The explosion of the Deepwater Horizon drilling rig in the Gulf of Mexico was unprecedented with millions barrels of crude oil release into the Gulf regions, and its environmental impact will take years to unveil. Application of large quantities of chemical dispersants makes its environmental impact even more complicated. In the Gulf of Mexico, coastal saltwater wetlands and tidal freshwater wetlands are sensitive to oil, both immediately and in the long term, because these wetlands have been vulnerable already duo to natural and anthropogenic stress. This project is to explore the mechanisms of nitrate-aided biodegradation of petroleum hydrocarbon. Unlike any previous studies, it is hypothesized that gaseous products (NO and N2O) of denitrification may play a critical role in hydrocarbon degradation, which has been entirely ignored.
There are two objectives to be obtained (two hypotheses to be tested) for this one-year study:
- Exploring the potential degradation of benzene, as a representative petroleum hydrocarbon, by the gas products (NO and N2O) of denitrification;
- Exploring the potential oxidation of Fe(II) to Fe(III), by the gas products (NO and N2O) of denitrification.
Little information is available on the oxidation potential of NO and N2O, and their effect on the degradation of petroleum hydrocarbon. The proposed approaches will provide the best opportunity to test such hypotheses according to the known knowledge. However, this high risk study can be of high reward if the hypotheses are proved to be true. It will provide an important insight on the redox biogeochemistry under anaerobic conditions, which plays a critical role in nutrient cycling and organic matter mineralization, including petroleum hydrocarbons, in various ecosystems.