A Metabolic View of Growth, Bleaching & Disease Using Temperature-Based Metabolic Budget Models of the Threatened Elkhorn Coral, Acropora cervicornis

The ability to predict metabolic deficits in coral holobiont metabolism is becoming increasingly important as water temperatures continue to rise. Physiological sensitivities to acute and cumulative thermal stress were compared in the threatened coral Acropora cervicornis from Broward County, Florida. Rates of respiration and photosynthesis were measured in acute and cumulative exposures at five distinct temperatures between 25 C to 37 C. The ratio of daily gross photosynthesis to respiration (Pg:R) was derived from these measurements to provide a means of estimating real time metabolic surplus using in situ temperature data (Poster 1). Remarkably, Pg:R model predictions agree with the thermal bleaching threshold for this population. To evaluate the utility of temperature-based metabolic models, the relationship between metabolism and growth, and the prevalence of bleaching and disease of outplanted corals on the inner Florida Reef Tract were examined, exploiting several years of in situ temperature and monitoring data (Poster 2). This technique offers the ability to combine a relatively simple lab-based model with real time environmental data. The potential utility of this model is examined in the context of growth, disease prevalence, and bleaching, offering managers and restoration practitioners the ability to identify at-risk species, prioritize conservation and restoration target areas, and predict the timing of greatest vulnerability.