This award provides support for one year of funding to construct and operate a biospectrologger (BSL) in a borehole in polar ice. Such an optical device has already been developed and tested for measuring dust in polar ice. The same general principle can be exploited to study microbes and biomolocules as a function of depth in glacial ice. Microbes adapted to oligotrophic, low-temperature environments are found in glacial ice, frigid lakes, in permafrost and in cold, deep ocean water and sediments. Polar ice contains the lowest concentrations, from a few hundred to about 104 cells/cm3, probably transported by wind into the atmosphere, precipitated with snow, and compacted into ice. The great majority are dormant or dead. With varying success, cultivation of microbes recovered from ice cores yields colony-forming units in a fraction (~10-4 to ~10-2 ) of dormant cells. Chemical, physical and biological arguments indicate that as many as 103 microbes/cm3 can extract enough energy from acids confined in narrow liquid veins in otherwise solid ice to survive for a few thousand years (or a smaller population for a correspondingly longer time). No search has yet been carried out for living bacteria in liquid veins. The biospectrologger will be field tested at Siple Dome, Antarctica during the 2001/02 field season as part of an existing borehole logging program there.