Transitory microbial habitat in the hyperarid Atacama Desert

Abstract

SignificanceIt has remained an unresolved question whether microorganisms recovered from the most arid environments on Earth are thriving under such extreme conditions or are just dead or dying vestiges of viable cells fortuitously deposited by atmospheric processes. Based on multiple lines of evidence, we show that indigenous microbial communities are present and temporally active even in the hyperarid soils of the Atacama Desert (Chile). Following extremely rare precipitation events in the driest parts of this desert, where rainfall often occurs only once per decade, we were able to detect episodic incidences of biological activity. Our findings expand the range of hyperarid environments temporarily habitable for terrestrial life, which by extension also applies to other planetary bodies like Mars.

Subsurface microbial habitats in an extreme desert Mars-analogue environment

“…It is notable that we have observed Antarctic mineral sediments, another Mars 15 analogue, generally yield higher recovery rates using similar methodologies, e.g. 20, 21 . 16…”

Extreme environments: microbiology leading to specialized metabolites

“…Until recently, it was believed that such harsh abiotic conditions made any form of life in the core region of the Atacama Desert virtually impossible (Navarro‐González et al ). However, it is now known that different groups of micro‐organisms have adapted to the extreme environmental conditions that prevail in the desert (Schulze‐Makuch et al ), so much so that a highly unusual rain event in the hyperarid core of the desert led to the decimation of surface microbial communities (Azua‐Bustos et al ).…”

Multiscale climate change impacts on plant diversity in the Atacama Desert

“…On interannual timescales and during the late Holocene, Atacama climate variability is driven mainly by El Niño Southern Oscillation (ENSO) (Vuille, Bradley, & Keimig, 2000). After large precipitation events, annual blooms are frequent, increasing plant richness and cover, and soil microbial activity (Schulze-Makuch et al, 2018). Ancient DNA (aDNA) of plant pathogens also increased in abundance and diversity in the Atacama during wetter events in the past (Wood et al, 2018).…”