N-146. Microbial Communities of a Low Order, Acid Mine Impacted Stream

S. Ghosh, M. Moitra, D. Antibus, C. Woolverton, L. Leff;
Kent State Univ., Kent, OH.

Acid mine drainage (AMD) is a significant environmental hazard that affects aquatic ecosystems around the world. AMD has negative potential impacts on aquatic systems through acidification, elevation of concentrations of iron and sulfate, and increased levels of soluble toxic metals. Extreme heavy metal and acid concentrations are toxic to much of the macrofauna and yet AMD impacted environments provide a suitable environment for acidophilic microorganisms. In nature, acidophilic microorganisms are likely to co-exist in mixed species communities with ample opportunities for mutualistic relationships. In this study, water and sediment samples were collected on several dates from three locations along an acid mine impacted stream (a low order tributary of Huff Run, near Mineral City, OH, USA). Microbial communities were characterized using culture-based and culture-independent methods. The pH of these sites ranged from 3.0 to 5.5, turbidity ranged between 0.42 to 0.50 NTU, and organic matter content of the benthos was estimated to be 10.05%. Attempts to enrich the natural flora from sediment samples resulted in an increase in the pH of a rich carbon source medium, however, addition of ferrous sulfate kept the pH in the acidic range. There was limited diversity in the cultured community and the colony forming units were 3.5 x 103 mL-1. Microscopic examination of the enriched samples predominantly revealed the presence of Gram-negative short rods and cocci. A few fungal species were also isolated from the samples. Overall, based on the findings, there were differences in the communities in the water and sediment, and variations among sites, perhaps related to differences in pH and other environmental conditions. In the coming year, remediation efforts will commence at the study site, and we will examine the changes in the microbial community in comparison to the baseline data reported here.