This session will focus on the microbiology of deep geological systems with special emphasis on potential geobiotechnological applications and respective risk assessments. For decades, it has been known that microbial activity is responsible for the degradation and conversion of hydrocarbons in oil, gas and coal reservoirs. The understanding of the related microbial processes and their environmental controls is not only of great scientific interest. It furthermore has substantial economic and societal relevance, since these processes directly or indirectly affect the quantity and quality of oil and gas reserves as well as the storage of oil and gas reserves in geological settings.

New interest in such deep subsurface systems is emerging related to different geobiotechnological developments. On the one hand, the capture and long-term storage of carbon dioxide (CCS, Carbon Capture and Storage), for example in depleted oil and gas reservoirs, coal bed strata or in deep saline aquifers, is considered an important option for mitigating greenhouse gas emissions and global warming. On the other hand, the increasing contribution of energy from natural and renewable sources, like wind, solar, geothermal energy or biogas production has led to increased interest in utilizing deep subsurface systems for storage of renewable energy carriers like biogas, methane or hydrogen. The conventional fossil fuels industry also stands to benefit from geobiotechnology, e.g., microbial enhanced oil recovery might offer perspectives to exploit oil reservoirs more efficiently, and enhanced biogas production from oil or coal as well as microbial control of oil reservoir souring are ways that geobiotechnology can lead to greener operations in this sector. Microbial degradation of hydrocarbons and other organic chemicals is also highly interesting for the remediation of contaminated aquifers. The understanding of in situ degradation and its quantification is important for natural attenuation concepts to manage contaminated aquifers as well as designing and validating in situ remediation approaches for clean-up.

Hydrocarbon contaminated aquifers as well as oil and gas reservoirs are anoxic habitats in porous matrices sharing similar features related to anoxic microbial processes. The session aims to bring together colleagues from industry and academia to promote an interdisciplinary interaction from different perspectives related to research and current challenges for the geomicrobiology and biogeochemistry of gas, oil and coal deposits as well as contaminated aquifers. This should foster the discussion and formulation of current and future geobiotechnological concepts and challenges.