Archipelago of endolithic microbial life in the hyper arid core of the Atacama Desert

Abstract

The hyper-arid core of the Atacama Desert is considered the driest and most life-limited place on Earth. As such, this desert is an ideal environment to study the survival and biological adaptation strategies of microorganisms to this extremely dry environment. The extreme aridity of the Atacama Desert allows us to address questions such as the potential for life in extraterrestrial environments such as the surface of Mars. Our results over the last six years of searching for microbial life in the hyper-arid core of the Atacama Desert shows the presence of various habitats capable of sustaining active microbial ecosystems. All of them belong to endolithic – inside the rocks – microbial habitats. We suggest that these endolithic habitats protect microbial communities from UV and excessive PAR radiation and supply increased moisture, thus providing environmental refuges – or islands of life - in the desert. This «archipelago» of microbial islands of life is composed by the following endolitically colonized substrates: a) halite rocks (Wierzchos et al., 2006; de los Ríos et al., 2010); b) gypsum crusts (Wierzchos et al., 2011), c) volcanic origin ignimbrite (Wierzchos et al., 2012) and d) rhyolite and calcite rocks (DiRuggiero et al., submitted).