Thorium isotopes as tracers of particles dynamics and deep water circulation in the Indian sector of the Southern Ocean (ANTARES IV)
Dissolved and particulate samples were collected to study the distribution of thorium isotopes (234Th, 232Th and 230Th) in the water column of the Indian sector of the Southern Ocean (from 42°S to 47°S and from 60°E to 66°E, north of the Polar Front) during Austral summer 1999. Vertical profiles of...
Published in: | Marine Chemistry |
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Main Authors: | , , , , |
Other Authors: | , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2006
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Subjects: | |
Online Access: | https://hal.science/hal-00280193 https://doi.org/10.1016/j.marchem.2005.10.019 |
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ftmeteofrance:oai:HAL:hal-00280193v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Météo-France: HAL |
op_collection_id |
ftmeteofrance |
language |
English |
topic |
Thorium-234 Thorium-230 Marine particles Southern Indian Ocean [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
spellingShingle |
Thorium-234 Thorium-230 Marine particles Southern Indian Ocean [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry Coppola, L. Roy-Barman, M. Mulsow, S. Povinec, P. Jeandel, C. Thorium isotopes as tracers of particles dynamics and deep water circulation in the Indian sector of the Southern Ocean (ANTARES IV) |
topic_facet |
Thorium-234 Thorium-230 Marine particles Southern Indian Ocean [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
description |
Dissolved and particulate samples were collected to study the distribution of thorium isotopes (234Th, 232Th and 230Th) in the water column of the Indian sector of the Southern Ocean (from 42°S to 47°S and from 60°E to 66°E, north of the Polar Front) during Austral summer 1999. Vertical profiles of excess 230Th (230Thxs) increases linearly with depth in surface water (0–100 m) and a model was applied to estimate a residence time relative to the thorium scavenging (τscav). Low τscav in the Polar Front Zone (PFZ) are found, compared to those estimated in the Subtropical Front Zone (STZ). Changes in particle composition between the PFZ and STZ could influence the 230Thxs scavenging efficiency and explain this difference. An innovative coupling between 234Th and 230Thxs was then used to simultaneously constrain the settling velocities of small (0.6–60 μm) and large (above 60 μm) particles. Although the different hydrological and biogeochemical regimes visited during the ANTARES IV cruise did not explain the spatial variation of sinking velocity estimates, our results indicate that less particles may reach the seafloor north (60 ± 2 m d− 1, station 8) than south of the Agulhas Return Current (119 ± 23 and 130 ± 5 m d− 1 at stations 3 and 7, respectively). This information is essential for understanding particle transport and by extension, carbon export. In the deep water column, the 230Thxs concentrations did not increase linearly with depth, probably due to lateral transport of North Atlantic Deep Water (NADW) from the Atlantic to the Indian sector, which renews the deep waters and decreases the 230Thxs concentrations. A specific 230Thxs transport model is applied in the deep water column and allows us to assess a “travel time” of NADW ranging from 2 to 15 years. |
author2 |
Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) Géochimie Des Impacts (GEDI) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Instituto de Geociencias Universidad Austral de Chile Marine Environment Laboratories Monaco (IAEA-MEL) International Atomic Energy Agency Vienna (IAEA) |
format |
Article in Journal/Newspaper |
author |
Coppola, L. Roy-Barman, M. Mulsow, S. Povinec, P. Jeandel, C. |
author_facet |
Coppola, L. Roy-Barman, M. Mulsow, S. Povinec, P. Jeandel, C. |
author_sort |
Coppola, L. |
title |
Thorium isotopes as tracers of particles dynamics and deep water circulation in the Indian sector of the Southern Ocean (ANTARES IV) |
title_short |
Thorium isotopes as tracers of particles dynamics and deep water circulation in the Indian sector of the Southern Ocean (ANTARES IV) |
title_full |
Thorium isotopes as tracers of particles dynamics and deep water circulation in the Indian sector of the Southern Ocean (ANTARES IV) |
title_fullStr |
Thorium isotopes as tracers of particles dynamics and deep water circulation in the Indian sector of the Southern Ocean (ANTARES IV) |
title_full_unstemmed |
Thorium isotopes as tracers of particles dynamics and deep water circulation in the Indian sector of the Southern Ocean (ANTARES IV) |
title_sort |
thorium isotopes as tracers of particles dynamics and deep water circulation in the indian sector of the southern ocean (antares iv) |
publisher |
HAL CCSD |
publishDate |
2006 |
url |
https://hal.science/hal-00280193 https://doi.org/10.1016/j.marchem.2005.10.019 |
genre |
NADW North Atlantic Deep Water North Atlantic Southern Ocean |
genre_facet |
NADW North Atlantic Deep Water North Atlantic Southern Ocean |
op_source |
ISSN: 0304-4203 Marine Chemistry https://hal.science/hal-00280193 Marine Chemistry, 2006, 100, pp.299-313. ⟨10.1016/j.marchem.2005.10.019⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.marchem.2005.10.019 hal-00280193 https://hal.science/hal-00280193 doi:10.1016/j.marchem.2005.10.019 |
op_doi |
https://doi.org/10.1016/j.marchem.2005.10.019 |
container_title |
Marine Chemistry |
container_volume |
100 |
container_issue |
3-4 |
container_start_page |
299 |
op_container_end_page |
313 |
_version_ |
1810457114676559872 |
spelling |
ftmeteofrance:oai:HAL:hal-00280193v1 2024-09-15T18:19:01+00:00 Thorium isotopes as tracers of particles dynamics and deep water circulation in the Indian sector of the Southern Ocean (ANTARES IV) Coppola, L. Roy-Barman, M. Mulsow, S. Povinec, P. Jeandel, C. Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) Géochimie Des Impacts (GEDI) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Instituto de Geociencias Universidad Austral de Chile Marine Environment Laboratories Monaco (IAEA-MEL) International Atomic Energy Agency Vienna (IAEA) 2006 https://hal.science/hal-00280193 https://doi.org/10.1016/j.marchem.2005.10.019 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.marchem.2005.10.019 hal-00280193 https://hal.science/hal-00280193 doi:10.1016/j.marchem.2005.10.019 ISSN: 0304-4203 Marine Chemistry https://hal.science/hal-00280193 Marine Chemistry, 2006, 100, pp.299-313. ⟨10.1016/j.marchem.2005.10.019⟩ Thorium-234 Thorium-230 Marine particles Southern Indian Ocean [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry info:eu-repo/semantics/article Journal articles 2006 ftmeteofrance https://doi.org/10.1016/j.marchem.2005.10.019 2024-06-25T00:15:02Z Dissolved and particulate samples were collected to study the distribution of thorium isotopes (234Th, 232Th and 230Th) in the water column of the Indian sector of the Southern Ocean (from 42°S to 47°S and from 60°E to 66°E, north of the Polar Front) during Austral summer 1999. Vertical profiles of excess 230Th (230Thxs) increases linearly with depth in surface water (0–100 m) and a model was applied to estimate a residence time relative to the thorium scavenging (τscav). Low τscav in the Polar Front Zone (PFZ) are found, compared to those estimated in the Subtropical Front Zone (STZ). Changes in particle composition between the PFZ and STZ could influence the 230Thxs scavenging efficiency and explain this difference. An innovative coupling between 234Th and 230Thxs was then used to simultaneously constrain the settling velocities of small (0.6–60 μm) and large (above 60 μm) particles. Although the different hydrological and biogeochemical regimes visited during the ANTARES IV cruise did not explain the spatial variation of sinking velocity estimates, our results indicate that less particles may reach the seafloor north (60 ± 2 m d− 1, station 8) than south of the Agulhas Return Current (119 ± 23 and 130 ± 5 m d− 1 at stations 3 and 7, respectively). This information is essential for understanding particle transport and by extension, carbon export. In the deep water column, the 230Thxs concentrations did not increase linearly with depth, probably due to lateral transport of North Atlantic Deep Water (NADW) from the Atlantic to the Indian sector, which renews the deep waters and decreases the 230Thxs concentrations. A specific 230Thxs transport model is applied in the deep water column and allows us to assess a “travel time” of NADW ranging from 2 to 15 years. Article in Journal/Newspaper NADW North Atlantic Deep Water North Atlantic Southern Ocean Météo-France: HAL Marine Chemistry 100 3-4 299 313 |