SALT MARSH SEDIMENT BIOGEOCHEMICAL RESPONSE TO DEEP WATER HORIZON OIL SPILL (OCEAN SPRINGS, MS)

By developing an understanding of how carbon loading from the Deep Water Horizon BP Oil Spill is affecting the microbial and biological communities of salt marshes, we can better predict the large scale impact of the spill on other biological communities. Sediment biogeochemical processes that degrade the enriched carbon pools through sulfate reduction are primarily responsible for the biological breakdown of the spilled hydrocarbons. Therefore, the determination of sulfide concentration at contaminated verses non-contaminated sites allows for an assessment of the oil spill impact on salt marsh at Marsh Point in Ocean Springs, MS. As a result of carbon loading, porewater sulfide (H₂S) concentrations will likely increase in the largely anoxic wetland sediment, making the sediment more toxic and inhospitable to marsh vegetation. Preliminary analysis of collected Marsh Point study area sediment cores indicates that sulfate reducing bacteria are significantly more active at the contaminated site producing sulfide concentrations 20x higher than non-contaminated sediments. Thus, salt marsh die back and growth reduction is more likely in oil contaminated sediments, which can affect the underground growth directly at the rhizosphere (or root zone) and induce above ground browning and dieback. The preliminary results provided allow for insights about how salt marshes affected by the oil spill might react to the carbon loading induced by hydrocarbon contamination.