A microbial oasis in the hypersaline atacama subsurface discovered by a life detector chip: Implications for the search for life on mars

Victor Parro*, Graciela De Diego-Castilla, Mercedes Moreno-Paz, Yolanda Blanco, Patricia Cruz-Gil, José Antonio Rodríguez-Manfredi, David Fernández-Remolar, Felipe Gómez, Manuel J. Gómez, Luis A. Rivas, Cecilia Demergasso, Alex Echeverría, Viviana N. Urtuvia, Marta Ruiz-Bermejo, Miriam García-Villadangos, Marina Postigo, Mónica Sánchez-Román, Guillermo Chong-Díaz, Javier Gómez-Elvira

*Corresponding author for this work

Research output: Contribution to JournalArticle

Abstract

The Atacama Desert has long been considered a good Mars analogue for testing instrumentation for planetary exploration, but very few data (if any) have been reported about the geomicrobiology of its salt-rich subsurface. We performed a Mars analogue drilling campaign next to the Salar Grande (Atacama, Chile) in July 2009, and several cores and powder samples from up to 5m deep were analyzed in situ with LDChip300 (a Life Detector Chip containing 300 antibodies). Here, we show the discovery of a hypersaline subsurface microbial habitat associated with halite-, nitrate-, and perchlorate-containing salts at 2m deep. LDChip300 detected bacteria, archaea, and other biological material (DNA, exopolysaccharides, some peptides) from the analysis of less than 0.5g of ground core sample. The results were supported by oligonucleotide microarray hybridization in the field and finally confirmed by molecular phylogenetic analysis and direct visualization of microbial cells bound to halite crystals in the laboratory. Geochemical analyses revealed a habitat with abundant hygroscopic salts like halite (up to 260g kg -1) and perchlorate (41.13μg g -1 maximum), which allow deliquescence events at low relative humidity. Thin liquid water films would permit microbes to proliferate by using detected organic acids like acetate (19.14μg g -1) or formate (76.06μg g -1) as electron donors, and sulfate (15875μg g -1), nitrate (13490μg g -1), or perchlorate as acceptors. Our results correlate with the discovery of similar hygroscopic salts and possible deliquescence processes on Mars, and open new search strategies for subsurface martian biota. The performance demonstrated by our LDChip300 validates this technology for planetary exploration, particularly for the search for life on Mars.

Original languageEnglish
Pages (from-to)969-996
Number of pages28
JournalAstrobiology
Volume11
Issue number10
DOIs
Publication statusPublished - 1 Dec 2011

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Keywords

  • Atacama Desert
  • Biopolymers
  • Biosensor
  • In situ measurement
  • Life detection

Cite this

Parro, V., De Diego-Castilla, G., Moreno-Paz, M., Blanco, Y., Cruz-Gil, P., Rodríguez-Manfredi, J. A., ... Gómez-Elvira, J. (2011). A microbial oasis in the hypersaline atacama subsurface discovered by a life detector chip: Implications for the search for life on mars. Astrobiology, 11(10), 969-996. https://doi.org/10.1089/ast.2011.0654