Sea Level controls on Agulhas Leakage Salinity and the Atlantic Overturning Circulation
The Indian Ocean has been proposed as an important source of salt for North Atlantic deep-water convection sites, via the Agulhas Leakage, and may thus drive changes in the ocean’s overturning circulation. However, while past changes in Agulhas leakage volume have been explored, little is known abou...
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ftarchimer:oai:archimer.ifremer.fr:84504 2023-05-15T17:25:25+02:00 Sea Level controls on Agulhas Leakage Salinity and the Atlantic Overturning Circulation Nuber, Sophie Rae, James Andersen, Morten Zhang, Xu De Boer, Bas Dumont, Matthew Sun, Yuchen Mithan, Huw Hall, Ian Barker, Stephen 2021-01 application/pdf https://archimer.ifremer.fr/doc/00733/84504/89584.pdf https://archimer.ifremer.fr/doc/00733/84504/89585.docx https://doi.org/10.21203/rs.3.rs-1038170/v1 https://archimer.ifremer.fr/doc/00733/84504/ eng eng Research Square Platform LLC https://archimer.ifremer.fr/doc/00733/84504/89584.pdf https://archimer.ifremer.fr/doc/00733/84504/89585.docx doi:10.21203/rs.3.rs-1038170/v1 https://archimer.ifremer.fr/doc/00733/84504/ info:eu-repo/semantics/openAccess restricted use Research Square (Research Square Platform LLC), 2021-01 , N. Version 1 , P. 12p. Agulhas leakage salinity Atlantic overturning circulation Indian Ocean text Publication info:eu-repo/semantics/article 2021 ftarchimer https://doi.org/10.21203/rs.3.rs-1038170/v1 2022-02-22T23:50:59Z The Indian Ocean has been proposed as an important source of salt for North Atlantic deep-water convection sites, via the Agulhas Leakage, and may thus drive changes in the ocean’s overturning circulation. However, while past changes in Agulhas leakage volume have been explored, little is known about this water’s salt content, representing a major gap in our understanding of Agulhas salinity supply. Here, we present new planktonic foraminiferal Mg/Ca-derived sea surface temperatures (SST) and stable isotope-derived salinity reconstructions for the last 1.2Ma from the western Indian Ocean source waters of the Agulhas Leakage to investigate glacial-interglacial changes in surface water properties. We find that SST and relative salinity both increase during glaciation, leading to high salinity and SST during glacial maxima. We show that the onset of surface salinification and warming in the Indian Ocean occurs during a phase of rapid land-bridge exposure in the Indonesian archipelago induced by sea level lowering. We link these findings to new global climate model results which show that the export of salt from the Indian Ocean via the Agulhas Leakage can directly impact the deglacial Atlantic meridional overturning circulation and therefore global climate. Article in Journal/Newspaper North Atlantic Deep Water North Atlantic Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Indian |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
topic |
Agulhas leakage salinity Atlantic overturning circulation Indian Ocean |
spellingShingle |
Agulhas leakage salinity Atlantic overturning circulation Indian Ocean Nuber, Sophie Rae, James Andersen, Morten Zhang, Xu De Boer, Bas Dumont, Matthew Sun, Yuchen Mithan, Huw Hall, Ian Barker, Stephen Sea Level controls on Agulhas Leakage Salinity and the Atlantic Overturning Circulation |
topic_facet |
Agulhas leakage salinity Atlantic overturning circulation Indian Ocean |
description |
The Indian Ocean has been proposed as an important source of salt for North Atlantic deep-water convection sites, via the Agulhas Leakage, and may thus drive changes in the ocean’s overturning circulation. However, while past changes in Agulhas leakage volume have been explored, little is known about this water’s salt content, representing a major gap in our understanding of Agulhas salinity supply. Here, we present new planktonic foraminiferal Mg/Ca-derived sea surface temperatures (SST) and stable isotope-derived salinity reconstructions for the last 1.2Ma from the western Indian Ocean source waters of the Agulhas Leakage to investigate glacial-interglacial changes in surface water properties. We find that SST and relative salinity both increase during glaciation, leading to high salinity and SST during glacial maxima. We show that the onset of surface salinification and warming in the Indian Ocean occurs during a phase of rapid land-bridge exposure in the Indonesian archipelago induced by sea level lowering. We link these findings to new global climate model results which show that the export of salt from the Indian Ocean via the Agulhas Leakage can directly impact the deglacial Atlantic meridional overturning circulation and therefore global climate. |
format |
Article in Journal/Newspaper |
author |
Nuber, Sophie Rae, James Andersen, Morten Zhang, Xu De Boer, Bas Dumont, Matthew Sun, Yuchen Mithan, Huw Hall, Ian Barker, Stephen |
author_facet |
Nuber, Sophie Rae, James Andersen, Morten Zhang, Xu De Boer, Bas Dumont, Matthew Sun, Yuchen Mithan, Huw Hall, Ian Barker, Stephen |
author_sort |
Nuber, Sophie |
title |
Sea Level controls on Agulhas Leakage Salinity and the Atlantic Overturning Circulation |
title_short |
Sea Level controls on Agulhas Leakage Salinity and the Atlantic Overturning Circulation |
title_full |
Sea Level controls on Agulhas Leakage Salinity and the Atlantic Overturning Circulation |
title_fullStr |
Sea Level controls on Agulhas Leakage Salinity and the Atlantic Overturning Circulation |
title_full_unstemmed |
Sea Level controls on Agulhas Leakage Salinity and the Atlantic Overturning Circulation |
title_sort |
sea level controls on agulhas leakage salinity and the atlantic overturning circulation |
publisher |
Research Square Platform LLC |
publishDate |
2021 |
url |
https://archimer.ifremer.fr/doc/00733/84504/89584.pdf https://archimer.ifremer.fr/doc/00733/84504/89585.docx https://doi.org/10.21203/rs.3.rs-1038170/v1 https://archimer.ifremer.fr/doc/00733/84504/ |
geographic |
Indian |
geographic_facet |
Indian |
genre |
North Atlantic Deep Water North Atlantic |
genre_facet |
North Atlantic Deep Water North Atlantic |
op_source |
Research Square (Research Square Platform LLC), 2021-01 , N. Version 1 , P. 12p. |
op_relation |
https://archimer.ifremer.fr/doc/00733/84504/89584.pdf https://archimer.ifremer.fr/doc/00733/84504/89585.docx doi:10.21203/rs.3.rs-1038170/v1 https://archimer.ifremer.fr/doc/00733/84504/ |
op_rights |
info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.21203/rs.3.rs-1038170/v1 |
_version_ |
1766116843927371776 |