Habitat-specific recovery of shallow subtidal communities following the Exxon Valdez oil spill

We contrasted impacts of the Exxon Valdez oil spill within kelp and eelgras s communities and examined recovery of these communities over a period of u p to 10 yr after the spill. Impacts were greatest in sheltered bays that we re subject to heavy oiling. The effects of oiling and associated cleanup ac tivities on nearshore subtidal communities within these bays were more evid ent in eelgrass than in kelp habitats. In 1990, a year after the spill, con centrations of total polycyclic aromatic hydrocarbons (TPAHs) were higher, more groups of organisms were impacted, and more groups showed a negative r esponse to oil (i.e., lower densities at oiled vs. reference sites) in eelg rass than in kelp beds. Recovery was slower in eelgrass than in kelp habita ts. About 80% of the groups impacted in eelgrass beds failed to show clear signs of recovery by 1995, six years after the spill. In contrast, most imp acted groups in kelp beds recovered within two years. The stronger, more pe rsistent impacts in eelgrass beds were probably related to the occurrence o f more sensitive species (especially crustaceans), the higher concentration of TPAHs, and the more persistent nature of oil within sheltered eelgrass beds than in kelp beds. These data corroborate earlier findings that sugges t that impacts from large oil spills are persistent, especially in soft-sed iment environments.