Microbial life under extreme CO2 exhalations

在mofettes中，地球成因的二氧化碳以极高的浓度排放到大气中，导致土壤酸化和缺氧。定植在mofettes核心区的微生物群落必须能够忍受这些极端情况，并且可能与未受影响的陆地参考点不同。由于在地质储层中捕获二氧化碳是一种很有前途的处理策略，因此mofettes可能是研究二氧化碳储存和泄漏对生物地球化学过程和微生物群落的潜在生态影响的理想场所。因此，该项目将揭示居住在Plesna山谷（捷克西北部）的微生物群落的多样性和生物地球化学。在缺氧的情况下，CO2的同化及其作为终端电子受体的使用对于mofettes中的微生物过程应该是重要的。孔隙水和土壤气体化合物中13C的组成与特定古细菌和细菌脂质中13C的消耗有关，这将进一步了解适应开采地源CO2的微生物种群的优势。由于CH4并不是在大多数mofette位点释放的，因此CO2可能会被产醋酸菌还原为乙酸，这将根据它们的功能fhs标记基因进行量化。它们的代谢多样性和氧耐受性可能使它们既能在二氧化碳浓度极高的缺氧土壤中定植，也能在植物的根际定植，比如Eriophorum vaginatum，植物似乎通过将氧气输送到根部来适应富含二氧化碳的土壤。对于新型“嗜湿性”微生物的富集和潜在分离，将使用梯度管技术并调整到原位条件。

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.