Shallow infaunal responses to the Deepwater Horizon event: Implications for studying future oil spills

Infaunal sedimentary communities underpin marine ecosystems worldwide. Understanding how disturbances such as oil spills influence infauna is therefore important, especially given that can be trapped in sediments for years or even decades. The 2010 Deepwater Horizon (DWH) event was the largest spill United States history, impacting habitats throughout Northern Gulf of Mexico. We investigated infaunal community structure at two shallow sites Chandeleur Islands, LA, States, over a 2-year period from 2015 to 2016 (5–6 post-spill). One site moderately contaminated with DWH spill, while other only lightly contaminated. Both featured patchy Ruppia seagrass meadows, allowing us compare between versus unvegetated sediment. moderately-oiled significantly different than oiled site; these differences were driven by altered abundance key taxa, some taxa being less abundant but others more abundant. During our second year sampling, crude slick moved transiently through site, directly observe responses an acute re-oiling event. Virtually every taxonomic and community-level metric declined during re-oiling, effects pronounced beds sole exception snail, Neritina usnea , which we found exclusively more-oiled site. Our observations suggest are entire guilds responding together. By identifying families genera showed signal this pair sites, begin laying groundwork understanding benthic most likely impacted spills, both immediate aftermath longer-term contamination. While studies will certainly needed, contribution step towards developing clear priori hypotheses inform future oil-spill work. Such would help focus sampling efforts, resources directed those responding, potential bio-indicators exposure.