Assessing the Impacts of Hydraulic Fracturing on Stream Health using Biofilm Diversity

Abstract:

Hydraulic fracturing is a method of gas and oil extraction that involves injecting high pressure liquids into bedrock, which causes a fracture and allows oil and gas to flow. Within the U.S. during 2015, there were 1.5 million active wells that produced 14 billion gallons of wastewater. Mismanagement of wastewater at fracking wells can lead to ground and surface water pollution that has the potential to impact ecosystems, including freshwater streams. Research on the effects of wastewater and other byproducts of hydraulic fracturing on streams is limited. Stream biofilms are layers of microorganisms, such as bacteria and algae, that adhere to benthic surfaces. Biofilms are the base of the stream food web; they fix gases, recycle organic matter, and serve as a food source for other stream life, including invertebrates and fish. Therefore, stress in these communities will impact the entire ecosystem. This study aims to explore the effects of hydraulic fracturing on streams by examining the biodiversity of bacteria and algae in biofilms close to hydraulic fracturing sites. We collected biofilm samples from 26 streams within WV with varying levels of hydraulic fracturing within the watershed. High levels of hydraulic fracturing development were associated with reductions in bacterial alpha diversity and changes in the community composition of biofilms. Additionally, impacted sites showed more variable alpha diversity indicative of community destabilization. Using indicator species analysis, we were able to identify bacterial families indicative of hydraulic fracturing development including Azospirillaceae, Hymenobacteraceae, and Rhodobacteraceae. Analysis of eukaryotic algea within these biofilms is in progress, and we hypothesize these communities to be similarly altered in streams close to hydraulic fracturing sites. Our results suggest hydraulic fracturing within a watershed affects stream biofilm microbial communities, and therefore, broader ecosystem function.