Detection of Microorganisms and Metabolism in Dune Sand of a Low Organic Content

• Published in: Journal of geophysical research. Biogeosciences 2021-10, Vol.126 (10), p.n/a
• Main Authors: Rychert, Krzysztof, Wink, Lisa, Blohs, Marcus, Kumpitsch, Christina, Neumann, Charlotte, Moissl‐Eichinger, Christine, Wielgat‐Rychert, Magdalena
• Format: Article
• Language: English
• Subjects: 16S rRNA; Abundance; Analogs; Astrobiology; ATP; Carbon dioxide; carbon dioxide efflux; Deserts; Detection; Distilled water; Dune sand; Dunes; Efflux; Environmental conditions; Extraterrestrial environments; Extraterrestrial life; Extraterrestrial materials; Metabolic rate; Metabolism; Methods; Microbial activity; Microorganisms; Microscopes; National parks; Organic matter; rRNA 16S; Sand; Sandy soils; Soil; Soils; Temperate zones; Testing
• ISSN: 2169-8953; 2169-8961
• DOI: 10.1029/2021JG006404

The main goal of astrobiological studies is the search for life beyond Earth. Developing life detection methods requires test locations that have similar environmental conditions to extraterrestrial sites or that simply have low organism abundances. In this study, we describe dune sand of a low organic matter content (0.11%) collected from a national park frequented by few people. It is located in temperate zone. We hypothesized that dune sand is characterized by the low abundance of microorganisms and metabolic rates that could be compared to analogs of extraterrestrial environments like the Antarctic McMurdo Dry Valleys or the Atacama Desert. Measurements of CO2 efflux and ATP concentration demonstrated that hydrating dune sand with sterile distilled water initiated a short period of substantial microbial metabolic activity that lasted from 4 to 5 days. The maximum CO2 efflux was 100 mgCO2 m−2 d−1, which was low compared to values reported for sandy dunes, deserts and poor soils, including McMurdo Dry Valleys. Microscopic observations demonstrated that the abundance of prokaryotic microorganisms in the dune sand was low at roughly one million per cm3 of sand and was comparable to the abundance reported from the Atacama Desert. The microbial communities in the dune sand were studied based on 16S rRNA gene analyses. The most prominent bacterial genera were Massilia and Bacillus. Study demonstrated that dune sand sampled from a national park area was as useful for testing life detection methods as are other well‐established analogs of extraterrestrial environments. Plain Language Summary One of the main goals of contemporary science is the search for life beyond Earth. Developing life detection methods requires test locations that have similar environmental conditions to extraterrestrial sites or that simply have low organism abundances. In this study, we describe dune sand that could be used for testing life detection methods. The dune sand was sampled from a national park that is frequented by few people. It was compared to sites used previously such as the Antarctic McMurdo Dry Valleys or the South American Atacama Desert. The microbial communities in the dune sand were studied with different microscopes and genetic methods. Studies confirmed that the sand contained only a sparse community of microorganisms. The rates of their life processes were low compared to values reported for other sandy dunes, deserts, and poor soils. Thus, the dune sand studied t