Seasonal Variation in an Acid Mine Drainage Microbial Community

Environmental oxidation and microbial metabolism drive production of Acid Mine Drainage (AMD). Understanding changes in the microbial community, due to geochemical and seasonal characteristics, is fundamental to AMD monitoring and remediation. We used direct sequencing of the 16S and 18S rRNA genes to identify Bacterial, Archaeal, and Eukaryote members of the microbial community at an AMD site in Northern Ontario, Canada, finding a dynamic community varying significantly across winter and summer sampling times. Community composition was correlated with physical and chemical properties including water temperature, pH, conductivity, winter ice thickness, and metal concentrations. Within Bacteria, Acidithiobacillus was the dominant genus during winter (11-57% of sequences) but Acidiphilium during summer (47-87%). Within Eukaryotes, Chrysophyceae (1.5-94%) and Microbotrymycetes (8-92%) dominated the winter community and LKM11 (4-62%) and Chrysophyceae (25-87%) the summer. The Archaeal domain was less diverse and less variable, with similar summer and winter communities comprised mainly of Thermoplasmata (33-64%) and Thermoprotei (5-20%) classes, but also including a large portion of unclassified reads (~40%). Overall, the active AMD community, varied significantly between winter and summer, with changing community profiles closely correlated to specific differences in AMD geochemical and physical properties, including pH, water temperature, ice thickness, and sulphate and metal concentrations.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author