Acclimatization of coral reefs to climate change : ecophysiology and geochemical signatures in an ocean acidification context
In a context of rapid and severe climate change, coral reefs are threatened with extinction. The increase in anthropogenic CO2 levels leads to ocean acidification, which can have devastating effects on marine organisms with carbonate skeletons, such as corals. Corals have the ability to acclimate th...
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Other Authors: | , , , , , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
Published: |
HAL CCSD
2023
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Subjects: | |
Online Access: | https://theses.hal.science/tel-04383070 https://theses.hal.science/tel-04383070/document https://theses.hal.science/tel-04383070/file/These-2023-SML-Ecologie_marine-TANVET_Clement.pdf |
Summary: | In a context of rapid and severe climate change, coral reefs are threatened with extinction. The increase in anthropogenic CO2 levels leads to ocean acidification, which can have devastating effects on marine organisms with carbonate skeletons, such as corals. Corals have the ability to acclimate through various mechanisms, including ecophysiological. This thesis explores the acclimatization capacities of coral reefs to climate change, particularly to ocean acidification. Recent studies have revealed a natural site in New Caledonia (Bouraké mangroves) hosting diverse coral reefs despite extreme and fluctuating H/Temperature/Dissolved oxygen seawater conditions. By coupling ecophysiological, metagenomic and geochemical approaches, the objectives of this thesis are to identify the mechanisms set up by Bouraké corals in response to these conditions, by comparing them to corals from an adjacent reference site. The first results of this thesis showed a strong coral recruitment at Bouraké. In addition, corals from Bouraké exposed to different levels of pCO2 showed increased calcification compared to corals from the reference site. We have shown symbiotic associations specific to Bouraké corals, as well as the influence of symbiotic communties on the regulation of coral calcification. Finally, we confirmed by a aleoenvironmental study that Bouraké corals have been acclimatized to extreme pH conditions for at least the last three decades. This thesis highlights the adaptive potential of some corals to the rapid climate change underway. Dans un contexte de changements climatiques rapides et sévères, les récifs coralliens sont menacés de disparition. L’élévation des teneurs en CO2 d’origine anthropique génère une acidification des océans qui peut avoir des effets dévastateurs sur les organismes marins à squelette carbonaté, tels que les coraux. Les coraux ont la capacité de s’acclimater via différents mécanismes, notamment écophysiologiques. Cette thèse explore les capacités d’acclimatation des récifs coralliens au ... |
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