PRELIMINARY ASSESSMENT OF THE MICROBIOLOGY OF MARCELLUS SHALE FRACTURE AND FLOWBACK WATERS

Natural gas extraction from the Marcellus Shale is poised to rapidly expand across the state of Pennsylvania. Thousands of wells are either in production or are planned for drilling. A typical well requires millions of gallons of water for the fracturing process, with varying amounts of flowback water coming back off the formation. Currently, much of the flowback water is stored in surface impoundments where it is treated and eventually re-injected. The rapid pace of the development of the Marcellus Shale necessitates equally rapid and thorough assessment of the environmental impacts of the drilling process. Our research aims to provide fundamental knowledge of the microbiology of these waters while also monitoring remediation efforts. Water samples were collected at various stages, from fracture water, flowback water, and short-term and long-term impoundments. The presence and number of microbes was determined using fluorescent DNA staining and microscopy. The microbial community was assessed using Fluorescent in situ Hybridization (FISH) with a suite of group-specific probes. Molecular microbial ecology techniques are planned to obtain a more detailed assessment of the microbial community. Targeted enrichments were done to isolate microbes potentially mediating important biogeochemical reactions in the impoundment waters. Lab-controlled experiments using these microbial enrichments can assess the impact of proposed biocides on the microbial community under various field-relevant conditions. Preliminary results suggest major differences in microbial communities among flowback waters from distinct wells with unique impoundment and treatment histories.