This project will investigate the effect of elevated temperature on release of symbiotic animals (zooxanthellae) by tropical corals and sea anemones. In the field, studies will attempt to determine which taxa are susceptible to elevated temperature-induced release, the time-temperature parameters which evoke release, and the mode of release. In the laboratory, studies will investigate the cellular mechanism by which elevated temperature evokes release of zooxanthellae by host cells, using the sea anemone Aiptasia pulchella and selected reef corals. Immunofluorescence and pharmacological agents will be used to characterize levels of free intracellular calcium, integrity of selected skeletal proteins in the cell, and synthesis of calcium-dependent adhesion proteins. Individual host cells will be obtained by maceration. Cells subjected to elevated temperature will be compared to controls at ambient temperature. The results will indicate in ecological terms the potential impact of elevated temperature on coral reef anthozoans, and in cellular terms how elevated temperature causes cell detachment, loss of zooxanthellae and destabilizaiton of marine symbioses which dominate tropical coral reefs.
