TWENTY-FIFTH ANNUAL EASTERN FISH HEALTH WORKSHOP MARCH 10-13, 2000   Complex Species Interactions In Healthy And Perturbed Coral Reefs      Les Kaufman, Chris Bentis, and Stjepko Gulubic   Boston University Marine Program, Department of Biology, 5 Cummington Street, Boston, MA  02215        "Insidious symbioses" that change in nature with shifts in relative abundance or environmental conditions, are common on coral reefs. Coral-fish and coral-endolith relationships are good examples.  The importance of algal gardeners is now widely accepted, but the possible role of endoliths in coral health has been largely ignored. Corals exist in a dynamic equilibrium with four principal partners: the coral itself, zooxanthellae, endolithic algae that penetrate the coral skeleton, and endolithic fungi that penetrate both skeleton and overlying coral tissue. Although the complexity of this consortium has been hinted at for more than a century, most attention has centered on coral-zooxanthellae relationships.  Le Campion-Alsumard et al. (1995) reported interaction between corals and fungal and algal endoliths in the massive Pacific coral Porites lobata, and described skeletal deposits ("cones") formed by the coral in response to attack by endolithic fungi.  Here we extend these observations to pocilloporid and acroporid corals at Johnston Atoll and cite similar examples from the tropical Atlantic.  Microscopic skeletal cones, evidence of fungal-coral interaction, are pandemic and often dense, indicating that the interaction may entail substantive energy expenditure on the part of the coral.  The projected rise in atmospheric CO2 by mid-century and its anticipated negative effects on skeletogenesis in corals are cause for concern.  Fungal-coral interactions should be considered in studies of coral banding and putative disease syndromes.   Return to 25th Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page