Astrobiology Lecture - 'Going to the Extreme: Life As We Know It'
Microorganisms have inhabited the Earth for 3.4 billion years, and they are key for the evolution of its major geochemical cycles and the composition of its atmosphere. Planets and moons explored thus far harbor extreme environmental conditions where it is more likely to find microorganisms than any other form of life. Using the Atacama Desert as a proxy for the Mars environment, we characterized microbial communities from a range of habitats in the desert. Our genomic data revealed extremely low microbial diversity in soil samples from the hyper-arid core of the Atacama Desert but flourishing microbial communities inside translucent rocks. We found that the structure and composition of these communities was directly correlated to water availability and substrate’s geochemical properties. Those ecological niches in the Atacama Desert can be considered environmental refuges for life and might provide guidance for where to best search for past or present life on Mars.