Different Environmental Response Strategies in Sympatric Corals from Pacific Islands

Coral reefs are severely threatened by global and local environmental changes. However, susceptibility to perturbations and subsequent mortality varies among coral species. In this study, we tested the contribution of genetic and environmental conditions to coral’s phenotypic response in Pocillopora spp. and Porites spp. sampled together at a large ecological and temporal scale throughout the Pacific Ocean. We assessed coral phenotype signatures using a multi-biomarker approach (animal and symbiont biomasses, protein carbonylation and ubiquitination and total antioxidant capacities). In both genera, we highlighted a strong anticorrelation between the redox state and the animal and symbiont biomasses. In addition, Pocillopora exhibited high phenotypic plasticity, responding to various environmental variables such as temperature, nutrients, phosphate, and carbonate chemistry. In contrast, Porites displayed more robust phenotypes influenced by both genetics and past climate events. In conclusion, co-located coral species display different phenotypic response strategies that are influenced by different environmental conditions. Pocillopora species, sampled on the TARA Pacific Expedition, have greater phenotypic plasticity in response to environmental variables than Porites species, whose phenotypes were dictated by coral host genetics and past climate, according to extensive multi-biomarker analysis.