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Project Progress

We continued over the past year our studies of microbial metabolism, nutrient cycling and repair processes in cold environments. In addition to the publication of an initial paper reporting the detection of low levels of racemization repair in Siberian permafrost organisms, we have obtained additional permafrost core samples from Siberia, as well as cores from two sites in Alaska. These samples are currently being analyzed. We are also beginning an investigation into the role of molecular evolution in governing the inherent susceptibility of proteins to racemization damage.

We have also analyzed an additional sample of microbially colonized Antarctic Dry Valley sandstone, obtaining amino acid concentration and D/L ratio data as a function of depth. These data are being combined with iron isotope data collected by Henry Sun and Clark Johnson to construct a model for element and nutrient cycling and utilization in Antarctic cryptoendolithic communities.

In addition, we have contributed our capability for very low level amino acid detection to a project involving possible biological activity in 1-2 km deep basalts from the Hawaiian Scientific Drilling Program. We were able to identify a concentration of amino acids in these samples consistent with cell densities of 10⁴-10⁵ cells per cubic centimeter.