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Nitrates as a Potential N Supply for Microbial Ecosystems in a Hyperarid Mars Analog System

Nitrate is common in Mars sediments owing to long-term atmospheric photolysis, oxidation, and potentially, impact shock heating. The Atacama Desert in Chile, which is the driest region on Earth and rich in nitrate deposits, is used as a Mars analog in this study to explore the potential effects of h...

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Autores principales: Shen, Jianxun, Zerkle, Aubrey L., Stueeken, Eva, Claire, Mark W.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6958444/
https://www.ncbi.nlm.nih.gov/pubmed/31635024
http://dx.doi.org/10.3390/life9040079
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author Shen, Jianxun
Zerkle, Aubrey L.
Stueeken, Eva
Claire, Mark W.
author_facet Shen, Jianxun
Zerkle, Aubrey L.
Stueeken, Eva
Claire, Mark W.
author_sort Shen, Jianxun
collection PubMed
description Nitrate is common in Mars sediments owing to long-term atmospheric photolysis, oxidation, and potentially, impact shock heating. The Atacama Desert in Chile, which is the driest region on Earth and rich in nitrate deposits, is used as a Mars analog in this study to explore the potential effects of high nitrate levels on growth of extremophilic ecosystems. Seven study sites sampled across an aridity gradient in the Atacama Desert were categorized into 3 clusters—hyperarid, middle, and arid sites—as defined by essential soil physical and chemical properties. 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 SiO(2)/Al(2)O(3) and grain sizes suggest that sedimentation rates may also be 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, nitrate levels on a more recent, hyperarid Mars could be sufficiently high to benefit potentially extant Martian microorganisms.
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spelling pubmed-69584442020-01-23 Nitrates as a Potential N Supply for Microbial Ecosystems in a Hyperarid Mars Analog System Shen, Jianxun Zerkle, Aubrey L. Stueeken, Eva Claire, Mark W. Life (Basel) Article Nitrate is common in Mars sediments owing to long-term atmospheric photolysis, oxidation, and potentially, impact shock heating. The Atacama Desert in Chile, which is the driest region on Earth and rich in nitrate deposits, is used as a Mars analog in this study to explore the potential effects of high nitrate levels on growth of extremophilic ecosystems. Seven study sites sampled across an aridity gradient in the Atacama Desert were categorized into 3 clusters—hyperarid, middle, and arid sites—as defined by essential soil physical and chemical properties. 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 SiO(2)/Al(2)O(3) and grain sizes suggest that sedimentation rates may also be 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, nitrate levels on a more recent, hyperarid Mars could be sufficiently high to benefit potentially extant Martian microorganisms. MDPI 2019-10-19 /pmc/articles/PMC6958444/ /pubmed/31635024 http://dx.doi.org/10.3390/life9040079 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Shen, Jianxun
Zerkle, Aubrey L.
Stueeken, Eva
Claire, Mark W.
Nitrates as a Potential N Supply for Microbial Ecosystems in a Hyperarid Mars Analog System
title Nitrates as a Potential N Supply for Microbial Ecosystems in a Hyperarid Mars Analog System
title_full Nitrates as a Potential N Supply for Microbial Ecosystems in a Hyperarid Mars Analog System
title_fullStr Nitrates as a Potential N Supply for Microbial Ecosystems in a Hyperarid Mars Analog System
title_full_unstemmed Nitrates as a Potential N Supply for Microbial Ecosystems in a Hyperarid Mars Analog System
title_short Nitrates as a Potential N Supply for Microbial Ecosystems in a Hyperarid Mars Analog System
title_sort nitrates as a potential n supply for microbial ecosystems in a hyperarid mars analog system
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6958444/
https://www.ncbi.nlm.nih.gov/pubmed/31635024
http://dx.doi.org/10.3390/life9040079
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