Research Product

Seven species of coral, Dichocoenia stokesii, Nontastrea annularis, Agarcia agaricites, Acropora cervicornis, Porites furcata, P. astreoids, and P. divaricata, were experimentally exposed to each of three concentrations (100, 316, 100 l/l) of drilling mud (obtained from an offshore oil well in the Gulf of Mexico), and control sea water for 96 hours to observe behavioral responses. Experiments were conducted at Carysfort Reef, Florida Keys, using closed aquaria located in three meters of water. Polyp behavior was determined with serial closeup photography which allowed counting of retracted, partially retracted, and non-retracted polyps in each colony. Response to drilling mud concentrations was measured as percent of polyps retracted. Montastrea annularis, Agaricia agaricites, and Acropora cervicornis were killed by exposure to 1,000 ul/l mud. A. cervicornis colonies survived this concentration in a replicate experiment. All corals except Dichocoenia stokesii and Porites divaricata showed significant (less than .05) polyp retraction during exposure to 100 l/l mud concentration, 316 ul/l mud was the minimum concentration which induced significant polyp retraction in Porites divaricata. Polyps of Dichocoenia stokesii did not detectably retract to any of the three concentrations.