Thermal stress reduces pocilloporid coral resilience to ocean acidification by impairing control over calcifying fluid chemistry

• Published in: Science Advances
• Main Authors: Guillermic, Maxence, Cameron, Louise, de Corte, Ilian, Misra, Sambuddha, Bijma, Jelle, de Beer, Dirk, Reymond, Claire, Westphal, Hildegard, Ries, Justin, Eagle, Robert A.
• Other Authors: Laboratoire Géosciences Océan (LGO), 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), Interdisciplinary Graduate School for the Blue planet, ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDE]Environmental Sciences; Ocean acidification
• Online Access: https://hal.univ-brest.fr/hal-03154497; https://hal.univ-brest.fr/hal-03154497/document; https://hal.univ-brest.fr/hal-03154497/file/eaba9958.full.pdf; https://doi.org/10.1126/sciadv.aba9958

International audience The combination of thermal stress and ocean acidification (OA) can more negatively affect coral calcification than an individual stressors, but the mechanism behind this interaction is unknown. We used two independent methods (microelectrode and boron geochemistry) to measure calcifying fluid pH (pHcf) and carbonate chemistry of the corals Pocillopora damicornis and Stylophora pistillata grown under various temperature and pCO2conditions. Although these approaches demonstrate that they record pHcf over different time scales, they reveal that both species can cope with OA under optimal temperatures (28°C) by elevating pHcf and aragonite saturation state (ωcf) in support of calcification. At 31°C, neither species elevated these parameters as they did at 28°C and, likewise, could not maintain substantially positive calcification rates under any pH treatment. These results reveal a previously uncharacterized influence of temperature on coral pHcf regulation-the apparent mechanism behind the negative interaction between thermal stress and OA on coral calcification.