Estimation of seasonal and interannual variations in the biomass and phytoplankton composition of the Indian sector of the Southern Ocean over the last two decades and evaluation of their ecological consequences
The Southern Ocean (SO) plays a critical role in the uptake and storage of anthropogenic carbon due to the combined action of physical and biological pumps (Boyd et al. 2019 DOI:10.1038/s41586-019-1098-2). Furthermore, the Southern Ocean provides half of the primary production of the biosphere. Rece...
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Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
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HAL CCSD
2023
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Online Access: | https://hal.science/tel-04255749 https://hal.science/tel-04255749v2/document https://hal.science/tel-04255749v2/file/LE_STER_Loic_these_2023.pdf |
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ftsorbonneuniv:oai:HAL:tel-04255749v2 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
HAL Sorbonne Université |
op_collection_id |
ftsorbonneuniv |
language |
English |
topic |
Phytoplankton Southern Ocean Remote sensing Bio-Logging Phytoplancton Océan Austral Couleur de l'eau [SDE.BE]Environmental Sciences/Biodiversity and Ecology [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
spellingShingle |
Phytoplankton Southern Ocean Remote sensing Bio-Logging Phytoplancton Océan Austral Couleur de l'eau [SDE.BE]Environmental Sciences/Biodiversity and Ecology [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography Le Ster, Loïc Estimation of seasonal and interannual variations in the biomass and phytoplankton composition of the Indian sector of the Southern Ocean over the last two decades and evaluation of their ecological consequences |
topic_facet |
Phytoplankton Southern Ocean Remote sensing Bio-Logging Phytoplancton Océan Austral Couleur de l'eau [SDE.BE]Environmental Sciences/Biodiversity and Ecology [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography |
description |
The Southern Ocean (SO) plays a critical role in the uptake and storage of anthropogenic carbon due to the combined action of physical and biological pumps (Boyd et al. 2019 DOI:10.1038/s41586-019-1098-2). Furthermore, the Southern Ocean provides half of the primary production of the biosphere. Recent analyses nevertheless suggest a change in surface chlorophyll-a (Chl-a) concentrations in the Southern Ocean with an increasing trend, especially over the winter period (Del Castillo et al. 2019 DOI:10.1029/2019GL083163). Given the phenology of the different phytoplankton species, this trend and the associated temporal shift could imply a change in the composition of phytoplankton communities succeeding each other during the year. This hypothesis is supported, but not verified, by work done at the CEBC revealing a continuous decrease in the δ13C isotopic signature of Kerguelen elephant seals over the period 2006-2018 while the signature of dissolved inorganic carbon (DIC) did not vary over the same period (SNO-OISO data, N. Metzl personal comm.). This change in elephant seal composition reflects a potential change in the quality of phytoplankton at the base of the food chains on which they depend (Schell et al., 1989 DOI:10.1007/BF00399575; Cherel and Hobson, 2007 DOI:10.3354/meps329281). The objective of the project is firstly to estimate quantitative variations in phytoplankton biomass in the Indian sector of the Southern Ocean, and secondly, to assess the associated qualitative changes in phytoplankton community composition, as well as their impacts on the ecology of large predators such as the elephant seal. L’Océan Austral (OA) joue un rôle essentiel dans l’absorption et le stockage du carbone d’origine anthropique du fait de l’action combinée des pompes physique et biologique (Boyd et al. 2019 DOI :10.1038/s41586-019-1098-2). Par ailleurs l’océan austral assure la moitié de la production primaire de la biosphère. Des analyses récentes suggèrent néanmoins une modification des concentrations en chlorophylle-a ... |
author2 |
Laboratoire d'océanographie de Villefranche (LOV) Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV) Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC) La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) Sorbonne Université Hervé Claustre Christophe Guinet |
format |
Doctoral or Postdoctoral Thesis |
author |
Le Ster, Loïc |
author_facet |
Le Ster, Loïc |
author_sort |
Le Ster, Loïc |
title |
Estimation of seasonal and interannual variations in the biomass and phytoplankton composition of the Indian sector of the Southern Ocean over the last two decades and evaluation of their ecological consequences |
title_short |
Estimation of seasonal and interannual variations in the biomass and phytoplankton composition of the Indian sector of the Southern Ocean over the last two decades and evaluation of their ecological consequences |
title_full |
Estimation of seasonal and interannual variations in the biomass and phytoplankton composition of the Indian sector of the Southern Ocean over the last two decades and evaluation of their ecological consequences |
title_fullStr |
Estimation of seasonal and interannual variations in the biomass and phytoplankton composition of the Indian sector of the Southern Ocean over the last two decades and evaluation of their ecological consequences |
title_full_unstemmed |
Estimation of seasonal and interannual variations in the biomass and phytoplankton composition of the Indian sector of the Southern Ocean over the last two decades and evaluation of their ecological consequences |
title_sort |
estimation of seasonal and interannual variations in the biomass and phytoplankton composition of the indian sector of the southern ocean over the last two decades and evaluation of their ecological consequences |
publisher |
HAL CCSD |
publishDate |
2023 |
url |
https://hal.science/tel-04255749 https://hal.science/tel-04255749v2/document https://hal.science/tel-04255749v2/file/LE_STER_Loic_these_2023.pdf |
geographic |
Austral Indian Kerguelen Southern Ocean |
geographic_facet |
Austral Indian Kerguelen Southern Ocean |
genre |
Elephant Seal Elephant Seals Southern Ocean |
genre_facet |
Elephant Seal Elephant Seals Southern Ocean |
op_source |
https://hal.science/tel-04255749 Biodiversity and Ecology. Sorbonne Université, 2023. English. ⟨NNT : 2023SORUS429⟩ |
op_relation |
NNT: 2023SORUS429 tel-04255749 https://hal.science/tel-04255749 https://hal.science/tel-04255749v2/document https://hal.science/tel-04255749v2/file/LE_STER_Loic_these_2023.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1802006460331196416 |
spelling |
ftsorbonneuniv:oai:HAL:tel-04255749v2 2024-06-16T07:39:42+00:00 Estimation of seasonal and interannual variations in the biomass and phytoplankton composition of the Indian sector of the Southern Ocean over the last two decades and evaluation of their ecological consequences Estimation des variations saisonnières et interannuelles de la biomasse et de la composition en phytoplancton du secteur indien de l’Océan Austral sur les deux dernières décennies et évaluation de leurs conséquences écologiques Le Ster, Loïc Laboratoire d'océanographie de Villefranche (LOV) Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV) Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC) La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) Sorbonne Université Hervé Claustre Christophe Guinet 2023-10-05 https://hal.science/tel-04255749 https://hal.science/tel-04255749v2/document https://hal.science/tel-04255749v2/file/LE_STER_Loic_these_2023.pdf en eng HAL CCSD NNT: 2023SORUS429 tel-04255749 https://hal.science/tel-04255749 https://hal.science/tel-04255749v2/document https://hal.science/tel-04255749v2/file/LE_STER_Loic_these_2023.pdf info:eu-repo/semantics/OpenAccess https://hal.science/tel-04255749 Biodiversity and Ecology. Sorbonne Université, 2023. English. ⟨NNT : 2023SORUS429⟩ Phytoplankton Southern Ocean Remote sensing Bio-Logging Phytoplancton Océan Austral Couleur de l'eau [SDE.BE]Environmental Sciences/Biodiversity and Ecology [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography info:eu-repo/semantics/doctoralThesis Theses 2023 ftsorbonneuniv 2024-05-23T23:44:26Z The Southern Ocean (SO) plays a critical role in the uptake and storage of anthropogenic carbon due to the combined action of physical and biological pumps (Boyd et al. 2019 DOI:10.1038/s41586-019-1098-2). Furthermore, the Southern Ocean provides half of the primary production of the biosphere. Recent analyses nevertheless suggest a change in surface chlorophyll-a (Chl-a) concentrations in the Southern Ocean with an increasing trend, especially over the winter period (Del Castillo et al. 2019 DOI:10.1029/2019GL083163). Given the phenology of the different phytoplankton species, this trend and the associated temporal shift could imply a change in the composition of phytoplankton communities succeeding each other during the year. This hypothesis is supported, but not verified, by work done at the CEBC revealing a continuous decrease in the δ13C isotopic signature of Kerguelen elephant seals over the period 2006-2018 while the signature of dissolved inorganic carbon (DIC) did not vary over the same period (SNO-OISO data, N. Metzl personal comm.). This change in elephant seal composition reflects a potential change in the quality of phytoplankton at the base of the food chains on which they depend (Schell et al., 1989 DOI:10.1007/BF00399575; Cherel and Hobson, 2007 DOI:10.3354/meps329281). The objective of the project is firstly to estimate quantitative variations in phytoplankton biomass in the Indian sector of the Southern Ocean, and secondly, to assess the associated qualitative changes in phytoplankton community composition, as well as their impacts on the ecology of large predators such as the elephant seal. L’Océan Austral (OA) joue un rôle essentiel dans l’absorption et le stockage du carbone d’origine anthropique du fait de l’action combinée des pompes physique et biologique (Boyd et al. 2019 DOI :10.1038/s41586-019-1098-2). Par ailleurs l’océan austral assure la moitié de la production primaire de la biosphère. Des analyses récentes suggèrent néanmoins une modification des concentrations en chlorophylle-a ... Doctoral or Postdoctoral Thesis Elephant Seal Elephant Seals Southern Ocean HAL Sorbonne Université Austral Indian Kerguelen Southern Ocean |