Clay ‐associated microbial communities and their relevance for a nuclear waste repository in the Opalinus Clay rock formation

Biocorrosion and microbial mineral transformation can affect the safety of deep geological repositories for high-level nuclear waste storage. We analyzed the composition and evaluated the importance of mineral-associated microbial communities in Opalinus Clay for safety purposes. Rock-attached communities were dominated by phyla capable of corrosive biofilm formation. Based on the abundance of potential iron-reducing bacteria and available electron acceptors, iron reduction appeared to be the most important process. Site-specific mineralogy and geochemistry have selected for subcommunities and specific metabolic functions. AbstractMicroorganisms are known to be natural agents of biocorrosion and mineral transformation, thereby potentially affecting the safety of deep geological repositories used for high-level nuclear waste storage. To better understand how resident microbial communities of the deep terrestrial biosphere may act on mineralogical and geochemical characteristics of insulating clays, we analyzed their structure and potential metabolic functions, as well as site-specific mineralogy and element composition from the dedicated Mont Terri underground research laboratory, Switzerland. We found that the Opalinus Clay formation is mainly colonized by Alphaproteobacteria, Firmicutes, and Bacteroidota, which are known for corrosive biofilm formation. Potential iron-reducing bacteria were predominant in comparison to methanogenic archaea and sulfate-reducing bacteria. Desp...
Source: MicrobiologyOpen - Category: Microbiology Authors: Tags: ORIGINAL ARTICLE Source Type: research