Microbial Signatures in Deep CO2-Saturated Miocene Sediments of the Active Hartoušov Mofette System (NW Czech Republic)

Qi Liu; Karsten Adler; Daniel Lipus; Horst Kämpf; Robert Bussert; Birgit Plessen; Hans-Martin Schulz; Patryk Krauze; Fabian Horn; Dirk Wagner; Kai Mangelsdorf; Mashal Alawi

doi:10.3389/fmicb.2020.543260

Microbial Signatures in Deep CO₂-Saturated Miocene Sediments of the Active Hartoušov Mofette System (NW Czech Republic)

Front Microbiol. 2020 Dec 14:11:543260. doi: 10.3389/fmicb.2020.543260. eCollection 2020.

Authors

Qi Liu^{1

2}, Karsten Adler^{2

3}, Daniel Lipus¹, Horst Kämpf³, Robert Bussert⁴, Birgit Plessen⁵, Hans-Martin Schulz³, Patryk Krauze^{1

2}, Fabian Horn¹, Dirk Wagner^{1

2}, Kai Mangelsdorf³, Mashal Alawi¹

Affiliations

¹ Section Geomicrobiology, GFZ German Research Centre for Geosciences, Potsdam, Germany.
² Institute of Geosciences, University of Potsdam, Potsdam, Germany.
³ Section Organic Geochemistry, GFZ German Research Centre for Geosciences, Potsdam, Germany.
⁴ Section Applied Geochemistry, Institute of Applied Geosciences, Technische Universität Berlin, Berlin, Germany.
⁵ Section Climate Dynamics and Landscape Evolution, GFZ German Research Centre for Geosciences, Potsdam, Germany.

Abstract

The Hartoušov mofette system is a natural CO₂ degassing site in the central Cheb Basin (Eger Rift, Central Europe). In early 2016 a 108 m deep core was obtained from this system to investigate the impact of ascending mantle-derived CO₂ on indigenous deep microbial communities and their surrounding life habitat. During drilling, a CO₂ blow out occurred at a depth of 78.5 meter below surface (mbs) suggesting a CO₂ reservoir associated with a deep low-permeable CO₂-saturated saline aquifer at the transition from Early Miocene terrestrial to lacustrine sediments. Past microbial communities were investigated by hopanoids and glycerol dialkyl glycerol tetraethers (GDGTs) reflecting the environmental conditions during the time of deposition rather than showing a signal of the current deep biosphere. The composition and distribution of the deep microbial community potentially stimulated by the upward migration of CO₂ starting during Mid Pleistocene time was investigated by intact polar lipids (IPLs), quantitative polymerase chain reaction (qPCR), and deoxyribonucleic acid (DNA) analysis. The deep biosphere is characterized by microorganisms that are linked to the distribution and migration of the ascending CO₂-saturated groundwater and the availability of organic matter instead of being linked to single lithological units of the investigated rock profile. Our findings revealed high relative abundances of common soil and water bacteria, in particular the facultative, anaerobic and potential iron-oxidizing Acidovorax and other members of the family Comamonadaceae across the whole recovered core. The results also highlighted the frequent detection of the putative sulfate-oxidizing and CO₂-fixating genus Sulfuricurvum at certain depths. A set of new IPLs are suggested to be indicative for microorganisms associated to CO₂ accumulation in the mofette system.

Keywords: CO2; Eger Rift; deep biosphere; geo-bio interaction; microbial diversity; microbial lipid biomarker; mofette systems; saline groundwater.