Evolution of 231Pa and 230Th in overflow waters of the North Atlantic
Many palaeoceanographic studies have sought to use the 231Pa∕230Th ratio as a proxy for deep ocean circulation rates in the North Atlantic. As of yet, however, no study has fully assessed the concentration of, or controls on, 230Th and 231Pa in waters immediately following ventilation at the start o...
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Language: | English |
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Copernicus GmbH
2018
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Online Access: | https://archimer.ifremer.fr/doc/00485/59667/62727.pdf https://archimer.ifremer.fr/doc/00485/59667/62728.pdf https://archimer.ifremer.fr/doc/00485/59667/62729.pdf https://archimer.ifremer.fr/doc/00485/59667/62730.pdf https://doi.org/10.5194/bg-15-7299-2018 https://archimer.ifremer.fr/doc/00485/59667/ |
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ftarchimer:oai:archimer.ifremer.fr:59667 2023-05-15T17:06:15+02:00 Evolution of 231Pa and 230Th in overflow waters of the North Atlantic Deng, Feifei Henderson, Gideon M. Castrillejo, Maxi Perez, Fiz F Steinfeldt, Reiner 2018-12 application/pdf https://archimer.ifremer.fr/doc/00485/59667/62727.pdf https://archimer.ifremer.fr/doc/00485/59667/62728.pdf https://archimer.ifremer.fr/doc/00485/59667/62729.pdf https://archimer.ifremer.fr/doc/00485/59667/62730.pdf https://doi.org/10.5194/bg-15-7299-2018 https://archimer.ifremer.fr/doc/00485/59667/ eng eng Copernicus GmbH https://archimer.ifremer.fr/doc/00485/59667/62727.pdf https://archimer.ifremer.fr/doc/00485/59667/62728.pdf https://archimer.ifremer.fr/doc/00485/59667/62729.pdf https://archimer.ifremer.fr/doc/00485/59667/62730.pdf doi:10.5194/bg-15-7299-2018 https://archimer.ifremer.fr/doc/00485/59667/ info:eu-repo/semantics/openAccess restricted use Biogeosciences (1726-4170) (Copernicus GmbH), 2018-12 , Vol. 15 , N. 23 , P. 7299-7313 text Publication info:eu-repo/semantics/article 2018 ftarchimer https://doi.org/10.5194/bg-15-7299-2018 2021-09-23T20:32:18Z Many palaeoceanographic studies have sought to use the 231Pa∕230Th ratio as a proxy for deep ocean circulation rates in the North Atlantic. As of yet, however, no study has fully assessed the concentration of, or controls on, 230Th and 231Pa in waters immediately following ventilation at the start of Atlantic meridional overturning. To that end, full water-column 231Pa and 230Th concentrations were measured along the GEOVIDE section, sampling a range of young North Atlantic deep waters. 230Th and 231Pa concentrations in the water column are lower than those observed further south in the Atlantic, ranging between 0.06 and 12.01 µBq kg−1 and between 0.37 and 4.80 µBq kg−1, respectively. Both 230Th and 231Pa profiles generally increase with water depth from surface to deep water, followed by decrease near the seafloor, with this feature most pronounced in the Labrador Sea (LA Sea) and Irminger Sea (IR Sea). Assessing this dataset using extended optimum multi-parameter (eOMP) analysis and CFC-based water mass age indicates that the low values of 230Th and 231Pa in water near the seafloor of the LA Sea and IR Sea are related to the young waters present in those regions. The importance of water age is confirmed for 230Th by a strong correlation between 230Th and water mass age (though this relationship with age is less clear for 231Pa and the 231Pa∕230Th ratio). Scavenged 231Pa and 230Th were estimated and compared to their potential concentrations in the water column due to ingrowth. This calculation indicates that more 230Th is scavenged (∼80 %) than 231Pa (∼40 %), consistent with the relatively higher particle reactivity of 230Th. Enhanced scavenging for both nuclides is demonstrated near the seafloor in young overflow waters. Calculation of the meridional transport of 230Th and 231Pa with this new GEOVIDE dataset enables a complete budget for 230Th and 231Pa for the North Atlantic. Results suggest that net transport southward of 230Th and 231Pa across GEOVIDE is smaller than transport further south in the Atlantic, and indicate that the flux to sediment in the North Atlantic is equivalent to 96 % of the production of 230Th and 74 % of the production for 231Pa. This result confirms a significantly higher advective loss of 231Pa to the south relative to 230Th and supports the use of 231Pa∕230Th to assess meridional transport at a basin scale. Article in Journal/Newspaper Labrador Sea North Atlantic Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Irminger Sea ENVELOPE(-34.041,-34.041,63.054,63.054) Biogeosciences 15 23 7299 7313 |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
description |
Many palaeoceanographic studies have sought to use the 231Pa∕230Th ratio as a proxy for deep ocean circulation rates in the North Atlantic. As of yet, however, no study has fully assessed the concentration of, or controls on, 230Th and 231Pa in waters immediately following ventilation at the start of Atlantic meridional overturning. To that end, full water-column 231Pa and 230Th concentrations were measured along the GEOVIDE section, sampling a range of young North Atlantic deep waters. 230Th and 231Pa concentrations in the water column are lower than those observed further south in the Atlantic, ranging between 0.06 and 12.01 µBq kg−1 and between 0.37 and 4.80 µBq kg−1, respectively. Both 230Th and 231Pa profiles generally increase with water depth from surface to deep water, followed by decrease near the seafloor, with this feature most pronounced in the Labrador Sea (LA Sea) and Irminger Sea (IR Sea). Assessing this dataset using extended optimum multi-parameter (eOMP) analysis and CFC-based water mass age indicates that the low values of 230Th and 231Pa in water near the seafloor of the LA Sea and IR Sea are related to the young waters present in those regions. The importance of water age is confirmed for 230Th by a strong correlation between 230Th and water mass age (though this relationship with age is less clear for 231Pa and the 231Pa∕230Th ratio). Scavenged 231Pa and 230Th were estimated and compared to their potential concentrations in the water column due to ingrowth. This calculation indicates that more 230Th is scavenged (∼80 %) than 231Pa (∼40 %), consistent with the relatively higher particle reactivity of 230Th. Enhanced scavenging for both nuclides is demonstrated near the seafloor in young overflow waters. Calculation of the meridional transport of 230Th and 231Pa with this new GEOVIDE dataset enables a complete budget for 230Th and 231Pa for the North Atlantic. Results suggest that net transport southward of 230Th and 231Pa across GEOVIDE is smaller than transport further south in the Atlantic, and indicate that the flux to sediment in the North Atlantic is equivalent to 96 % of the production of 230Th and 74 % of the production for 231Pa. This result confirms a significantly higher advective loss of 231Pa to the south relative to 230Th and supports the use of 231Pa∕230Th to assess meridional transport at a basin scale. |
format |
Article in Journal/Newspaper |
author |
Deng, Feifei Henderson, Gideon M. Castrillejo, Maxi Perez, Fiz F Steinfeldt, Reiner |
spellingShingle |
Deng, Feifei Henderson, Gideon M. Castrillejo, Maxi Perez, Fiz F Steinfeldt, Reiner Evolution of 231Pa and 230Th in overflow waters of the North Atlantic |
author_facet |
Deng, Feifei Henderson, Gideon M. Castrillejo, Maxi Perez, Fiz F Steinfeldt, Reiner |
author_sort |
Deng, Feifei |
title |
Evolution of 231Pa and 230Th in overflow waters of the North Atlantic |
title_short |
Evolution of 231Pa and 230Th in overflow waters of the North Atlantic |
title_full |
Evolution of 231Pa and 230Th in overflow waters of the North Atlantic |
title_fullStr |
Evolution of 231Pa and 230Th in overflow waters of the North Atlantic |
title_full_unstemmed |
Evolution of 231Pa and 230Th in overflow waters of the North Atlantic |
title_sort |
evolution of 231pa and 230th in overflow waters of the north atlantic |
publisher |
Copernicus GmbH |
publishDate |
2018 |
url |
https://archimer.ifremer.fr/doc/00485/59667/62727.pdf https://archimer.ifremer.fr/doc/00485/59667/62728.pdf https://archimer.ifremer.fr/doc/00485/59667/62729.pdf https://archimer.ifremer.fr/doc/00485/59667/62730.pdf https://doi.org/10.5194/bg-15-7299-2018 https://archimer.ifremer.fr/doc/00485/59667/ |
long_lat |
ENVELOPE(-34.041,-34.041,63.054,63.054) |
geographic |
Irminger Sea |
geographic_facet |
Irminger Sea |
genre |
Labrador Sea North Atlantic |
genre_facet |
Labrador Sea North Atlantic |
op_source |
Biogeosciences (1726-4170) (Copernicus GmbH), 2018-12 , Vol. 15 , N. 23 , P. 7299-7313 |
op_relation |
https://archimer.ifremer.fr/doc/00485/59667/62727.pdf https://archimer.ifremer.fr/doc/00485/59667/62728.pdf https://archimer.ifremer.fr/doc/00485/59667/62729.pdf https://archimer.ifremer.fr/doc/00485/59667/62730.pdf doi:10.5194/bg-15-7299-2018 https://archimer.ifremer.fr/doc/00485/59667/ |
op_rights |
info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.5194/bg-15-7299-2018 |
container_title |
Biogeosciences |
container_volume |
15 |
container_issue |
23 |
container_start_page |
7299 |
op_container_end_page |
7313 |
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1766061297981456384 |