Abstract

Unique worldwide, nitrate/iodine deposits (NIDs) are located along a 700 km geologicalbelt in the Atacama Desert, Chile. They serve as the primary source of mineral ores for the extractionof iodine, sodium, and potassium nitrates. NIDs have been relatively underexplored from a biologicalperspective. To address this, we collected sixteen soil samples from abandoned mines in OficinasPissis and Savona for chemical, mineralogical, and metagenomic analyses. The soils primarilyconsisted of halite and darapskite, with only one sample being predominantly composed of thenardite.Deliquescence and water activity measurements yielded values ranging from 0.02% to 0.40% and0.47 to 0.62, respectively. To investigate the presence, identification, relative abundance, and diversityof microbial life in NID soils, we employed MiSeq high-throughput sequencing and bioinformatictools. The dominant phyla observed were Firmicutes and Proteobacteria, with Actinobacteria andCyanobacteria being predominant in two soil samples. Furthermore, we detected nitrate/perchlorate-reducing bacterial activity in enriched cultures from the soil samples. This study sheds light onthe resilience of microbial life in the Atacama Desert NIDs, providing compelling evidence for itsexistence and offering insight into factors that could facilitate it within this unique environment