Microbial diversity and biogeochemical interactions in the seismically active and CO- rich Eger Rift ecosystem.

The Eger Rift subsurface is characterized by frequent seismic activity and consistently high CO concentrations, making it a unique deep biosphere ecosystem and a suitable site to study the interactions between volcanism, tectonics, and microbiological activity. Pulses of geogenic H during earthquakes may provide substrates for methanogenic and chemolithoautotrophic processes, but very little is currently known about the role of subsurface microorganisms and their cellular processes in this type of environment. To assess the impact of geologic activity on microbial life, we analyzed the geological, geochemical, and microbiological composition of rock and sediment samples from a 238 m deep drill core, running across six lithostratigraphic zones.

Enrichment of rare methanogenic Archaea shows their important ecological role in natural high-CO terrestrial subsurface environments.

Introduction: Long-term stability of underground CO storage is partially affected by microbial activity but our knowledge of these effects is limited, mainly due to a lack of sites. A consistently high flux of mantle-derived CO makes the Eger Rift in the Czech Republic a natural analogue to underground CO storage. The Eger Rift is a seismically active region and H is produced abiotically during earthquakes, providing energy to indigenous microbial communities.

Metagenome-Assembled Genome of a Putative Methanogenic sp. Strain Enriched from Terrestrial High-CO Subsurface Sediments.

A metagenome-assembled genome (MAG), named sp. strain ERenArc_MAG2, was obtained from a 3-month-old H/CO atmosphere enrichment culture, originally inoculated with 60-m deep drill core sediment collected from the tectonic Eger Rift terrestrial subsurface. Annotation of the recovered draft genome revealed putative archaeal methanogenesis genes in the deep biosphere.

Circular Metagenome-Assembled Genome of sp. Strain ERen5, a Putative Methanogenic, H-Utilizing Terrestrial Subsurface Archaeon.

A circular, single-contig sp. metagenome-assembled genome (MAG) was recovered from high-CO enrichments inoculated with drill core material from the tectonic Eger Rift terrestrial subsurface. Annotation of the recovered MAG highlighted putative methanogenesis genes, providing valuable information on archaeal activity in the deep biosphere.