Macroinfauna abundance and diversity after Deepwater Horizon Oil Spill, 2011-10-20 to 2018-10-30

Macroinfauna species data from oil-impacted and reference salt marshes in Barataria Bay, Louisiana. Samples were collected from 2011-2018 from 21 sites located over an area 8 km × 5 km, between coordinates N 29.44060°and 29.47459°, W 89.88492° and 89.94647°. Long-term sites consisted of replicated (n = 7) salt marsh shorelines designated as “reference” (RF, no visible oiling), “moderately oiled” (MD), or “heavily oiled” (HV). A hand-held corer was used to take two sediment cores to a depth of 2 cm from each plot. Both cores were combined into a single sample cup and fixed in 4% formalin in the field. Cups were shaken to break up soil clumps and to mix with formalin. In the laboratory, samples were sieved through a 500 µm sieve stacked on top of a 63 µm sieve. All material, including roots, rhizomes and macrofauna, retained on both sieves was preserved for analysis of macroinfauna.