Evaluating the role of orbitally-induced paleoceanographic changes in subtropical South Atlantic for the global climate over the last 800,000 years

Anthropogenic activity has reshaped Earth's climate by increasing atmospheric CO2 and global warming, often linked to an Atlantic Meridional Overturning Circulation (AMOC) slowdown. The AMOC redistributes heat and carbon via the South Atlantic Subtropical Gyre (SASG), acting with the Intertropi...

Full description

Bibliographic Details
Main Author: Ballalai, João Marcelo
Other Authors: Geo-Ocean (GEO-OCEAN), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne occidentale - Brest, Universidade Federal Fluminense (Brésil), Stéphan Jorry, Ana Luiza Albuquerque
Format: Doctoral or Postdoctoral Thesis
Language:English
Published: HAL CCSD 2023
Subjects:
Online Access:https://theses.hal.science/tel-04261916
https://theses.hal.science/tel-04261916/document
https://theses.hal.science/tel-04261916/file/These-2023-SML-Geosciences_marines-BALLALAI_Joao.pdf
id ftunivbrest:oai:HAL:tel-04261916v1
record_format openpolar
institution Open Polar
collection Université de Bretagne Occidentale: HAL
op_collection_id ftunivbrest
language English
topic Atlantic meridional overturning circulation
Orbital cycles
South Atlantic subtropical gyre
Interhemispheric heat transfer
South Atlantic controls on climate
Mg/Ca analysis
Circulation méridienne de l'Atlantique
Cycles orbitaux
Gyre Subtropical de l'Atlantique Sud
Transfert de chaleur inter-hémisphérique
Contrôles de l'Atlantique Sud sur le climat
Analyses de Mg/Ca
Circulação de revolvimento meridional do Atlântico
Ciclos orbitais
Giro subtropical do Atlântico Sul
Transferência de calor inter-hemisférica
Controles do Atlântico Sul no clima
Análise de Mg/Ca
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
spellingShingle Atlantic meridional overturning circulation
Orbital cycles
South Atlantic subtropical gyre
Interhemispheric heat transfer
South Atlantic controls on climate
Mg/Ca analysis
Circulation méridienne de l'Atlantique
Cycles orbitaux
Gyre Subtropical de l'Atlantique Sud
Transfert de chaleur inter-hémisphérique
Contrôles de l'Atlantique Sud sur le climat
Analyses de Mg/Ca
Circulação de revolvimento meridional do Atlântico
Ciclos orbitais
Giro subtropical do Atlântico Sul
Transferência de calor inter-hemisférica
Controles do Atlântico Sul no clima
Análise de Mg/Ca
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Ballalai, João Marcelo
Evaluating the role of orbitally-induced paleoceanographic changes in subtropical South Atlantic for the global climate over the last 800,000 years
topic_facet Atlantic meridional overturning circulation
Orbital cycles
South Atlantic subtropical gyre
Interhemispheric heat transfer
South Atlantic controls on climate
Mg/Ca analysis
Circulation méridienne de l'Atlantique
Cycles orbitaux
Gyre Subtropical de l'Atlantique Sud
Transfert de chaleur inter-hémisphérique
Contrôles de l'Atlantique Sud sur le climat
Analyses de Mg/Ca
Circulação de revolvimento meridional do Atlântico
Ciclos orbitais
Giro subtropical do Atlântico Sul
Transferência de calor inter-hemisférica
Controles do Atlântico Sul no clima
Análise de Mg/Ca
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
description Anthropogenic activity has reshaped Earth's climate by increasing atmospheric CO2 and global warming, often linked to an Atlantic Meridional Overturning Circulation (AMOC) slowdown. The AMOC redistributes heat and carbon via the South Atlantic Subtropical Gyre (SASG), acting with the Intertropical Convergence Zone (ITCZ), pursuing global energy equilibrium. Orbital variations can induce long-term climate shifts through insolation changes. This thesis investigates orbital influences on subtropical South Atlantic paleoceanography over 800 ka, analyzing benthic and planktic foraminifera δ18O, δ13C from GL-854 and MD08-3167 cores and thermocline Mg/Ca temperature from MD08- 3167. This framework unveils orbital-scale deep-water and ocean-atmosphere processes and controls on the Benguela Upwelling System (BUS), exploring AMOC's connections to climate. Chapters 1 to 3 set objectives, methods, and results. Chapter 4 explores 770 ka deep-water dynamics, where four AMOC modes controlled by orbitally-induced changes in Antarctic sea ice are proposed. The provided framework connects deep water, sea-ice, and ocean-atmosphere dynamics, shaping the Late Pleistocene climate. Chapter 5 discusses 365 ka of BUS variability. Intensified North Atlantic deep-water formation during positive precession periods enhances inter-hemispheric energy transfer, shifting SASG and ITCZ northwards, boosting upwelling. The mechanism controlling BUS connects AMOC intensity and global atmospheric patterns to atmospheric CO2 decline. Chapter 6 outlines Mg/Ca protocol performed on ICP-MS at IFREMER. Merging both surface and deep water perspectives seeks to clarify mechanisms controlling AMOC for the global climate. Les activités anthropiques ont remodelé le climat de la Terre en augmentant le CO2 atmosphérique et le réchauffement climatique, souvent lié au ralentissement de la circulation méridionale de renversement de l'Atlantique (AMOC). L'AMOC redistribue la chaleur et le carbone via le gyre subtropical de l'Atlantique Sud (SASG), agissant avec ...
author2 Geo-Ocean (GEO-OCEAN)
Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Université de Bretagne occidentale - Brest
Universidade Federal Fluminense (Brésil)
Stéphan Jorry
Ana Luiza Albuquerque
format Doctoral or Postdoctoral Thesis
author Ballalai, João Marcelo
author_facet Ballalai, João Marcelo
author_sort Ballalai, João Marcelo
title Evaluating the role of orbitally-induced paleoceanographic changes in subtropical South Atlantic for the global climate over the last 800,000 years
title_short Evaluating the role of orbitally-induced paleoceanographic changes in subtropical South Atlantic for the global climate over the last 800,000 years
title_full Evaluating the role of orbitally-induced paleoceanographic changes in subtropical South Atlantic for the global climate over the last 800,000 years
title_fullStr Evaluating the role of orbitally-induced paleoceanographic changes in subtropical South Atlantic for the global climate over the last 800,000 years
title_full_unstemmed Evaluating the role of orbitally-induced paleoceanographic changes in subtropical South Atlantic for the global climate over the last 800,000 years
title_sort evaluating the role of orbitally-induced paleoceanographic changes in subtropical south atlantic for the global climate over the last 800,000 years
publisher HAL CCSD
publishDate 2023
url https://theses.hal.science/tel-04261916
https://theses.hal.science/tel-04261916/document
https://theses.hal.science/tel-04261916/file/These-2023-SML-Geosciences_marines-BALLALAI_Joao.pdf
geographic Antarctic
geographic_facet Antarctic
genre Antarc*
Antarctic
North Atlantic Deep Water
North Atlantic
Sea ice
genre_facet Antarc*
Antarctic
North Atlantic Deep Water
North Atlantic
Sea ice
op_source https://theses.hal.science/tel-04261916
Earth Sciences. Université de Bretagne occidentale - Brest; Universidade Federal Fluminense (Brésil), 2023. English. ⟨NNT : 2023BRES0038⟩
op_relation NNT: 2023BRES0038
tel-04261916
https://theses.hal.science/tel-04261916
https://theses.hal.science/tel-04261916/document
https://theses.hal.science/tel-04261916/file/These-2023-SML-Geosciences_marines-BALLALAI_Joao.pdf
op_rights info:eu-repo/semantics/OpenAccess
_version_ 1784902067959103488
spelling ftunivbrest:oai:HAL:tel-04261916v1 2023-12-10T09:41:27+01:00 Evaluating the role of orbitally-induced paleoceanographic changes in subtropical South Atlantic for the global climate over the last 800,000 years Changements paléoocéanographiques induits par l'orbite dans l'Atlantique Sud subtropical pour le climat mondial au cours des 800 000 dernières années Mudanças paleoceanográficas induzidas orbitalmente no Atlântico Sul subtropical para o clima global nos últimos 800.000 anos Ballalai, João Marcelo Geo-Ocean (GEO-OCEAN) Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) Université de Bretagne occidentale - Brest Universidade Federal Fluminense (Brésil) Stéphan Jorry Ana Luiza Albuquerque 2023-07-07 https://theses.hal.science/tel-04261916 https://theses.hal.science/tel-04261916/document https://theses.hal.science/tel-04261916/file/These-2023-SML-Geosciences_marines-BALLALAI_Joao.pdf en eng HAL CCSD NNT: 2023BRES0038 tel-04261916 https://theses.hal.science/tel-04261916 https://theses.hal.science/tel-04261916/document https://theses.hal.science/tel-04261916/file/These-2023-SML-Geosciences_marines-BALLALAI_Joao.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-04261916 Earth Sciences. Université de Bretagne occidentale - Brest; Universidade Federal Fluminense (Brésil), 2023. English. ⟨NNT : 2023BRES0038⟩ Atlantic meridional overturning circulation Orbital cycles South Atlantic subtropical gyre Interhemispheric heat transfer South Atlantic controls on climate Mg/Ca analysis Circulation méridienne de l'Atlantique Cycles orbitaux Gyre Subtropical de l'Atlantique Sud Transfert de chaleur inter-hémisphérique Contrôles de l'Atlantique Sud sur le climat Analyses de Mg/Ca Circulação de revolvimento meridional do Atlântico Ciclos orbitais Giro subtropical do Atlântico Sul Transferência de calor inter-hemisférica Controles do Atlântico Sul no clima Análise de Mg/Ca [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/doctoralThesis Theses 2023 ftunivbrest 2023-11-14T23:36:08Z Anthropogenic activity has reshaped Earth's climate by increasing atmospheric CO2 and global warming, often linked to an Atlantic Meridional Overturning Circulation (AMOC) slowdown. The AMOC redistributes heat and carbon via the South Atlantic Subtropical Gyre (SASG), acting with the Intertropical Convergence Zone (ITCZ), pursuing global energy equilibrium. Orbital variations can induce long-term climate shifts through insolation changes. This thesis investigates orbital influences on subtropical South Atlantic paleoceanography over 800 ka, analyzing benthic and planktic foraminifera δ18O, δ13C from GL-854 and MD08-3167 cores and thermocline Mg/Ca temperature from MD08- 3167. This framework unveils orbital-scale deep-water and ocean-atmosphere processes and controls on the Benguela Upwelling System (BUS), exploring AMOC's connections to climate. Chapters 1 to 3 set objectives, methods, and results. Chapter 4 explores 770 ka deep-water dynamics, where four AMOC modes controlled by orbitally-induced changes in Antarctic sea ice are proposed. The provided framework connects deep water, sea-ice, and ocean-atmosphere dynamics, shaping the Late Pleistocene climate. Chapter 5 discusses 365 ka of BUS variability. Intensified North Atlantic deep-water formation during positive precession periods enhances inter-hemispheric energy transfer, shifting SASG and ITCZ northwards, boosting upwelling. The mechanism controlling BUS connects AMOC intensity and global atmospheric patterns to atmospheric CO2 decline. Chapter 6 outlines Mg/Ca protocol performed on ICP-MS at IFREMER. Merging both surface and deep water perspectives seeks to clarify mechanisms controlling AMOC for the global climate. Les activités anthropiques ont remodelé le climat de la Terre en augmentant le CO2 atmosphérique et le réchauffement climatique, souvent lié au ralentissement de la circulation méridionale de renversement de l'Atlantique (AMOC). L'AMOC redistribue la chaleur et le carbone via le gyre subtropical de l'Atlantique Sud (SASG), agissant avec ... Doctoral or Postdoctoral Thesis Antarc* Antarctic North Atlantic Deep Water North Atlantic Sea ice Université de Bretagne Occidentale: HAL Antarctic