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Project Progress

Our focus is to identify forms of microbial life that are chemosynthetically supported by water-rock interaction, and to develop high-resolution geochemical techniques capable of measuring the biological signatures of their activity. We are specifically interrogating microbial interactions with the crust in the deep ocean and subsurface, which together comprise the largest unexplored habitats on Earth. During the past year, we have extended these studies from our work on modern-day bioalteration of basaltic glasses to make comparisons to putative biosignatures preserved in ancient glasses.

Basaltic glasses from the Costa Rica Rift (5.9 Ma) previously interpreted as containing a variety of “tubular” and “granular” bioalteration features (by Harald Furnes, Hubert Staudigel and colleagues) were reanalyzed using high-resolution synchrotron-based x-ray microprobe measurements. Strong elemental redistribution profiles were obtained across all “bioalteration” features, particularly for Ti, Fe, Mn and Ca. These elemental maps were then coupled with spatially-resolved x-ray spectroscopic data to quantify variations in Fe and Mn speciation (particularly oxidation state) at the micron-scale. Our data demonstrates clear redox transitions across the alteration fronts that will help to constrain the mechanisms of bioalteration.

A separate project involved exploratory work focused on the potential to cultivate psychrophilic, chemolithoautotrophic microorganisms involved in sulfur-cycling on glaciers located at Borup Fiord, in the Canadian High Arctic (a potential terrestrial analog site for Europa). This work will be significantly expanded in the next year as part of a NASA DDF award.