| interconnection between microorganisms capable of growing under hypersaline conditions and their effectiveness in surviving high doses of ionizing radiation has been previously demonstrated. It has been proposed that radiation resistance is the result repair mechanisms that deal with damage resulting from desiccation. We isolated 955 organisms from samples collected from hypersaline ponds in Antarctica. The ability of these organisms to grow in broth containing 0-25% NaCl was assessed. The ionizing radiation tolerance of a select number of organisms was determined by the use of an electron beam linear accelerator. Those organisms with a wide range of growth in salt were able to withstand moderate or high levels of radiation. Therefore, using salinity to screen for organisms that grow well in a wide range of salt concentrations may allow for finding organisms that are also tolerant to radiation, and may perhaps have unique mechanisms for their tolerances. There were vast differences in tolerance to both salt and radiation among isolates identified as the same organism. This shows that genes and proteins are evolving to provide tolerance at a faster rate than the 16S ribosomal DNA is changing, and has major implications for analyses where 16S sequencing is used to identify community structure, since divergent evolution may have rendered some of the individuals completely different than the commonly accepted type species. Key Words: salt, radiation, desiccation |