Study of microbial diversity in an oil sands composite tailings deposit with depth

Composite tailings (CT), an engineered, alkaline, saline mixture of oil sands tailings, processed sand and gypsum (CaSO4) is used as a dry reclamation strategy in the Alberta Oil Sands Region. Oil sands tailings ponds, which comprise a portion of CT, have been demonstrated to contain a variety of microbial metabolisms including sulfur oxidation and reduction, iron reduction, fermentation, and methanogenesis. The objectives of this study were to characterize depth dependent bacterial communities in composite tailings with respect to sulphur, iron and organic carbon geochemistry.