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Project Progress

Progress for Year 1 under CAN-6 includes both field and laboratory activities. We conducted a field reconnaissance mission to Yellowstone National Park to locate and assess the status of anoxygenic mats dominated by the green non-sulfur phototroph Chloroflexus. The mats were healthy, but were located deep in a spring that is difficult to access. This initial assessment has allowed us to begin working out the technical difficulties of performing field measurements of biogenic gases and volatile organic compounds using the Hiden HPR40 membrane inlet quadrupole mass spectrometer, which we will undertake in the summer of Year 2.

For the laboratory studies, we have obtained a large anaerobic chamber and are installing it in the rooftop greenhouse facility at NASA Ames Research Center, which houses the marine/hypersaline microbial mats. We are also developing small vessels that cores of the mat can be placed in so that we can quantify gas fluxes under (1) different starting atmospheric compositions (modern and Archean), (2) different light regimes (full sun, Archean high UV, M dwarf radiation), and (3) different electron donors (H₂, H₂S, Fe(II)). We are obtaining baseline data for the mats in the oxygenic state, and will transition them to anoxia in two months.

Through team member Nancy Kiang, we also established a collaboration with Spanish astronomers Esther Sanromá and Enric Pallé. We measured the reflectance spectra of purple non-sulfur anoxygenic phototrophs for use in their radiative transfer model, which simulated the visible and near-IR radiation reflected by an Archean Earth. That project resulted in a publication which is under review (Sanromá et al., submitted).