Antarctic icebergs reorganize ocean circulation during Pleistocene glacials
The dominant feature of large-scale mass transfer in the modern ocean is the Atlantic meridional overturning circulation (AMOC). The geometry and vigour of this circulation influences global climate on various timescales. Palaeoceanographic evidence suggests that during glacial periods of the past 1...
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ftunivrhodeislan:oai:digitalcommons.uri.edu:gsofacpubs-3168 2024-02-11T09:58:46+01:00 Antarctic icebergs reorganize ocean circulation during Pleistocene glacials Starr, Aidan Hall, Ian R. Barker, Stephen Rackow, Thomas Zhang, Xu Hemming, Sidney R. van der Lubbe, H. J.L. Knorr, Gregor Berke, Melissa A. Bigg, Grant R. Cartagena-Sierra, Alejandra Jiménez-Espejo, Francisco J. Gong, Xun Gruetzner, Jens Lathika, Nambiyathodi LeVay, Leah J. Robinson, Rebecca S. Ziegler, Martin Brentegani, Luna Caley, Thibaut Charles, Christopher D. Coenen, Jason J. Crespin, Julien G. Franzese, Allison M. Han, Xibin Hines, Sophia K.V. Jimenez Espejo, Francisco J. Just, Janna Koutsodendris, Andreas Kubota, Kaoru Norris, Richard D. dos Santos, Thiago Pereira Rolison, John M. Simon, Margit H. Tangunan, Deborah 2021-01-14T08:00:00Z https://digitalcommons.uri.edu/gsofacpubs/2199 https://doi.org/10.1038/s41586-020-03094-7 unknown DigitalCommons@URI https://digitalcommons.uri.edu/gsofacpubs/2199 doi:10.1038/s41586-020-03094-7 https://doi.org/10.1038/s41586-020-03094-7 Graduate School of Oceanography Faculty Publications text 2021 ftunivrhodeislan https://doi.org/10.1038/s41586-020-03094-7 2024-01-15T19:10:03Z The dominant feature of large-scale mass transfer in the modern ocean is the Atlantic meridional overturning circulation (AMOC). The geometry and vigour of this circulation influences global climate on various timescales. Palaeoceanographic evidence suggests that during glacial periods of the past 1.5 million years the AMOC had markedly different features from today1; in the Atlantic basin, deep waters of Southern Ocean origin increased in volume while above them the core of the North Atlantic Deep Water (NADW) shoaled2. An absence of evidence on the origin of this phenomenon means that the sequence of events leading to global glacial conditions remains unclear. Here we present multi-proxy evidence showing that northward shifts in Antarctic iceberg melt in the Indian–Atlantic Southern Ocean (0–50° E) systematically preceded deep-water mass reorganizations by one to two thousand years during Pleistocene-era glaciations. With the aid of iceberg-trajectory model experiments, we demonstrate that such a shift in iceberg trajectories during glacial periods can result in a considerable redistribution of freshwater in the Southern Ocean. We suggest that this, in concert with increased sea-ice cover, enabled positive buoyancy anomalies to ‘escape’ into the upper limb of the AMOC, providing a teleconnection between surface Southern Ocean conditions and the formation of NADW. The magnitude and pacing of this mechanism evolved substantially across the mid-Pleistocene transition, and the coeval increase in magnitude of the ‘southern escape’ and deep circulation perturbations implicate this mechanism as a key feedback in the transition to the ‘100-kyr world’, in which glacial–interglacial cycles occur at roughly 100,000-year periods. Text Antarc* Antarctic Iceberg* NADW North Atlantic Deep Water North Atlantic Sea ice Southern Ocean University of Rhode Island: DigitalCommons@URI Antarctic Southern Ocean Indian Nature 589 7841 236 241 |
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Open Polar |
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University of Rhode Island: DigitalCommons@URI |
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ftunivrhodeislan |
language |
unknown |
description |
The dominant feature of large-scale mass transfer in the modern ocean is the Atlantic meridional overturning circulation (AMOC). The geometry and vigour of this circulation influences global climate on various timescales. Palaeoceanographic evidence suggests that during glacial periods of the past 1.5 million years the AMOC had markedly different features from today1; in the Atlantic basin, deep waters of Southern Ocean origin increased in volume while above them the core of the North Atlantic Deep Water (NADW) shoaled2. An absence of evidence on the origin of this phenomenon means that the sequence of events leading to global glacial conditions remains unclear. Here we present multi-proxy evidence showing that northward shifts in Antarctic iceberg melt in the Indian–Atlantic Southern Ocean (0–50° E) systematically preceded deep-water mass reorganizations by one to two thousand years during Pleistocene-era glaciations. With the aid of iceberg-trajectory model experiments, we demonstrate that such a shift in iceberg trajectories during glacial periods can result in a considerable redistribution of freshwater in the Southern Ocean. We suggest that this, in concert with increased sea-ice cover, enabled positive buoyancy anomalies to ‘escape’ into the upper limb of the AMOC, providing a teleconnection between surface Southern Ocean conditions and the formation of NADW. The magnitude and pacing of this mechanism evolved substantially across the mid-Pleistocene transition, and the coeval increase in magnitude of the ‘southern escape’ and deep circulation perturbations implicate this mechanism as a key feedback in the transition to the ‘100-kyr world’, in which glacial–interglacial cycles occur at roughly 100,000-year periods. |
format |
Text |
author |
Starr, Aidan Hall, Ian R. Barker, Stephen Rackow, Thomas Zhang, Xu Hemming, Sidney R. van der Lubbe, H. J.L. Knorr, Gregor Berke, Melissa A. Bigg, Grant R. Cartagena-Sierra, Alejandra Jiménez-Espejo, Francisco J. Gong, Xun Gruetzner, Jens Lathika, Nambiyathodi LeVay, Leah J. Robinson, Rebecca S. Ziegler, Martin Brentegani, Luna Caley, Thibaut Charles, Christopher D. Coenen, Jason J. Crespin, Julien G. Franzese, Allison M. Han, Xibin Hines, Sophia K.V. Jimenez Espejo, Francisco J. Just, Janna Koutsodendris, Andreas Kubota, Kaoru Norris, Richard D. dos Santos, Thiago Pereira Rolison, John M. Simon, Margit H. Tangunan, Deborah |
spellingShingle |
Starr, Aidan Hall, Ian R. Barker, Stephen Rackow, Thomas Zhang, Xu Hemming, Sidney R. van der Lubbe, H. J.L. Knorr, Gregor Berke, Melissa A. Bigg, Grant R. Cartagena-Sierra, Alejandra Jiménez-Espejo, Francisco J. Gong, Xun Gruetzner, Jens Lathika, Nambiyathodi LeVay, Leah J. Robinson, Rebecca S. Ziegler, Martin Brentegani, Luna Caley, Thibaut Charles, Christopher D. Coenen, Jason J. Crespin, Julien G. Franzese, Allison M. Han, Xibin Hines, Sophia K.V. Jimenez Espejo, Francisco J. Just, Janna Koutsodendris, Andreas Kubota, Kaoru Norris, Richard D. dos Santos, Thiago Pereira Rolison, John M. Simon, Margit H. Tangunan, Deborah Antarctic icebergs reorganize ocean circulation during Pleistocene glacials |
author_facet |
Starr, Aidan Hall, Ian R. Barker, Stephen Rackow, Thomas Zhang, Xu Hemming, Sidney R. van der Lubbe, H. J.L. Knorr, Gregor Berke, Melissa A. Bigg, Grant R. Cartagena-Sierra, Alejandra Jiménez-Espejo, Francisco J. Gong, Xun Gruetzner, Jens Lathika, Nambiyathodi LeVay, Leah J. Robinson, Rebecca S. Ziegler, Martin Brentegani, Luna Caley, Thibaut Charles, Christopher D. Coenen, Jason J. Crespin, Julien G. Franzese, Allison M. Han, Xibin Hines, Sophia K.V. Jimenez Espejo, Francisco J. Just, Janna Koutsodendris, Andreas Kubota, Kaoru Norris, Richard D. dos Santos, Thiago Pereira Rolison, John M. Simon, Margit H. Tangunan, Deborah |
author_sort |
Starr, Aidan |
title |
Antarctic icebergs reorganize ocean circulation during Pleistocene glacials |
title_short |
Antarctic icebergs reorganize ocean circulation during Pleistocene glacials |
title_full |
Antarctic icebergs reorganize ocean circulation during Pleistocene glacials |
title_fullStr |
Antarctic icebergs reorganize ocean circulation during Pleistocene glacials |
title_full_unstemmed |
Antarctic icebergs reorganize ocean circulation during Pleistocene glacials |
title_sort |
antarctic icebergs reorganize ocean circulation during pleistocene glacials |
publisher |
DigitalCommons@URI |
publishDate |
2021 |
url |
https://digitalcommons.uri.edu/gsofacpubs/2199 https://doi.org/10.1038/s41586-020-03094-7 |
geographic |
Antarctic Southern Ocean Indian |
geographic_facet |
Antarctic Southern Ocean Indian |
genre |
Antarc* Antarctic Iceberg* NADW North Atlantic Deep Water North Atlantic Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Iceberg* NADW North Atlantic Deep Water North Atlantic Sea ice Southern Ocean |
op_source |
Graduate School of Oceanography Faculty Publications |
op_relation |
https://digitalcommons.uri.edu/gsofacpubs/2199 doi:10.1038/s41586-020-03094-7 https://doi.org/10.1038/s41586-020-03094-7 |
op_doi |
https://doi.org/10.1038/s41586-020-03094-7 |
container_title |
Nature |
container_volume |
589 |
container_issue |
7841 |
container_start_page |
236 |
op_container_end_page |
241 |
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1790594518114893824 |