The composition of endolithic communities in gypcrete is determined by the specific microhabitat architecture

Abstract. Endolithic microhabitats have been described as the last refuge for life in arid and hyper-arid deserts where has to deal with harsh environmental conditions. A number of rock substrates from Atacama Desert, colonized by endolithic microbial communities such halite, gypsum crusts, gypcrete, calcite, granite ignimbrite, characterized compared using different approaches. In this work, three are described, each one a particular origin architecture, found within lithic substrate known gypcrete. Gypcrete, an evaporitic mainly composed (CaSO4 ⋅ 2H2O) collected Cordón de Lila area desert (Preandean Desert), was harbour cryptoendolithic (within pore spaces rock), chasmoendolithic cracks fissures) hypoendolithic microcave-like pores bottom layer rock) microhabitats. combination microscopy investigation high-throughput sequencing approaches were used characterize their habitats at microscale same piece Microscopy techniques revealed differences architecture distribution microorganisms those Cyanobacteria Proteobacteria dominant communities, which community least diverse hosted unique taxa, result less access sun radiation. These results show, first time, that microhabitat, even substrate, play essential role shaping diversity composition communities.