| Microbial diversity and abundance were studied in order to further understand the biological functions taking place in Carbondale, a constructed wetland treating acid coal mine drainage in Ohio, USA. Molecular techniques, based on polymerase chain reaction (PCR), fluorescent in situ hybridization (FISH), denaturing gradient gel electrophoresis (DGGE), restriction fragment length polymorphism (RFLP), and complete 16S rRNA gene sequencing, revealed 18 bacterial species present in this wetland. Two dominant acidophilic iron- and sulfur-oxidizing bacterial species prevailed—Thiobacillus ferrooxidans (44% of total 16S rDNA clone library) and T. thiooxidans (37%). Minor species included eubacteria (TRA2-10, TRA3-20, TRA5-3), heterotrophic bacteria (Stenotrophomas maltophilia, Bordetella spp., Alcaligenes sp., Alcaligenes faecalis , arsenite-oxidizing bacteria BEN-4), and nine novel species.; Sediment samples were collected from two locations (Cells 1 and 4) in the wetland during August and October 1999 in order to identify spatial and temporal variations occurring within the microbial communities. Cell 1 is located at the mouth of the inflowing acid mine drainage while cell 4 is located in the middle of the system. Based upon results of the FISH method, no spatial differences were noted in microbial species between Cells 1 and 2. This is consistent with pH data which are also differed by only 0.2 to 0.5 units. Temporal differences were noted in the microbial community and could be possible due to changes either caused by flood water due to high rain in October, microorganism predation effects, and/or other unidentified reasons.; A descriptive summary of the microbial community in the wetland clearly indicates that the Bacteria and Eukarya domains were the major microorganisms present. Archaea was found at less than 0.01% of the total microbial community. T. ferrooxidans was the most dominant bacterial species in this wetland comprised at least 48% of the total bacterial populations. The heterotrophic Acidiphilium spp. comprised almost one-quarter of the total bacteria. Leptospirillum ferrooxidans was found at less than 0.003% of the total bacterial community. |
