Microbial diversity and biosignatures of amorphous silica deposits in orthoquartzite caves.

ABSTRACT: Chemical mobility of crystalline and amorphous SiO₂ plays a fundamental role in several geochemical and biological processes, with silicate minerals being the most abundant components of the Earth's crust. Although the oldest evidences of life on Earth are fossilized in microcrystalline silica deposits, little is known about the functional role that bacteria can exert on silica mobility at non-thermal and neutral pH conditions. Here, a microbial influence on silica mobilization event occurring in the Earth's largest orthoquartzite cave is described. Transition from the pristine orthoquartzite to amorphous silica opaline precipitates in the form of stromatolite-like structures is documented through mineralogical, microscopic and geochemical analyses showing an increase of metals

SUBMITTER: Sauro F 

PROVIDER: S-EPMC6279750 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature