Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing
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_2 during the Last Glacial Maximum (LGM), but data supporting this id...
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American Geophysical Union
2011
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Online Access: | https://authors.library.caltech.edu/23209/ https://authors.library.caltech.edu/23209/1/Lund2011p13288Paleoceanography.pdf https://resolver.caltech.edu/CaltechAUTHORS:20110401-143100821 |
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ftcaltechauth:oai:authors.library.caltech.edu:23209 2023-05-15T13:37:31+02:00 Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing Lund, D. C. Adkins, J. F. Ferrari, R. 2011-03-19 application/pdf https://authors.library.caltech.edu/23209/ https://authors.library.caltech.edu/23209/1/Lund2011p13288Paleoceanography.pdf https://resolver.caltech.edu/CaltechAUTHORS:20110401-143100821 en eng American Geophysical Union https://authors.library.caltech.edu/23209/1/Lund2011p13288Paleoceanography.pdf Lund, D. C. and Adkins, J. F. and Ferrari, R. (2011) Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing. Paleoceanography, 26 . Art. No. PA1213. ISSN 0883-8305. doi:10.1029/2010PA001938. https://resolver.caltech.edu/CaltechAUTHORS:20110401-143100821 <https://resolver.caltech.edu/CaltechAUTHORS:20110401-143100821> other Article PeerReviewed 2011 ftcaltechauth https://doi.org/10.1029/2010PA001938 2021-11-11T18:46:40Z 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_2 during the Last Glacial Maximum (LGM), but data supporting this idea have remained elusive. The δ^(13)C of benthic foraminifera indicate the Atlantic Ocean was more chemically stratified during the LGM, but the nonconservative nature of δ^(13)C complicates interpretation of the LGM signal. Here we use benthic foraminiferal δ^(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. Article in Journal/Newspaper Antarc* Antarctic Caltech Authors (California Institute of Technology) Antarctic Paleoceanography 26 1 |
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Caltech Authors (California Institute of Technology) |
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ftcaltechauth |
language |
English |
description |
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_2 during the Last Glacial Maximum (LGM), but data supporting this idea have remained elusive. The δ^(13)C of benthic foraminifera indicate the Atlantic Ocean was more chemically stratified during the LGM, but the nonconservative nature of δ^(13)C complicates interpretation of the LGM signal. Here we use benthic foraminiferal δ^(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. |
format |
Article in Journal/Newspaper |
author |
Lund, D. C. Adkins, J. F. Ferrari, R. |
spellingShingle |
Lund, D. C. Adkins, J. F. Ferrari, R. Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing |
author_facet |
Lund, D. C. Adkins, J. F. Ferrari, R. |
author_sort |
Lund, D. C. |
title |
Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing |
title_short |
Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing |
title_full |
Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing |
title_fullStr |
Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing |
title_full_unstemmed |
Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing |
title_sort |
abyssal atlantic circulation during the last glacial maximum: constraining the ratio between transport and vertical mixing |
publisher |
American Geophysical Union |
publishDate |
2011 |
url |
https://authors.library.caltech.edu/23209/ https://authors.library.caltech.edu/23209/1/Lund2011p13288Paleoceanography.pdf https://resolver.caltech.edu/CaltechAUTHORS:20110401-143100821 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
https://authors.library.caltech.edu/23209/1/Lund2011p13288Paleoceanography.pdf Lund, D. C. and Adkins, J. F. and Ferrari, R. (2011) Abyssal Atlantic circulation during the Last Glacial Maximum: Constraining the ratio between transport and vertical mixing. Paleoceanography, 26 . Art. No. PA1213. ISSN 0883-8305. doi:10.1029/2010PA001938. https://resolver.caltech.edu/CaltechAUTHORS:20110401-143100821 <https://resolver.caltech.edu/CaltechAUTHORS:20110401-143100821> |
op_rights |
other |
op_doi |
https://doi.org/10.1029/2010PA001938 |
container_title |
Paleoceanography |
container_volume |
26 |
container_issue |
1 |
_version_ |
1766092839300628480 |