title: Heterotrophy promotes the re-establishment of photosynthate translocation in a symbiotic coral after heat stress.
abstract: 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.
authors.affiliation: Centre Scientifique de Monaco, Monaco.
authors.forename: Pascale
authors.initials: P
authors.lastname: Tremblay
authors.affiliation: Centre Scientifique de Monaco, Monaco.
authors.forename: Andrea
authors.initials: A
authors.lastname: Gori
authors.affiliation: LEMAR - UMR 6539 UBO/CNRS/IRD, Institut Universitaire Européen de la Mer, Place Nicolas Copernic, Plouzané, France.
authors.forename: Jean François
authors.initials: JF
authors.lastname: Maguer
authors.affiliation: School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, Australia.
authors.forename: Mia
authors.initials: M
authors.lastname: Hoogenboom
authors.affiliation: Centre Scientifique de Monaco, Monaco.
authors.forename: Christine
authors.initials: C
authors.lastname: Ferrier-Pagès
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000378:metabolism / Q000469:parasitology / Q000502:physiology*; D052818:Autotrophic Processes / Q000502:physiology; D002113:Calcification, Physiologic / Q000502:physiology; D002244:Carbon / Q000378:metabolism; D057231:Climate Change; D004141:Dinoflagellida / Q000502:physiology; D018869:Heat-Shock Response / Q000502:physiology*; D052836:Heterotrophic Processes / Q000502:physiology*; D006358:Hot Temperature; D008027:Light; D010788:Photosynthesis / Q000502:physiology*; D013559:Symbiosis / Q000502:physiology
chemical_list: D002244:Carbon