Microbial Syntrophy Drives Methanogenesis From Residual Hydrocarbons in Anaerobic Oil Sands Tailings

Anaerobic oil sands tailings can generate methane for decades as residual naphtha‐range and petroleum hydrocarbons sustain microbial metabolism, but how microbial interactions link hydrocarbon turnover to methanogenesis remains poorly resolved. To characterize these microbial associations, we analyse two naphtha‐amended anaerobic tailings incubation series using 16S rRNA gene relative abundance, hydrocarbon consumption, and methane production data within a cooperative game‐theoretical framework. The abundance‐informed Shapley analysis attributes system‐level variation to bacterial–archaeal coalitions, highlighting key syntrophic partnerships. Several taxa show inferred contributions to methanogenesis that are disproportionate to their relative abundance, indicating that model‐based attribution can differ from abundance ranking. Sensitivity analysis shows that the main methane‐attribution patterns remain interpretable across alternative abundance‐weighted coefficient formulations. These interaction patterns shift across incubation phases, showing that microbial control over hydrocarbon‐dependent methanogenesis changes through time. When incorporated into stochastic forecasting, Shapley‐derived reaction intensities improve predictive performance compared with reduced microbial and non‐microbial benchmarks. Together, our results indicate that methane production in oil sands tailings can be interpreted through abundance‐informed bacterial–archaeal coalition structure, providing a coalition‐aware basis for interpreting and forecasting methanogenic hydrocarbon transformation.