DEEP MICROBIAL SIGNATURES IN TERTIARY SEDIMENTS OF THE HARTOUŠOV CO2 MOFETTE SYSTEM, NW BOHEMIA

Abstract

Summary Past and present microbial signatures were investigated in deep sedimentary successions of the Hartousov CO2 mofette system (NW Bohemia, Czech Republic). In about 78 m depth a CO2 reservoir was penetrated by the Hartousov borehole leading to a CO2 blow out. This core interval was selected for further analysis to test whether this section could represent a specific habitat stimulating a deep CO2-related microbial ecosystem. We applied organic geochemical, biogeochemical and microbiological approaches to characterize the deep mofette ecosystem. Necrotic microbial biomarkers reflect the microbial biomass during time of deposition and are not suitable to trace the deep biosphere at the Hartousov site. Common intact phospholipid life markers (IPLs) were not detected in significant amounts. However, two clusters of unknown lipids presumably with a sulfonic head group and ether side chains with different chain length could be identified, which might represent specific mofette related bacteria. Microbiological analysis point to a low abundant but characteristic microbial community consisting of Acidovorax, Aquabacterium, Hydrogenophaga, Sulfuricurvum and unknown genera of the family Comamonadaceae. Overall, although there is an adapted deep microbial community in the CO2 reservoir of the mofette system, this interval does not seem to represent a specific hotspot for deep microbial life.