Subglacial Environments: The Other Deep Biosphere.
When: April 5, 2011 2:30PM PDT
Although glaciers and ice sheets have conventionally been viewed as environments inhospitable for life, recent work has documented viable microorganisms in ancient ice cores and it is estimated that ~10^24 prokaryotic cells are archived globally in glacial ice. Liquid water is abundant beneath the Antarctic ice sheets and the subglacial aquifer volume is thought to be at least 107 km3. Based on available data from the ice and sediments, the subglacial environment of Antarctica may harbor ~10^29 prokaryotic cells, which equates to ~4.5 petagrams C and is ~20% of that reported for all surface soils on Earth. This new vision of life in the polar regions has provided an informed perspective to define the boundaries of the biosphere and extrapolate the likelihood of life surviving and persisting on icy planets and moons in the solar system and beyond.