Abstract

The Deep Water Horizon (DWH) oil spill occurred in the Northern Gulf of Mexico (NGoM) in 2010. Over 700 million liters of oil spilled into the NGoM over 87 days. Samples were taken from sites annually to semi-annually from 2010-2023 to provide a spatiotemporal benthic assessment for the NGoM. Reference conditions provide an ecological snapshot of the marine environment and allow for a quantitative assessment of the impact and response for future oil spills. Benthic foraminifera, are single-celled, testate organisms. They are excellent indicators and records of ecological change. Due to the stable carbon isotopes in benthic foraminifera, tests have proven effective indicators of petroleum carbon incorporation into the benthic system. Seafloor sediment cores were collected in 2023, at specific time series sites in the NGoM, as a part of the Scientist-At-Sea program. Cores were subsampled at 2 mm increments. Calcareous foraminifera species, Cibicidoides pachyderma and C. wuellerstorfi, were isolated for stable isotope (oxygen and carbon) analysis using a SIRMS. Stable isotopes from two of the time-series sites have been measured continually from 2010 to 2017. This study provides a comparison of the latest benthic foraminifera stable carbon isotope profiles with previous collections to determine long-term recovery of the system, gain insight into natural variability, and establish long-term preservation of the DWH signal in fossil (downcore) benthic foraminifera tests. These records will continue to aid in the understanding of natural seafloor carbon cycling, and also in the event of future pollution events such as oil spills. 

 For more information: jschell@eckerd.edu