Microbial sulfur geochemistry in acid environments

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Canada is a world leader in mining and mineral exploration and associated technologies to promote environmentally sustainable mining practises. However AMD remains a significant and growing Canadian water quality issue. Microorganisms are widespread across aquatic environmental systems where they affect many important geochemical processes. The proposed research will carry out one of the first comprehensive monitoring programs evaluating microbial S geochemistry in situ. Integrated floc S geochemistry and microbial community will be investigated under environmentally characterized conditions over seasonal and annual scales. Field results will capture the synergistic interactions amongst these factors in a key and poorly studied aquatic compartment, suspended floc, providing a more realistic and necessary map of microbially driven S oxidation and acid generation in acidic mine waters. Companion laboratory experiments will delineate the roles of poorly studied, microbially relevant and common mine environmental factors such as Fe(III) and NO3- as drivers for microbial floc S geochemistry. The short term goals of the proposed research will specifically constrain the role of suspended floc as a reactive microbial compartment involved in acid generation, the magnitude of bacterially driven acid generation over seasonal and annual timescales, and evaluate the ecological diversity of Acidithiobacilli floc S geochemistry in situ in acid mine systems. This research will generate (1) new fundamental understanding of key processes involved in AMD generation (2) new diagnostic indicators for more accurate surveillance and monitoring programs and (3) new strategies for mitigation and bioremediation improving the health and quality of life for Canadians. This interdisciplinary field and laboratory program will train 3 PhD and up to 5 undergraduate HQP in leading edge environmental geochemical and microbiological techniques.