CONTINUING TRENDS OF BENTHIC COMMUNITY CHARACTERIZATION IN THE NORTHERN GULF OF MEXICO

Evan Baran, Eckerd College, Marine Science Discipline 

Patrick Schwing, Eckerd College, Marine Science Discipline 

Gregg Brooks, Eckerd College, Marine Science Discipline 

Rebekka Larson, Eckerd College, Marine Science Discipline  

From April to July of 2010, the Deepwater Horizon (DWH) event released over 4.0 million barrels of oil into the Gulf of Mexico. As much as 14% was deposited on the seafloor in the form of flocculent material through a process called marine oil snow sedimentation and flocculent accumulation (MOSSFA). While much of the oil has been degraded through natural processes, impacts of the oil spill can still be seen today in benthic (seafloor) macrofauna and microfauna such as foraminifera. Benthic Foraminifera are single-celled protists widely used as bioindicators of system health due to their high diversity and number of species. Prior to DWH in the Northern Gulf of Mexico (NGOM), there was a lack of baseline conditions, resulting in inaccuracies in estimating environmental impact and response. Since 2010, Sediment cores from seven time series sites have been collected annually in the NGOM in order to assess benthic community health and determine the rates of benthic foraminiferal recovery. Data from the sediment cores has been implemented into an ongoing time series to more accurately assess ecological health. This presentation will report ecological indices of species richness (Fisher's Alpha, S), heterogeneity (Shannon, H) and density as primary indicators of benthic foraminiferal community health from eight subsamples of each core top (<5 cm), continuing the time series through 2022. Measures of benthic health are essential for establishing current baselines, natural variability and providing a template for determining ecological impact and recovery from both future and ongoing ecological impacts.

For more information: embaran@eckerd.edu