DIVERSITY OF MICROORGANISMS IN A TACONITE TAILINGS BASIN IN NORTHERN MINNESOTA
Charles Thunder1, Daniel Jones2, Jake Bailey2.
1Minneapolis Community and Technical College, Minneapolis, MN, 2University of Minnesota, Minneapolis, MN.
Little is known about the microbial biogeochemistry and diversity of taconite tailings basins. Taconite tailings are fine-grained waste materials that are separated from iron ore during the taconite mining process. Tailings are removed from the taconite processing facility in a slurry and piped out to a basin for permanent storage. The water is reclaimed, collected in a return cell, and reused in the refinement processes. Taconite tailings basins represent a unique biogeochemical environment with circumneutral pH (7 - 8), very little organic matter, and include both oxidized and reduced sulfur and iron in aqueous and mineral phases. We are investigating the presence and diversity of microorganisms in a taconite tailings basin near Mountain Iron, Minnesota. In June 2015, the Minnesota Department of Natural Resources (DNR) collected shallow cores (up to 4 m length) with a Giddings probe from multiple locations in the basin. Within a day of collection, we sampled the cores at various depths, and are now in the process of describing the microbial communities using culture-independent methods. Preliminary results indicate that the tailings harbor low microbial biomass (< 106 cells/g sediment). Gene sequencing, rRNA, is in progress and will reveal the identity and diversity of the microorganisms. Our findings will help us begin to understand the biological processes that are occurring in the basin which will help interpret sulfur and iron biogeochemistry and may suggest novel reclamation and mitigation strategies.