Preprint Article Version 1 This version is not peer-reviewed

Atmospheric Nitrate as a Potential Nutrient for Life on Mars

Version 1 : Received: 24 July 2019 / Approved: 25 July 2019 / Online: 25 July 2019 (11:52:52 CEST)

A peer-reviewed article of this Preprint also exists.

Shen, J.; Zerkle, A.L.; Stueeken, E.; Claire, M.W. Nitrates as a Potential N Supply for Microbial Ecosystems in a Hyperarid Mars Analog System. Life 2019, 9, 79. Shen, J.; Zerkle, A.L.; Stueeken, E.; Claire, M.W. Nitrates as a Potential N Supply for Microbial Ecosystems in a Hyperarid Mars Analog System. Life 2019, 9, 79.

Journal reference: Life 2019, 9, 79
DOI: 10.3390/life9040079

Abstract

Nitrate is rich in Mars sediments owing to long-term atmospheric photolysis, oxidation, and deposition coupled with a lack of leaching via rainfall. The Atacama Desert in Chile, which is similarly dry and rich in nitrate deposits, is used as a Mars analog in this study to explore the potential effects of high nitrate levels on microbial growth. Seven study sites sampled across an aridity gradient in the Atacama Desert were categorized into 3 clusters – hyperarid, intermediate, and arid sites, as defined by major elements in the regolith, associated biomass, and precipitation. Intriguingly, the distribution of nitrate concentrations in the shallow subsurface suggests that the buildup of nitrate is not solely controlled by precipitation. Correlations of nitrate with SiO2/Al2O3 and grain sizes suggest that sedimentation rates are also important in controlling nitrate distribution. At arid sites receiving more than 10 mm/yr precipitation, rainfall shows a stronger impact on biomass than nitrate does. However, high nitrate to organic carbon ratios are generally beneficial to N assimilation as evidenced both by soil geochemistry and enriched culturing experiments. This study suggests that even in the absence of precipitation on contemporary Mars, the nitrate levels are sufficiently high to benefit potentially extant Martian microorganisms.

Subject Areas

nitrate; Mars; Atacama Desert; sedimentation rates; biomass preservation; extremophiles

Comments (0)

We encourage comments and feedback from a broad range of readers. See criteria for comments and our diversity statement.

Leave a public comment
Send a private comment to the author(s)
Views 0
Downloads 0
Comments 0
Metrics 0


×
Alerts
Notify me about updates to this article or when a peer-reviewed version is published.