Phylogenetic Profiling and Diversity of Bacterial Communities in the Death Valley, an Extreme Habitat in the Atacama Desert

Abstract

The Atacama Desert, one of the driest deserts in the world, represents a unique extreme environmental ecosystem to explore the bacterial diversity as it is considered to be at the dry limit for life. A 16S rRNA gene (spanning the hyper variable V3 region) library was constructed from an alkaline sample of unvegetated soil at the hyperarid margin in the Atacama Desert. A total of 244 clone sequences were used for MOTHUR analysis, which revealed 20 unique phylotypes or operational taxonomic units (OTUs). V3 region amplicons of the 16S rRNA were suitable for distinguishing the bacterial community to the genus and specie level. We found that all OTUs were affiliated with taxa representative of the Firmicutes phylum. The extremely high abundance of Firmicutes indicated that most bacteria in the soil were spore-forming survivors. In this study we detected a narrower diversity as compared to other ecological studies performed in other areas of the Atacama Desert. The reported genera were Oceanobacillus (representing the 69.5 % of the clones sequenced), Bacillus, Thalassobacillus and Virgibacillus. The present work shows physical and chemical parameters have a prominent impact on the microbial community structure. It constitutes an example of the communities adapted to live in extreme conditions caused by dryness and metal concentrations.

Inhabited subsurface wet smectites in the hyperarid core of the Atacama Desert as an analog for the search for life on Mars

“…The case of Bacillus spp. is worth mentioning, as species of this genus are among the first and one of the most common type of bacteria reported in Yungay 27,65,66 and also in other sites of the hyperarid core of the Atacama [67][68][69] .…”

Living at the Frontiers of Life: Extremophiles in Chile and Their Potential for Bioremediation

“…Previous studies using culture-dependent methods have reported low numbers of bacteria in Atacama Desert soils, ranging from not detectable to 10 6 CFU per g of soil, with a high degree of spatial heterogeneity ( Crits-Christoph et al, 2013 ). Analysis through culture-independent methods on the subsurface layers of the hyper-arid core showed limited abundance of microbial communities including Proteobacteria, Actinobacteria, Cyanobacteria, Chloroflexi, Firmicutes, Gemmatimonadetes , Planctomycetes , and Thermomicrobia phyla ( Dong et al, 2007 ; Crits-Christoph et al, 2013 ; Azua-Bustos et al, 2015 ; Piubeli et al, 2015 ; Azua-Bustos et al, 2017 ).…”

Extreme Environments and High-Level Bacterial Tellurite Resistance

“…From the deepest seafloor to the top of the highest mountain, or the hottest desert to the coldest Antarctic plain, microorganisms have been recovered. Extreme habitats can support diverse bacterial communities [18,[75][76][77][78][79][80]. The investigation of the microbial communities which have managed to establish themselves under harsh conditions has helped further our understanding of how life evolved.…”