Groundwater microbial diversity from Icelandic basaltic subsurface
The objective of the study was to characterize bacterial and archaeal diversity in Iceland's deep basaltic aquifers and to test how environmental gradients, temperature (30 to 110), pH (7.0 to 11.0), and bedrock age (0.01 to 15 Myr), together with host-rock reactivity (inferred from groundwater chemistry, including redox potential and thermodynamic and kinetic proxies for silicate dissolution) structure subsurface microbial communities. Using 16S rRNA gene metabarcoding across 22 geothermal wells, the study tried to link geochemical context to community composition, particularly among deep-biosphere lineages such as hydrogenotrophs and sulfate reducers, and to identify candidate taxa for future experiments probing microbe, mineral interactions and silicate-weathering processes.