Ecological and genomic profiling of anaerobic methane-oxidizing archaea in a deep granitic environment.

Recent single-gene-based surveys of deep continental aquifers demonstrated the widespread occurrence of archaea related to Candidatus Methanoperedens nitroreducens (ANME-2d) known to mediate anaerobic oxidation of methane (AOM). However, it is unclear whether ANME-2d mediates AOM in the deep continental biosphere. In this study, we found the dominance of ANME-2d in groundwater enriched in sulfate and methane from a 300-m deep underground borehole in granitic rock.

Deep microbial life in high-quality granitic groundwater from geochemically and geographically distinct underground boreholes.

Deep granitic aquifer is one of the largest, but least understood, microbial habitats. To avoid contamination from the surface biosphere, underground drilling was conducted for 300 m deep granitic rocks at the Mizunami underground research laboratory (URL), Japan. Slightly alkaline groundwater was characterized by low concentrations of dissolved organic matter and sulfate and the presence of > 100 nM H2 .

An EXAFS study on the adsorption structure of phenyl-substituted organoarsenic compounds on ferrihydrite.

Adsorption structures of mono- and diphenyl substituted organoarsenic compounds (PAA and DPAA, respectively) on ferrihydrite were analyzed by extended X-ray absorption fine structure (EXAFS), which suggested that PAA and DPAA form inner-sphere complexes with ferrihydrite regardless of their bulky functional groups. In addition, coexistence of two types of inner-sphere complex modes, i.e.