BACTERIAL COMMUNITIES IN EUKARYOTE-DOMINATED BIOFILMS GROWING IN ACID MINE DRAINAGE, GREEN VALLEY MINE, WESTERN INDIANA

Several species of bacteria have been identified in eukaryote-dominated biofilms growing in acid mine drainage (AMD) at the abandoned Green Valley coal mine site, western Indiana. The dominant eukaryotic biofilm consists mainly of Euglena mutabilis cells with minor amounts (< 20 %) of the acidophilic protozoan Chlamydomonas, diatoms, fungi and bacteria. Biofilms were sampled in January and May 2007, during which AMD pH ranged from 2.7 to 3.5. Bacteria were isolated by streaking biofilm material on plates containing either ferrous sulfate tryptone soy basal salts agar (FeTSB) or nutrient agar (NA) and resulting colonies were sub-cultured. Cultures were grown aerobically at 10 or 20̊C depending on AMD temperature at time of sample collection. Types of isolated bacteria differed depending on date of field sampling and type of media. A wide range of species were isolated including the S oxidizer Acidothiobacillus. Identification of additional bacterial species will be presented. Future experiments will investigate synergistic interactions between bacteria and the dominant biofilm former E. mutabilis and their effects on AMD chemistry and biomineralization.