The physiological mechanisms of acclimatization in tropical reef corals

The ability of scleractinian corals to survive changes that are predicted i n the global environment over the next century will lie in their physiologi cal mechanisms of acclimatization. Corals display rapid modifications in be havior, morphology and physiology enabling them to photoacclimate to changi ng light conditions, a scenario that demonstrates considerable biological f lexibility. Here we argue that the acclimatization mechanisms in corals are fundamentally similar to those exhibited by other invertebrate taxa, We di scuss protein metabolism as a mechanism underlying acclimatization response s in reef corals, and explore the relationship between protein turnover, me tabolic rate, growth rate, and acclimatization capacity. Our preliminary an alyses suggest that corals with low growth rates (mu Ca/mgN/h) and high met abolic rates (mu O-2/cm(2)/hr), such as the massive species, acclimatize mo re effectively than those with high growth rates and low metabolic rates, a feature that is characteristic of branching species. We conclude that stud ies of protein turnover, combined with temporally relevant investigations i nto the dynamic aspects of coral dinoflagellate symbioses will provide cons iderable insight into why corals exhibit such a high level of variation in response to the same environmental challenge. Furthermore, a more detailed understanding of acclimatization mechanisms is essential if we are to predi ct how a coral assemblage will respond to present and future environmental challenges.