Effects of the Deepwater Horizon Oil Spill on Coastal Salt Marsh Habitat

Salt marshes in Louisiana were most intensively polluted by the oil spill. At least 350 miles of coastal marsh shoreline in Louisiana was injured. Even trace oiling of plant stems in Louisiana salt marshes reduced plant cover in the marsh, and affected plant growth, particularly in the marsh edge zone closest to the shoreline. The marsh edge is most productive zone because it provides migrating animals access to flooded marsh surfaces for refuge and foraging.

Oil damage to plants and oysters, as well as oil clean-up measures (see graphic), increased the erosion of marsh shorelines between 2010 and 2013. Increased erosion of oiled vegetated shorelines is estimated to have occurred over at least 108 miles of shoreline throughout the Gulf. Marsh recovery is expected to take more than 10 years for long-lived species such as periwinkle, while eroded shoreline has been permanently lost. All data collected as part of the Deepwater Horizon NRDA are available online.