Meeting Abstract
Climate change threatens the health of reef-building corals. Under prolonged hyperthermic stress, coral-dinoflagellate partnerships collapse, resulting in coral bleaching or the loss of dinoflagellates from the host. The physiological and molecular consequence of symbiosis and elevated temperature on host-symbiont associations in adult corals has been widely investigated. However, very few studies have examined the ramifications of these combined stressors on coral larvae. Understanding the mechanisms that underlie the formation of coral-algal partnership during early developmental stages is critical to predict how coral recruitment and resilience will change in periods of warmer seas forecasted with climate change. This project extends the investigation of the combined stress from temperature and symbiosis by examining larval health and survival, symbiont colonization, and gene transcriptional profiling. In this study, we monitored early stages of symbiosis in the larvae of Acropora digitifera, a coral model that is thermally sensitive. From the survivorship analysis, both temperature and symbiotic state were found to have an effect on larval survival rates, with increased mortality in larvae exposed to the combined stress. The combined stress also decreased symbiont colonization and symbiont density of the larvae over two weeks of observation. Lastly, we identified novel transcriptional patterns in the coral molecular stress-response through RNASeq, an unbiased, high-throughput approach to expression profiling. Our data suggest that the combination of physical and biotic pressures can dramatically decrease larval health in A. digitifera.
