Long-term monitoring (2.5 years) of effects of short-term field exposure of stony corals to dispersed and undispersed crude oil

All sites contained shallow subtidal coral reefs. One site was designated as a control. One site received dispersed oil at a target concentration of 50ppm for 24hr (high exposure); one received only crude oil at an amount of c1 l/m² for c48hr (moderate exposure). Coverage of all organisms, hard corals, all animals, and all plants was significantly depressed in the Dispersed Oil treatment compared to the Control station. Little recovery of most organisms was evident some 20 months after initial treatment. Coverage parameters of the Oil Only treatment were generally lower than, but not usually significantly different from coverage of the Control. Of the four coral species investigated for growth, two (Agaricia tenuifolia and Porites porites) showed significant effects from exposure to dispersed oil (reduced blade and tip extension rate at the dispersed oil site). -from Authors