Research Product

A study was conducted in October 2005 to assess effects on benthic fauna and habitat quality in coastal waters of Louisiana, Mississippi, and Alabama following Hurricane Katrina, which struck the coast of Louisiana, between New Orleans and Biloxi, Mississippi on August 29, 2005. Samples for analysis of macroinfauna, chemical contamination of sediments, and other abiotic and biotic habitat characteristics were collected at 30 sites in Lake Pontchartrain, Louisiana and 30 sites in Mississippi Sound from Dauphin Island, Alabama to the western side of Lake Borgne, Louisiana. Pre-hurricane reference conditions from the same areas, based on similar indicators and protocols, were available for comparison from EPA’s National Coastal Assessment (NCA) program. There were notable differences in benthic communities between pre- and post-hurricane periods (e.g., reductions in number of taxa, H’ diversity, and total faunal abundance; and shifts in the composition and ranking of dominant taxa) in both coastal systems. Such effects could not be linked to chemical contamination, organic enrichment of sediments, or hypoxia. Storm-related changes in salinity were a more likely cause of the observed benthic changes in both survey areas. Storm-induced scouring of sediments could have contributed to these effects as well.