Prokaryotic Community Structure and Metabolisms in Shallow Subsurface of Atacama Desert Playas and Alluvial Fans After Heavy Rains: Repairing and Preparing for Next Dry Period

Miguel Ángel Fernández-Martínez, Rita Dos Santos Severino, Mercedes Moreno-Paz, Ignacio Gallardo-Carreño, Yolanda Blanco, Kimberley Warren-Rhodes, Miriam García-Villadangos, Marta Ruiz-Bermejo, Albert Barberán, David Wettergreen, Nathalie Cabrol, Víctor Parro

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

The Atacama Desert, the oldest and driest desert on Earth, displays significant rains only once per decade. To investigate how microbial communities take advantage of these sporadic wet events, we carried out a geomicrobiological study a few days after a heavy rain event in 2015. Different physicochemical and microbial community analyses were conducted on samples collected from playas and an alluvial fan from surface, 10, 20, 50, and 80 cm depth. Gravimetric moisture content peaks were measured in 10 and 20 cm depth samples (from 1.65 to 4.1% w/w maximum values) while, in general, main anions such as chloride, nitrate, and sulfate concentrations increased with depth, with maximum values of 13–1,125; 168–10,109; and 9,904–30,952 ppm, respectively. Small organic anions such as formate and acetate had maximum concentrations from 2.61 to 3.44 ppm and 6.73 to 28.75 ppm, respectively. Microbial diversity inferred from DNA analysis showed Actinobacteria and Alphaproteobacteria as the most abundant and widespread bacterial taxa among the samples, followed by Chloroflexi and Firmicutes at specific sites. Archaea were mainly dominated by Nitrososphaerales, Methanobacteria, with the detection of other groups such as Halobacteria. Metaproteomics showed a high and even distribution of proteins involved in primary metabolic processes such as energy production and biosynthetic pathways, and a limited but remarkable presence of proteins related to resistance to environmental stressors such as radiation, oxidation, or desiccation. The results indicated that extra humidity in the system allows the microbial community to repair, and prepare for the upcoming hyperarid period. Additionally, it supplies biomarkers to the medium whose preservation potential could be high under strong desiccation conditions and relevant for planetary exploration.

Original languageEnglish (US)
Article number1641
JournalFrontiers in Microbiology
Volume10
DOIs
StatePublished - 2019

Keywords

  • Atacama Desert playa
  • high-throughput DNA sequencing
  • immunoassay microarrays
  • metaproteomics
  • microbial ecology
  • rainfall event
  • subsurface environments

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)

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