Microbial Considerations for the Permanent Geological Storage of <scp> CO ₂ </scp>

Carbon capture and storage (CCS) is a cornerstone strategy for achieving Net Zero emissions, yet the role of microbial life in subsurface CO₂ storage remains underexplored. This mini-review highlights the deep biosphere as a key but overlooked player in CCS operations across saline aquifers, depleted hydrocarbon reservoirs and basalt formations. It synthesizes evidence that microbial communities can both compromise and enhance CO₂ storage via processes like methanogenesis, sulfidogenesis, corrosion and carbonate mineralization. Drawing on insights from hydrocarbon extraction and early CCS case studies, the review emphasizes the need for comprehensive microbial and geochemical monitoring to assess risks and harness potential benefits. The authors advocate for a holistic biogeochemistry toolkit and cross-sector collaboration to ensure safe, effective and microbiologically informed CCS deployment.