Indian Ocean salinity build-up primes deglacial ocean circulation recovery

Funding: This work was mainly funded through UK NERC grant NE/P000878/1 provided to S.N. by S.B. J.W.B.R. received funding for this work from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grant agreement 805246) which also funded M.D.D. S.N....

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Bibliographic Details
Published in:Nature
Main Authors: Nuber, Sophie, Rae, James W. B., Zhang, Xu, Andersen, Morten B., Dumont, Matthew D., Mithan, Huw T., Sun, Yuchen, de Boer, Bas, Hall, Ian R., Barker, Stephen
Other Authors: European Research Council, University of St Andrews.School of Earth & Environmental Sciences, University of St Andrews.Centre for Energy Ethics, University of St Andrews.St Andrews Isotope Geochemistry
Format: Article in Journal/Newspaper
Language:English
Published: 2023
Subjects:
GB Physical geography
DAS
SDG 13 - Climate Action
MCC
GB
Indian
North Atlantic Deep Water
North Atlantic
ren
Online Access:https://hdl.handle.net/10023/28653
https://doi.org/10.1038/s41586-023-05866-3
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Summary:Funding: This work was mainly funded through UK NERC grant NE/P000878/1 provided to S.N. by S.B. J.W.B.R. received funding for this work from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grant agreement 805246) which also funded M.D.D. S.N. received further funds from the Ministry of Science and Technology, Taiwan (MOST 111-2636-M-002-020) granted to H. Ren. X.Z. and Y.S. were funded through the Natural Science Foundation of China (41988101 and 42075047) and German Helmholtz Postdoc Program (PD-301). X.Z. also acknowledges support from the National Key Scientific and Technological Infrastructure project “Earth System Science Numerical Simulator Facility” (EarthLab). H.T.M. was funded through the Ministry of Science and Technology, Taiwan (110-2811-M-002-647 and 111-2811-M-002-116). The Indian Ocean provides a source of salt for North Atlantic deep-water convection sites, via the Agulhas Leakage, and may thus drive changes in the ocean’s overturning circulation1–3. However, little is known about the salt content variability of Indian Ocean and Agulhas Leakage waters during past glacial cycles and how this may influence circulation. Here we show that the glacial Indian Ocean surface salt budget was notably different from the modern, responding dynamically to changes in sea level. Indian Ocean surface salinity increased during glacial intensification, peaking in glacial maxima. We find that this is due to rapid land exposure in the Indonesian archipelago induced by glacial sea-level lowering, and we suggest a mechanistic link via reduced input of relatively fresh Indonesian Throughflow waters into the Indian Ocean. Using climate model results, we show that the release of this glacial Indian Ocean salinity via the Agulhas Leakage during deglaciation can directly impact the Atlantic Meridional Overturning Circulation and global climate. Peer reviewed

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