Function and diversity of sulfate- and iron-reducing bacteria in mine tailings submitted to various physico-chemical conditions

微生物还原铁和硫酸盐已被提出作为一种生物修复技术，以减轻酸性矿山废水（AMD）在采矿影响的环境（如湖泊）和矿山尾矿。这两种微生物过程都产生碱性，可以降低尾矿中现有的酸性，硫酸盐还原促进有毒重金属以金属硫化物的形式沉淀，从而降低AMD和重金属负荷对邻近水生和陆地生态系统的影响。正在进行的D. Fortin的实验室研究表明，铁还原菌（FeRB）和硫酸盐还原菌（SRB）广泛存在于铜锌和Au尾矿中，但它们在尾矿库中的活性取决于各种生物地球化学因素，包括有机底物的有效性、电子受体、pH值、氧化还原和温度。例如，春季铜锌尾矿（融雪后）的硫酸盐还原活性大大降低，此时尾矿的酸性更强且有机碳含量更低。另一方面，FeRB种群往往在春季增加，可能是由于缺乏与SRB种群的竞争。这些结果表明，微生物多样性和功能的FeRB和硫酸盐还原菌在尾矿中发生在广泛的物理化学条件下，必须首先了解之前，设计适当的生物修复技术的尾矿残留物居住在温带气候地区。生物修复技术必须全年有效，不依赖于物理化学因素。拟议的研究计划使用一个缩影的方法来评估硫酸盐还原菌和铁还原菌的多样性和功能的基本金属尾矿提交各种物理化学条件。

Microbial  iron- and sulfate- reduction  have been proposed as a bioremediation technologies to attenuate acid mine drainage (AMD) in mining impacted environments (such as lakes) and mine tailings. Both microbial processes generate alkalinity which can reduce the existing acidity in the tailings and  sulfate reduction promotes the precipitation of toxic heavy metals as metal sulfides, therefore lowering the impact of AMD and heavy metal loading to adjacent aquatic and terrestrial ecosystems. Ongoing research in D. Fortin's laboratory has shown that iron-reducing bacteria (FeRB) and sulfate-reducing bacteria (SRB) are widespread in Cu-Zn and Au tailings, but their activity in tailings impoundments  is dependent on various biogeochemical factors, including availability or organic substrates, electron acceptors, pH, redox and temperature. For instance, sulfate reduction activity is greatly reduced in the spring in Cu-Zn tailings (after snowmelt), when the tailings are more acidic and low in organic carbon. On the other hand, FeRB populations tend to increase in the spring, likely as the result of the lack of competition with SRB populations. Such results indicate that microbial diversity and function of FeRB and SRB in mine tailings occurring under a wide range of physico-chemical conditions must first be understood before designing  appropriate bioremediation technologies for mine tailings residues residing in temperate climate regions. Bioremediation technologies must be effective all year around and not be dependent on  physico-chemical factors. The proposed research plans to use a microcosm approach to assess SRB and FeRB diversity and function in base-metal mine tailings submitted to various physico-chemical conditions.