THE USE OF BACTERIAL COMMUNITY COMPOSITION AS AN INDICATOR OF WATER QUALITY

Acid mine drainage (AMD) is a result of extensive mining from coal, metal, and textile industries. Currently, there are 5500 miles of streams impacted by AMD in Pennsylvania alone. Once the geochemical process of AMD starts it can’t be stopped, only treated. Thus, cost-effective options are being explored to treat AMD. Passive remediation systems are an affordable option for treating AMD and consist of a series of ponds, aeration methods, wetlands, and when needed, limestone to remediate the water. The success of the system relies on geochemical and biological processes. Overall these systems have shown long term success, however, the efficiency in these systems can vary and often decline over time requiring maintenance and/or repair. Routine water quality analysis can be used as a system check but can become costly overtime. Bioindicators are an alternative way to check system efficiency. Bacteria are one of the few groups of living organisms that can survive in AMD and are capable of rapidly adapting to their environment, making them ideal candidates for bioindicators. The current research focuses on three passive remediation systems in Southwestern Pennsylvania: a high functioning system (Middle Branch), one with seasonal variation (Lowber), and an overloaded system which fails to successfully remediate the water (Boyce). Through 16S sequencing analysis, spatiotemporal changes in bacterial community composition were identified revealing that the high functioning system had a stable community composition, while the systems that showed variability in system efficiency had a less predictable composition. Genus identification showed groups of bacteria that were resistant to high levels of contamination and other groups that were sensitive. One potential “sensitive” bioindicator found at the end of all three systems, but never at the beginning, was Luteolibacter spp.. Primers specific to Leutilibacter spp. confirmed the sequencing data, detecting Luteolibacter spp. only in the end of all three systems. Future work can use Leutilibacter specific primers to quickly and affordably screen system efficiency. Finding cost effective ways to screen water quality and overall passive remediation system efficiency is essential for the early detection of changes in water quality.