The oil sands operations emit 70 Mt of greenhouse gases (GHG) per year and contribute roughly 25% to Alberta’s overall GHG emissions, which does not include emissions from tailings ponds that contribute substantially to methane and carbon dioxide emissions. Total fugitive GHG emissions from major oil sands operators’ tailings ponds, measured in situ using floating flux chambers in 2011, were estimated at 2.3 million tonnes of CO2-eq per year.  These emissions are a concern for the climate. Additionally, they may affect tailings reclamation in pit lakes by inducing chemical flux and the transfer of bitumen from underlying tailings to the upper water layer. Therefore, studying methane mitigation strategies is of interest for environmental and reclamation reasons.

Methane emissions from oil sands tailings primarily come from the metabolism of residual hydrocarbons under methanogenic conditions. Because oil sands tailings harbour diverse microbial communities, introducing alternative electron acceptors provides a competitive advantage to specific microorganisms over methane producers, thereby mitigating methane production. Successful methane mitigation by establishing alternative redox conditions has been observed in laboratory experiments, which opens the research direction to investigate metabolic pathways to get an in-depth insight into the microbial redox processes in oil sands tailings for methane mitigation