Upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release
Radiocarbon in the atmosphere is regulated largely by ocean circulation, which controls the sequestration of carbon dioxide (CO2) in the deep sea through atmosphere–ocean carbon exchange. During the last glaciation, lower atmospheric CO2 levels were accompanied by increased atmospheric radiocarbon c...
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ftunivauckland:oai:researchspace.auckland.ac.nz:2292/10305 2023-05-15T18:24:56+02:00 Upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release Rose, KA Sikes, EL Guilderson, TP Shane, P Hill, TM Zahn, R Spero, HJ 2010 http://hdl.handle.net/2292/10305 https://doi.org/10.1038/nature09288 unknown Nature Publishing Group Nature Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from http://www.sherpa.ac.uk/romeo/issn/0028-0836/ https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm Copyright: Nature Publishing Group http://purl.org/eprint/accessRights/RestrictedAccess http://dx.doi.org/10.1038/nature09288 Journal Article 2010 ftunivauckland https://doi.org/10.1038/nature09288 2013-12-07T09:07:30Z Radiocarbon in the atmosphere is regulated largely by ocean circulation, which controls the sequestration of carbon dioxide (CO2) in the deep sea through atmosphere–ocean carbon exchange. During the last glaciation, lower atmospheric CO2 levels were accompanied by increased atmospheric radiocarbon concentrations that have been attributed to greater storage of CO2 in a poorly ventilated abyssal ocean1, 2. The end of the ice age was marked by a rapid increase in atmospheric CO2 concentrations2 that coincided with reduced 14C/12C ratios (Δ14C) in the atmosphere3, suggesting the release of very ‘old’ (14C-depleted) CO2 from the deep ocean to the atmosphere3. Here we present radiocarbon records of surface and intermediate-depth waters from two sediment cores in the southwest Pacific and Southern oceans. We find a steady 170 per mil decrease in Δ14C that precedes and roughly equals in magnitude the decrease in the atmospheric radiocarbon signal during the early stages of the glacial–interglacial climatic transition. The atmospheric decrease in the radiocarbon signal coincides with regionally intensified upwelling and marine biological productivity4, suggesting that CO2 released by means of deep water upwelling in the Southern Ocean lost most of its original depleted-14C imprint as a result of exchange and isotopic equilibration with the atmosphere. Our data imply that the deglacial 14C depletion previously identified in the eastern tropical North Pacific5 must have involved contributions from sources other than the previously suggested carbon release by way of a deep Southern Ocean pathway5, and may reflect the expanded influence of the 14C-depleted North Pacific carbon reservoir across this interval. Accordingly, shallow water masses advecting north across the South Pacific in the early deglaciation had little or no residual 14C-depleted signals owing to degassing of CO2 and biological uptake in the Southern Ocean. Article in Journal/Newspaper Southern Ocean University of Auckland Research Repository - ResearchSpace Pacific Southern Ocean Nature 466 7310 1093 1097 |
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University of Auckland Research Repository - ResearchSpace |
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ftunivauckland |
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unknown |
description |
Radiocarbon in the atmosphere is regulated largely by ocean circulation, which controls the sequestration of carbon dioxide (CO2) in the deep sea through atmosphere–ocean carbon exchange. During the last glaciation, lower atmospheric CO2 levels were accompanied by increased atmospheric radiocarbon concentrations that have been attributed to greater storage of CO2 in a poorly ventilated abyssal ocean1, 2. The end of the ice age was marked by a rapid increase in atmospheric CO2 concentrations2 that coincided with reduced 14C/12C ratios (Δ14C) in the atmosphere3, suggesting the release of very ‘old’ (14C-depleted) CO2 from the deep ocean to the atmosphere3. Here we present radiocarbon records of surface and intermediate-depth waters from two sediment cores in the southwest Pacific and Southern oceans. We find a steady 170 per mil decrease in Δ14C that precedes and roughly equals in magnitude the decrease in the atmospheric radiocarbon signal during the early stages of the glacial–interglacial climatic transition. The atmospheric decrease in the radiocarbon signal coincides with regionally intensified upwelling and marine biological productivity4, suggesting that CO2 released by means of deep water upwelling in the Southern Ocean lost most of its original depleted-14C imprint as a result of exchange and isotopic equilibration with the atmosphere. Our data imply that the deglacial 14C depletion previously identified in the eastern tropical North Pacific5 must have involved contributions from sources other than the previously suggested carbon release by way of a deep Southern Ocean pathway5, and may reflect the expanded influence of the 14C-depleted North Pacific carbon reservoir across this interval. Accordingly, shallow water masses advecting north across the South Pacific in the early deglaciation had little or no residual 14C-depleted signals owing to degassing of CO2 and biological uptake in the Southern Ocean. |
format |
Article in Journal/Newspaper |
author |
Rose, KA Sikes, EL Guilderson, TP Shane, P Hill, TM Zahn, R Spero, HJ |
spellingShingle |
Rose, KA Sikes, EL Guilderson, TP Shane, P Hill, TM Zahn, R Spero, HJ Upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release |
author_facet |
Rose, KA Sikes, EL Guilderson, TP Shane, P Hill, TM Zahn, R Spero, HJ |
author_sort |
Rose, KA |
title |
Upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release |
title_short |
Upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release |
title_full |
Upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release |
title_fullStr |
Upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release |
title_full_unstemmed |
Upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release |
title_sort |
upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release |
publisher |
Nature Publishing Group |
publishDate |
2010 |
url |
http://hdl.handle.net/2292/10305 https://doi.org/10.1038/nature09288 |
geographic |
Pacific Southern Ocean |
geographic_facet |
Pacific Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
http://dx.doi.org/10.1038/nature09288 |
op_relation |
Nature |
op_rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from http://www.sherpa.ac.uk/romeo/issn/0028-0836/ https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm Copyright: Nature Publishing Group http://purl.org/eprint/accessRights/RestrictedAccess |
op_doi |
https://doi.org/10.1038/nature09288 |
container_title |
Nature |
container_volume |
466 |
container_issue |
7310 |
container_start_page |
1093 |
op_container_end_page |
1097 |
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1766205972912537600 |