Environmental stress (thermal, osmotic) causes elimination of symbiotic algae from reef-building corals and other tropical cnidarians, e.g., sea anemones, often with catastrophic results. A continued investigation will be conducted on the organismic and cellular mechanisms by which corals and other cnidarians maintain stable symbioses, and mechanisms by which stress causes elimination of symbiotic algae. Emphasis will be placed on studies of expulsion and digestion of zooxanthellae, and nutrient limitation phenomena.
