Oil spill response-related injuries on sand beaches: when shoreline treatment extends the impacts beyond the oil

Studies of oil spills on sand beaches have focused traditionally on the effects of shortterm oil exposure, with recovery of sand beach macrobenthic communities occurring within several weeks to several years. The Deepwater Horizon spill resulted in chronic, multi-year re-oiling and up to 4 yr of extensive and often intensive treatments. Of the 965 km of sand beaches that were oiled, shoreline treatment was documented on 683 km. Intensive mechanical treatment was conducted from 9 to 45 mo after the initial oiling on 32.4 km of shoreline in Louisiana, and deep beach excavation/sifting and tilling was conducted along 60.5 km in Louisiana, Alabama, and Florida, often along contiguous lengths of beach. Recovery of sand beach invertebrate communities from the combined effects of oiling and treatment would likely be delayed by 2 to 6 yr after the last response action was completed. We introduce the concept of ‘Response Injury’ categories that reflect both intensity and frequency of beach treatment methods. We use the literature on similar types of disturbances to sand beach communities (foot traffic, vehicular traffic, wrack removal, beach nourishment) to describe the expected impacts. Temporal patterns of responserelated disturbances can affect seasonal recruitment of organisms and the overall rate of ecosystem recovery from both oil exposure and treatment disturbance. This concept provides a framework for specifically assessing response-related impacts in future spills, which has not been considered in previous injury assessments.