Researchers have revealed new information on the dry tolerance of microorganisms by studying biomolecules in soils from the Atacama Desert in Chile. Samples from the Atacama were compared to additional samples collected from biologically active, wetter soils a few hundred kilometers away. The results of the study indicate that there is no microbial growth in the driest soils from the Atacama, and that microbial activity is likely limited to repair and cellular maintenance.

‘Dryness’ is a major environmental challenge for microorganisms, and studying life’s tolerance to dryness can help constrain the limits for life as we know it on Earth. This information is also relevant to understanding life’s potential in water-limited environments beyond Earth, such as Mars. The researchers believe that the driest Atacama surface soils could be representative of an environment where microorganisms have met their limit for growth and reproduction.

The study, “Constraints on the Metabolic Activity of Microorganisms in Atacama Surface Soils Inferred from Refractory Biomarkers: Implications for Martian Habitability and Biomarker Detection,” was published in the journal Astrobiology. The work was supported by NASA Astrobiology through the Exobiology Program.