High resolution reconstruction of Southwest Atlantic sea-ice and its role in the carbon cycle during marine isotope stages 3 and 2
Recent modeling suggests that changes in Southern Ocean sea-ice extent potentially regulated the exchange of CO2 release between the ocean and atmosphere during glacials. Unfortunately, a lack of high-resolution sea-ice records from the Southern Ocean has prevented detailed testing of these model-ba...
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American Geophysical Union
2012
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ftnerc:oai:nora.nerc.ac.uk:16544 2023-05-15T16:39:26+02:00 High resolution reconstruction of Southwest Atlantic sea-ice and its role in the carbon cycle during marine isotope stages 3 and 2 Collins, Lewis G. Pike, Jennifer Allen, Claire S. Hodgson, Dominic A. 2012 http://nora.nerc.ac.uk/id/eprint/16544/ http://www.agu.org/journals/pa/pa1203/2011PA002264/2011PA002264.pdf unknown American Geophysical Union Collins, Lewis G.; Pike, Jennifer; Allen, Claire S. orcid:0000-0002-0938-0551 Hodgson, Dominic A. orcid:0000-0002-3841-3746 . 2012 High resolution reconstruction of Southwest Atlantic sea-ice and its role in the carbon cycle during marine isotope stages 3 and 2. Paleoceanography, 27, PA3217. 17, pp. https://doi.org/10.1029/2011PA002264 <https://doi.org/10.1029/2011PA002264> Publication - Article PeerReviewed 2012 ftnerc https://doi.org/10.1029/2011PA002264 2023-02-04T19:30:35Z Recent modeling suggests that changes in Southern Ocean sea-ice extent potentially regulated the exchange of CO2 release between the ocean and atmosphere during glacials. Unfortunately, a lack of high-resolution sea-ice records from the Southern Ocean has prevented detailed testing of these model-based hypotheses with field data. Here we present high-resolution records of Southern Ocean sea-ice, for the period 35–15 cal ka BP, derived from diatom assemblages measured in three glacial sediment cores forming an ∼8° transect across the Scotia Sea, southwest Atlantic. Chronological control was achieved through a novel combination of diatom abundance stratigraphy, relative geomagnetic paleointensity data, and down-core magnetic susceptibility and ice core dust correlation. Results showed that the winter sea-ice edge reached its maximum northward extent of ∼53°S, at least 3° north of its modern limit, between ∼25 and ∼23.5 cal ka BP, predating the Last Glacial Maximum (LGM). Maximum northward expansion of the summer sea-ice edge also pre-dated the LGM, advancing to at least 61°S, and possibly as far north as 55°S between ∼31 and ∼23.5 cal ka BP, a ∼12° advance from its modern position. A clear shift in the seasonal sea-ice zone is evident following summer sea-ice edge retreat at ∼23.5 cal ka BP, potentially related to austral insolation forcing. This resulted in an expanded seasonal sea-ice zone between ∼22.5 cal ka BP and deglaciation. Our field data confirm that Southern Ocean sea-ice had the physical potential to influence the carbon cycle both as a physical barrier and more importantly through the suppression of vertical mixing and cycling of pre-formed nutrients. Our data indicates that Southern Ocean sea-ice was most effective as a physical barrier between ∼31 and ∼23.5 cal ka BP and as a mechanism capable of reducing vertical mixing between ∼22.5 cal ka BP and deglaciation. However, poor correlations with atmospheric CO2 variability recorded in ice cores, particularly the lack of a CO2 response during a rapid ... Article in Journal/Newspaper ice core Scotia Sea Sea ice Southern Ocean Natural Environment Research Council: NERC Open Research Archive Southern Ocean Austral Scotia Sea Paleoceanography 27 3 n/a n/a |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
description |
Recent modeling suggests that changes in Southern Ocean sea-ice extent potentially regulated the exchange of CO2 release between the ocean and atmosphere during glacials. Unfortunately, a lack of high-resolution sea-ice records from the Southern Ocean has prevented detailed testing of these model-based hypotheses with field data. Here we present high-resolution records of Southern Ocean sea-ice, for the period 35–15 cal ka BP, derived from diatom assemblages measured in three glacial sediment cores forming an ∼8° transect across the Scotia Sea, southwest Atlantic. Chronological control was achieved through a novel combination of diatom abundance stratigraphy, relative geomagnetic paleointensity data, and down-core magnetic susceptibility and ice core dust correlation. Results showed that the winter sea-ice edge reached its maximum northward extent of ∼53°S, at least 3° north of its modern limit, between ∼25 and ∼23.5 cal ka BP, predating the Last Glacial Maximum (LGM). Maximum northward expansion of the summer sea-ice edge also pre-dated the LGM, advancing to at least 61°S, and possibly as far north as 55°S between ∼31 and ∼23.5 cal ka BP, a ∼12° advance from its modern position. A clear shift in the seasonal sea-ice zone is evident following summer sea-ice edge retreat at ∼23.5 cal ka BP, potentially related to austral insolation forcing. This resulted in an expanded seasonal sea-ice zone between ∼22.5 cal ka BP and deglaciation. Our field data confirm that Southern Ocean sea-ice had the physical potential to influence the carbon cycle both as a physical barrier and more importantly through the suppression of vertical mixing and cycling of pre-formed nutrients. Our data indicates that Southern Ocean sea-ice was most effective as a physical barrier between ∼31 and ∼23.5 cal ka BP and as a mechanism capable of reducing vertical mixing between ∼22.5 cal ka BP and deglaciation. However, poor correlations with atmospheric CO2 variability recorded in ice cores, particularly the lack of a CO2 response during a rapid ... |
format |
Article in Journal/Newspaper |
author |
Collins, Lewis G. Pike, Jennifer Allen, Claire S. Hodgson, Dominic A. |
spellingShingle |
Collins, Lewis G. Pike, Jennifer Allen, Claire S. Hodgson, Dominic A. High resolution reconstruction of Southwest Atlantic sea-ice and its role in the carbon cycle during marine isotope stages 3 and 2 |
author_facet |
Collins, Lewis G. Pike, Jennifer Allen, Claire S. Hodgson, Dominic A. |
author_sort |
Collins, Lewis G. |
title |
High resolution reconstruction of Southwest Atlantic sea-ice and its role in the carbon cycle during marine isotope stages 3 and 2 |
title_short |
High resolution reconstruction of Southwest Atlantic sea-ice and its role in the carbon cycle during marine isotope stages 3 and 2 |
title_full |
High resolution reconstruction of Southwest Atlantic sea-ice and its role in the carbon cycle during marine isotope stages 3 and 2 |
title_fullStr |
High resolution reconstruction of Southwest Atlantic sea-ice and its role in the carbon cycle during marine isotope stages 3 and 2 |
title_full_unstemmed |
High resolution reconstruction of Southwest Atlantic sea-ice and its role in the carbon cycle during marine isotope stages 3 and 2 |
title_sort |
high resolution reconstruction of southwest atlantic sea-ice and its role in the carbon cycle during marine isotope stages 3 and 2 |
publisher |
American Geophysical Union |
publishDate |
2012 |
url |
http://nora.nerc.ac.uk/id/eprint/16544/ http://www.agu.org/journals/pa/pa1203/2011PA002264/2011PA002264.pdf |
geographic |
Southern Ocean Austral Scotia Sea |
geographic_facet |
Southern Ocean Austral Scotia Sea |
genre |
ice core Scotia Sea Sea ice Southern Ocean |
genre_facet |
ice core Scotia Sea Sea ice Southern Ocean |
op_relation |
Collins, Lewis G.; Pike, Jennifer; Allen, Claire S. orcid:0000-0002-0938-0551 Hodgson, Dominic A. orcid:0000-0002-3841-3746 . 2012 High resolution reconstruction of Southwest Atlantic sea-ice and its role in the carbon cycle during marine isotope stages 3 and 2. Paleoceanography, 27, PA3217. 17, pp. https://doi.org/10.1029/2011PA002264 <https://doi.org/10.1029/2011PA002264> |
op_doi |
https://doi.org/10.1029/2011PA002264 |
container_title |
Paleoceanography |
container_volume |
27 |
container_issue |
3 |
container_start_page |
n/a |
op_container_end_page |
n/a |
_version_ |
1766029789063282688 |