Life in icy habitats: new insights supporting panspermia theory

Panspermia theory holds that microbial life is present in space or on bodies like comets or asteroids, and it can be safely delivered to Earth and start life there. For the theory of panspermia to have credence, it is necessary to demonstrate that life could exist in the harsh condition of space. The discovery of microorganisms able to survive permanently in frozen environments, such as ancient permafrost and ice, makes in principle realistic for bacteria to be carried through space in ice-cold comets. Due to the increasing interest in astrobiology, research in the microbial ecology and diversity of psychrophiles has increased considerably over the past years. In this review, a brief summary of the latest results on biology, ecology and physiology of microorganisms colonizing cold and icy habitats is reported.