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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fttriple:oai:gotriple.eu:10670/1.odmf55 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 https://doi.org/10.21203/rs.3.rs-1038170/v1 https://archimer.ifremer.fr/doc/00733/84504/89584.pdf https://archimer.ifremer.fr/doc/00733/84504/89585.docx en eng Research Square Platform LLC doi:10.21203/rs.3.rs-1038170/v1 10670/1.odmf55 https://archimer.ifremer.fr/doc/00733/84504/89584.pdf https://archimer.ifremer.fr/doc/00733/84504/89585.docx other Archimer, archive institutionnelle de l'Ifremer ??? (Research Square Platform LLC) In Press envir anthro-se Text https://vocabularies.coar-repositories.org/resource_types/c_18cf/ fttriple https://doi.org/10.21203/rs.3.rs-1038170/v1 2023-01-22T18:35:03Z 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. Text North Atlantic Deep Water North Atlantic Unknown Indian |
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envir anthro-se 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 |
envir anthro-se |
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 |
Text |
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 |
url |
https://doi.org/10.21203/rs.3.rs-1038170/v1 https://archimer.ifremer.fr/doc/00733/84504/89584.pdf https://archimer.ifremer.fr/doc/00733/84504/89585.docx |
geographic |
Indian |
geographic_facet |
Indian |
genre |
North Atlantic Deep Water North Atlantic |
genre_facet |
North Atlantic Deep Water North Atlantic |
op_source |
Archimer, archive institutionnelle de l'Ifremer ??? (Research Square Platform LLC) In Press |
op_relation |
doi:10.21203/rs.3.rs-1038170/v1 10670/1.odmf55 https://archimer.ifremer.fr/doc/00733/84504/89584.pdf https://archimer.ifremer.fr/doc/00733/84504/89585.docx |
op_rights |
other |
op_doi |
https://doi.org/10.21203/rs.3.rs-1038170/v1 |
_version_ |
1766116830983749632 |