Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years
The Arctic Ocean has an important role in Earth’s climate, both through surface processes such as sea-ice formation and transport, and through the production and export of waters at depth that contribute to the global thermohaline circulation. Deciphering the deep Arctic Ocean’s palaeo-oceanographic...
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ftcolumbiauniv:oai:academiccommons.columbia.edu:10.7916/D8DZ0KBX 2023-05-15T14:33:32+02:00 Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years Hoffmann, Sharon S. McManus, Jerry F. Curry, William B. Brown-Ledger, L. Susan 2013 https://doi.org/10.7916/D8DZ0KBX English eng https://doi.org/10.7916/D8DZ0KBX Environmental sciences Ecology Oceanography Articles 2013 ftcolumbiauniv https://doi.org/10.7916/D8DZ0KBX 2019-04-04T08:09:45Z The Arctic Ocean has an important role in Earth’s climate, both through surface processes such as sea-ice formation and transport, and through the production and export of waters at depth that contribute to the global thermohaline circulation. Deciphering the deep Arctic Ocean’s palaeo-oceanographic history is a crucial part of understanding its role in climatic change. Here we show that sedimentary ratios of the radionuclides thorium-230 (230Th) and protactinium-231 (231Pa), which are produced in sea water and removed by particle scavenging on timescales of decades to centuries, respectively, record consistent evidence for the export of 231Pa from the deep Arctic and may indicate continuous deep-water exchange between the Arctic and Atlantic oceans throughout the past 35,000 years. Seven well-dated box-core records provide a comprehensive overview of 231Pa and 230Th burial in Arctic sediments during glacial, deglacial and interglacial conditions. Sedimentary 231Pa/230Th ratios decrease nearly linearly with increasing water depth above the core sites, indicating efficient particle scavenging in the upper water column and greater influence of removal by lateral transport at depth. Although the measured 230Th burial is in balance with its production in Arctic sea water, integrated depth profiles for all time intervals reveal a deficit in 231Pa burial that can be balanced only by lateral export in the water column. Because no enhanced sink for 231Pa has yet been found in the Arctic, our records suggest that deep-water exchange through the Fram strait may export 231Pa. Such export may have continued for the past 35,000 years, suggesting a century-scale replacement time for deep waters in the Arctic Ocean since the most recent glaciation and a persistent contribution of Arctic waters to the global ocean circulation. Article in Journal/Newspaper Arctic Arctic Ocean Fram Strait Sea ice Columbia University: Academic Commons Arctic Arctic Ocean |
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Open Polar |
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Columbia University: Academic Commons |
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ftcolumbiauniv |
language |
English |
topic |
Environmental sciences Ecology Oceanography |
spellingShingle |
Environmental sciences Ecology Oceanography Hoffmann, Sharon S. McManus, Jerry F. Curry, William B. Brown-Ledger, L. Susan Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years |
topic_facet |
Environmental sciences Ecology Oceanography |
description |
The Arctic Ocean has an important role in Earth’s climate, both through surface processes such as sea-ice formation and transport, and through the production and export of waters at depth that contribute to the global thermohaline circulation. Deciphering the deep Arctic Ocean’s palaeo-oceanographic history is a crucial part of understanding its role in climatic change. Here we show that sedimentary ratios of the radionuclides thorium-230 (230Th) and protactinium-231 (231Pa), which are produced in sea water and removed by particle scavenging on timescales of decades to centuries, respectively, record consistent evidence for the export of 231Pa from the deep Arctic and may indicate continuous deep-water exchange between the Arctic and Atlantic oceans throughout the past 35,000 years. Seven well-dated box-core records provide a comprehensive overview of 231Pa and 230Th burial in Arctic sediments during glacial, deglacial and interglacial conditions. Sedimentary 231Pa/230Th ratios decrease nearly linearly with increasing water depth above the core sites, indicating efficient particle scavenging in the upper water column and greater influence of removal by lateral transport at depth. Although the measured 230Th burial is in balance with its production in Arctic sea water, integrated depth profiles for all time intervals reveal a deficit in 231Pa burial that can be balanced only by lateral export in the water column. Because no enhanced sink for 231Pa has yet been found in the Arctic, our records suggest that deep-water exchange through the Fram strait may export 231Pa. Such export may have continued for the past 35,000 years, suggesting a century-scale replacement time for deep waters in the Arctic Ocean since the most recent glaciation and a persistent contribution of Arctic waters to the global ocean circulation. |
format |
Article in Journal/Newspaper |
author |
Hoffmann, Sharon S. McManus, Jerry F. Curry, William B. Brown-Ledger, L. Susan |
author_facet |
Hoffmann, Sharon S. McManus, Jerry F. Curry, William B. Brown-Ledger, L. Susan |
author_sort |
Hoffmann, Sharon S. |
title |
Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years |
title_short |
Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years |
title_full |
Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years |
title_fullStr |
Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years |
title_full_unstemmed |
Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years |
title_sort |
persistent export of 231pa from the deep central arctic ocean over the past 35,000 years |
publishDate |
2013 |
url |
https://doi.org/10.7916/D8DZ0KBX |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Fram Strait Sea ice |
genre_facet |
Arctic Arctic Ocean Fram Strait Sea ice |
op_relation |
https://doi.org/10.7916/D8DZ0KBX |
op_doi |
https://doi.org/10.7916/D8DZ0KBX |
_version_ |
1766306750833623040 |