Disturbance and recovery of salt marsh arthropod communities in Louisiana and Mississippi following the 2010 BP Deepwater Horizon oil spill in the Gulf of Mexico

Oil spills represent a major environmental threat to coastal wetlands, which provide a variety of critical ecosystem services to humanity. The U.S. Gulf of Mexico is a hub of oil and gas exploration and production with recognized consequences on intertidal habitats, such as the salt marsh. Following the BP Deepwater Horizon oil spill, we sampled the marine invertebrate and the terrestrial arthropod community found in stands of Spartina alterniflora, the most abundant plant in coastal salt marshes, in 2010 as oil was washing ashore and a year later in 2011. In 2010, intertidal crabs and terrestrial arthropods (insects and spiders) were suppressed by oil exposure even in seemingly unaffected stands of plants; however, Littoraria snails appeared unaffected. One year later, crab and arthropods appeared to have largely recovered. Our work is the first attempt that we know of assessing vulnerability of the salt marsh arthropod community to oil exposure, and it suggests that arthropods are both quite vulnerable to oil exposure, and quite resilient, able to recover from exposure within a year if host plants remain healthy. BP's Deepwater Horizon spill in the Gulf Coast presented an opportunity to understand how stress from an oil spill might affect variables that we were measuring in the area. The study was conducted at sites in Louisiana and Mississippi. At each site, a 100m transect was sampled within 5m of the dead zone boundary. Sampling was conducted in August 2010 and August 2011. The number of sites and location of sites differed slightly among years.