The biogeochemical silicon cycle in the Southern Ocean tracked by isotopic approaches
Southern Ocean biogeochemistry plays a crucial role on global marine primary production by impacting the nutrient availability even in low latitude surface water. Variations in the silicon (Si) cycle are large and its coupling to other nutrient biogeochemical cycles is still not well understood in t...
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Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
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HAL CCSD
2015
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Online Access: | https://theses.hal.science/tel-01182436 https://theses.hal.science/tel-01182436v2/document https://theses.hal.science/tel-01182436v2/file/2015PA066124.pdf |
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openpolar |
institution |
Open Polar |
collection |
HAL Sorbonne Université |
op_collection_id |
ftsorbonneuniv |
language |
English |
topic |
Silicon (Si) cycle Southern Ocean Océan Austral Isotopes Cycle du silicium Silice biogénique Production/Dissolution Diatomées [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
spellingShingle |
Silicon (Si) cycle Southern Ocean Océan Austral Isotopes Cycle du silicium Silice biogénique Production/Dissolution Diatomées [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry Closset, Ivia The biogeochemical silicon cycle in the Southern Ocean tracked by isotopic approaches |
topic_facet |
Silicon (Si) cycle Southern Ocean Océan Austral Isotopes Cycle du silicium Silice biogénique Production/Dissolution Diatomées [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
description |
Southern Ocean biogeochemistry plays a crucial role on global marine primary production by impacting the nutrient availability even in low latitude surface water. Variations in the silicon (Si) cycle are large and its coupling to other nutrient biogeochemical cycles is still not well understood in this ocean. Results of two different isotopic approaches suggested that a strong silicon pump was quickly initiated in spring by a switch from regenerated to new biogenic silica production. The seasonal evolution of natural Si isotopic composition (δ30Si) was mainly driven by the balance between the “dissolution to production” and “Si-supply to Si-uptake” ratios that decoupled the isotopic dynamics of particulate and dissolved Si-pools (DSi and BSi, repectively). We also used δ30Si measurements to track seasonal flows of BSi to the deep sea with. These results confirmed that the δ30Si is well preserved during particles settling. The seasonal evolution of δ30Si signal allows for the first time to quantify important features about the processes controlling the diatoms’ productivity and its fate, such as mixing events that bring nutrient in the ML or the seasonal evolution of particles sinking velocities. These insights confirm that the δ30Si of DSi and BSi, combined to isotopic technics to measure Si fluxes in the ML, are promising tools to improve our understanding on the Si-biogeochemical cycle and provide new constraints for application to biogeochemical models. La biogéochimie de l’Océan austral joue un rôle crucial dans la régulation de la production primaire marine globale en contrôlant la disponibilité des nutriments dans les eaux de surface des basses latitudes. Les variations du cycle du silicium (Si) sont nombreuses et son couplage avec les autres éléments n’est pas encore bien compris dans cet océan. Les résultats issus de deux approches isotopiques différentes suggèrent qu’une pompe de Si active est rapidement initiée au printemps par la transition d’un mode de production de silice biogénique régénéré à une ... |
author2 |
Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN) Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Université Pierre et Marie Curie - Paris VI Damien Cardinal |
format |
Doctoral or Postdoctoral Thesis |
author |
Closset, Ivia |
author_facet |
Closset, Ivia |
author_sort |
Closset, Ivia |
title |
The biogeochemical silicon cycle in the Southern Ocean tracked by isotopic approaches |
title_short |
The biogeochemical silicon cycle in the Southern Ocean tracked by isotopic approaches |
title_full |
The biogeochemical silicon cycle in the Southern Ocean tracked by isotopic approaches |
title_fullStr |
The biogeochemical silicon cycle in the Southern Ocean tracked by isotopic approaches |
title_full_unstemmed |
The biogeochemical silicon cycle in the Southern Ocean tracked by isotopic approaches |
title_sort |
biogeochemical silicon cycle in the southern ocean tracked by isotopic approaches |
publisher |
HAL CCSD |
publishDate |
2015 |
url |
https://theses.hal.science/tel-01182436 https://theses.hal.science/tel-01182436v2/document https://theses.hal.science/tel-01182436v2/file/2015PA066124.pdf |
geographic |
Austral Southern Ocean |
geographic_facet |
Austral Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
https://theses.hal.science/tel-01182436 Geochemistry. Université Pierre et Marie Curie - Paris VI, 2015. English. ⟨NNT : 2015PA066124⟩ |
op_relation |
NNT: 2015PA066124 tel-01182436 https://theses.hal.science/tel-01182436 https://theses.hal.science/tel-01182436v2/document https://theses.hal.science/tel-01182436v2/file/2015PA066124.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1802011125695381504 |
spelling |
ftsorbonneuniv:oai:HAL:tel-01182436v2 2024-06-16T07:43:18+00:00 The biogeochemical silicon cycle in the Southern Ocean tracked by isotopic approaches Le cycle biogéochimique du silicium dans l’Océan Austral par les approches isotopiques Closset, Ivia Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN) Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Université Pierre et Marie Curie - Paris VI Damien Cardinal 2015-04-07 https://theses.hal.science/tel-01182436 https://theses.hal.science/tel-01182436v2/document https://theses.hal.science/tel-01182436v2/file/2015PA066124.pdf en eng HAL CCSD NNT: 2015PA066124 tel-01182436 https://theses.hal.science/tel-01182436 https://theses.hal.science/tel-01182436v2/document https://theses.hal.science/tel-01182436v2/file/2015PA066124.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-01182436 Geochemistry. Université Pierre et Marie Curie - Paris VI, 2015. English. ⟨NNT : 2015PA066124⟩ Silicon (Si) cycle Southern Ocean Océan Austral Isotopes Cycle du silicium Silice biogénique Production/Dissolution Diatomées [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry info:eu-repo/semantics/doctoralThesis Theses 2015 ftsorbonneuniv 2024-05-23T23:52:31Z Southern Ocean biogeochemistry plays a crucial role on global marine primary production by impacting the nutrient availability even in low latitude surface water. Variations in the silicon (Si) cycle are large and its coupling to other nutrient biogeochemical cycles is still not well understood in this ocean. Results of two different isotopic approaches suggested that a strong silicon pump was quickly initiated in spring by a switch from regenerated to new biogenic silica production. The seasonal evolution of natural Si isotopic composition (δ30Si) was mainly driven by the balance between the “dissolution to production” and “Si-supply to Si-uptake” ratios that decoupled the isotopic dynamics of particulate and dissolved Si-pools (DSi and BSi, repectively). We also used δ30Si measurements to track seasonal flows of BSi to the deep sea with. These results confirmed that the δ30Si is well preserved during particles settling. The seasonal evolution of δ30Si signal allows for the first time to quantify important features about the processes controlling the diatoms’ productivity and its fate, such as mixing events that bring nutrient in the ML or the seasonal evolution of particles sinking velocities. These insights confirm that the δ30Si of DSi and BSi, combined to isotopic technics to measure Si fluxes in the ML, are promising tools to improve our understanding on the Si-biogeochemical cycle and provide new constraints for application to biogeochemical models. La biogéochimie de l’Océan austral joue un rôle crucial dans la régulation de la production primaire marine globale en contrôlant la disponibilité des nutriments dans les eaux de surface des basses latitudes. Les variations du cycle du silicium (Si) sont nombreuses et son couplage avec les autres éléments n’est pas encore bien compris dans cet océan. Les résultats issus de deux approches isotopiques différentes suggèrent qu’une pompe de Si active est rapidement initiée au printemps par la transition d’un mode de production de silice biogénique régénéré à une ... Doctoral or Postdoctoral Thesis Southern Ocean HAL Sorbonne Université Austral Southern Ocean |