Water and salt dependent, living microbial communities in 6 million years old Atacama Desert sediments.

The Paleo Pit, a soil pit of 4.20 depth covering the depositional record of the last 6 million years was excavated in the hyperarid region of Yungay located in the Chilean part of the Atacama Desert. In this extreme environment the harsh conditions including low water availability, high salt concentrations and the consequent low organic content are important factors influencing microbial community structure.We extracted intracellular DNA from different soil horizons of the Paleo Pit and applied a 16S rRNA amplicon based approach using universal primers to retrieve sequences for both, Bacteria and Archaea. Shifts in community composition were correlated to abiotic properties of the different profile sections in order to get an understanding of microbial dynamics within the subsurface habitat of the hyperarid Atacama Desert.