Abstract
The northern Gulf of Mexico was inundated by crude, Macondo oil following the April 2010 disaster. This study investigated the historical benthic diatom assemblages of 6 different sites between 2 bays, Barataria and Terrebonne, Louisiana, to create an otherwise absent baseline dataset. Thirty-five samples and 19,036 diatom valves were counted via oil-immersion microscopy for this project to enumerate changes in the diatom community relative to sediment-oil composition variation. The Terrebonne Bay cores were sampled across a salinity gradient with no residual hopane present, while the Barataria Bay cores were sampled in similar salinity and were heavily oiled. The diatom assemblages did not exhibit significant changes according to oil presence but there were 19 individual species (indicators) which had significant correlations with oil. This study shows that the benthic diatom populations were not significantly impacted by oil while there were some individual indicator species of oil presence.