Oiling effects on oxygen and hydrogen sulfide depth profiles and sulfate-reducing bacterial communities in coastal marine sediments

Some sulfate-reducing bacteria (SRB) can degrade aromatic hydrocarbons and play a significant role in the remediation of coastal oil spills. For a better understanding of the diversity of SRB populations and their response to hydrocarbon contamination, a sediment microcosm experiment was conducted using microelectrodes and high-throughput 16S rRNA and dissimilatory (bi)sulfite reductase (dsrB) gene amplicon sequencing. Exposure to the water accommodated fraction (WAF) of crude oil created a reduced environment reflected in both bacterial community structure and oxygen profiles. The diversity of 16S rRNA and dsrB phylotypes was diminished in most WAF-exposed sediment samples. Rapid community shifts were observed to SRB taxa previously reported with hydrocarbon contamination. We concluded that SRB communities can rapidly respond to WAF exposure and expand upon the known diversity of SRB in coastal marine ecosystems impacted by hydrocarbons.