Onstott, Tullis C.

Metagenomic sequencing of fracture fluid from South Africa recovered a nearly complete “ Candidatus Bathyarchaeota” archaeon genome. The metagenome-assembled genome of BE326-BA-RLH contains genes involved in methane metabolism and dissimilatory nitrate reduction.

DNA from low-biodiversity fracture water collected at 2.8-kilometer depth in a South African gold mine was sequenced and assembled into a single, complete genome. This bacterium, Candidatus Desulforudis audaxviator , composes >99.9% of the microorganisms inhabiting the fluid phase of this particular fracture. Its genome indicates a motile, sporulating, sulfate-reducing, chemoautotrophic thermophile that can fix its own nitrogen and carbon by using machinery shared with archaea. Candidatus Desulforudis audaxviator is capable of an independent life-style well suited to long-term isolation from the photosphere deep within Earth's crust and offers an example of a natural ecosystem that appears to have its biological component entirely encoded within a single genome.