Life at the Freezing Point

Microbial communities are known to exist in extremely hot environments such as hydrothermal vents, but what about extremely cold regions? In their Research Commentary, Psenner and Sattler discuss results reported in the same issue by Priscu et al. in which a microbial assemblage was discovered in Antarctic lake ice. Although this environment is marked by permanent ice cover, pockets of liquid water can form during part of the year, allowing active growth and reproduction of organisms.