Influence of intense scavenging on Pa-Th fractionation in the wake of Kerguelen Island (Southern Ocean)
Dissolved and particulate excess (230)Th and (231)Pa concentrations (noted (230)Th(xs) and (231)Pa(xs) respectively) and (231)Pa(xs)/(230)Th(xs) activity ratios were investigated on and out of the Kerguelen plateau (Southern Ocean) in the framework of the Kerguelen Ocean and Plateau compared Study p...
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Online Access: | https://archimer.ifremer.fr/doc/00228/33894/32272.pdf https://doi.org/10.5194/bg-8-3187-2011 https://archimer.ifremer.fr/doc/00228/33894/ |
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ftarchimer:oai:archimer.ifremer.fr:33894 2023-05-15T18:25:12+02:00 Influence of intense scavenging on Pa-Th fractionation in the wake of Kerguelen Island (Southern Ocean) Venchiarutti, C. Roy-barman, M. Freydier, R. Van Beek, P. Souhaut, M. Jeandel, C. 2011 application/pdf https://archimer.ifremer.fr/doc/00228/33894/32272.pdf https://doi.org/10.5194/bg-8-3187-2011 https://archimer.ifremer.fr/doc/00228/33894/ eng eng Copernicus Gesellschaft Mbh https://archimer.ifremer.fr/doc/00228/33894/32272.pdf doi:10.5194/bg-8-3187-2011 https://archimer.ifremer.fr/doc/00228/33894/ Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 License. info:eu-repo/semantics/openAccess restricted use CC-BY Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2011 , Vol. 8 , N. 11 , P. 3187-3201 text Publication info:eu-repo/semantics/article 2011 ftarchimer https://doi.org/10.5194/bg-8-3187-2011 2021-09-23T20:25:10Z Dissolved and particulate excess (230)Th and (231)Pa concentrations (noted (230)Th(xs) and (231)Pa(xs) respectively) and (231)Pa(xs)/(230)Th(xs) activity ratios were investigated on and out of the Kerguelen plateau (Southern Ocean) in the framework of the Kerguelen Ocean and Plateau compared Study project in order to better understand the influence of particle flux and particle chemistry and advection on the scavenging of (231)Pa. In the wake of Kerguelen, particulate (231)Pa(xs) is relatively abundant compared to its content in the dissolved phase. This, together with the low fractionation observed between (230)Th and (231)Pa (F(Th/Pa) ranging from 0.06 +/- 0.01 to 1.6 +/- 0.2) reflects the domination of the biogenic silica in the particle pool. Along the eastern escarpment of the Kerguelen plateau, the strong (231)Pa(xs) horizontal gradient in the deep waters highlights the intense removal of (231)Pa at depth, as already observed for (230)Th(xs). This local boundary scavenging was attributed to re-suspension of opal-rich particles by nepheloid layers, resulting in fractionation factors F(Th/Pa) <= 1 along the Kerguelen plateau slope. Therefore, both the composition (biogenic opal) and the flux (intense along the margin) of particles control the scavenging of the two radionuclides in the Kerguelen wake. The modelling of (231)Pa distribution with an advection-scavenging model demonstrates that lateral advection of open ocean water on the Kerguelen plateau could supply most of the (231)Pa, which is then efficiently scavenged on the highly productive plateau, as previously proposed for (230)Th(xs). It stresses that lateral advection can play a significant role in the overall budget of particle reactive trace elements in a coastal-open ocean system. Article in Journal/Newspaper Southern Ocean Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Kerguelen Kerguelen Island ENVELOPE(69.500,69.500,-49.250,-49.250) Southern Ocean Biogeosciences 8 11 3187 3201 |
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 |
Dissolved and particulate excess (230)Th and (231)Pa concentrations (noted (230)Th(xs) and (231)Pa(xs) respectively) and (231)Pa(xs)/(230)Th(xs) activity ratios were investigated on and out of the Kerguelen plateau (Southern Ocean) in the framework of the Kerguelen Ocean and Plateau compared Study project in order to better understand the influence of particle flux and particle chemistry and advection on the scavenging of (231)Pa. In the wake of Kerguelen, particulate (231)Pa(xs) is relatively abundant compared to its content in the dissolved phase. This, together with the low fractionation observed between (230)Th and (231)Pa (F(Th/Pa) ranging from 0.06 +/- 0.01 to 1.6 +/- 0.2) reflects the domination of the biogenic silica in the particle pool. Along the eastern escarpment of the Kerguelen plateau, the strong (231)Pa(xs) horizontal gradient in the deep waters highlights the intense removal of (231)Pa at depth, as already observed for (230)Th(xs). This local boundary scavenging was attributed to re-suspension of opal-rich particles by nepheloid layers, resulting in fractionation factors F(Th/Pa) <= 1 along the Kerguelen plateau slope. Therefore, both the composition (biogenic opal) and the flux (intense along the margin) of particles control the scavenging of the two radionuclides in the Kerguelen wake. The modelling of (231)Pa distribution with an advection-scavenging model demonstrates that lateral advection of open ocean water on the Kerguelen plateau could supply most of the (231)Pa, which is then efficiently scavenged on the highly productive plateau, as previously proposed for (230)Th(xs). It stresses that lateral advection can play a significant role in the overall budget of particle reactive trace elements in a coastal-open ocean system. |
format |
Article in Journal/Newspaper |
author |
Venchiarutti, C. Roy-barman, M. Freydier, R. Van Beek, P. Souhaut, M. Jeandel, C. |
spellingShingle |
Venchiarutti, C. Roy-barman, M. Freydier, R. Van Beek, P. Souhaut, M. Jeandel, C. Influence of intense scavenging on Pa-Th fractionation in the wake of Kerguelen Island (Southern Ocean) |
author_facet |
Venchiarutti, C. Roy-barman, M. Freydier, R. Van Beek, P. Souhaut, M. Jeandel, C. |
author_sort |
Venchiarutti, C. |
title |
Influence of intense scavenging on Pa-Th fractionation in the wake of Kerguelen Island (Southern Ocean) |
title_short |
Influence of intense scavenging on Pa-Th fractionation in the wake of Kerguelen Island (Southern Ocean) |
title_full |
Influence of intense scavenging on Pa-Th fractionation in the wake of Kerguelen Island (Southern Ocean) |
title_fullStr |
Influence of intense scavenging on Pa-Th fractionation in the wake of Kerguelen Island (Southern Ocean) |
title_full_unstemmed |
Influence of intense scavenging on Pa-Th fractionation in the wake of Kerguelen Island (Southern Ocean) |
title_sort |
influence of intense scavenging on pa-th fractionation in the wake of kerguelen island (southern ocean) |
publisher |
Copernicus Gesellschaft Mbh |
publishDate |
2011 |
url |
https://archimer.ifremer.fr/doc/00228/33894/32272.pdf https://doi.org/10.5194/bg-8-3187-2011 https://archimer.ifremer.fr/doc/00228/33894/ |
long_lat |
ENVELOPE(69.500,69.500,-49.250,-49.250) |
geographic |
Kerguelen Kerguelen Island Southern Ocean |
geographic_facet |
Kerguelen Kerguelen Island Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2011 , Vol. 8 , N. 11 , P. 3187-3201 |
op_relation |
https://archimer.ifremer.fr/doc/00228/33894/32272.pdf doi:10.5194/bg-8-3187-2011 https://archimer.ifremer.fr/doc/00228/33894/ |
op_rights |
Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 License. info:eu-repo/semantics/openAccess restricted use |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/bg-8-3187-2011 |
container_title |
Biogeosciences |
container_volume |
8 |
container_issue |
11 |
container_start_page |
3187 |
op_container_end_page |
3201 |
_version_ |
1766206478038859776 |