Jocelyne DiRuggiero (Johns Hopkins University)
Microorganisms have inhabited the Earth for 3.4 billion years of its history, there are essential for the evolution of its minerals, its major geochemical cycles, and its atmosphere, and therefore we cannot consider the evolution of our planet without considering the evolution of its microorganisms. In addition, planets and moons explored thus far harbor extreme environmental conditions where it is more likely to find microorganisms than any other form of life. I will present recent findings on the adaptation of microorganisms to extreme desiccation and radiation, and on microbial communities colonizing some of the driest places on Earth. The broader implications of these results lies both in term of our understanding of limits for Life as we know it and in linking geochemistry and microbial activity at the ecosystem level to interpret spectra and molecular signatures observed from extraterrestrial bodies.