Long-term physical and biological recovery of disturbed intertidal beach habitat from simulated oil spill cleanup in Prince William Sound, Alaska

Abstract

Following the Exxon Valdez oil spill, hydraulic techniques using combinations of high-pressure and heated water were used to mobilize weathered oil from impacted shorelines. During treatment, concerns were raised over the ecological impacts of these treatment methods. We report on a long-term study comparing grain size and infaunal communities in washed and unwashed plots at unoiled beaches treated using these methods. Despite the long-term (nine-year) disruption of grain size structure, total infaunal abundance showed no significant differences between washed and unwashed plots after only one year and species diversity metrics had recovered by the third year post-treatment. Similarly, community structure appeared to have recovered by year three. Reasons for this apparent physical/biological disconnect may be related to the native lack of fine-grained sediments in the Prince William Sound system, and inherently robust infaunal reproductive and recolonizing strategies. This work has practical implications for spill response, damage assessment, and restoration.