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

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. •Experimental beach plots were washed to simulate aggressive treatments used during the Exxon Valdez oil spill cleanup in Alaska•Physical and biological recovery were tracked for a period of 12 years•Infaunal recovery occurred more quickly than physical beach substrate recovery (1-3 year vs. 7-9 years)•Restoration of grain size structure was not a necessary precursor to infaunal recovery•Results provide guidance for future oil spill responses in high latitude regions