Changes in microbial communities of a passive coal mine drainage bioremediation system

Drainage from abandoned mines is one factor greatly affecting the streams and vegetation in and around Pittsburgh and the Appalachian Mountains where coal mining occurred. This drainage may be more acidic, alkaline, or metal based. Different methods for remediation exist. Passive remediation is one method used to naturally allow the metals to precipitate out and aid in cleaning up the water. The goal of this study is to sample different holding ponds in a sequential passive remediation system and determine microbial communities present at each site of an abandoned coal mine drainage site. Sequencing of the 16S rRNA gene of the sediment indicated the most abundant phyla at each of the 5 ponds and wetland area included Proteobacteria (36%–43%), Bacteroidetes (12%–37%), Firmicutes (3%–11%), and Verrucomicrobia (6%–11%). Analysis of genera between the first, and most polluted, pond included Solitalea, Pedosphaera, and Rhodocyclus, whereas the microbial community from the wetland site at the end of the remediation system included Ignavibacterium, Pelotomaculum, and Petrimonas. The results of our microbial community composition study of sediment from a passive treatment system are in line with organisms commonly found in sediment regardless of iron oxide precipitation, while others are preferentially found in the less polluted wetland site.