Biogeochemical cycling of gold: Transforming gold particles from arctic Finland

Cycling of biogenic elements drives biogeochemical gold cycling

“…Multispecies biofilms are commonly found on natural placer gold particles and are known to play a key-role in their biotransformation (Fig. 2; Reith et al, 2010;Reith et al, 2018;Reith et al, 2012b;Rea et al, 2016;Rea et al, 2018). This next section will therefore briefly summarize our current understanding concerning the composition and the functional roles of the organisms constituting these biofilms.…”

“…Taxonomic evaluation and studies of putative functional abilities have shown that bacterial groups capable of carbon, nitrogen and sulfur biotransformation (including carbon-and nitrogen fixation, nitrification, denitrification, sulfur oxidation, sulfate reduction) are present in these biofilms (Fig. 6; Rea et al, 2016;Rea et al, 2018;Reith et al, 2018). Carbon-and nitrogen fixation are essential for the initial bacterial colonization of the gold particles in many placer environments, because organic carbon concentrations are commonly so low that they alone are likely insufficient to support the growth and proliferation of heterotrophic bacteria.…”

Gold particle geomicrobiology: Using viable bacteria as a model for understanding microbe–mineral interactions

“…The presence of bacterial biofilms on other gold particles have been inferred from amplified OTUs (i.e. Rea et al , 2016; Reith et al , 2018). In this study, the number of bacterial cells on the surface of particles observed by microscopy was low relative to the diverse types of bacteria interpreted from the molecular analysis in other studies.…”

Reflecting on Gold Geomicrobiology Research: Thoughts and Considerations for Future Endeavors

“…Polymorphic layers are comprised of clay minerals, residual organic material, bacterial cells, and secondary Au structures. These layers often occur within crevices, which is to say, topographically-low regions, at the surface of Au particles [64,66,67,78]. Secondary Au structures are nanometer-micrometer-scale features that occur on Au particles.…”

“…Though Au is conventionally considered an inert metal, the interaction between microbes and Au particles highlights not only an influence of bacteria on Au-particle-structure and chemistry, but on microbial diversity as well, with regards increased resistance to Au toxicity. the surface of Au particles [64,66,67,78]. Secondary Au structures are nanometer-micrometer-scale features that occur on Au particles.…”