Integrated effects of the Deepwater Horizon oil spill on nearshore ecosystems Marine Ecology Progress Series

The interconnected nearshore habitats of the northern Gulf of Mexico provide refuge and feeding opportunities for fish and wildlife, including open water, shoreline, and terrestrial species. The Deepwater Horizon oil spill natural resource damage assessment documented injury as a result of the oiling of over 2113 km (1300 miles) of shoreline over an 87 d release from the wellhead. Field and laboratory studies indicate that oil degraded the health of coastal marsh vegetation and associated fauna, resulted in the loss of nearshore oyster cover, and increased erosion of oiled marsh edge habitat over approximately 174 km (108 miles) of shoreline. Sand beach habitat, submersed aquatic vegetation, and subtidal oysters were injured by a combination of oiling and response actions. The loss of billions of oysters resulted in failed recruitment over several years in the most severely affected areas (Barataria Bay, Black Bay/Breton Sound, and Mississippi Sound). Affected ecosystem services include supporting services (e.g. primary production) and provisioning services (e.g. fish and invertebrate abundance). Loss of vegetation and nearshore oysters and increased shoreline erosion may have disrupted regulating services associated with stable marsh (e.g. coastal storm and flood protection). The loss of marsh vegetation and oysters likely reduced nutrient cycling and water filtration services. Recovery of natural resources may take more than 20 yr in some areas. To prepare for future spills, we recommend that natural resource trustees develop generic conceptual models and prepare integrated injury assessment approaches for nearshore habitats to facilitate future injury quantification. Additional exploration of the trade-offs between response options could minimize or shift natural resource injury for future spills.