Metabolomic signatures of increases in temperature and ocean acidification from the reef-building coral, Pocillopora damicornis

Introduction As a changing climate threatens the persistence of terrestrial and marine ecosystems by altering community composition and function, differential performance of taxa highlights the need for predictive metrics and mechanistic understanding of the factors underlying positive performance in the face of environmental disturbances. Biochemical reactions within cells provide a snapshot of molecular regulation and flexibility during exposure to environmental stressors. However, because the organism is the unit of selection there is a need for the integration of metabolite data with organism physiology to understand mechanisms responsible for individual success under a changing climate. Objectives Our study aims to characterize the molecular response of reef corals to simulated global climate change stressors. Furthermore, we seek to relate changes in the molecular physiology to observations in overall colony response. Methods To this end, we applied a non-targeted metabolomic approach to describe lipid and primary metabolite composition after exposure of the reef-building coral Pocillopora damicornis to ambient and elevated experimental climate change conditions. We compared these metabolite data to organism physiology, specifically the key processes of photosynthesis, respiration, and calcification. Results Corals significantly altered their lipid and primary metabolite profiles in response to experimental treatments. Primary metabolite profiles predicted organisms' net photosynthesis, but not calcification or respiration measures. Despite challenges in metabolome annotation, our data indicated corals alter carbohydrate composition, cell structural lipids, and signaling compounds in response to elevated treatment conditions. Conclusions The integration of metabolite and physiological data highlights the predictive power of metabolomics in defining organism performance and provides biomarkers for future studies. Here, we present a multivariate biomarker approach to assess climate change impacts and advance our mechanistic understanding of stress response in this keystone species.