Meeting Abstract
The continued rise in ocean pCO2 and temperature is of concern for marine organisms, especially highly susceptible reef-building corals that rely on a relationship with symbiotic algae, which governs the success of the coral holobiont. Diverse physiological responses of coral holobionts, at individual and species levels, will determine the future success of coral reefs. We investigated the independent and combined effects of acidification (280−3300 µatm) and warming (28, 31 °C) on the physiological responses of coral hosts and algal symbionts of 4 Caribbean coral species (Siderastrea siderea, Pseudodiploria strigosa, Porites astreoides, Undaria tenuifolia) from inshore and offshore reefs on the Belize Mesoamerican Barrier Reef System. To illuminate molecular underpinnings of these responses, gene expression of S. siderea were explored. Warming more negatively altered host physiology of S. siderea, while symbiont physiology responded to warming and acidification. Preliminary gene expression showed transcriptome resilience across stressors, however, natal reef drove gene expression profiles. Warming reduced P. strigosa host and symbiont physiology, although inshore symbionts were less affected. Host physiology and chlorophyll a of P. astreoides were reduced under acidification, while chlorophyll a increased with warming. Determination of U. tenuifolia physiology was difficult due to high mortality. These results highlight diverse physiological responses of coral holobionts under global change and understanding this variation is critical to predicting the future of Caribbean reefs as global change continues.
