EAPSI: Assessing Microbial Activity in the Shale and Implications for Natural Gas Extraction

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Extracting natural gas from shales by hydrofracturing has increased globally in recent years. Hydrofracturing is a modified version of oil well drilling that is designed for extraction gases rather than fluids from a subsurface reservoir. Hydrofracturing produces millions of liters of contaminated waste fluid that is difficult to dispose of in an economical and environmentally-friendly manner. Treatment of these fluids is a great public health concern. The origin of contaminants in waste fluids is not well understood nor is the role of microorganisms that can remain biologically active in the fluids and shales. This research will investigate the degree to which microbial cells present on shales are active and the types of carbon sources that they utilize including whether these sources can come from the shale itself. The research will be conducted in collaboration with Drs. Fumio Inagaki and Yuki Morono, experts on subsurface microbial communities, at the Japan Agency for Marine-Earth Science and Technology which will provide access to a premier biogeochemistry laboratory. This research will develop a better understanding of biogeochemical processes occurring during shale hydrofracturing and should lead to improved waste fluid treatment and hydrofracturing methods to reduce environmental contamination. The breakdown of organic compounds in the subsurface by microbiological activity can result in the co-release of toxic elements such as heavy metals. This research will determine what organic compounds associated with drilling fluids and Marcellus shale are biologically available. Nano secondary ion mass spectrometry (NanoSIMS) will be used to trace the assimilation of stable isotope-labeled organic compounds into microbial cells derived from waste fluids as well as whether cells attached to shale can utilize native organic compounds in the shale. NanoSIMS analysis determines the percentage of cells that assimilate a certain stable isotope-labeled or shale-derived carbon source. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science.