Biochemical responses of cnidarian larvae to mercury and benzo(a)pyrene exposure.

The biochemical responses of planulae from the coral Porites astreoides exposed to 10 microg/L of benzo(a)pyrene (B(a)P) and to 10 microg/L of mercury (Hg) was evaluated. The survivorship of larvae only dropped significantly after 48 h of B(a)P exposure, whereas it remained at 98% for Hg exposure and up to 96 h. Exposure to B(a)P significantly increased free thiols, and the activity of glutathione-S-transferase and catalase were unaltered under exposure of any of the contaminants.