Distribution of naturally occurring radionuclides (226Ra and 227Ac) along GA01 section in the North Atlantic
The Subpolar North Atlantic, being a region of deep water mass formation, is a key region for the global thermohaline circulation and is thus sensitive to climate change. In this context, the GEOVIDE cruise was carried out between Portugal, Greenland and Newfoundland as part of the GEOTRACES program...
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Other Authors: | , , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
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HAL CCSD
2019
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Online Access: | https://tel.archives-ouvertes.fr/tel-02454460 https://tel.archives-ouvertes.fr/tel-02454460/document https://tel.archives-ouvertes.fr/tel-02454460/file/ManuscritThese.pdf |
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ftccsdartic:oai:HAL:tel-02454460v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
French |
topic |
Actinium Barium Radium GEOTRACES radionuclides North Atlantic Ocean Baryum Radionucléides Océan Atlantique Nord [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [CHIM.RADIO]Chemical Sciences/Radiochemistry |
spellingShingle |
Actinium Barium Radium GEOTRACES radionuclides North Atlantic Ocean Baryum Radionucléides Océan Atlantique Nord [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [CHIM.RADIO]Chemical Sciences/Radiochemistry Le Roy, Emilie Distribution of naturally occurring radionuclides (226Ra and 227Ac) along GA01 section in the North Atlantic |
topic_facet |
Actinium Barium Radium GEOTRACES radionuclides North Atlantic Ocean Baryum Radionucléides Océan Atlantique Nord [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [CHIM.RADIO]Chemical Sciences/Radiochemistry |
description |
The Subpolar North Atlantic, being a region of deep water mass formation, is a key region for the global thermohaline circulation and is thus sensitive to climate change. In this context, the GEOVIDE cruise was carried out between Portugal, Greenland and Newfoundland as part of the GEOTRACES program (GA01; May 15 to June 30, 2014—R/V Pourquoi Pas?). This cruise, which crossed different topographic features and biogeochemical regions, provided a unique framework for the study of i) ocean mixing, ii) transport of water masses and iii) inputs of chemical elements released by the sediments deposited onto continental margins. Naturally occurring radionuclides is used as tracers: radium-226 (226Ra, t1/2 = 1602 y) and actinium-227 (227Ac, t1/2 = 21.7 y). Due to their different half-lives, these radionuclides behave differently in the ocean and can be used to study these various processes. First, a detailed section of dissolved 226Ra activities associated with dissolved barium (Ba) concentration is reported. Because 226Ra and Ba have been widely used as tracers of water masses and ocean mixing, their behavior in this crucial region is investigated more thoroughly. The use of the 226Ra/Ba ratio as a chronometer of the global circulation is evaluated using an optimum multiparameter analysis. Results show that 226Ra and Ba distributions mainly result from conservative mixing, notably at intermediate depths (i.e., away from the ocean interfaces). 226Ra and Ba can thus be considered as conservative tracers of water mass transport in the ocean interior at basin scales. However, at the ocean boundaries 226Ra and Ba displayed non-conservative behaviors due to sedimentary, river and possibly hydrothermal inputs. Suspended particles that form in the upper water column which settle to the seafloor may also impact the distributions of 226Ra and Ba. Second, the behavior of 227Ac in the North Atlantic is investigated. 227Ac is primarily released by deep-sea sediments. Due to the low abundance of 227Ac in seawater, the analysis of ... |
author2 |
Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS) Université de Toulouse III – Paul Sabatier Pieter Van Beek François Lacan |
format |
Doctoral or Postdoctoral Thesis |
author |
Le Roy, Emilie |
author_facet |
Le Roy, Emilie |
author_sort |
Le Roy, Emilie |
title |
Distribution of naturally occurring radionuclides (226Ra and 227Ac) along GA01 section in the North Atlantic |
title_short |
Distribution of naturally occurring radionuclides (226Ra and 227Ac) along GA01 section in the North Atlantic |
title_full |
Distribution of naturally occurring radionuclides (226Ra and 227Ac) along GA01 section in the North Atlantic |
title_fullStr |
Distribution of naturally occurring radionuclides (226Ra and 227Ac) along GA01 section in the North Atlantic |
title_full_unstemmed |
Distribution of naturally occurring radionuclides (226Ra and 227Ac) along GA01 section in the North Atlantic |
title_sort |
distribution of naturally occurring radionuclides (226ra and 227ac) along ga01 section in the north atlantic |
publisher |
HAL CCSD |
publishDate |
2019 |
url |
https://tel.archives-ouvertes.fr/tel-02454460 https://tel.archives-ouvertes.fr/tel-02454460/document https://tel.archives-ouvertes.fr/tel-02454460/file/ManuscritThese.pdf |
long_lat |
ENVELOPE(135.783,135.783,-66.083,-66.083) ENVELOPE(-67.450,-67.450,-67.700,-67.700) ENVELOPE(135.750,135.750,-66.200,-66.200) |
geographic |
Greenland Pourquoi Pas Pourquoi-Pas Pourquoi-Pas? |
geographic_facet |
Greenland Pourquoi Pas Pourquoi-Pas Pourquoi-Pas? |
genre |
Greenland Newfoundland North Atlantic |
genre_facet |
Greenland Newfoundland North Atlantic |
op_source |
https://tel.archives-ouvertes.fr/tel-02454460 Océanographie. Université de Toulouse III – Paul Sabatier, 2019. Français |
op_relation |
tel-02454460 https://tel.archives-ouvertes.fr/tel-02454460 https://tel.archives-ouvertes.fr/tel-02454460/document https://tel.archives-ouvertes.fr/tel-02454460/file/ManuscritThese.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766020347441709056 |
spelling |
ftccsdartic:oai:HAL:tel-02454460v1 2023-05-15T16:30:37+02:00 Distribution of naturally occurring radionuclides (226Ra and 227Ac) along GA01 section in the North Atlantic Distribution des radionucléides naturels ( 226Ra et 227Ac) le long de la section GA01 dans l’Atlantique Nord Le Roy, Emilie Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS) Université de Toulouse III – Paul Sabatier Pieter Van Beek François Lacan 2019-02-15 https://tel.archives-ouvertes.fr/tel-02454460 https://tel.archives-ouvertes.fr/tel-02454460/document https://tel.archives-ouvertes.fr/tel-02454460/file/ManuscritThese.pdf fr fre HAL CCSD tel-02454460 https://tel.archives-ouvertes.fr/tel-02454460 https://tel.archives-ouvertes.fr/tel-02454460/document https://tel.archives-ouvertes.fr/tel-02454460/file/ManuscritThese.pdf info:eu-repo/semantics/OpenAccess https://tel.archives-ouvertes.fr/tel-02454460 Océanographie. Université de Toulouse III – Paul Sabatier, 2019. Français Actinium Barium Radium GEOTRACES radionuclides North Atlantic Ocean Baryum Radionucléides Océan Atlantique Nord [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry [CHIM.RADIO]Chemical Sciences/Radiochemistry info:eu-repo/semantics/doctoralThesis Theses 2019 ftccsdartic 2021-11-07T01:22:55Z The Subpolar North Atlantic, being a region of deep water mass formation, is a key region for the global thermohaline circulation and is thus sensitive to climate change. In this context, the GEOVIDE cruise was carried out between Portugal, Greenland and Newfoundland as part of the GEOTRACES program (GA01; May 15 to June 30, 2014—R/V Pourquoi Pas?). This cruise, which crossed different topographic features and biogeochemical regions, provided a unique framework for the study of i) ocean mixing, ii) transport of water masses and iii) inputs of chemical elements released by the sediments deposited onto continental margins. Naturally occurring radionuclides is used as tracers: radium-226 (226Ra, t1/2 = 1602 y) and actinium-227 (227Ac, t1/2 = 21.7 y). Due to their different half-lives, these radionuclides behave differently in the ocean and can be used to study these various processes. First, a detailed section of dissolved 226Ra activities associated with dissolved barium (Ba) concentration is reported. Because 226Ra and Ba have been widely used as tracers of water masses and ocean mixing, their behavior in this crucial region is investigated more thoroughly. The use of the 226Ra/Ba ratio as a chronometer of the global circulation is evaluated using an optimum multiparameter analysis. Results show that 226Ra and Ba distributions mainly result from conservative mixing, notably at intermediate depths (i.e., away from the ocean interfaces). 226Ra and Ba can thus be considered as conservative tracers of water mass transport in the ocean interior at basin scales. However, at the ocean boundaries 226Ra and Ba displayed non-conservative behaviors due to sedimentary, river and possibly hydrothermal inputs. Suspended particles that form in the upper water column which settle to the seafloor may also impact the distributions of 226Ra and Ba. Second, the behavior of 227Ac in the North Atlantic is investigated. 227Ac is primarily released by deep-sea sediments. Due to the low abundance of 227Ac in seawater, the analysis of ... Doctoral or Postdoctoral Thesis Greenland Newfoundland North Atlantic Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Greenland Pourquoi Pas ENVELOPE(135.783,135.783,-66.083,-66.083) Pourquoi-Pas ENVELOPE(-67.450,-67.450,-67.700,-67.700) Pourquoi-Pas? ENVELOPE(135.750,135.750,-66.200,-66.200) |