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Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing

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Show simple item record Ferrari, Raffaele Lund, D. C. Adkins, Jess F. 2012-10-09T15:02:28Z 2012-10-09T15:02:28Z 2011-03 2010-11
dc.identifier.issn 0883-8305
dc.description.abstract The ocean's role in regulating atmospheric carbon dioxide on glacial-interglacial timescales remains an unresolved issue in paleoclimatology. Reduced mixing between deep water masses may have aided oceanic storage of atmospheric CO[subscript 2] during the Last Glacial Maximum (LGM), but data supporting this idea have remained elusive. The δ[superscript 13]C of benthic foraminifera indicate the Atlantic Ocean was more chemically stratified during the LGM, but the nonconservative nature of δ[superscript 13]C complicates interpretation of the LGM signal. Here we use benthic foraminiferal δ[superscript 18]O as a conservative tracer to constrain the ratio of meridional transport to vertical diffusivity in the deep Atlantic. Our calculations suggest that the ratio was at least twice as large at the LGM. We speculate that the primary cause was reduced mixing between northern and southern component waters, associated with movement of this water mass boundary away from the zone of intense mixing near the seafloor. The shallower water mass boundary yields an order of magnitude increase in the volume of southern component water, suggesting its residence time may have increased substantially. Our analysis supports the idea that an expanded volume of Antarctic Bottom Water and limited vertical mixing enhanced the abyssal ocean's ability to trap carbon during glacial times. en_US
dc.language.iso en_US
dc.publisher American Geophysical Union (AGU) en_US
dc.relation.isversionof en_US
dc.rights Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. en_US
dc.source MIT web domain en_US
dc.title Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing en_US
dc.type Article en_US
dc.identifier.citation Lund, D. C., J. F. Adkins, and R. Ferrari. “Abyssal Atlantic Circulation During the Last Glacial Maximum: Constraining the Ratio Between Transport and Vertical Mixing.” Paleoceanography 26.1 (2011). ©2012 American Geophysical Union en_US
dc.contributor.department Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences en_US
dc.contributor.mitauthor Ferrari, Raffaele
dc.relation.journal Paleoceanography en_US
dc.identifier.mitlicense PUBLISHER_POLICY en_US
dc.eprint.version Final published version en_US
dc.type.uri en_US
eprint.status en_US
dspace.orderedauthors Lund, D. C.; Adkins, J. F.; Ferrari, R. en

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