Freshening, stratification and deep-water formation in the Nordic Seas during marine isotope stage 11
The Atlantic meridional overturning circulation (AMOC) is a critical element of Earth's climate system and it is currently weakening. While this weakening is frequently explained by freshwater-driven dis- ruptions to deep-water formation, uncertainties about the impacts of prolonged freshening...
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ftawi:oai:epic.awi.de:54808 2023-05-15T17:24:16+02:00 Freshening, stratification and deep-water formation in the Nordic Seas during marine isotope stage 11 Doherty, John M. Ling, Yuet F. Not, Christelle Erler, Dirk Bauch, Henning A. Paytan, Adina Thibodeau, Benoit 2021 https://epic.awi.de/id/eprint/54808/ https://doi.org/10.1016/j.quascirev.2021.107231 https://hdl.handle.net/10013/epic.01f80c00-1e08-475a-a460-bd88b38ba6cf unknown Doherty, J. M. , Ling, Y. F. , Not, C. , Erler, D. , Bauch, H. A. , Paytan, A. and Thibodeau, B. (2021) Freshening, stratification and deep-water formation in the Nordic Seas during marine isotope stage 11 , Quaternary Science Reviews, 272 , p. 107231 . doi:10.1016/j.quascirev.2021.107231 <https://doi.org/10.1016/j.quascirev.2021.107231> , hdl:10013/epic.01f80c00-1e08-475a-a460-bd88b38ba6cf EPIC3Quaternary Science Reviews, 272, pp. 107231, ISSN: 02773791 Article peerRev 2021 ftawi https://doi.org/10.1016/j.quascirev.2021.107231 2021-12-24T15:46:32Z The Atlantic meridional overturning circulation (AMOC) is a critical element of Earth's climate system and it is currently weakening. While this weakening is frequently explained by freshwater-driven dis- ruptions to deep-water formation, uncertainties about the impacts of prolonged freshening limit our capacity to predict its future state. For example, during the warm and unusually long marine isotope stage (MIS) 11 interglacial, ~424 to 374 ka, several lines of evidence suggest that a strong AMOC persisted concomitant with fresher-than-present conditions in the Nordic Seas, challenging our current under- standing of deep-water formation. Here, we present new foraminifer-bound nitrogen isotope data along with multiple additional geochemical reconstructions of upper-ocean hydrography in the Nordic Seas during this anomalous interval. Our data suggest that a weak summer stratification was driven by the prolonged upper-ocean accumulation of freshwater beginning at the onset of the climatic optimum, ~410 to 407 ka, which could have helped precondition the region for deep-water formation. A box model constrained by paleo-proxy data additionally suggests that the density gradient between the subpolar North Atlantic and Nordic Seas was favorable for the onset of deep-water formation in the Nordic Seas during the climatic optimum. It is thus likely that the Nordic Seas became a locus of deep-water for- mation around this time. Enhanced northern-hemisphere heating driven by deep-water formation in the Nordic Seas may have been important for delaying glacial conditions, thereby driving the extended warming characteristic of MIS 11. Such findings may also be relevant for near-future changes under a relatively fresher high-latitude North Atlantic. Article in Journal/Newspaper Nordic Seas North Atlantic Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Quaternary Science Reviews 272 107231 |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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ftawi |
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description |
The Atlantic meridional overturning circulation (AMOC) is a critical element of Earth's climate system and it is currently weakening. While this weakening is frequently explained by freshwater-driven dis- ruptions to deep-water formation, uncertainties about the impacts of prolonged freshening limit our capacity to predict its future state. For example, during the warm and unusually long marine isotope stage (MIS) 11 interglacial, ~424 to 374 ka, several lines of evidence suggest that a strong AMOC persisted concomitant with fresher-than-present conditions in the Nordic Seas, challenging our current under- standing of deep-water formation. Here, we present new foraminifer-bound nitrogen isotope data along with multiple additional geochemical reconstructions of upper-ocean hydrography in the Nordic Seas during this anomalous interval. Our data suggest that a weak summer stratification was driven by the prolonged upper-ocean accumulation of freshwater beginning at the onset of the climatic optimum, ~410 to 407 ka, which could have helped precondition the region for deep-water formation. A box model constrained by paleo-proxy data additionally suggests that the density gradient between the subpolar North Atlantic and Nordic Seas was favorable for the onset of deep-water formation in the Nordic Seas during the climatic optimum. It is thus likely that the Nordic Seas became a locus of deep-water for- mation around this time. Enhanced northern-hemisphere heating driven by deep-water formation in the Nordic Seas may have been important for delaying glacial conditions, thereby driving the extended warming characteristic of MIS 11. Such findings may also be relevant for near-future changes under a relatively fresher high-latitude North Atlantic. |
format |
Article in Journal/Newspaper |
author |
Doherty, John M. Ling, Yuet F. Not, Christelle Erler, Dirk Bauch, Henning A. Paytan, Adina Thibodeau, Benoit |
spellingShingle |
Doherty, John M. Ling, Yuet F. Not, Christelle Erler, Dirk Bauch, Henning A. Paytan, Adina Thibodeau, Benoit Freshening, stratification and deep-water formation in the Nordic Seas during marine isotope stage 11 |
author_facet |
Doherty, John M. Ling, Yuet F. Not, Christelle Erler, Dirk Bauch, Henning A. Paytan, Adina Thibodeau, Benoit |
author_sort |
Doherty, John M. |
title |
Freshening, stratification and deep-water formation in the Nordic Seas during marine isotope stage 11 |
title_short |
Freshening, stratification and deep-water formation in the Nordic Seas during marine isotope stage 11 |
title_full |
Freshening, stratification and deep-water formation in the Nordic Seas during marine isotope stage 11 |
title_fullStr |
Freshening, stratification and deep-water formation in the Nordic Seas during marine isotope stage 11 |
title_full_unstemmed |
Freshening, stratification and deep-water formation in the Nordic Seas during marine isotope stage 11 |
title_sort |
freshening, stratification and deep-water formation in the nordic seas during marine isotope stage 11 |
publishDate |
2021 |
url |
https://epic.awi.de/id/eprint/54808/ https://doi.org/10.1016/j.quascirev.2021.107231 https://hdl.handle.net/10013/epic.01f80c00-1e08-475a-a460-bd88b38ba6cf |
genre |
Nordic Seas North Atlantic |
genre_facet |
Nordic Seas North Atlantic |
op_source |
EPIC3Quaternary Science Reviews, 272, pp. 107231, ISSN: 02773791 |
op_relation |
Doherty, J. M. , Ling, Y. F. , Not, C. , Erler, D. , Bauch, H. A. , Paytan, A. and Thibodeau, B. (2021) Freshening, stratification and deep-water formation in the Nordic Seas during marine isotope stage 11 , Quaternary Science Reviews, 272 , p. 107231 . doi:10.1016/j.quascirev.2021.107231 <https://doi.org/10.1016/j.quascirev.2021.107231> , hdl:10013/epic.01f80c00-1e08-475a-a460-bd88b38ba6cf |
op_doi |
https://doi.org/10.1016/j.quascirev.2021.107231 |
container_title |
Quaternary Science Reviews |
container_volume |
272 |
container_start_page |
107231 |
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1766115201236598784 |