Microbial life under extreme CO2 exhalations

• Applicant: Professorin Dr. Kirsten Küsel
• Subject Area: Microbial Ecology and Applied Microbiology
• Term: from 2010 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 183403997

In mofettes, geogenic CO2 is emitted in extremely high concentrations to the atmosphere leading to soil acidification and anoxic conditions. The microbial community colonizing the core zone of mofettes has to be able to tolerate these extremes and might be distinct from unaffected terrestrial reference sites. Since capture of CO2 in geological reservoirs is discussed as promising disposal strategy, mofettes might be an ideal site to study potential ecological impacts of CO2 storage and leakage on biogeochemical processes and microbial communities. Thus, this project will unravel the diversity and biogeochemistry of the microbial community inhabiting a mofette located in the Plesna valley (NW-Czechia). The assimilation of CO2 and its use as terminal electron acceptor in the absence of oxygen should be significant for microbial processes in mofettes. The composition of 13C in pore water and soil gas compounds linked with 13C depletion of specific archaeal and bacterial lipids will give further insights into the dominance of microbial populations adapted to exploiting geogenic CO2. Since CH4 is not emitted at most mofette sites, CO2 might be reduced to acetate by acetogenic bacteria which will be quantified based on their functional fhs marker gene. Their metabolic versatility and oxygen tolerance might enable acetogens to colonize both anoxic soils with extremely high CO2 concentrations and also the rhizosphere of plants, like Eriophorum vaginatum, that appears to be adapted to CO2-rich soils by the transport of O2 to their roots. For enrichment and potential isolation of novel “moffetophilic” microorganisms, the gradient tube technique will be used and adjusted to the in situ conditions.

• DFG Programme: Research Grants