The article explores the utilization of carbonate minerals as an inorganic carbon source for methanogenic microbial communities under alkaline conditions. The study demonstrated that calcium carbonate can serve as the sole source of inorganic carbon, leading to increased methane concentrations and mineral dissolution in the presence of a methanogen, Methanobacterium sp., and five bacterial community members. Genome-resolved metagenomics confirmed the metabolic potential for hydrogenotrophic methanogenesis. The research highlights the impact of hydrogenotrophic methanogens on carbon biogeochemistry and carbonate mineral stability, providing insights into environmental systems. Microbial activity, particularly hydrogenotrophic methanogenesis, may play a crucial role in influencing mineral dissolution and altering local chemistry, emphasizing the importance of understanding microbial contributions to carbon cycling and climate change mitigation strategies.