g/ C a va l ue s a r e of f s e t be c a us e t he 320 325m m de pt h r e pr e s e nt s a c ol d pe r i od i n t he G ul f of M e xi c o r e l a t i ve t o t he 20 t h c e nt ur y. I n F i gu r e 16 M g/ C a i s pl ot t e d a ga i ns t t e s t s i z e f o r t he w hi t e va r i e t y of G r ube r f or t he s a m e 2 de pt h ho r i z ons A s obs e r ve d i n t he 8 O da t a t he r e i s no s i gni f i c a nt c or r e l a t i on be t w e e n s i z e a nd M g/ C a L e a s t s qua r e s r e gr e s s i on l i ne s a r e f i t t hr ough e a c h da t a s e t a nd t he R 2 va l ue s a r e < 0 1. T he t ot a l r a ng e of M g/ C a va r i a bi l i t y a m ong t he di f f e r e nt s i z e f r a c t i ons i s a s l a r ge a s t ha t obs e r ve d i n t he 1400 ye a r t i m e s e r i e s f r om t he P i gm y B a s i n ( s e e F i gur e 6 ) T he r e i s c l e a r l y a w e l l de f i ne d r e l a t i ons hi p be t w e e n s i z e a nd M g/ C a va l ue s i n t he pi nk va r i e t y o f G r ube r ( F i gur e 15 ) T he 0 8 m m o l / m ol ( 2 C ) r a nge of M g/ C a va l ue s e xhi bi t e d f r om t he s m a l l e s t t o t he l a r ge s t s i z e c l a s s i s ne a r l y a s l a r ge a s t he L I A t o m ode r n r a nge o f va r i a bi l i t y. T hi s i l l us t r a t e s t he ne c e s s i t y f or de t e r m i ni ng a l i m i t e d s i z e r a nge on w hi c h t o pe r f o r m e l e m e nt a l a na l ys e s

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23 N o s i z e r e l at i ons hi p i n w hi t e G r ube r ? T he l a c k of a n a ppa r e nt r e l a t i ons hi p be t w e e n s i z e a nd e l e m e nt a l / oxyge n i s ot opi c r a t i os i n t he w hi t e va r i e t y of G r ube r i s pe r pl e xi ng gi ve n t he s t r ong r e l a t i ons hi p e xhi bi t e d i n t he pi nk va r i e t y O ne hypot he s i s t ha t c oul d e xpl a i n t he di s c r e pa nc y i nvoke s t he di f f e r e nt s e a s ona l di s t r i but i ons of t he t w o va r i e t i e s F l ux da t a s how t w o m a j or pe a ks i n t he f l ux of w hi t e G r ube r : t he f i r s t oc c ur s i n e a r l y s pr i ng w he n S S T s a r e c ool e s t a nd t he s e c ond oc c ur s i n l a t e s um m e r w he n S S T s a r e w a r m e s t ( D e us e r 1987) T hus a gi ve n s a m pl e of w hi t e G r ube r w oul d r e c or d t he e nt i r e r a nge ( 9 C ) o f a nnua l S S T va r i a bi l i t y i n t he G ul f o f M e xi c o ( L e vi t us 2003 ) W he n us i ng a s m a l l s a m pl e s i z e of 20 i ndi vi dua l f or a m i ni f e r a l t e s t s i t i s pos s i bl e t ha t s a m pl e s a r e b i a s e d t ow a r ds a pa r t i c ul a r s e a s on. F or i ns t a nc e a s a m pl e of 12 f or a m i n i f e r a m a y i nc l ude one i ndi vi dua l f r om e a c h o f t he 12 m ont hs of t he ye a r w hi l e a not he r s a m pl e i nc l ude s 10 i ndi vi dua l s l i vi ng i n A ugus t a nd 2 f r om J a nua r y. T he r e f or e t he a s s um pt i on t ha t b ot h s a m pl e s r e pr e s e nt a n a nnua l a ve r a ge i s i nc or r e c t U s i ng a l a r ge r s a m pl e s i z e ( i e > 100 t e s t s ) w oul d i m p r ove t he odds o f ha vi ng a s a m pl e r e pr e s e nt a t i ve of a nnua l a ve r a ge c ondi t i o ns S i nc e i t ha s be e n e s t a bl i s he d t ha t pi nks a r e l i vi ng du r i ng a m or e na r r ow S S T r a nge d ur i ng t he ye a r t he da t a a r e i nhe r e nt l y l e s s noi s y. C O N C L U S I O N S W hi l e m os t s t udi e s c onc l ude t ha t t he r e i s a s i gni f i c a nt pos i t i ve r e l a t i ons hi p be t w e e n t e s t s i z e a nd c a r bon i s ot opi c c om pos i t i on ( B e r ge r e t a l 1978; C ur r y a nd M a t t he w s 1981; E l de r f i e l d e t a l 2002; R a ve l o a nd F a i r ba nks 1995; W i l l i a m s e t a l 1981) t he r e i s l i t t l e a gr e e m e nt a m ong s t udi e s r e ga r di ng t he e f f e c t of s i z e on M g/ C a or oxyge n i s ot opi c c om pos i t i on. T hi s s t udy s how s a c l e a r e f f e c t of t e s t s i z e on e l e m e nt a l

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24 a nd oxyge n i s ot opi c r a t i os i n t he pi nk va r i e t y of G r ube r but i nc onc l us i ve r e s ul t s w i t h r e s pe c t t o w hi t e G r ube r A n e xpe r i m e nt a l de s i gn w hi c h c oul d be t t e r c ons t r a i n t he e nvi r onm e nt a l c ondi t i ons unde r w hi c h t he f or a m i n i f e r a w e r e c a l c i f yi ng ( i e c ul t ur e o r s e di m e nt t r a p s a m pl e s ) w oul d he l p t o r e ve a l t he s o ur c e of t he di s c r e pa nc y be t w e e n t he pi nk a nd w hi t e G r ube r da t a T he l a r ge r a nge of va r i a bi l i t y obs e r ve d i n 3 C 8 O a nd M g/ C a be t w e e n t he di f f e r e nt s i z e f r a c t i ons of t he pl a nkt oni c f or a m i ni f e r G r ube r i l l us t r a t e s t he ne c e s s i t y f or c hoos i ng a na r r ow s i z e r a nge on w hi c h t o pe r f o r m ge oc he m i c a l a na l ys e s R e duc i ng t he e f f e c t s of non e qui l i br i um f r a c t i ona t i on on t e s t ge o c he m i s t r y w i l l i nc r e a s e t he r obus t ne s s of t he e nvi r onm e nt a l va r i a bi l i t y i n t he s i gna l

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25 T ab l e 1 : C or e t op M g/ C a f or 3 P i gm y B a s i n s ub c or e s T he M g/ C a of t he 250 300 m s i z e f r a c t i on of G r ube r ( w hi t e ) w a s m e a s ur e d on t he c or e t op s a m pl e s f or e a c h of 3 s ub c or e s f r om pi g m y B a s i n box c or e P B B C 1. T ab l e 2 : T he or e t i c a l c a l c ul a t i ons of 1 8 O s e a w a t e r a nd S S T F or e a c h of t he s i z e f r a c t i ons of bot h pi nk a nd w hi t e G r ube r S S T a nd 1 8 O s e a w a t e r w e r e c a l c ul a t e d us i ng m e a s ur e d 1 8 O c a l c i t e a nd w i t h a m ode r n S S T or 1 8 O s e a w a t e r va l ue s f r om t he l i t e r a t ur e T he f ol l ow i ng e qua t i on w a s us e d f or t he s e c a l c ul a t i ons : S S T ( C ) = 14. 9 4. 8 ( c s w ) f r om B e m i s e t a l ( 1998) A 1 8 O s e a w a t e r va l ue o f 1. 1 w a s i nput f or pi nk G r ube r a nd 1. 2 w a s i nput f or w hi t e s t o c a l c ul a t e S S T f r om 1 8 O c a l c i t e ( F a i r ba nk s e t a l 1992 ) M ode r n S S T va l ue s of 28. 0 C a nd 25. 4 C w e r e us e d a s i nput s i nt o t he e qua t i on f or pi nk a nd w hi t e G r ube r r e s pe c t i ve l y. T he s e va l ue s a r e t he m ode r n s um m e r a nd a nnua l a ve r a ge s f or t he G O M ( f r om L e vi t us 2003) T he hi ghl i ght e d va l ue s poi nt out t ha t t he 1 8 O c a l c i t e da t a f or t he 250 300 m s i z e f r a c t i on of pi nk G r ube r pr oduc e r e a s ona bl e S S T a nd 1 8 O s e a w a t e r va l ue s gi ve n t he a s s um pt i ons m a de he r e

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26 F i gu r e 1 M a p o f t he G ul f o f M e xi c o. T he P i gm y B a s i n i s a n i nt r a s l ope ba s i n i n t he nor t he r n G ul f of M e xi c o. C or e P B B C 1 w a s r a i s e d f r om a w a t e r de pt h of 2, 259 m a t ( 27 11. 61 N 91 24. 54 W )

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27 F i gu r e 2 A ge m ode l f or c or e P B B C 1 T he a ge m ode l i s ba s e d on 7 A M S 1 4 C da t e s t ha t w e r e c onve r t e d t o c a l e nda r ye a r s us i ng t he C A L I B 5. 0 P r ogr a m w i t h a 400 ye a r r e s e r voi r c or r e c t i on ( S t ui ve r e t a l 1998 ) D a t e s a r e m e a s ur e d f r om 8 12 m g s a m pl e s of m i xe d pl a nkt oni c s pe c i e s f r om t he > 150 m s i z e f r a c t i on ( A ) A l e a s t s qua r e s r e gr e s s i on l i ne i s f i t t hr ough t he 7 poi nt s gi vi ng a l i ne a r s e di m e nt a t i on r a t e w i t h a n R 2 = 0. 995. ( B ) T a bl e s how s t he r a w 1 4 C da t e s w i t h e r r o r s a nd c a l i br a t e d c a l e nda r ye a r s w i t h e r r o r s

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28 F i gu r e 3 T i m e s e r i e s of [ A l ] [ F e ] a nd [ M n] i n c or e P B B C 1 M g/ C a ( gr e y) i s pl ot t e d a ga i ns t c o r e de pt h. C or r e s pondi ng [ F e ] ( l i ght bl ue ) [ A l ] ( da r k bl ue ) a nd [ M n] ( r e d) a r e pl ot t e d a ga i ns t c or e de pt h t o i l l us t r a t e t ha t s i l i c a t e a nd m e t a l oxi de c ont a m i na nt s do not c ova r y w i t h M g/ C a

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29 F i gu r e 4 S c a t t e r pl ot of [ A l ] [ F e ] a nd [ M n] ve r s us M g/ C a L e a s t s qua r e s r e gr e s s i on l i ne s a r e f i t t h r ough e a c h da t a s e t a nd R 2 va l ue s a r e s how n t o i l l us t r a t e t ha t t he r e i s no s i gni f i c a nt r e l a t i ons hi p be t w e e n M g/ C a a nd A l F e o r M n c onc e nt r a t i ons

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30 F i gu r e 5 C om pa r i s on o f c a l c ul a t e d S S T us i ng di f f e r e nt c a l i b r a t i on e qua t i ons S S T i s c a l c ul a t e d f r om M g/ C a a c c or di ng t o t he e xpone nt i a l e qua t i on: M g/ C a = B e xp( A *S S T ) T hi s f i gur e i l l us t r a t e s t he S S T r e c or d ge ne r a t e d us i ng di f f e r e nt A a nd B c ons t a nt s f r om A na nd e t a l ( 2003) ( bl ue ) D e ke ns e t a l ( 2002) ( r e d) a n a r bi t r a r i l y l a r ge A ( l i ght gr e y) a nd a n a r bi t r a r i l y s m a l l A ( da r k gr e y) A r r ow s on t he r i ght ha nd a xi s i ndi c a t e t he r e s pe c t i ve t e m pe r a t ur e r a nge f r om t he c or e t op v a l ue t o t he m i ni m um 200 yr s B P f or e a c h c ur ve T hi s pur pos e i s t o i l l us t r a t e t he e f f e c t s of c ha ngi ng t h e pr e e xpone nt i a l ( B ) a nd e xpone nt i a l ( A ) c ons t a nt s C ha ngi ng B pr i m a r i l y a f f e c t s t he pos i t i on of t he c ur ve on t he y a xi s w he r e c ha ngi ng A a f f e c t s t he a m pl i t ude of t he c ur ve

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31 F i gu r e 6 M g/ C a de r i ve d S S T R e c or d a nd N o r t he r n H e m i s phe r e r e c ons t r uc t i on. ( A ) M g/ C a of G l obi ge r i noi de s r ube r ( w hi t e va r i e t y) f r om c or e P B B C 1. T he M g/ C a r e c or d i s pl ot t e d w i t h t he c o r r e s pondi ng S S T ( C ) va l ue s o n t he s e c onda r y a xi s M a r ke r s i ndi c a t e i ndi vi dua l M g/ C a m e a s ur e m e nt s a nd s ol i d l i ne i s a 3 pt r unni ng m e a n. T he ove r a l l pr e c i s i on of t he M g/ C a da t a i s 0. 16 m m ol / m ol ( B ) R C S c ur ve f r om E s pe r e t a l ( 2002) I ns e t s how s a n ove r pl ot o f M g/ C a c ur ve f r om P B B C 1 a nd t he R C S c ur ve f r om E s pe r e t a l ( 2002) P i gm y B a s i n a nd R C S r e c or ds a r e p l ot t e d a ga i ns t t he i r i nde pe nde nt t i m e s c a l e s

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32 F i gu r e 7 O ve r pl ot o f r a w M g/ C a r e c or d f r om w h i t e a nd pi nk G r ube r A 3 poi nt r unni ng m e a n of t he r a w M g/ C a va l ue s f or G r ube r w hi t e ( bl ue c ur ve ) a nd pi nk ( r e d c u r ve )

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33 F i gu r e 8 P i gm y B a s i n % G s ac c ul i f e r 1 8 O c a l c i t e a nd G I S P 2 s s N a ( A ) R e l a t i ve a bunda nc e va r i a t i ons of t he pl a nkt i c f or a m i ni f e r G l obi ge r i noi de s s ac c ul i f e r ( B ) a nd G r ube r ( w hi t e va r i e t y) 1 8 O m e a s ur e d i n c or e P B B C 1 pl ot t e d a ga i ns t c a l i b r a t e d c a l e nda r yr B P M a r ke r s s how i ndi vi dua l m e a s ur e m e nt s w hi l e s ol i d l i ne s a r e 3 poi nt r unni ng m e a ns ( C ) S e a s a l t s odi um ( s s N a ) r e c or d f r om G I S P 2 i c e c or e T he s s N a r e c or d i s a 20 yr s m oot he d ve r s i on, r e s a m pl e d a t 6 yr r e s ol ut i o n, a nd i s pl ot t e d a ga i n s t t he t i m e s c a l e f or G I S P 2 ( f r om M e e ke r a nd M a ye w s ki 2002)

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34 F i gu r e 9 C a l c ul a t e d 1 8 O s e a w a t e r M a r ke r s i ndi c a t e i ndi vi dua l va l ue s a nd 3 poi nt r unni ng m e a n i s s how n i n bol d. 1 8 O s e a w a t e r w a s c a l c ul a t e d f r om pa i r e d M g/ C a S S T e s t i m a t e s a nd 1 8 O c a l c i t e m e a s ur e m e nt s us i ng t he e qua t i on f or t he pl a nkt oni c f or a m i ni f e r O r bul i na uni v e r s a ( hi gh l i ght ) [ S S T ( C ) = 14 9 4. 8( c w ) ] f r o m B e m i s e t a l ( 1998 ) T he r e s ul t i ng 1 8 O s e a w a t e r i s c onve r t e d f r om V P D B t o V S M O W by a ddi ng 0. 27

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35 F i gu r e 10 C om pa r i s on of 1 8 O s e a w a t e r w i t h % a bunda nc e G r ub e r ( w hi t e ) T he % a bunda nc e o f w hi t e G r ube r ( bl ue c ur ve ) i s ove r pl ot t e d on t he 1 8 O s e a w a t e r r e c or d ( r e d) I n c r e a s i ng 1 8 O s e a w a t e r va l ue s a r e i nt e r pr e t e d a s i nc r e a s i ng s a l i ni t y. N ot e t ha t t he % a bunda nc e a xi s i s pl ot t e d i nve r s e l y, s o t ha t % a b unda nc e a nd 1 8 O s e a w a t e r a r e a nt i c or r e l a t e d.

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36 F i gu r e 11 M ode l of G ul f o f M e xi c o s a l i ni t y dur i ng t he m ont h of A p r i l T hi s f i gur e r e pr e s e nt s a s ur f a c e s a l i ni t y m ode l f or t he G O M d ur i ng f or A pr i l t he m ont h o f m a xi m um M i s s i s s i ppi R i ve r di s c ha r ge T he m ode l i l l us t r a t e s t ha t e ve n dur i ng m a xi m um M i s s i s s i ppi R i ve r d i s c ha r ge t he s ur f a c e s a l i ni t y of t he ope n G O M ove r t he P i gm y B a s i n, i s not a f f e c t e d. ( ht t p: / / w w w dyna l ys i s c om / P r oj e c t s / gom / gom / i m a ge s / m a i n. ht m )

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37 F i gu r e 12 S i z e f r a c t i on ve r s us 1 3 C f or w hi t e a nd pi nk G r ube r ! 3 C i s pl ot t e d a s a f unc t i on of s i z e f or G r ube r w hi t e ( c i r c l e ) and G r ube r pi nk ( s qua r e ) X a xi s va l ue s r e pr e s e nt t h e l ow e nd of t he s i z e r a nge ( i e 150 212 m i s pl ot t e d a s 150 m ) A l e a s t s qua r e s r e gr e s s i on l i ne a nd R 2 va l ue s a r e s how n f or bot h d a t a s e t s

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38 F i gu r e 13 G r ube r 1 3 C r e c or d ( pi nk a nd w hi t e ) R e d c ur ve r e p r e s e nt s r a w 1 3 C da t a f or t he 250 300 m s i z e f r a c t i on o f pi nk G r ube r f or c or e P B B C 1, a nd bl ue c ur ve r e pr e s e nt s r a w 1 3 C da t a f or t he 250 300 m s i z e f r a c t i on of w hi t e G r ube r T he a ve r a g e di f f e r e nc e w a s c a l c ul a t e d be t w e e n t he 2 c u r ve s a n d r e s ul t e d i n a 0. 35 e nr i c hm e nt i n pi nk G r ube r r e l a t i ve t o w hi t e

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39 F i gu r e 14 S i z e f r a c t i on ve r s us 1 8 O f o r w hi t e a nd pi nk G r ube r ! 8 O i s p l ot t e d a s a f unc t i on of s i z e f or G r ube r pi nk ( s qua r e ) a nd G r ube r w h i t e ( c i r c l e ) N ot e t ha t t he Y a xi s ! 8 O va l ue s a r e pl ot t e d i nve r s e l y. L e a s t s qua r e s r e gr e s s i on l i ne a nd R 2 va l ue s a r e s how n f or bot h da t a s e t s

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40 F i gu r e 15 S i z e f r a c t i on ve r s us M g/ C a f or G r ube r ( pi nk) D a t a i s s how n f or t w o di f f e r e nt c or e de pt hs of P i gm y B a s i n box c or e P B B C 1, 20 25 m m ( b l ue ) a nd 320 325m m ( r e d ) L e a s t s qua r e s r e gr e s s i on l i ne s a r e pl ot t e d w i t h R 2 v a l ue s

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41 F i gu r e 16 S i z e f r a c t i on ve r s us M g/ C a f or G r ube r ( w hi t e ) D a t a i s s how n f or t w o di f f e r e nt c or e de pt hs of P i gm y B a s i n box c or e P B B C 1, 20 25 m m ( b l ue ) a nd 320 325m m ( r e d ) L e a s t s qua r e s r e gr e s s i on l i ne s a r e pl ot t e d w i t h R 2 v a l ue s

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42 R E F E R E N C E S A na nd, P E l d e r f i e l d H a nd C on t e M H 2003, C a l i br a t i on of M g / C a t he r m o m e t r y i n p l a nk t oni c f o r a m i n i f e r a f r o m a s e d i m e n t t r a p t i m e s e r i e s : P a l e o c e a no g r a ph y v. 18, 1050 do i : 10. 1029 / 2002P A 000846. B a r ke r S G r e a ve s M E l de r f i e l d H 2 003, A s t udy of c l e a ni ng pr oc e dur e s us e d f or f or a m i ni f e r a l M g/ C a pa l e ot he r m om e t r y: G e oc he m i s t r y G e ophys i c s G e os ys t e m s v. 4 doi : 10. 1 029/ 2003G C 000559. B e m i s B E S pe r o, H J B i j m a J a nd L e a D W 1998, R e e va l ua t i on of t he oxyge n i s ot opi c c om pos i t i on of pl a nkt on i c f o r a m i ni f e r a : E xpe r i m e nt a l r e s ul t s a nd r e vi s e d pa l e ot e m pe r a t ur e e qua t i ons : P a l e oc e a nogr a phy, v 13, p 150 160 B e r ge r W A K i l l i ngl e y, J S a nd V i nc e nt E 19 78, S t a bl e i s ot ope s i n de e p s e a c a r bona t e s : B ox c or e E R D C 92 w e s t e qua t or i a l P a c i f i c : O c e a nol ogi c a A c t a v 1, p 203 216 B r oe c ke r W S 2001 P a l e oc l i m a t e W a s t he m e di e va l w a r m pe r i od gl oba l ? : S c i e nc e v. 291 p 1497 1499 B oum a A H a nd C ol e m a n, J M 1986 I nt r a s l op e ba s i n de pos i t s a nd t he pot e nt i a l r e l a t i on t o t he c ont i ne nt a l s he l f nor t he r n G ul f of M e xi c o: T r a ns a c t i ons G ul f C oa s t A s s o c i a t i on of G e ol ogi c a l S oc i e t i e s v. X X X V I p 4 19 428. B ow e n, G L a nd R e ve na ugh, J 2003, I nt e r pol a t i ng t he i s ot opi c c om pos i t i on o f m ode r n m e t e or i c pr e c i pi t a t i on: W a t e r R e s our c e R e s e a r c h, v. 39, doi : 10. 1029/ 2003W R 002086. B oyl e E A a nd K e i gw i n, L D 198 5, C om pa r i s on of A t l a nt i c a nd P a c i f i c pa l e oc he m i c a l r e c or ds f or t he L a s t 215 000 ye a r s : C ha nge s i n de e p oc e a n c i r c ul a t i on a nd c he m i c a l i nve nt o r i e s : E a r t h a nd P l a ne t a r y S c i e nc e L e t t e r s v 76 p. 135 150 C r ow l e y, T J a nd L ow e r y T 2000 H ow W a r m w a s t he M e di e va l W a r m P e r i od? : A m bi o, v 29 p 51 54. C ur r y, W B a nd M a t t he w s R K 1981, E qui l i b r i um 1 8 O f r a c t i ona t i on i n s m a l l s i z e f r a c t i on pl a nkt i c f or a m i ni f e r a : E vi de nc e f r om r e c e nt I ndi a n O c e a n s e di m e nt s : M ar i ne M i c r opal e ont ol ogy v 6 p 327 337.

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43 D e ke ns P S L e a D W P a k D K a nd S pe r o H J 2002 C or e t op c a l i b r a t i on of M g/ C a i n t r opi c a l f o r a m i ni f e r a : R e f i ni ng pa l e ot e m pe r a t ur e e s t i m a t i on: G e oc he m i s t r y, G e ophys i c s G e os ys t e m s v. 3, doi : 10. 129/ 2001/ G C 000200. D e us e r W G 1987, S e a s ona l va r i a t i ons i n i s ot opi c c om pos i t i on a nd de e p w a t e r f l uxe s of t he t e s t s of pe r e nni a l l y a bunda nt pl a nkt oni c f o r a m i ni f e r a of t he S a r ga s s o S e a : R e s ul t s f r om s e di m e nt t r a p c ol l e c t i ons a nd t he i r pa l e oc e a nogr a phi c s i gni f i c a nc e : J our na l of F o r a m i nf e r a l R e s e a r c h, v. 17 p. 14 27 E l d e r f i e l d H V a ut r a ve r s M a nd C oope r M 20 02, T he r e l a t i ons hi p be t w e e n s he l l s i z e a nd M g/ C a S r / C a d18O a nd d13C of s pe c i e s of p l a nkt oni c f or m a i ni f e r a : G e oc he m i s t r y G e ophys i c s a nd G e os y s t e m s v. 3 d oi : 10. 1029/ 2001G C 000194. E s pe r J C ook, E R a nd S c hw e i ngr ube r F H 2 002, L ow f r e que nc y s i gna l s i n l ong t r e e r i ng c h r onol ogi e s f or r e c ons t r uc t i ng pa s t t e m p e r a t ur e va r i a bi l i t y: S c i e nc e v. 295 p 2250 2254 F a i r ba nks R G C ha r l e s C D W r i ght J D 199 2, O r i gi n of G l oba l M e l t w a t e r P ul s e s R a di oc a r bon a f t e r F ou r D e c a de s : A n I nt e r di s c i pl i n a r y P e r s pe c t i ve R E T a yl o r e t a l ( e ds ) S pr i nge r V e r l a g N e w Y or k F l ow e r B P H a s t i ngs D W H i l l H W Q ui nn T M 2004 P ha s i ng o f de gl a c i a l w a r m i ng a nd L a ur e nt i de I c e S he e t m e l t w a t e r i n t h e G ul f of M e xi c o: G e ol ogy v 32, p 597 600 G i a nni ni A K us hni r Y a nd C a ne M A 2000 I nt e r a nnua l va r i a bi l i t y of C a r i bbe a n r a i nf a l l E N S O a nd t he A t l a nt i c O c e a n: J our na l of C l i m a t e v. 13, p. 297 311 G oodki n, N F H ughe n, K A C ohe n, A L a nd S m i t h, S R 2005, R e c or d of L i t t l e I c e A ge s e a s ur f a c e t e m pe r a t ur e s a t B e r m uda us i ng a gr ow t h de pe nde nt c a l i br a t i on of c or a l S r / C a : P a l e oc e a nogr a phy, v. 20, P A 4016 doi : 10. 1029/ 2005P A 001140 K e i gw i n, L D 1996, T he L i t t l e I c e A ge a nd M e di e va l W a r m P e r i od i n t he S a r ga s s o S e a : S c i e nc e v. 274, p. 1504 1508. L e vi t us S 2003, N a t i ona l O c e a nogr a phi c D a t a C e nt e r W or l d O c e a n A t l a s 1994 a t ht t p: / / w w w c dc noa a gov/ C l i m D a t a C e nt B oul de r C ol o. L oD i c o, J M B P F l ow e r a nd T M Q ui nn 200 6, S ubc e nt e nni a l s c a l e c l i m a t i c a nd hydr ol ogi c va r i a bi l i t y i n t he G ul f of M e xi c o dur i n g t he e a r l y H ol oc e ne : P a l e oc e a nogr a phy, v. 21, P A 3015, doi : 10. 1029 / 20 05P A 001243. L und, D C a nd C ur r y W 2006 F l o r i da c ur r e nt s ur f a c e t e m pe r a t ur e a nd s a l i ni t y va r i a bi l i t y dur i ng t he l a s t m i l l e nni um : P a l e oc e a nogr a phy, v 21 P A 2009 doi : 10. 1029/ 2005P A A 001218.

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44 M a nn, M E a nd J one s P D 2003, G l oba l s ur f a c e t e m pe r a t ur e ove r t he pa s t t w o m i l l e nni a : G e ophys i c a l R e s e a r c h L e t t e r s v. 30, p. 1820 182 3. M c C onna ughe y, T A 2003, S ub e qui l i b r i um oxy ge n 18 a nd c a r bon 13 l e ve l s i n bi ol ogi c a l c a r bona t e s : c a r bona t e a nd ki ne t i c m ode l s : C or al R e e f s v 22 p 316 327. M e e ke r L D M a ye w s ki P A 2002, A 1400 ye a r hi gh r e s ol ut i on r e c or d o f a t m os phe r i c c i r c ul a t i on ove r t he N or t h A t l a nt i c a n d A s i a : T he H ol oc e ne v. 12, p. 257 266. M obe r g, A S one c hki n D M H ol m gr e n, K D a t s e nko, N M a nd K a r l n W 2005 H i ghl y va r i a bl e N or t he r n H e m i s phe r e t e m pe r a t u r e s r e c ons t r uc t e d f r om l ow a nd hi gh r e s o l ut i on pr oxy da t a : N a t ur e v 433 p 613 617. N e w t on, A T hune l l R a nd S t o t t L 2006, C l i m a t e a nd hydr ogr a phi c va r i a bi l i t y i n t he I ndo P a c i f i c W a r m P ool dur i ng t he l a s t m i l l e nni u m : G e ophys i c a l R e s e a r c h L e t t e r s v 33 p L 19710, doi : 10 1029/ 200 6G L 02 7234. O r t ne r P B L e e T N M i l ne P J Z i ka R G C l a r ke M E P ode s t a G P S w a r t P K T e s t e r P A A t ki ns on, L P J ohns on, W R 1995, M i s s i s s i ppi R i ve r f l ood w a t e r s t ha t r e a c he d t he G ul f S t r e a m : J our na l of G e ophys i c a l R e s e a r c h, v. 100, p. 595 601. P e na L D C a l vo, E C a c ho, I E ggi ns S a nd P e l e j e r o, C 2005 I de nt i f i c a t i on a nd r e m ova l of M n M g r i c h c ont a m i na nt pha s e s on f or a m i ni f e r a l t e s t s : I m pl i c a t i ons f or M g/ C a pa s t t e m pe r a t ur e r e c ons t r uc t i ons : G e oc he m i s t r y, G e ophys i c s G e os ys t e m s v. 6 Q 09 P 02, doi : 10. 1029/ 2005G C 0 00930. P oor e R Z Q ui nn T M a nd V e r a r do S 2004, C e nt ur y s c a l e m ove m e nt of t he A t l a nt i c I nt e r t r opi c a l C onve r ge nc e Z one l i nke d t o s ol a r va r i a bi l i t y: G e ophys i c a l R e s e a r c h L e t t e r s v. 31, L 12214 doi : 10. 1029/ 200 4G L 019940. R a ve l o, A C a nd F a i r ba nks R G 1995 C a r bon i s ot opi c f r a c t i ona t i on i n m ul t i pl e s pe c i e s of pl a nkt oni c f or a m i ni f e r a f r om c o r e t ops i n t he t r op i c a l A t l a nt i c : J our na l of F or a m i n i f e r a l R e s e a r c h, v 25 p 53 74 S c h m i t t R W B ogde n, P S D or m a n C E 198 9, E va po r a t i on m i nus p r e c i pi t a t i on a nd de ns i t y f l uxe s f or t he N or t h A t l a nt i c : J our na l of P h ys i c a l O c e a nogr a phy, v. 19 p 1208 1221. S t ui ve r M R e i m e r P J B a r d, E B e c k, J W B ur r G S H ughe n K A K r om e r B M c C or m a c F G V a n D e r P l i c ht J a nd S pu r k M 1998, I N T C A L 98 r a di oc a r bon a ge c a l i br a t i on 24, 000 0 c a l B P : R a di oc a r bon, v 40 p 1041 1083

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45 W a t a na be T W i nt e r A a nd O ba T 2001 S e a s o na l c ha nge s i n s e a s ur f a c e t e m pe r a t ur e a n d s a l i ni t y dur i ng t he L i t t l e I c e A ge i n t he C a r i bb e a n S e a de duc e d f r om M g/ C a a nd 1 8 O / 1 6 O r a t i ons i n c or a l s : M a r i ne G e ol ogy, v. 173, p 21 35 W a ng, C a nd E nf i e l d, C B 2001, T he t r opi c a l W e s t e r n H e m i s phe r e W a r m P ool : G e ophys i c a l R e s e a r c h L e t t e r s v 28 p 1635 1638 W i l l i a m s D F B e A W H a nd F a i r ba nks R G 1981, S e a s ona l s t a bl e i s ot opi c va r i a t i ons i n l i vi ng pl a nkt oni c f or a m i ni f e r a f r om B e r m uda pl a nkt on t ow s : P a l e oge ogr a phy, P a l e oc l i m a t ol ogy P a l e oe c ol ogy, v. 33 p 71 102 W i nt e r A I s hi or os hi H W a t a na be T O ba T a nd C hr i s t y, J 2000 C a r i bbe a n S e a s ur f a c e t e m pe r a t ur e s : T w o t o t h r e e de gr e e s c ool e r t ha n pr e s e nt dur i ng t he L i t t l e I c e A ge : G e ophys i c a l R e s e a r c h L e t t e r s v 27 p 3 365 3368.

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46 A P P E N D I C E S

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47 A p p e n d i x I D a t a T a bl e f o r w hi t e G r ube r

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48 A p p e n d i x I D a t a T a bl e f o r w hi t e G r ube r ( c ont i nue d)

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49 A p p e n d i x I D a t a T a bl e f o r w hi t e G r ube r ( c ont i nue d)

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50 A p p e n d i x I D a t a T a bl e f o r w hi t e G r ube r ( c ont i nue d)

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51 A p p e n d i x I I D a t a T a bl e f or pi nk G r ube r

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52 A p p e n d i x I I D a t a T a bl e f or pi nk G r ube r ( c ont i nue d)

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53 A p p e n d i x I I D a t a T a bl e f or pi nk G r ube r ( c ont i nue d)

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54 A p p e n d i x I I D a t a T a bl e f or pi nk G r ube r ( c ont i nue d)

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55 A p p e n d i x I I I F a una l a bunda nc e f o r 5 c om m on p l a nkt i c f or a m i ni f e r s

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56 A p p e n d i x I I I F a una l a bunda nc e f or 5 c om m on p l a nkt i c f or a m i ni f e r s ( c ont i nue d)

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57 A p p e n d i x I I I F a una l a bunda nc e f or 5 c om m on p l a nkt i c f or a m i ni f e r s ( c ont i nue d)

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58 A p p e n d i x I I I F a una l a bunda nc e f or 5 c om m on p l a nkt i c f or a m i ni f e r s ( c ont i nue d)

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59 A p p e n d i x I V S e a s ur f a c e s a l i ni t y e s t i m a t e s F i gu r e I V 1 M i xi ng m ode l f or e s t i m a t i ng s e a s ur f a c e s a l i ni t y ( S S S ) us i ng t he m ode r n r e l a t i ons hi p b e t w e e n 1 8 O s e a w a t e r a nd s a l i ni t y i n t he G O M P r e c i pi t a t i on a nd t he M i s s i s s i ppi R i ve r ( M R ) a r e t he 2 s our c e s of f r e s hw a t e r ( s a l i ni t y= 0 ps u) t o t he G O M w i t h m ode r n r e s pe c t i ve 1 8 O e nd m e m be r s of 3. 5 ( B ow e n a nd R e ve na ugh, 2004) a nd 7 ( O r t ne r e t a l 1995) T he y a r e c om pa r e d w i t h t h e m ode r n G O M 1 8 O s e a w a t e r o f 1. 2 a nd a s a l i ni t y of 36 ps u ( F a i r ba nks e t a l 1992) N ot e t ha t t he s l op e of t he l i ne us i ng a pr e c i pi t a t i on e nd m e m be r ( A ) i s m uc h s m a l l e r t ha n t he s l op e w i t h t he M R e nd m e m be r ( B ) a nd t he r e f or e r e qui r e s l a r ge r c ha nge s i n S S S pe r uni t c ha nge i n 1 8 O s e a w a t e r

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60 A p p e n d i x I V S e a s ur f a c e s a l i ni t y e s t i m a t e s ( c ont i nue d) F i gu r e I V 2 E s t i m a t e d s a l i ni t y r e c or d c a l c ul a t e d f r om P i gm y B a s i n 1 8 O s e a w a t e r us i ng t he p r e c i pi t a t i on 1 8 O e nd m e m be r of 3 5 ( r e d) a nd t he M R e nd m e m be r of 7 ( bl ue ) T he s ha de d ba r r e pr e s e nt s t he m od e r n a nnua l s a l i ni t y r a nge of 34 36 ps u f o r t he G O M ( L e vi t us 2003 ) N ot e t ha t us i ng t he pr e c i pi t a t i on e nd m e m be r r e s ul t s i n a n e s t i m a t e d S S S r e c or d w i t h a s a l i ni t y r a nge of 27 39 ps u ove r t he pa s t 1400 ye a r s T he M R e nd m e m be r yi e l ds a m uc h m or e r e a s ona b l e S S S r a nge ( 32 38 ps u)


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APA

Cras ut cursus ante, a fringilla nunc. Mauris lorem nunc, cursus sit amet enim ac, vehicula vestibulum mi. Mauris viverra nisl vel enim faucibus porta. Praesent sit amet ornare diam, non finibus nulla.

MLA

Cras efficitur magna et sapien varius, luctus ullamcorper dolor convallis. Orci varius natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Fusce sit amet justo ut erat laoreet congue sed a ante.

CHICAGO

Phasellus ornare in augue eu imperdiet. Donec malesuada sapien ante, at vehicula orci tempor molestie. Proin vitae urna elit. Pellentesque vitae nisi et diam euismod malesuada aliquet non erat.

WIKIPEDIA

Nunc fringilla dolor ut dictum placerat. Proin ac neque rutrum, consectetur ligula id, laoreet ligula. Nulla lorem massa, consectetur vitae consequat in, lobortis at dolor. Nunc sed leo odio.