2002 Annual Science Report
NASA Jet Propulsion Laboratory Reporting | JUL 2001 – JUN 2002
Organic Molecules as Biosignatures
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.
PROJECT MEMBERS:Michael Storrie-Lombardi
RELATED OBJECTIVES:Objective 6.0
Define how ecophysiological processes structure microbial communities, influence their adaptation and evolution, and affect their detection on other planets.
Identify the environmental limits for life by examining biological adaptations to extremes in environmental conditions.
Search for evidence of ancient climates, extinct life and potential habitats for extant life on Mars.
Define climatological and geological effects upon the limits of habitable zones around the Sun and other stars to help define the frequency of habitable planets in the universe.