Petroleum-Degrading Bacteria Community Response to Limiting Nutrients in Marine Sediment and Desert Soil

Though humans have over a century of experience with catastrophic marine and terrestrial oil spills, response plans and cleanup techniques are still active areas of research and development. This work evaluated the oil degradation potential and changes in the microbial community following nutrient additions in polluted marine sediment and desert soil. Biostimulation experiments on Alaskan beach sediment still contaminated by the Exxon Valdez tanker oil spill demonstrated that ambient air and hydrogen peroxide both serve as suitable sources of oxygen to stimulate aerobic microbial degradation of the oil. The addition of oxygen to the oil-contaminated sediment stimulated the growth of Proteobacteria, which made up 77-92% of the population in the presence of ambient oxygen and 76-88% with hydrogen peroxide. These experiments also revealed that sediment samples collected from a non-contaminated portion of the beach also contained a large fraction of microbial species that are known oil degraders. A phytoremediation experiment using mesquite trees in motor-oil-contaminated desert soil indicated that the use of compost as a soil amendment enhanced oil degradation, while biochar hindered degradation activity