Dr Christner explores life in permanently frozen environments and is interested in better understanding how microbial life survives and persists in extremely cold, dark, and low nutrient environments. Recent studies have found bacteria in glacial ice samples hundreds of thousands to millions of years old. Dr Christner and others are studying habitat requirements necessary for microbes to continue slow metabolic processes in ice. This is significant because 70% of all freshwater, and currently 10% of the earth’s surface, is covered in glacial ice. Dr. Christner’s research is helping to expand the definition of the biosphere.