Master of Science, The Ohio State University, 2016, Earth Sciences

While life is known to exist in the subsurface environment, specific limitations to microbial populations inhabiting deep subsurface habitats are assumed and include organic substrate and terminal electron acceptor availability, temperature and space to live. Microbial populations have been found in environments where they are least expected, notably 3 km deep in granite as well as in the boreholes and near-borehole environment of oil and gas wells where they often cause problems for oil and gas operators. While an anthropogenic source is assumed for microbes in and near the borehole of oil and gas wells in the Utica-Point Pleasant system due to the high temperatures the rock has undergone, the question remains whether microbial populations could have survived in less mature rock to the West of contemporary oil and gas operations. As a component of an NSF funded study “Microbial Biodiversity and Functionality of Deep Shale and it's Interfaces” this research attempts to answer whether microbes could have survived to the present day in pores as well as questions relating to biological limitations and whether these are present in the Utica-Point Pleasant. Looking at sulfur, organic carbon and potential micro-lithologies within the Utica-Point Pleasant organic-rich mudstone may yield a better understanding of how the diagenesis of a marine mud affects anaerobic microbial populations established in these muds. Utilizing a variety of petrophysical, geochemical and high resolution imaging techniques this research has identified micro-lithologies within the Utica-Point Pleasant system that likely provided safe harbor for anaerobic microbes until the habitat was either sterilized due to temperature or in-filled with minerals, sealing off these habitats. Further, these micro-lithologies may respond to hydraulic fracturing chemicals and processes and become inhabitable for anthropogenically introduced microbial populations.

Committee: David Cole PhD (Advisor); Matthew Saltzman PhD (Committee Member); Michael Wilkins PhD (Committee Member) Subjects: Chemistry; Earth; Geology; Microbiology