Microbial and Isotopic Evidence for Methane Cycling in Hydro carbon-Containing Groundwater from the Pennsylvania Region

TitleMicrobial and Isotopic Evidence for Methane Cycling in Hydro carbon-Containing Groundwater from the Pennsylvania Region
Publication TypeJournal Article
Year of Publication2017
AuthorsVigneron A., Bishop A., Alsop E.B, Hull K., Rhodes I., Hendricks R., Head IM, Tsesmetzis N.
JournalFrontiers in Microbiology
Volume8
Date PublishedApr
ISBN Number1664-302X
Accession NumberWOS:000398440800001
KeywordsOil and Gas Degradation
AbstractThe Pennsylvania region hosts numerous oil and gas reservoirs and the presence of hydrocarbons in groundwater has been locally observed. However, these methane-containing freshwater ecosystems remain poorly explored despite their potential importance in the carbon cycle. Methane isotope analysis and analysis of low molecular weight hydrocarbon gases from 18 wate r wells indicated that active methane cycling may be occurring in methane-containing groundwater from the Pennsylvania region. Consistent with this observation, multigenic qPCR and gene sequencing (16S rRNA genes, mcrA, and pmoA genes) indicated abundant populations of methanogens, ANME-2d ( ave ra ge of 1.54 x 10(4) mcrA gene per milliliter of water) and bacteria associated with methane oxidation (NC10, aerobic methanotrophs, methylotrophs; average of 2.52 x 10(3) pmoA gene per milliliter of water). Methane cycling therefore likely represents an important process in these hydrocarbon-containing aquifers. The microbial taxa and functional genes identified and geochemical data suggested that (i) methane present is at least in part due to me thanogens identified in situ; (ii) Potential for aerobic and anaerobic methane oxidation is important in groundwater with the presence of lineages associated with both anaerobic an aerobic methanotrophy; (iii) the dominant methane oxidation process (aerobic or anaerobic) can vary according to prevailing conditions (oxic or anoxic) in the aquifers; (iv) the methane cycle is closely associated with the nitrogen cycle in groundwater methane seeps with methane and/or methanol oxidation coupled to denitrification or nitrate and nitrite reduction.
DOI10.3389/fmicb.2017.00593