Date of Graduation


Document Type


Degree Name

Master of Science in Biology (MS)

Degree Level



Biological Sciences


Michael E. Douglas

Committee Member

Jeffrey A. Lewis

Second Committee Member

Marlis R. Douglas

Third Committee Member

Franck Carbonero


Biological sciences, Earth sciences, Biofilm, Bioinformatics, Bioremediators, Fracking, Microorganism, Streams


In the past decade, 29 shale basins have been actively developed across 20 states for extraction of natural gas (NG) via horizontal drilling/hydraulic fracturing (=fracking). This includes ~5000 wells within the Fayetteville shale of north-central Arkansas. Development often impacts both river- and landscapes, and management requires catchment-level evaluations over time, with organismal presence/absence as indicators. For this study next-generation sequencing was used to identify/characterize microbial communities within biofilm of eight Arkansas River tributaries, so as to gauge potential catchment influences. Streams spanned a gradient of landscape features and hydrological flows, with four serving as ‘potentially impacted catchment zones’ (PICZ) and four as ‘minimally impacted catchment zones’ (MICZ). Overall, 46 bacterial phyla and 141 classes were identified, with 24 phyla (52%) and 54 classes (38%) extending across samples. A principal coordinate analysis arrayed samples according to stream order, suggesting a relationship between communities and gradients. With regard to river- and landscape disturbance, three preliminary indicators emerged: (1) Synechococcophycideae and Oscillatoriophycideae (=Cyanobacteria that act as primary producers exhibiting a positive correlation with increased nitrogen and phosphorus) were significantly more abundant at PICZ sites (P