Semester

Summer

Date of Graduation

2019

Document Type

Dissertation

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Geology and Geography

Committee Chair

Shikha Sharma

Committee Co-Chair

Timothy Carr

Committee Member

Timothy Carr

Committee Member

Paula Mouser

Committee Member

Jaime Toro

Committee Member

Amy Weislogel

Abstract

The deep subsurface environment has been known to host microbes as early as 1926 and has also been suggested to potentially account for as much as 50% of the Earth`s biomass. Researchers have shown that microbes alter their membrane lipid components in response to physiological stress, producing stress indicative lipid biomarkers. However, little effort has been made to understand the subsurface microbial community of the shale ecosystem which is increasingly being exploited and altered by addition of drilling and hydraulic fluids to meet our growing energy needs. Phospholipid fatty acids (PLFAs) are microbial lipid biomarkers and are found in all cellular membranes. Their presence in sediments has been used to provide evidence of living microbes while diglyceride fatty acids (DGFAs) are microbial lipid biomarkers which serve as indicators of non-viable microbes. PLFAs and DGFAs are some of the most important proxies used to determine the physiological state of microbes in natural environmental systems. Currently, techniques for the evaluation of subsurface microbial community have mostly been focused on shallow subsurface environments and aquifer settings. This stems from the lack of appropriate techniques that can monitor the deep subsurface ecosystem. Developing such techniques require pristine subsurface rock samples, appropriate instruments and an understanding of the geology and biogeochemistry of the subsurface.

The goal of this dissertation is to develop understanding of microbial life in subsurface (>7000 ft.) Marcellus Shale Formation in the Appalachian Basin. The study focuses on the extraction and analyses of PLFAs and DGFAs to investigate the viable and non-viable microbial communities in these deep geologic formations. Samples used for this research were acquired from cores owned by the Marcellus Shale Energy and Environment Laboratory (MSEEL), the Department of Geology and Geography at West Virginia University (WVU), and the West Virginia Geological and Economic Survey (WVGES). A good understanding of microbial community of deep surface black shales like the Marcellus Shale, affords enormous opportunities for improving biocides in the shale energy industry, understanding subsurface microbial colonization, and engineering efforts for enhanced gas recovery.

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