The ecological physiology and conservation biology of Floridian reef corals

Coral reefs are among the most diverse habitats on earth, but are in a state of decline worldwide. The three dimensional structure of coral reefs, and subsequent community development, is determined by the recruitment, survival and growth of coral colonies. The present study investigates coral recruitment into existing populations. Ceramic tiles were deployed in the Florida Keys for three successive years to investigate coral recruitment. The study revealed: recruitment in the Florida Keys is lower than elsewhere in the Caribbean; hydrocoral recruitment greatly exceeds scleractinian recruitment; recruitment is limited to small non-reef building species that brood larvae; recruitment appears to be highly localized; coral recruitment is highest at the deepest, most diverse site studied; and recruitment is variable from year to year.; The success of corals is dependent upon the symbiotic relationship between photosynthetic algae and the coral host. Photosynthesis and respiration rates are influenced by temperature and light availability; however, few studies have examined the influence of these seasonal changes on oxygen metabolism. The purpose of the second portion of the present study is to investigate seasonal photosynthetic patterns of a dominant reef coral, Montastrea annularis c.f. faveolata. Specimens were incubated for 24 hours in an underwater respirometer each month. The resulting data were used to construct photosynthesis irradiance curves and the following patterns were observed: Ic, Ik, and rc decrease in winter; a increases in winter; and pnet max peaks in early summer and declines with increasing temperatures until fall. Decreases in Gross P/R in late summer correspond with decreased photosynthetic efficiency and biomasses measured in other studies.; Temperature and irradiance values were used to model photosynthesis. Day length and Itot predict Ik very well. Temperature and Itot predict rc and Ic well. Pnet max, Gross P/R and a were modeled poorly. Additional factors, such as the ability of the algae to utilize light, would improve these models.; Photosynthetic patterns for the entire year were modeled using surface irradiance measurements. This model predicts that Montastrea annularis is photoautotrophic for the year at 8 m depth in the Florida Keys. Additional data are also required to strengthen these models.