Intellectual merit: This proposal describes a series of laboratory studies designed to assess the genomic and molecular patterns of petroleum biodegradation under a range of conditions relevant to the Earth?s surface and subsurface. The concerted application of comprehensive, two-dimensional gas chromatography, Fourier transform ion cyclotron resonance mass spectrometry, and pyrosequencing-based metagenomics will provide unparalleled insight into petroleum biodegradation and the responsible microbes, and distinguishes this work from any previous studies. The primary hypotheses to be tested are the following: 1) Hydrocarbon biodegradation by microbes acts simultaneously on thousands of distinct compounds, not in a strictly stepwise fashion. 2) Hydrocarbon preference pattern and associated genomic potential for a microbial community are controlled primarily by the redox potential of the terminal electron-accepting process. 3) High-molecular-weight and polar compounds are bio-transformed through incomplete oxidation and structural alteration, not through complete remineralization. These hypotheses will be tested by conducting time-series laboratory experiments in which petroleum is biodegraded with different electron acceptors and at different temperatures. The loss and gain patterns for molecules within each treatment and differences across treatments in these patterns and in genomic content will provide the data to test these hypotheses. Results are further anticipated to reveal novel metabolic actions and genomic capacity, and yield molecular degradation patterns that can relate environmental genomic and petroleum content to the relevant biological processes. New data analysis tools will also be developed and validated.
Broader Impact: Results from this research will contribute broadly to an understanding of petroleum biodegradation and carbon cycling in the Earth system, and will be broadly disseminated through popular outlets with assistance from a professional artist. Knowledge gained from this research will also be translated directly to federal agencies including the NOAA?s Assessment and Restoration Division, as well as to private industry through existing corporate ties. Direct educational impacts of this research include the training and education of high school, undergraduate, and graduate students, as well as the advanced training of postdoctoral researchers. High school students will be incorporated through existing summer research programs targeting students from underserved regions. Undergraduate students will be incorporated into all aspects of the proposed research through integration into coursework and REU support. Mentoring of a graduate student and postdoctoral researchers will be provided by the PIs.
" focused on the consumption of hydrocarbons by microbes in natural settings, including the ocean and in the deposits that make up the sea floor. Through this study we have been able to identify important pathways by which hydrocarbons are broken apart by microbes, as well as provide insight as to the products that derive from such activity. Our results provide a timescale by which select chemicals are biodegraded in nature, and further identify a host of compounds that are not biodegraded over these same timescales. Furthermore, these results indicate that the breakdown of hydrocarbons is not a complete process, but that many chemicals are retained in a modified state that eludes detection by standard methods. Our results further point toward new analytical approaches holding the potential to unlock hydrocarbon metabolism in deep subsurface environments. Results from this project further provide a context for the fate of hydrocarbons following the largest ever accidental discharge of oil to the ocean – the Deepwater Horizon spill in the Gulf of Mexico. The application of our approach to this incident provided for a holistic perspective as to the coupling of chemistry, microbiology and ocean currents, and how this coupling impacted the distribution of hydrocarbons released during this event. Lastly, this project enabled a host of broader impacts that include training of students and postdoctoral scholars, but that also include informed engagement in the national discussion surrounding the Deepwater Horizon event and petroleum pollution in general. For example, project personnel were directly involved in assisting federal agencies in the response to the Deepwater Horizon event, and further provided their expertise in an unbiased fashion to numerous major media outlets.
