Transition metal stable isotope geochemistry: Potential tool to detect biosignatures and characterize microbial metabolisms in the subsurface environments

Abstract

Discovery of deep biosphere brought us astrobiological questions about the evolution and distribution of life. Such questions include how successful we can identify microbiological activity in apparently barren geologic materials and what metabolism such microbes employ. Recent studies have shown that large isotope fractionations occur during biological redox reactions of transition metals. Such characteristic signature of metal isotopes may be used not only as a tool to detect potential biosignatures but also to constrain the nature of metabolisms operating in the subsurface environments.