Variability and stability of anthropogenic CO 2 in Antarctic Bottom Water observed in the Indian sector of the Southern Ocean, 1978–2018

International audience Antarctic Bottom Water (AABW) is known as a long-term sink for anthropogenic CO 2 (Cant), but the sink is hardly quantified because of the scarcity of observations, specifically at an interannual scale. We present in this paper an original dataset combining 40 years of carbona...

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Published in:Ocean Science
Main Authors: Mahieu, Léo, Lo Monaco, Claire, Metzl, Nicolas, Fin, Jonathan, Mignon, Claude
Other Authors: School of Environmental Sciences Liverpool, University of Liverpool, Cycles biogéochimiques marins : processus et perturbations (CYBIOM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), European Project: GOCE-511176-1, European Project: 264879,EC:FP7:ENV,FP7-ENV-2010,CARBOCHANGE(2011)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2020
Subjects:
Online Access:https://hal.science/hal-03087101
https://hal.science/hal-03087101/document
https://hal.science/hal-03087101/file/os-16-1559-2020.pdf
https://doi.org/10.5194/os-16-1559-2020
id ftsorbonneuniv:oai:HAL:hal-03087101v1
record_format openpolar
institution Open Polar
collection HAL Sorbonne Université
op_collection_id ftsorbonneuniv
language English
topic [SDE.MCG]Environmental Sciences/Global Changes
spellingShingle [SDE.MCG]Environmental Sciences/Global Changes
Mahieu, Léo
Lo Monaco, Claire
Metzl, Nicolas
Fin, Jonathan
Mignon, Claude
Variability and stability of anthropogenic CO 2 in Antarctic Bottom Water observed in the Indian sector of the Southern Ocean, 1978–2018
topic_facet [SDE.MCG]Environmental Sciences/Global Changes
description International audience Antarctic Bottom Water (AABW) is known as a long-term sink for anthropogenic CO 2 (Cant), but the sink is hardly quantified because of the scarcity of observations, specifically at an interannual scale. We present in this paper an original dataset combining 40 years of carbonate system observations in the Indian sector of the Southern Ocean (Enderby Basin) to evaluate and interpret the interannual variability of Cant in the AABW. This investigation is based on regular observations collected at the same location (63∘ E–56.5∘ S) in the framework of the French observatory OISO from 1998 to 2018 extended by GEOSECS and INDIGO observations (1978, 1985 and 1987).At this location the main sources of AABW sampled is the low-salinity Cape Darnley Bottom Water (CDBW) and the Weddell Sea Deep Water (WSDW). Our calculations reveal that Cant concentrations increased significantly in the AABW, from an average concentration of 7 µmol kg−1 calculated for the period 1978–1987 to an average concentration of 13 µmol kg−1 for the period 2010–2018. This is comparable to previous estimates in other Southern Ocean (SO) basins, with the exception of bottom water close to formation sites where Cant concentrations are about twice as large. Our analysis shows that total carbon (CT) and Cant increasing rates in the AABW are about the same over the period 1978–2018, and we conclude that the long-term change in CT is mainly due to the uptake of Cant in the different formation regions. This is, however, modulated by significant interannual to multi-annual variability associated with variations in hydrographic (potential temperature, Θ; salinity, S) and biogeochemical (CT; total alkalinity, AT; dissolved oxygen, O2) properties. A surprising result is the apparent stability of Cant concentrations in recent years despite the increase in CT and the gradual acceleration of atmospheric CO 2 . The interannual variability at play in AABW needs to be carefully considered in the extrapolated estimation of Cant sequestration ...
author2 School of Environmental Sciences Liverpool
University of Liverpool
Cycles biogéochimiques marins : processus et perturbations (CYBIOM)
Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN)
Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636))
École normale supérieure - Paris (ENS-PSL)
Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL)
Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636))
Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
European Project: GOCE-511176-1
European Project: 264879,EC:FP7:ENV,FP7-ENV-2010,CARBOCHANGE(2011)
format Article in Journal/Newspaper
author Mahieu, Léo
Lo Monaco, Claire
Metzl, Nicolas
Fin, Jonathan
Mignon, Claude
author_facet Mahieu, Léo
Lo Monaco, Claire
Metzl, Nicolas
Fin, Jonathan
Mignon, Claude
author_sort Mahieu, Léo
title Variability and stability of anthropogenic CO 2 in Antarctic Bottom Water observed in the Indian sector of the Southern Ocean, 1978–2018
title_short Variability and stability of anthropogenic CO 2 in Antarctic Bottom Water observed in the Indian sector of the Southern Ocean, 1978–2018
title_full Variability and stability of anthropogenic CO 2 in Antarctic Bottom Water observed in the Indian sector of the Southern Ocean, 1978–2018
title_fullStr Variability and stability of anthropogenic CO 2 in Antarctic Bottom Water observed in the Indian sector of the Southern Ocean, 1978–2018
title_full_unstemmed Variability and stability of anthropogenic CO 2 in Antarctic Bottom Water observed in the Indian sector of the Southern Ocean, 1978–2018
title_sort variability and stability of anthropogenic co 2 in antarctic bottom water observed in the indian sector of the southern ocean, 1978–2018
publisher HAL CCSD
publishDate 2020
url https://hal.science/hal-03087101
https://hal.science/hal-03087101/document
https://hal.science/hal-03087101/file/os-16-1559-2020.pdf
https://doi.org/10.5194/os-16-1559-2020
genre Antarc*
Antarctic
Southern Ocean
Weddell Sea
genre_facet Antarc*
Antarctic
Southern Ocean
Weddell Sea
op_source ISSN: 1812-0784
EISSN: 1812-0792
Ocean Science
https://hal.science/hal-03087101
Ocean Science, 2020, 16 (6), pp.1559-1576. ⟨10.5194/os-16-1559-2020⟩
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info:eu-repo/grantAgreement/EC/FP7/264879/EU/Changes in carbon uptake and emissions by oceans in a changing climate/CARBOCHANGE
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https://hal.science/hal-03087101
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doi:10.5194/os-16-1559-2020
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op_rights http://creativecommons.org/licenses/by/
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op_doi https://doi.org/10.5194/os-16-1559-2020
container_title Ocean Science
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spelling ftsorbonneuniv:oai:HAL:hal-03087101v1 2024-05-19T07:32:03+00:00 Variability and stability of anthropogenic CO 2 in Antarctic Bottom Water observed in the Indian sector of the Southern Ocean, 1978–2018 Mahieu, Léo Lo Monaco, Claire Metzl, Nicolas Fin, Jonathan Mignon, Claude School of Environmental Sciences Liverpool University of Liverpool Cycles biogéochimiques marins : processus et perturbations (CYBIOM) Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN) Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)) École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité) European Project: GOCE-511176-1 European Project: 264879,EC:FP7:ENV,FP7-ENV-2010,CARBOCHANGE(2011) 2020 https://hal.science/hal-03087101 https://hal.science/hal-03087101/document https://hal.science/hal-03087101/file/os-16-1559-2020.pdf https://doi.org/10.5194/os-16-1559-2020 en eng HAL CCSD European Geosciences Union info:eu-repo/semantics/altIdentifier/doi/10.5194/os-16-1559-2020 info:eu-repo/grantAgreement//GOCE-511176-1/EU/CarboOcean/ info:eu-repo/grantAgreement/EC/FP7/264879/EU/Changes in carbon uptake and emissions by oceans in a changing climate/CARBOCHANGE hal-03087101 https://hal.science/hal-03087101 https://hal.science/hal-03087101/document https://hal.science/hal-03087101/file/os-16-1559-2020.pdf doi:10.5194/os-16-1559-2020 WOS: 000600429500002 http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess ISSN: 1812-0784 EISSN: 1812-0792 Ocean Science https://hal.science/hal-03087101 Ocean Science, 2020, 16 (6), pp.1559-1576. ⟨10.5194/os-16-1559-2020⟩ [SDE.MCG]Environmental Sciences/Global Changes info:eu-repo/semantics/article Journal articles 2020 ftsorbonneuniv https://doi.org/10.5194/os-16-1559-2020 2024-04-25T03:59:04Z International audience Antarctic Bottom Water (AABW) is known as a long-term sink for anthropogenic CO 2 (Cant), but the sink is hardly quantified because of the scarcity of observations, specifically at an interannual scale. We present in this paper an original dataset combining 40 years of carbonate system observations in the Indian sector of the Southern Ocean (Enderby Basin) to evaluate and interpret the interannual variability of Cant in the AABW. This investigation is based on regular observations collected at the same location (63∘ E–56.5∘ S) in the framework of the French observatory OISO from 1998 to 2018 extended by GEOSECS and INDIGO observations (1978, 1985 and 1987).At this location the main sources of AABW sampled is the low-salinity Cape Darnley Bottom Water (CDBW) and the Weddell Sea Deep Water (WSDW). Our calculations reveal that Cant concentrations increased significantly in the AABW, from an average concentration of 7 µmol kg−1 calculated for the period 1978–1987 to an average concentration of 13 µmol kg−1 for the period 2010–2018. This is comparable to previous estimates in other Southern Ocean (SO) basins, with the exception of bottom water close to formation sites where Cant concentrations are about twice as large. Our analysis shows that total carbon (CT) and Cant increasing rates in the AABW are about the same over the period 1978–2018, and we conclude that the long-term change in CT is mainly due to the uptake of Cant in the different formation regions. This is, however, modulated by significant interannual to multi-annual variability associated with variations in hydrographic (potential temperature, Θ; salinity, S) and biogeochemical (CT; total alkalinity, AT; dissolved oxygen, O2) properties. A surprising result is the apparent stability of Cant concentrations in recent years despite the increase in CT and the gradual acceleration of atmospheric CO 2 . The interannual variability at play in AABW needs to be carefully considered in the extrapolated estimation of Cant sequestration ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Weddell Sea HAL Sorbonne Université Ocean Science 16 6 1559 1576