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Coral energetics: the metabolic response to resource scarcity and subsequent cost of recovery
The fitness of an organism depends on its energetics, which includes both the amount of energy entering the individual and the distribution of energy within the individual. The present thesis examined the energetics of a scleractinian coral during and immediately following resource limitation. The first study (Study 1) questioned how long energy reserves could support normal metabolic activity, and whether corals are capable of a downwardly shifting respiration rates (i.e. metabolic depression) to preserve energy reserves during resource limitation. Study 1 provided the first empirical evidence from a single study necessary to parameterize a Dynamic Energy Budget model of a symbiotic coral. A second study (Study 2) investigated if coral recovery from resource limitation is dependent on the source of energy (autotrophic or heterotrophic) or the temperature of the seawater. Study 1 indicates that corals are able to adjust respiration rates, biomass catabolism, and calcification during resource limitation. Study 2 provided no evidence that recovery of biomass is dependent on the source of energy or temperature, however the availability of autotrophic resources enhanced the recovery of calcification and respiration. Both studies investigate how and when a coral adjusts its energetic expenditure and investment, providing insight into how and when a coral is able to perceive a change in its environment.