Composition and Functional Diversity of Subsurface Microbial Communities at an Acid Mine Drainage Site

Acid mine drainage (AMD) is "the most important and widespread industry related pollution problem." (California Mining Water Study, 1988). The northern Appalachian Plateau in the eastern United States has widespread damage with 8,000 km of streams polluted by AMD. Biological passive treatment using acidophilic bacteria is a promising alternative to the traditional treatment systems. Toward this end, many studies have examined surface microbial communities at AMD sites. However, few have examined the role subsurface communities play in biogeochemical cycling at these sites. In order to develop efficient biological treatment systems it is necessary to understand the role of both surface and subsurface microbial communities. Brubaker Run is a highly acidic, metal laden stream located near Ashville, PA. The majority of water at this site follows subsurface paths. Therefore, the evolution of water chemistry downstream is affected by both surface and subsurface microbial communities. Understanding the roles microbes are playing in the subsurface, and how it differs from surface communities is extremely important in understanding the system as a whole. We investigated the microbial community composition, functional diversity, and metabolic potential of surface and subsurface microbial communities using 16S clone libraries and GeoChip gene assays. A total of five samples have been investigated using 16S clone libraries. Forty-two samples were investigated with Geochip gene assays. Preliminary results suggests that surface microbial communities are distinct when compared to subsurface communities. This suggests they may differ in their metabolic potential and, therefore, in their influence on AMD water chemistry.