Research Product

Nine muds were tested; eight from outer continental shelf (OCS) drilling operations; one was the NBS (National Bureau of Standards) standard mud. At the 25-ppm exposure level, none of the nine muds tested by us produced observable zooxanthellae loss, however substantial protein loss occurred in P4-exposed corals. Loss in P1- and P5-exposed corals could only be demonstrated statistically using skeletal weight as the normalizing parameter. Similarly, reduced calcification rates occurred in P4- and P1-exposed corals. Rates were reduced in P5-exposed corals as well, however most statistical comparisons were equivocal. The three muds, P4, P5, and P1, also were the only muds to cause significant changes in the relative composition of the FAA pool (Table 4). Serine-threonine levels decreased relative to aspartate-alanine-glutamate in all three cases. The remaining muds produced slight, occasionally significant reductions in the FAA pool at the 25-ppm exposure level, but most significant results were equivocal. In all cases although only certain amino acids showed significant changes, the effect could not be distinguished from a general, moderate decrease in pool size.