Evolution of the Global Overturning Circulation since the Last Glacial Maximum based on marine authigenic neodymium isotopes
The Global Overturning Circulation is linked to climate change on glacial-interglacial and multi-millennial timescales. The understanding of past climate-circulation links remains hindered by apparent conflicts among proxy measures of circulation. Here we reconstruct circulation changes since the La...
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ftethz:oai:www.research-collection.ethz.ch:20.500.11850/423888 2023-05-15T17:29:46+02:00 Evolution of the Global Overturning Circulation since the Last Glacial Maximum based on marine authigenic neodymium isotopes Du, Jianghui Haley, Brian A. Mix, Alan C. 2020-08 application/application/pdf https://hdl.handle.net/20.500.11850/423888 https://doi.org/10.3929/ethz-b-000423888 en eng Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.quascirev.2020.106396 info:eu-repo/semantics/altIdentifier/wos/000551471300006 http://hdl.handle.net/20.500.11850/423888 doi:10.3929/ethz-b-000423888 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/4.0/ Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International CC-BY-NC-ND Quaternary Science Reviews, 241 Ocean circulation Last glacial maximum Last deglaciation Paleoceanography Paleoclimate Neodymium isotopes Marine Nd Cycle Authigenic phase Detrital sediments info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2020 ftethz https://doi.org/20.500.11850/423888 https://doi.org/10.3929/ethz-b-000423888 https://doi.org/10.1016/j.quascirev.2020.106396 2022-04-25T14:12:30Z The Global Overturning Circulation is linked to climate change on glacial-interglacial and multi-millennial timescales. The understanding of past climate-circulation links remains hindered by apparent conflicts among proxy measures of circulation. Here we reconstruct circulation changes since the Last Glacial Maximum (LGM) based on a global synthesis of authigenic neodymium isotope records (εNd). We propose the bottom-up framework of interpreting seawater and authigenic εNd considering not only conservative watermass mixing, but also the preformed properties and the non-conservative behavior of εNd, both subject to sedimentary influences. We extract the major spatial-temporal modes of authigenic εNd using Principal Component Analysis, and make a first-order circulation reconstruction with budget-constrained box model simulations. We show that during the LGM, the source region of North Atlantic overturning shifted southward, which led to more radiogenic preformed εNd of glacial Northern Source Water (NSW). Considering this preformed effect, we infer that glacial deep Atlantic had a similar proportion of NSW as today, although the overall strength of glacial circulation appears reduced from both North Atlantic and Southern Ocean sources, which increased the relative importance of non-conservative behavior of εNd and may have facilitated accumulation of respired carbon in the deep ocean. During the deglaciation, we find that Southern Ocean overturning increased, which offset suppressed North Atlantic overturning and resulted in a net stronger global abyssal circulation. Faster global scale deglacial circulation reduced the relative importance of non-conservative effects, resulting in Atlantic-Pacific convergence of abyssal εNd signatures. Variations of Southern Ocean overturning likely drove a significant fraction of deglacial changes in atmospheric CO2 and oceanic heat budget. ISSN:0277-3791 Article in Journal/Newspaper North Atlantic Southern Ocean ETH Zürich Research Collection Pacific Southern Ocean |
institution |
Open Polar |
collection |
ETH Zürich Research Collection |
op_collection_id |
ftethz |
language |
English |
topic |
Ocean circulation Last glacial maximum Last deglaciation Paleoceanography Paleoclimate Neodymium isotopes Marine Nd Cycle Authigenic phase Detrital sediments |
spellingShingle |
Ocean circulation Last glacial maximum Last deglaciation Paleoceanography Paleoclimate Neodymium isotopes Marine Nd Cycle Authigenic phase Detrital sediments Du, Jianghui Haley, Brian A. Mix, Alan C. Evolution of the Global Overturning Circulation since the Last Glacial Maximum based on marine authigenic neodymium isotopes |
topic_facet |
Ocean circulation Last glacial maximum Last deglaciation Paleoceanography Paleoclimate Neodymium isotopes Marine Nd Cycle Authigenic phase Detrital sediments |
description |
The Global Overturning Circulation is linked to climate change on glacial-interglacial and multi-millennial timescales. The understanding of past climate-circulation links remains hindered by apparent conflicts among proxy measures of circulation. Here we reconstruct circulation changes since the Last Glacial Maximum (LGM) based on a global synthesis of authigenic neodymium isotope records (εNd). We propose the bottom-up framework of interpreting seawater and authigenic εNd considering not only conservative watermass mixing, but also the preformed properties and the non-conservative behavior of εNd, both subject to sedimentary influences. We extract the major spatial-temporal modes of authigenic εNd using Principal Component Analysis, and make a first-order circulation reconstruction with budget-constrained box model simulations. We show that during the LGM, the source region of North Atlantic overturning shifted southward, which led to more radiogenic preformed εNd of glacial Northern Source Water (NSW). Considering this preformed effect, we infer that glacial deep Atlantic had a similar proportion of NSW as today, although the overall strength of glacial circulation appears reduced from both North Atlantic and Southern Ocean sources, which increased the relative importance of non-conservative behavior of εNd and may have facilitated accumulation of respired carbon in the deep ocean. During the deglaciation, we find that Southern Ocean overturning increased, which offset suppressed North Atlantic overturning and resulted in a net stronger global abyssal circulation. Faster global scale deglacial circulation reduced the relative importance of non-conservative effects, resulting in Atlantic-Pacific convergence of abyssal εNd signatures. Variations of Southern Ocean overturning likely drove a significant fraction of deglacial changes in atmospheric CO2 and oceanic heat budget. ISSN:0277-3791 |
format |
Article in Journal/Newspaper |
author |
Du, Jianghui Haley, Brian A. Mix, Alan C. |
author_facet |
Du, Jianghui Haley, Brian A. Mix, Alan C. |
author_sort |
Du, Jianghui |
title |
Evolution of the Global Overturning Circulation since the Last Glacial Maximum based on marine authigenic neodymium isotopes |
title_short |
Evolution of the Global Overturning Circulation since the Last Glacial Maximum based on marine authigenic neodymium isotopes |
title_full |
Evolution of the Global Overturning Circulation since the Last Glacial Maximum based on marine authigenic neodymium isotopes |
title_fullStr |
Evolution of the Global Overturning Circulation since the Last Glacial Maximum based on marine authigenic neodymium isotopes |
title_full_unstemmed |
Evolution of the Global Overturning Circulation since the Last Glacial Maximum based on marine authigenic neodymium isotopes |
title_sort |
evolution of the global overturning circulation since the last glacial maximum based on marine authigenic neodymium isotopes |
publisher |
Elsevier |
publishDate |
2020 |
url |
https://hdl.handle.net/20.500.11850/423888 https://doi.org/10.3929/ethz-b-000423888 |
geographic |
Pacific Southern Ocean |
geographic_facet |
Pacific Southern Ocean |
genre |
North Atlantic Southern Ocean |
genre_facet |
North Atlantic Southern Ocean |
op_source |
Quaternary Science Reviews, 241 |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.quascirev.2020.106396 info:eu-repo/semantics/altIdentifier/wos/000551471300006 http://hdl.handle.net/20.500.11850/423888 doi:10.3929/ethz-b-000423888 |
op_rights |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-nd/4.0/ Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/20.500.11850/423888 https://doi.org/10.3929/ethz-b-000423888 https://doi.org/10.1016/j.quascirev.2020.106396 |
_version_ |
1766124566955950080 |