Residual hydrocarbons during the degradation of light Louisiana sweet crude oil by deep-sea sediment bacterial communities

The Deepwater Horizon blowout resulted in the deposition of substantial amount of oil in the seafloor. The hydrocarbon concentration near the wellhead was very high immediately after the spill, but returned to the background level a few years after the spill. The microbial communities in the deep-sea are thought to be responsible for the intrinsic degradation of hydrocarbons. To investigate the oil degradation potential and examine the bacterial communities during oil degradation, we collected deep-sea sediment close to the DWH site. We amended the sediments with oil and both oil and Corexit dispersant and incubated for 6 months at 5ºC. Residual hydrocarbons and DNA were periodically extracted and analyzed. The data showed the concentrations of residual alkanes (C11-C35) and residual PAHs(16 priority PAHs) at the beginning of the experiment, 0.5, 1, 2, 4, and 6 months of incubation. All values are normalized based on C30- hopane as a conservative biomarker.