1. Shale gas development has limited effects on stream biology and geochemistry in a gradient-based, multiparameter study in Pennsylvania
- Author
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Jason Ditty, Josh Lookenbill, Adam C. Mumford, Luke Ulsamer, Kelly O. Maloney, Isabelle M. Cozzarelli, Sarah Nettemann, Arianne Proctor, and Denise M. Akob
- Subjects
Watershed ,macroinvertebrates ,STREAMS ,Biology ,hydraulic fracturing ,water quality ,Rivers ,Animals ,Ecosystem ,Oil and Gas Fields ,Hydrology ,Multidisciplinary ,Bacteria ,Chemistry ,microbiology ,Biota ,Biological Sciences ,Pennsylvania ,Invertebrates ,Current (stream) ,Benthic zone ,Physical Sciences ,Marcellus Shale ,Water quality ,Oil shale ,Environmental Sciences ,Environmental Monitoring - Abstract
Significance This investigation provides a comprehensive evaluation of the geochemical and biological effects of shale gas development on 25 small watersheds over the course of 2 y. Sampling headwater streams seasonally over two consecutive years yielded no statistically significant relationships between the intensity, presence, or absence of shale gas development and any signal in a comprehensive set of chemical constituents (including those recognized as oil and gas geochemical tracers) or any changes in microbial or benthic macroinvertebrate community composition. This work provides a framework for investigations of anthropogenic effects stemming from natural resource development, and highlights the importance of conducting studies which control for regional and temporal variability., The number of horizontally drilled shale oil and gas wells in the United States has increased from nearly 28,000 in 2007 to nearly 127,000 in 2017, and research has suggested the potential for the development of shale resources to affect nearby stream ecosystems. However, the ability to generalize current studies is limited by the small geographic scope as well as limited breadth and integration of measured chemical and biological indicators parameters. This study tested the hypothesis that a quantifiable, significant relationship exists between the density of oil and gas (OG) development, increasing stream water concentrations of known geochemical tracers of OG extraction, and the composition of benthic macroinvertebrate and microbial communities. Twenty-five headwater streams that drain lands across a gradient of shale gas development intensity were sampled. Our strategy included comprehensive measurements across multiple seasons of sampling to account for temporal variability of geochemical parameters, including known shale OG geochemical tracers, and microbial and benthic macroinvertebrate communities. No significant relationships were found between the intensity of OG development, shale OG geochemical tracers, or benthic macroinvertebrate or microbial community composition, whereas significant seasonal differences in stream chemistry were observed. These results highlight the importance of considering spatial and temporal variability in stream chemistry and biota and not only the presence of anthropogenic activities in a watershed. This comprehensive, integrated study of geochemical and biological variability of headwater streams in watersheds undergoing OG development provides a robust framework for examining the effects of energy development at a regional scale. more...
- Published
- 2020