title: Microbial communities in flowback water impoundments from hydraulic fracturing for recovery of shale gas.
abstract: Hydraulic fracturing for natural gas extraction from shale produces waste brine known as flowback that is impounded at the surface prior to reuse and/or disposal. During impoundment, microbial activity can alter the fate of metals including radionuclides, give rise to odorous compounds, and result in biocorrosion that complicates water and waste management and increases production costs. Here, we describe the microbial ecology at multiple depths of three flowback impoundments from the Marcellus shale that were managed differently. 16S rRNA gene clone libraries revealed that bacterial communities in the untreated and biocide-amended impoundments were depth dependent, diverse, and most similar to species within the taxa γ-proteobacteria, α-proteobacteria, δ-proteobacteria, Clostridia, Synergistetes, Thermotogae, Spirochetes, and Bacteroidetes. The bacterial community in the pretreated and aerated impoundment was uniform with depth, less diverse, and most similar to known iodide-oxidizing bacteria in the α-proteobacteria. Archaea were identified only in the untreated and biocide-amended impoundments and were affiliated to the Methanomicrobia class. This is the first study of microbial communities in flowback water impoundments from hydraulic fracturing. The findings expand our knowledge of microbial diversity of an emergent and unexplored environment and may guide the management of flowback impoundments.
authors.affiliation: National Energy Technology Laboratory, Pittsburgh, PA, USA; Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
authors.forename: Arvind
authors.initials: A
authors.lastname: Murali Mohan
authors.forename: Angela
authors.initials: A
authors.lastname: Hartsock
authors.forename: Richard W
authors.initials: RW
authors.lastname: Hammack
authors.forename: Radisav D
authors.initials: RD
authors.lastname: Vidic
authors.forename: Kelvin B
authors.initials: KB
authors.lastname: Gregory
mesh_terms: D001105:Archaea / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D019641:DNA, Archaeal / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D019652:Extraction and Processing Industry; D019015:Geologic Sediments / Q000382:microbiology; D059206:Natural Gas; D009518:New York; D010578:Petroleum; D020560:Proteobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D062065:Wastewater / Q000382:microbiology; D014871:Water Microbiology
chemical_list: D019641:DNA, Archaeal; D004269:DNA, Bacterial; D059206:Natural Gas; D010578:Petroleum; D012336:RNA, Ribosomal, 16S; D062065:Wastewater
keywords: flowback water; hydraulic fracturing; impoundments; petroleum microbiology