Heterotrophy promotes the re-establishment of photosynthate translocation in a symbiotic coral after heat stress

• Published in: Scientific Reports
• Main Authors: Tremblay, Pascale, Gori, Andrea, Maguer, Jean-François, Hoogenboom, Mia, Ferrier-Pagès, Christine
• Other Authors: Centre Scientifique de Monaco (CSM), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), School of marine and tropical biology (Townsville, Australie), James Cook University (JCU)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: stylophora-pistillata; organic-carbon fluxes; Scleractinian corals; bleached corals; climate-change; dinoflagellate symbiosis; marine ecosystems; ocean acidification; thermal-stress; turbinaria-reniformis; ACL; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Ocean acidification
• Online Access: https://hal.science/hal-01483218; https://hal.science/hal-01483218/document; https://hal.science/hal-01483218/file/srep38112.pdf; https://doi.org/10.1038/srep38112

00000 ăWOS:000389129900001 International audience Symbiotic scleractinian corals are particularly affected by climate change stress and respond by bleaching (losing their symbiotic dinoflagellate partners). Recently, the energetic status of corals is emerging as a particularly important factor that determines the corals' vulnerability to heat stress. However, detailed studies of coral energetic that trace the flow of carbon from symbionts to host are still sparse. The present study thus investigates the impact of heat stress on the nutritional interactions between dinoflagellates and coral Stylophora pistillata maintained under auto-and heterotrophy. First, we demonstrated that the percentage of autotrophic carbon retained in the symbionts was significantly higher during heat stress than under non-stressful conditions, in both fed and unfed colonies. This higher photosynthate retention in symbionts translated into lower rates of carbon translocation, which required the coral host to use tissue energy reserves to sustain its respiratory needs. As calcification rates were positively correlated to carbon translocation, a significant decrease in skeletal growth was observed during heat stress. This study also provides evidence that heterotrophic nutrient supply enhances the re-establishment of normal nutritional exchanges between the two symbiotic partners in the coral S. pistillata, but it did not mitigate the effects of temperature stress on coral calcification.