georefid:2013-035827SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1029/2010PA0020152011-01-01publicationgeorefid:2013-035827doi:10.1029/2010PA002015Bahr, AndreLeibniz Institute for Marine Sciences, Kiel, GermanyauthorNuernberg, DirkChristian-Albrechts-Universitaet zu Kiel, GermanyauthorSchoenfeld, JoachimauthorGarbe-Schoenberg, DieterauthorAmerican Geophysical Union, Washington, DC, United StatespublisherdocumentHardcopyPaleoceanography26 (2)Modeling and proxy studies indicate that a reduction of Atlantic Meridional Overturning Circulation (AMOC) strength profoundly impacts temperatures and salinities in the (sub)tropical Atlantic, especially on subsurface levels. While previous studies focused on prominent periods of AMOC reduction during the last deglaciation, we aim to test whether similar reconfigurations of the subtropical hydrography occurred during the moderate climatic alterations punctuating the last interglacial Marine Isotope Stage (MIS) 5. Here, we present temperature and salinity records from a Florida Straits core by combining delta (super 18) O and Mg/Ca analyses on surface (Globigerinoides ruber, white) and deep-dwelling (Globorotalia crassaformis) foraminifera covering MIS 5 in high resolution. The data reveal increasing salinities at intermediate depths during interglacial cooling episodes, decoupled from relatively stable surface conditions. This probably indicates the spatial expansion of saline subtropical gyre waters due to enhanced Ekman downwelling and might also point to a changed density structure and altered geostrophic balance in Florida Straits. Notably, these oceanographic alterations are not consistently occurring during periods of AMOC reduction. The data suggest that the expansion of gyre waters into Florida Straits was impeded by the increasing influence of Antarctic Intermediate Water (AAIW) from MIS 5.5 to approximately 107 kyr BP. Afterward, increasingly positive benthic delta (super 13) C values imply a recession of AAIW, allowing the temporary expansion of gyre waters into Florida Straits. We argue that the inferred transient subtropical salt accumulation and warm pool expansion might have played a pivotal role in reinvigorating meridional overturning and dampen the severity of interglacial cold phases.completedQuaternary geologyabsolute agealkaline earth metalsAtlantic Meridional Overturning CirculationAtlantic OceanC-13/C-12C-14calciumcarbonCaribbean SeaCenozoicchemostratigraphychronostratigraphyColombian BasincoresForaminiferaInvertebrataisotope ratiosisotopesLeg 165lithostratigraphymagnesiummarine sedimentsmetalsMg/CamicrofossilsMIS 5North AtlanticO-18/O-16ocean circulationOcean Drilling ProgramODP Site 999oxygenpaleo-oceanographypaleoclimatologypaleotemperaturePleistoceneProtistaQuaternaryradioactive isotopessalinitysea-surface temperaturesedimentsstable isotopesStraits of Floridatemperatureupper Pleistoceneurn:org.iodp:exp:165urnlargerWorkCitationcampaignurn:org.iodp:exp:165:site:999urnlargerWorkCitationstudyurn:org.iodp:exp:165urnlargerWorkCitationcampaignEnglishgeoscientificInformation-83.5300-80.530024.045924.0459