Role of the Southern Ocean in the millennial scale climatic events of the last Glacial-Holocene transition : geochemical and micropaleontological approach
The last 22 kyr are marked by abrupt climatic events, non-synchronous between the southern and northern hemispheres. A see-saw mechanism of the polar temperatures, amplified by the deep oceanability to store and release a portion of atmospheric CO₂, depending on the intensity of the thermohaline cir...
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2016
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Online Access: | https://tel.archives-ouvertes.fr/tel-01451734 https://tel.archives-ouvertes.fr/tel-01451734/document https://tel.archives-ouvertes.fr/tel-01451734/file/73625_HADDAM_2016_diffusion.pdf |
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ftunivnantes:oai:HAL:tel-01451734v1 2023-05-15T14:01:27+02:00 Role of the Southern Ocean in the millennial scale climatic events of the last Glacial-Holocene transition : geochemical and micropaleontological approach Rôle de l’Océan Austral dans les variations climatiques rapides de la dernière transition Glaciaire-Holocène : approche géochimique et micropaléontologique Haddam, Naoufel Abdeldjalyl Géosciences Paris Sud (GEOPS) Université Paris-Sud - Paris 11 (UP11)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS) Université Paris Saclay (COmUE) Giuseppe Siani 2016-12-12 https://tel.archives-ouvertes.fr/tel-01451734 https://tel.archives-ouvertes.fr/tel-01451734/document https://tel.archives-ouvertes.fr/tel-01451734/file/73625_HADDAM_2016_diffusion.pdf fr fre HAL CCSD NNT: 2016SACLS555 tel-01451734 https://tel.archives-ouvertes.fr/tel-01451734 https://tel.archives-ouvertes.fr/tel-01451734/document https://tel.archives-ouvertes.fr/tel-01451734/file/73625_HADDAM_2016_diffusion.pdf info:eu-repo/semantics/OpenAccess https://tel.archives-ouvertes.fr/tel-01451734 Sciences de la Terre. Université Paris Saclay (COmUE), 2016. Français. ⟨NNT : 2016SACLS555⟩ Southeast Pacific Deglaciation Antarctic intermediate waters Sst Oceanic fronts Foraminifera Pacifique Sud-Est Déglaciation Foraminifères Fronts océaniques Eaux intermédiaires antarctiques [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/doctoralThesis Theses 2016 ftunivnantes 2022-10-19T00:14:14Z The last 22 kyr are marked by abrupt climatic events, non-synchronous between the southern and northern hemispheres. A see-saw mechanism of the polar temperatures, amplified by the deep oceanability to store and release a portion of atmospheric CO₂, depending on the intensity of the thermohaline circulation and the large upwellings along the southern divergence, has been proposed to explain these observations. The main aim of this thesis was to assess the role of the southern ocean during these millennial events, by studying 3 marine cores, retrieved along the Chilean margin, under the influence of oceanic fronts and the westerly winds. The reconstruction of the sea surface temperatures (SST) allowed tracing the evolution of the SST latitudinal gradient during the last 22 kyr, highlighting southward migrations of the Subtropical Front, especially during the deglaciation, marked by benthic and planktonic foraminifera faunal changes which can be interpreted as surface nutrients inputs increase, accompanied by an enrichment of the bottom water [O₂] in the bottom water. These events could be related to stronger upwellings at the southern divergence leading to an increase of the Antarctic intermediate waters ventilation. These changes occur during atmospheric CO₂ increases recorded in Antarctic ice cores, marking the deglaciation, and suggesting an intimate link between upwellings, the intensity of the intermediate waters ventilation, and deep ocean-atmosphere CO₂ transfers. Les derniers 22 kans sont marqués par des évènements climatiques rapides, non synchrones entre l‘hémisphère Sud et le Nord. Un mécanisme de bascule des températures polaires, amplifié par la capacité de l‘océan profond à stocker et à restituer une partie du CO₂ atmosphérique en fonction de l‘intensité de la circulation océanique et des upwellings le long de la divergence Australe, a été proposé pour expliquer ces évènements. L‘objectif principal de cette thèse a été de définir quel est le rôle de l‘Océan Austral durant ces variations ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Antarctique* Planktonic foraminifera Southern Ocean Université de Nantes: HAL-UNIV-NANTES Antarctic Austral Pacific Southern Ocean The Antarctic |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
French |
topic |
Southeast Pacific Deglaciation Antarctic intermediate waters Sst Oceanic fronts Foraminifera Pacifique Sud-Est Déglaciation Foraminifères Fronts océaniques Eaux intermédiaires antarctiques [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
Southeast Pacific Deglaciation Antarctic intermediate waters Sst Oceanic fronts Foraminifera Pacifique Sud-Est Déglaciation Foraminifères Fronts océaniques Eaux intermédiaires antarctiques [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Haddam, Naoufel Abdeldjalyl Role of the Southern Ocean in the millennial scale climatic events of the last Glacial-Holocene transition : geochemical and micropaleontological approach |
topic_facet |
Southeast Pacific Deglaciation Antarctic intermediate waters Sst Oceanic fronts Foraminifera Pacifique Sud-Est Déglaciation Foraminifères Fronts océaniques Eaux intermédiaires antarctiques [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
The last 22 kyr are marked by abrupt climatic events, non-synchronous between the southern and northern hemispheres. A see-saw mechanism of the polar temperatures, amplified by the deep oceanability to store and release a portion of atmospheric CO₂, depending on the intensity of the thermohaline circulation and the large upwellings along the southern divergence, has been proposed to explain these observations. The main aim of this thesis was to assess the role of the southern ocean during these millennial events, by studying 3 marine cores, retrieved along the Chilean margin, under the influence of oceanic fronts and the westerly winds. The reconstruction of the sea surface temperatures (SST) allowed tracing the evolution of the SST latitudinal gradient during the last 22 kyr, highlighting southward migrations of the Subtropical Front, especially during the deglaciation, marked by benthic and planktonic foraminifera faunal changes which can be interpreted as surface nutrients inputs increase, accompanied by an enrichment of the bottom water [O₂] in the bottom water. These events could be related to stronger upwellings at the southern divergence leading to an increase of the Antarctic intermediate waters ventilation. These changes occur during atmospheric CO₂ increases recorded in Antarctic ice cores, marking the deglaciation, and suggesting an intimate link between upwellings, the intensity of the intermediate waters ventilation, and deep ocean-atmosphere CO₂ transfers. Les derniers 22 kans sont marqués par des évènements climatiques rapides, non synchrones entre l‘hémisphère Sud et le Nord. Un mécanisme de bascule des températures polaires, amplifié par la capacité de l‘océan profond à stocker et à restituer une partie du CO₂ atmosphérique en fonction de l‘intensité de la circulation océanique et des upwellings le long de la divergence Australe, a été proposé pour expliquer ces évènements. L‘objectif principal de cette thèse a été de définir quel est le rôle de l‘Océan Austral durant ces variations ... |
author2 |
Géosciences Paris Sud (GEOPS) Université Paris-Sud - Paris 11 (UP11)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS) Université Paris Saclay (COmUE) Giuseppe Siani |
format |
Doctoral or Postdoctoral Thesis |
author |
Haddam, Naoufel Abdeldjalyl |
author_facet |
Haddam, Naoufel Abdeldjalyl |
author_sort |
Haddam, Naoufel Abdeldjalyl |
title |
Role of the Southern Ocean in the millennial scale climatic events of the last Glacial-Holocene transition : geochemical and micropaleontological approach |
title_short |
Role of the Southern Ocean in the millennial scale climatic events of the last Glacial-Holocene transition : geochemical and micropaleontological approach |
title_full |
Role of the Southern Ocean in the millennial scale climatic events of the last Glacial-Holocene transition : geochemical and micropaleontological approach |
title_fullStr |
Role of the Southern Ocean in the millennial scale climatic events of the last Glacial-Holocene transition : geochemical and micropaleontological approach |
title_full_unstemmed |
Role of the Southern Ocean in the millennial scale climatic events of the last Glacial-Holocene transition : geochemical and micropaleontological approach |
title_sort |
role of the southern ocean in the millennial scale climatic events of the last glacial-holocene transition : geochemical and micropaleontological approach |
publisher |
HAL CCSD |
publishDate |
2016 |
url |
https://tel.archives-ouvertes.fr/tel-01451734 https://tel.archives-ouvertes.fr/tel-01451734/document https://tel.archives-ouvertes.fr/tel-01451734/file/73625_HADDAM_2016_diffusion.pdf |
geographic |
Antarctic Austral Pacific Southern Ocean The Antarctic |
geographic_facet |
Antarctic Austral Pacific Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Antarctique* Planktonic foraminifera Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctique* Planktonic foraminifera Southern Ocean |
op_source |
https://tel.archives-ouvertes.fr/tel-01451734 Sciences de la Terre. Université Paris Saclay (COmUE), 2016. Français. ⟨NNT : 2016SACLS555⟩ |
op_relation |
NNT: 2016SACLS555 tel-01451734 https://tel.archives-ouvertes.fr/tel-01451734 https://tel.archives-ouvertes.fr/tel-01451734/document https://tel.archives-ouvertes.fr/tel-01451734/file/73625_HADDAM_2016_diffusion.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766271276111888384 |