title: Assessing impacts of unconventional natural gas extraction on microbial communities in headwater stream ecosystems in Northwestern Pennsylvania.
abstract: Hydraulic fracturing and horizontal drilling have increased dramatically in Pennsylvania Marcellus shale formations, however the potential for major environmental impacts are still incompletely understood. High-throughput sequencing of the 16S rRNA gene was performed to characterize the microbial community structure of water, sediment, bryophyte, and biofilm samples from 26 headwater stream sites in northwestern Pennsylvania with different histories of fracking activity within Marcellus shale formations. Further, we describe the relationship between microbial community structure and environmental parameters measured. Approximately 3.2 million 16S rRNA gene sequences were retrieved from a total of 58 samples. Microbial community analyses showed significant reductions in species richness as well as evenness in sites with Marcellus shale activity. Beta diversity analyses revealed distinct microbial community structure between sites with and without Marcellus shale activity. For example, operational taxonomic units (OTUs) within the Acetobacteracea, Methylocystaceae, Acidobacteriaceae, and Phenylobacterium were greater than three log-fold more abundant in MSA+ sites as compared to MSA- sites. Further, several of these OTUs were strongly negatively correlated with pH and positively correlated with the number of wellpads in a watershed. It should be noted that many of the OTUs enriched in MSA+ sites are putative acidophilic and/or methanotrophic populations. This study revealed apparent shifts in the autochthonous microbial communities and highlighted potential members that could be responding to changing stream conditions as a result of nascent industrial activity in these aquatic ecosystems.
authors.affiliation: Juniata College, Department of Biology Huntingdon, PA, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Trexler
authors.affiliation: Juniata College, Department of Biology Huntingdon, PA, USA.
authors.forename: Caroline
authors.initials: C
authors.lastname: Solomon
authors.affiliation: Juniata College, Department of Biology Huntingdon, PA, USA.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Brislawn
authors.affiliation: Juniata College, Department of Biology Huntingdon, PA, USA.
authors.forename: Justin R
authors.initials: JR
authors.lastname: Wright
authors.affiliation: Juniata College, Department of Biology Huntingdon, PA, USA.
authors.forename: Abigail
authors.initials: A
authors.lastname: Rosenberger
authors.affiliation: Juniata College, Department of Biology Huntingdon, PA, USA.
authors.forename: Erin E
authors.initials: EE
authors.lastname: McClure
authors.affiliation: Juniata College, Department of Biology Huntingdon, PA, USA.
authors.forename: Alyssa M
authors.initials: AM
authors.lastname: Grube
authors.affiliation: Juniata College, Department of Biology Huntingdon, PA, USA ; Department of Biology and Huck Institutes of Life Sciences, Pennsylvania State University University Park, PA, USA.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Peterson
authors.affiliation: DNA Sequencing and Genotyping Facility, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Keddache
authors.affiliation: Department of Earth, Ocean, and Atmospheric Science, Florida State University Tallahassee, FL, USA.
authors.forename: Olivia U
authors.initials: OU
authors.lastname: Mason
authors.affiliation: Department of Civil and Environmental Engineering, University of Tennessee Knoxville Knoxville, TN, USA ; Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA.
authors.forename: Terry C
authors.initials: TC
authors.lastname: Hazen
authors.affiliation: Juniata College, Department of Biology Huntingdon, PA, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Grant
authors.affiliation: Juniata College, Department of Biology Huntingdon, PA, USA.
authors.forename: Regina
authors.initials: R
authors.lastname: Lamendella
keywords: 16S rRNA gene sequencing; acidophilic; beta diversity; fracking; marcellus shale; methanotrophs; next generation sequencing