Reconstructing ocean acidificationfron deep-sea coral geochemistry
Ocean acidification is caused by the absorption of rising atmospheric CO2 by seawater andrepresents a major environmental issue. Since the beginning of the industrial era, seawater pH hasdecreased by 0.1 pH units and is already threatening calcifying organisms. Boron isotopes (11B) haveproved to be...
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ftunivnantes:oai:HAL:tel-01164967v1 2023-05-15T17:08:50+02:00 Reconstructing ocean acidificationfron deep-sea coral geochemistry Quantification de l'acidification de l'océan par l'analyse géochimique des coraux profonds Gonzalez, Cécile 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 Sud - Paris XI Anne Juillet Leclerc 2014-01-30 https://theses.hal.science/tel-01164967 https://theses.hal.science/tel-01164967/document https://theses.hal.science/tel-01164967/file/VD2_GONZALEZ_CECILE_30012014.pdf fr fre HAL CCSD NNT: 2014PA112009 tel-01164967 https://theses.hal.science/tel-01164967 https://theses.hal.science/tel-01164967/document https://theses.hal.science/tel-01164967/file/VD2_GONZALEZ_CECILE_30012014.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-01164967 Sciences de la Terre. Université Paris Sud - Paris XI, 2014. Français. ⟨NNT : 2014PA112009⟩ Ocean acidification Boron isotopes MC-ICPMS Neptune Vital effect Cold-water corals Last Glacial Maximum Neoproterozoic Acidification de l’océan PH Isotopes du bore Effet vital Coraux profonds Dernier Maximum Glaciaire Néoprotérozoïque [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/doctoralThesis Theses 2014 ftunivnantes 2023-03-08T07:28:07Z Ocean acidification is caused by the absorption of rising atmospheric CO2 by seawater andrepresents a major environmental issue. Since the beginning of the industrial era, seawater pH hasdecreased by 0.1 pH units and is already threatening calcifying organisms. Boron isotopes (11B) haveproved to be a powerful geochemical tool for the reconstruction of pH variations, but has not yet beenapplied to deep-sea corals (DSC). Accurate and precise measurements of boron isotopes in coralsand seawaters were performed in order to measure small pH variations.The technique of pH reconstruction based on boron isotopes (pH-11B) was used on two specimens of the DSC Madrepora oculata and Lophelia pertusa collected alive in the Norwegian Sea and spanning an age of 40 (3) and 67 (3) years, respectively. Acidification rates were calculated by applying a new pH-11B calibration obtained from the geochemical analysis M. oculata and L. pertusa samples cultured under different pCO2 conditions. The contribution of a biological-related vital effect on d11B was observed at macrometer scale, and a correction was finally suggested based on oxygen and carbon isotopes. Overall, the coral δ 11B-based reconstructions show a pH decrease in the Norwegian Sea since the 1940s, which seems to be related to the local hydrodynamics. The pH-11B technique was also applied to fossil DSC fragments from two “on-mound sediment cores” retrieved in the Siculo-Tunisian Strait with the aim to reconstruct the pH during the Last Glacial Maximum and the Holocene periods. Finally, well-preserved limestone samples from the stratigraphic sequence Nama (551-543 Ma) in Namibia were investigated for 11B to study the pH variations at the beginning of the Cambrian evolutive radiation. L’acidification des océans provoquée par l’absorption du CO2 atmosphérique par l’eau de merest devenue une préoccupation écologique majeure et menace déjà les organismes calcifiants. Suiteà la révolution industrielle, le pH de l’océan de surface a diminué de 0,1 unité-pH. En ... Doctoral or Postdoctoral Thesis Lophelia pertusa Norwegian Sea Ocean acidification Université de Nantes: HAL-UNIV-NANTES Norwegian Sea |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
French |
topic |
Ocean acidification Boron isotopes MC-ICPMS Neptune Vital effect Cold-water corals Last Glacial Maximum Neoproterozoic Acidification de l’océan PH Isotopes du bore Effet vital Coraux profonds Dernier Maximum Glaciaire Néoprotérozoïque [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
Ocean acidification Boron isotopes MC-ICPMS Neptune Vital effect Cold-water corals Last Glacial Maximum Neoproterozoic Acidification de l’océan PH Isotopes du bore Effet vital Coraux profonds Dernier Maximum Glaciaire Néoprotérozoïque [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Gonzalez, Cécile Reconstructing ocean acidificationfron deep-sea coral geochemistry |
topic_facet |
Ocean acidification Boron isotopes MC-ICPMS Neptune Vital effect Cold-water corals Last Glacial Maximum Neoproterozoic Acidification de l’océan PH Isotopes du bore Effet vital Coraux profonds Dernier Maximum Glaciaire Néoprotérozoïque [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
Ocean acidification is caused by the absorption of rising atmospheric CO2 by seawater andrepresents a major environmental issue. Since the beginning of the industrial era, seawater pH hasdecreased by 0.1 pH units and is already threatening calcifying organisms. Boron isotopes (11B) haveproved to be a powerful geochemical tool for the reconstruction of pH variations, but has not yet beenapplied to deep-sea corals (DSC). Accurate and precise measurements of boron isotopes in coralsand seawaters were performed in order to measure small pH variations.The technique of pH reconstruction based on boron isotopes (pH-11B) was used on two specimens of the DSC Madrepora oculata and Lophelia pertusa collected alive in the Norwegian Sea and spanning an age of 40 (3) and 67 (3) years, respectively. Acidification rates were calculated by applying a new pH-11B calibration obtained from the geochemical analysis M. oculata and L. pertusa samples cultured under different pCO2 conditions. The contribution of a biological-related vital effect on d11B was observed at macrometer scale, and a correction was finally suggested based on oxygen and carbon isotopes. Overall, the coral δ 11B-based reconstructions show a pH decrease in the Norwegian Sea since the 1940s, which seems to be related to the local hydrodynamics. The pH-11B technique was also applied to fossil DSC fragments from two “on-mound sediment cores” retrieved in the Siculo-Tunisian Strait with the aim to reconstruct the pH during the Last Glacial Maximum and the Holocene periods. Finally, well-preserved limestone samples from the stratigraphic sequence Nama (551-543 Ma) in Namibia were investigated for 11B to study the pH variations at the beginning of the Cambrian evolutive radiation. L’acidification des océans provoquée par l’absorption du CO2 atmosphérique par l’eau de merest devenue une préoccupation écologique majeure et menace déjà les organismes calcifiants. Suiteà la révolution industrielle, le pH de l’océan de surface a diminué de 0,1 unité-pH. En ... |
author2 |
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 Sud - Paris XI Anne Juillet Leclerc |
format |
Doctoral or Postdoctoral Thesis |
author |
Gonzalez, Cécile |
author_facet |
Gonzalez, Cécile |
author_sort |
Gonzalez, Cécile |
title |
Reconstructing ocean acidificationfron deep-sea coral geochemistry |
title_short |
Reconstructing ocean acidificationfron deep-sea coral geochemistry |
title_full |
Reconstructing ocean acidificationfron deep-sea coral geochemistry |
title_fullStr |
Reconstructing ocean acidificationfron deep-sea coral geochemistry |
title_full_unstemmed |
Reconstructing ocean acidificationfron deep-sea coral geochemistry |
title_sort |
reconstructing ocean acidificationfron deep-sea coral geochemistry |
publisher |
HAL CCSD |
publishDate |
2014 |
url |
https://theses.hal.science/tel-01164967 https://theses.hal.science/tel-01164967/document https://theses.hal.science/tel-01164967/file/VD2_GONZALEZ_CECILE_30012014.pdf |
geographic |
Norwegian Sea |
geographic_facet |
Norwegian Sea |
genre |
Lophelia pertusa Norwegian Sea Ocean acidification |
genre_facet |
Lophelia pertusa Norwegian Sea Ocean acidification |
op_source |
https://theses.hal.science/tel-01164967 Sciences de la Terre. Université Paris Sud - Paris XI, 2014. Français. ⟨NNT : 2014PA112009⟩ |
op_relation |
NNT: 2014PA112009 tel-01164967 https://theses.hal.science/tel-01164967 https://theses.hal.science/tel-01164967/document https://theses.hal.science/tel-01164967/file/VD2_GONZALEZ_CECILE_30012014.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766064701875159040 |