MICROBIAL DENSITY IN SAMPLES FROM EXTREME ENVIRONMENTS AND AMENABILITY TO IN SITU CHEMICAL EXTRACTION AND FLUORESCENT DETECTION

The collection of samples from a variety of extreme environments has revealed certain geological and geobiological formations in which the density of microbial life is significantly enhanced. These include Antarctic endoliths, desert cryptogamic crusts, and gypsum-inhabiting cyanobacteria. These studies aid the selection of choices of samples to target via robotic sampling on other planets, either for in situ study or sample return. The challenge for the former is to be able to process the samples in a manner that disrupts the communities as little as possible while permitting unambiguous detection of microbes. We present several methods for fluorescent imaging of rock and soil samples designed to maximize microbial visibility while minimizing robotic sample preparation and destruction of the sample.