Format

Send to

Choose Destination
Sci Rep. 2018 Dec 4;8(1):17569. doi: 10.1038/s41598-018-35532-y.

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

Author information

1
Department of Biological Geological and Environmental Sciences, University of Bologna, 40126, Bologna, Italy.
2
La Venta Geographic Explorations Association, 31100, Treviso, Italy.
3
Department of Pharmacy and BioTechnology, University of Bologna, Bologna, 40126, Italy. martina.cappelletti2@unibo.it.
4
Department of Pharmacy and BioTechnology, University of Bologna, Bologna, 40126, Italy.
5
Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
6
The University of Queensland, Centre for Clinical Research (UQCCR), Herston, 4029, Australia.
7
College of Medicine, King Saud bin Abdulaziz University for Health Sciences, 3130, Riyadh, Saudi Arabia.
8
Department of Earth, Environment and Life, University of Genoa, Genoa, 16132, Italy.
9
Department of Earth Sciences, University of Florence, 50121, Florence, Italy.
10
Teraphosa Exploring Team, Puerto Ordaz, Venezuela.

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 and other bioessential elements accompanied by permineralized bacterial cells and ultrastructures. Illumina sequencing of the 16S rRNA gene describes the bacterial diversity characterizing the consecutive amorphization steps to provide clues on the biogeochemical factors playing a role in the silica solubilization and precipitation processes. These results show that both quartz weathering and silica mobility are affected by chemotrophic bacterial communities, providing insights for the understanding of the silica cycle in the subsurface.

PMID:
30514906
PMCID:
PMC6279750
DOI:
10.1038/s41598-018-35532-y
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Nature Publishing Group Icon for PubMed Central
Loading ...
Support Center