Connecting Geo and Bio in extreme environments

Acidic mine waters are among the most singular and biogeochemically extreme environments in the Earth’s crust. For this reason, they are subject to extensive international research under different perspetives including (i) thermodynamic calculations and lab experiments, (ii) high-resolution studies of biominerals by HRTEM, S/TEM, cryoTEM, EELS or XAS, or (iii) search for novel microbial species with potential biotechnological or astrobiological interest through the combined use of lab cultures and different “omics” tools. A common feature of all these problems is the tight interdependence between microbiology and (geo-)chemistry, which in most cases are imposible to separate and need to be studied under a transdisciplinary perspective. In my talk, I will briefly revise some of the most relevant issues, like the catalytic role of bacteria and archaea in redox reactions, intra- and extra-celular biomineralization, biogeochemical cycling of Fe, S, C or N, or the identification of dominant microorganisms and metabolisms in previously unexplored deep anoxic zones. The contribution of environmental geochemistry and high-resolution mineralogy is essential for the understanding of most of these aspects, which may also have an important astrobiological component.