Deglacial diatom productivity and surface ocean properties over the Bermuda Rise, northeast Sargasso Sea


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dc.contributor.author Gil, Isabelle M.
dc.contributor.author Keigwin, Lloyd D.
dc.contributor.author Abrantes, Fatima G.
dc.date.accessioned 2010-06-16T13:26:42Z
dc.date.available 2010-06-16T13:26:42Z
dc.date.issued 2009-12-12
dc.identifier.citation Paleoceanography 24 (2009): PA4101 en_US
dc.identifier.uri http://hdl.handle.net/1912/3645
dc.description Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 24 (2009): PA4101, doi:10.1029/2008PA001729. en_US
dc.description.abstract Diatom assemblages document surface hydrographic changes over the Bermuda Rise. Between 19.2 and 14.5 ka, subtropical diatom species and Chaetoceros resting spores dominate the flora, as in North Atlantic productive regions today. From 16.9 to 14.6 ka, brackish and fresh water diatoms are common and their contribution is generally coupled with total diatom abundance. This same interval also contains rare grains of ice-rafted debris. Coupling between those proxies suggests that successive discharge of icebergs might have stimulated productivity during Heinrich event 1 (H1). Iceberg migration to the subtropics likely created an isolated environment involving turbulent mixing, upwelled water, and nutrient-rich meltwater, supporting diatom productivity in an otherwise oligotrophic setting. In addition, the occurrence of mode water eddies likely brought silica-rich waters of Southern Ocean origin to the euphotic zone. The persistence of lower-salinity surface water beyond the last ice rafting suggests continued injection of fresh water by cold-core rings and advection around the subtropical gyre. These results indicate that opal productivity may have biased estimates of meridional overturning based on 231Pa/230Th ratios in Bermuda Rise sediments during H1. en_US
dc.description.sponsorship Support for this research was provided by the Fundação para a Ciência e Tecnologia through the grant BPD/27214/2006 to I. M. Gil. en_US
dc.format.mimetype text/plain
dc.format.mimetype application/pdf
dc.language.iso en_US en_US
dc.publisher American Geophysical Union en_US
dc.relation.uri http://dx.doi.org/10.1029/2008PA001729
dc.subject Bermuda Rise en_US
dc.subject Diatom en_US
dc.subject Heinrich event 1 en_US
dc.title Deglacial diatom productivity and surface ocean properties over the Bermuda Rise, northeast Sargasso Sea en_US
dc.type Article en_US
dc.identifier.doi 10.1029/2008PA001729

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