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Shen J, Huang T, Zhang H, Lin W. Hydrochemical and isotopic characteristics of water sources for biological activity across a massive evaporite basin on the Tibetan Plateau: Implications for aquatic environments on early Mars. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 935:173442. [PMID: 38788948 DOI: 10.1016/j.scitotenv.2024.173442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/28/2024] [Accepted: 05/20/2024] [Indexed: 05/26/2024]
Abstract
Covered by vast eolian landforms, gravel deposits, and playas, the worldwide typical evaporite deposit land, Qaidam Basin, in northwestern China is analogous to early Mars when the aridification process had lasted for millions of years since the end of a wetter climate. This study aims to investigate the chemical and isotopic characteristics of waters in an evaporite-rich environment, as well as the habitable conditions therein, that have undergone a transformation similar to early Mars. In May 2023, a total of 26 water samples were collected across the representative central axis of a longitudinal aridity gradient in the Qaidam Basin, including categories of meteoric water, freshwater, standing water accumulated after precipitation, salty lacustrine water, and hypersaline brines to inspect compounds made up of carbon, nitrogen, phosphorus, sulfur, halogen, and metallic elements. As evaporation intensified, the salt types transformed from HCO3-Ca·Na to Cl·SO4-Na or ClMg. The dominance of carbonate will gradually be replaced by sulfate and chloride, leaving much more dilute and less detectable contents. The presence of trace ClO4-, ClO3-, ClO2-, and BrO3- was confirmed in a few of the sampled Qaidam waters, indicating the preservation of oxyhalides in waters within an arid region and possibly the presence of relevant microbial enzymes. The isotopes of water, carbonaceous, and nitrogenous compounds provide valuable references for either abiogenic or biogenic signatures. With undetectable amount, phosphorus was found to be the limiting nutrient in evaporative aquatic environments but not necessarily antibiosignatures. Overall, these results suggest that the paleo-lacustrine environments on Mars are more likely to preserve biosignatures if they feature the dominance of carbonate minerals, bioavailable nitrate, phosphorus, and organic carbon, the presence of thermodynamically unstable oxyhalides, and isotope ratios that point to the involvement of biological activity.
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Affiliation(s)
- Jianxun Shen
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Tianming Huang
- Key Laboratory of Shale Gas and Geoengineering, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huiqing Zhang
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Lin
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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Moreno-Paz M, dos Santos Severino RS, Sánchez-García L, Manchado JM, García-Villadangos M, Aguirre J, Fernández-Martínez MA, Carrizo D, Kobayashi L, Dave A, Warren-Rhodes K, Davila A, Stoker CR, Glass B, Parro V. Life Detection and Microbial Biomarker Profiling with Signs of Life Detector-Life Detector Chip During a Mars Drilling Simulation Campaign in the Hyperarid Core of the Atacama Desert. ASTROBIOLOGY 2023; 23:1259-1283. [PMID: 37930382 PMCID: PMC10825288 DOI: 10.1089/ast.2021.0174] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 07/02/2023] [Indexed: 11/07/2023]
Abstract
The low organic matter content in the hyperarid core of the Atacama Desert, together with abrupt temperature shifts and high ultraviolet radiation at its surface, makes this region one of the best terrestrial analogs of Mars and one of the best scenarios for testing instrumentation devoted to in situ planetary exploration. We have operated remotely and autonomously the SOLID-LDChip (Signs of Life Detector-Life Detector Chip), an antibody microarray-based sensor instrument, as part of a rover payload during the 2019 NASA Atacama Rover Astrobiology Drilling Studies (ARADS) Mars drilling simulation campaign. A robotic arm collected drilled cuttings down to 80 cm depth and loaded SOLID to process and assay them with LDChip for searching for molecular biomarkers. A remote science team received and analyzed telemetry data and LDChip results. The data revealed the presence of microbial markers from Proteobacteria, Acidobacteria, Bacteroidetes, Actinobacteria, Firmicutes, and Cyanobacteria to be relatively more abundant in the middle layer (40-50 cm). In addition, the detection of several proteins from nitrogen metabolism indicates a pivotal role in the system. These findings were corroborated and complemented on "returned samples" to the lab by a comprehensive analysis that included DNA sequencing, metaproteomics, and a metabolic reconstruction of the sampled area. Altogether, the results describe a relatively complex microbial community with members capable of nitrogen fixation and denitrification, sulfur oxidation and reduction, or triggering oxidative stress responses, among other traits. This remote operation demonstrated the high maturity of SOLID-LDChip as a powerful tool for remote in situ life detection for future missions in the Solar System.
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Affiliation(s)
- Mercedes Moreno-Paz
- Department of Molecular Evolution, Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain
| | - Rita Sofia dos Santos Severino
- Department of Molecular Evolution, Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain
- Departament of Física y Matemáticas y de Automática, University of Alcalá de Henares (UAH), Madrid, Spain
| | - Laura Sánchez-García
- Department of Molecular Evolution, Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain
| | - Juan Manuel Manchado
- Department of Molecular Evolution, Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain
| | | | - Jacobo Aguirre
- Department of Molecular Evolution, Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain
| | - Miguel Angel Fernández-Martínez
- Department of Molecular Evolution, Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain
- Department of Natural Resource Sciences, McGill University, Québec, Canada
| | - Daniel Carrizo
- Department of Molecular Evolution, Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain
| | - Linda Kobayashi
- Space Science Division and Astrobiology Division, NASA Ames Research Center, Moffett Field, California, USA
| | - Arwen Dave
- Space Science Division and Astrobiology Division, NASA Ames Research Center, Moffett Field, California, USA
| | - Kim Warren-Rhodes
- Space Science Division and Astrobiology Division, NASA Ames Research Center, Moffett Field, California, USA
- Carl Sagan Center, SETI Institute, Mountain View, California, USA
| | - Alfonso Davila
- Space Science Division and Astrobiology Division, NASA Ames Research Center, Moffett Field, California, USA
| | - Carol R. Stoker
- Space Science Division and Astrobiology Division, NASA Ames Research Center, Moffett Field, California, USA
| | - Brian Glass
- Space Science Division and Astrobiology Division, NASA Ames Research Center, Moffett Field, California, USA
| | - Víctor Parro
- Department of Molecular Evolution, Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain
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Shen J, Zerkle AL, Claire MW. Nitrogen Cycling and Biosignatures in a Hyperarid Mars Analog Environment. ASTROBIOLOGY 2022; 22:127-142. [PMID: 34652219 PMCID: PMC8861911 DOI: 10.1089/ast.2021.0012] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 09/11/2021] [Indexed: 05/20/2023]
Abstract
The hyperarid Atacama Desert is a unique Mars-analog environment with a large near-surface soil nitrate reservoir due to the lack of rainfall leaching for millennia. We investigated nitrogen (N) cycling and organic matter dynamics in this nitrate-rich terrestrial environment by analyzing the concentrations and isotopic compositions of nitrate, organic C, and organic N, coupled with microbial pathway-enzyme inferences, across a naturally occurring rainfall gradient. Nitrate deposits in sites with an annual precipitation of <10 mm carry atmospheric δ15N, δ18O, and Δ17O signatures, while these values are overprinted by biological cycling in sites with >15 mm annual precipitation. Metagenomic analyses suggest that the Atacama Desert harbors a unique biological nitrogen cycle driven by nitrifier denitrification, nitric oxide dioxygenase-driven alternative nitrification, and organic N loss pathways. Nitrate assimilation is the only nitrate consumption pathway available in the driest sites, although some hyperarid sites also support organisms with ammonia lyase- and nitric oxide synthase-driven organic N loss. Nitrifier denitrification is enhanced in the "transition zone" desert environments, which are generally hyperarid but see occasional large rainfall events, and shifts to nitric oxide dioxygenase-driven alternative nitrifications in wetter arid sites. Since extremophilic microorganisms tend to exploit all reachable nutrients, both N and O isotope fractionations during N transformations are reduced. These results suggest that N cycling on the more recent dry Mars might be dominated by nitrate assimilation that cycles atmospheric nitrate and exchanges water O during intermittent wetting, resulting stable isotope biosignatures could shift away from martian atmospheric nitrate endmember. Early wetter Mars could nurture putative life that metabolized nitrate with traceable paleoenvironmental isotopic markers similar to microbial denitrification and nitrification stored in deep subsurface.
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Affiliation(s)
- Jianxun Shen
- School of Earth and Environmental Sciences and Centre for Exoplanet Science, University of St Andrews, St Andrews, United Kingdom
- Address correspondence to: Jianxun Shen, Centre for Exoplanet Science, School of Earth and Environmental Sciences, University of St Andrews, Irvine Building, North Street, St Andrews KY16 9AL, United Kingdom, USA
| | - Aubrey L. Zerkle
- School of Earth and Environmental Sciences and Centre for Exoplanet Science, University of St Andrews, St Andrews, United Kingdom
| | - Mark W. Claire
- School of Earth and Environmental Sciences and Centre for Exoplanet Science, University of St Andrews, St Andrews, United Kingdom
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Shen J, Wyness AJ, Claire MW, Zerkle AL. Spatial Variability of Microbial Communities and Salt Distributions Across a Latitudinal Aridity Gradient in the Atacama Desert. MICROBIAL ECOLOGY 2021; 82:442-458. [PMID: 33438074 PMCID: PMC8384830 DOI: 10.1007/s00248-020-01672-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/21/2020] [Indexed: 05/13/2023]
Abstract
Over the past 150 million years, the Chilean Atacama Desert has been transformed into one of the most inhospitable landscapes by geophysical changes, which makes it an ideal Mars analog that has been explored for decades. However, a heavy rainfall that occurred in the Atacama in 2017 provides a unique opportunity to study the response of resident extremophiles to rapid environmental change associated with excessive water and salt shock. Here we combine mineral/salt composition measurements, amendment cell culture experiments, and next-generation sequencing analyses to study the variations in salts and microbial communities along a latitudinal aridity gradient of the Atacama Desert. In addition, we examine the reshuffling of Atacama microbiomes after the rainfall event. Analysis of microbial community composition revealed that soils within the southern arid desert were consistently dominated by Actinobacteria, Chloroflexi, Proteobacteria, Firmicutes, Bacteroidetes, Gemmatimonadetes, Planctomycetes, and Acidobacteria, and Verrucomicrobia. Intriguingly, the hyperarid microbial consortia exhibited a similar pattern to the more southern desert. Salts at the shallow subsurface were dissolved and leached down to a deeper layer, challenging indigenous microorganisms with the increasing osmotic stress. Microbial viability was found to change with aridity and rainfall events. This study sheds light on the structure of xerotolerant, halotolerant, and radioresistant microbiomes from the hyperarid northern desert to the less arid southern transition region, as well as their response to changes in water availability.
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Affiliation(s)
- Jianxun Shen
- School of Earth and Environmental Sciences and Centre for Exoplanet Science, University of St Andrews, St Andrews, KY16 9AL, UK.
| | - Adam J Wyness
- Sediment Ecology Research Group, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, KY16 8LB, UK
- Coastal Research Group, Department of Zoology and Entomology, Rhodes University, Grahamstown, 6139, South Africa
| | - Mark W Claire
- School of Earth and Environmental Sciences and Centre for Exoplanet Science, University of St Andrews, St Andrews, KY16 9AL, UK
| | - Aubrey L Zerkle
- School of Earth and Environmental Sciences and Centre for Exoplanet Science, University of St Andrews, St Andrews, KY16 9AL, UK
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Reid RP, Oehlert AM, Suosaari EP, Demergasso C, Chong G, Escudero LV, Piggot AM, Lascu I, Palma AT. Electrical conductivity as a driver of biological and geological spatial heterogeneity in the Puquios, Salar de Llamara, Atacama Desert, Chile. Sci Rep 2021; 11:12769. [PMID: 34140571 PMCID: PMC8211675 DOI: 10.1038/s41598-021-92105-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 06/04/2021] [Indexed: 02/05/2023] Open
Abstract
Reputed to be the driest desert in the world, the Atacama Desert in the Central Andes of Northern Chile is an extreme environment with high UV radiation, wide temperature variation, and minimum precipitation. Scarce lagoons associated with salt flats (salars) in this desert are the surface expression of shallow groundwater; these ponds serve as refugia for life and often host microbial communities associated with evaporitic mineral deposition. Results based on multidisciplinary field campaigns and associated laboratory examination of samples collected from the Puquios of the Salar de Llamara in the Atacama Desert during austral summer provide unprecedented detail regarding the spatial heterogeneity of physical, chemical, and biological characteristics of these salar environments. Four main lagoons ('Puquios') and more than 400 smaller ponds occur within an area less than 5 km2, and are characterized by high variability in electrical conductivity, benthic and planktonic biota, microbiota, lagoon bottom type, and style of mineral deposition. Results suggest that electrical conductivity is a driving force of system heterogeneity. Such spatial heterogeneity within the Puquios is likely to be expanded with temporal observations incorporating expected seasonal changes in electrical conductivity. The complexity of these Andean ecosystems may be key to their ability to persist in extreme environments at the edge of habitability.
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Affiliation(s)
- R P Reid
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, 33149, USA.
- Bahamas Marine EcoCentre, Miami, FL, 33156, USA.
| | - A M Oehlert
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, 33149, USA
- Bahamas Marine EcoCentre, Miami, FL, 33156, USA
| | - E P Suosaari
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, 33149, USA
- Bahamas Marine EcoCentre, Miami, FL, 33156, USA
- Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington DC, 20560, USA
| | - C Demergasso
- Centro de Biotecnología , Universidad Católica del Norte, Antofagasta, Chile
| | - G Chong
- Departamento de Ciencias Geológicas , Universidad Católica del Norte, Antofagasta, Chile
| | - L V Escudero
- Centro de Biotecnología , Universidad Católica del Norte, Antofagasta, Chile
| | - A M Piggot
- Bahamas Marine EcoCentre, Miami, FL, 33156, USA
- AP Research Inc., Miami, FL, 33157, USA
| | - I Lascu
- Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington DC, 20560, USA
| | - A T Palma
- FisioAqua, Las Condes , 7550024, Santiago, Chile
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Shen J, Smith AC, Claire MW, Zerkle AL. Unraveling biogeochemical phosphorus dynamics in hyperarid Mars-analogue soils using stable oxygen isotopes in phosphate. GEOBIOLOGY 2020; 18:760-779. [PMID: 32822094 DOI: 10.1111/gbi.12408] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 05/14/2020] [Accepted: 07/20/2020] [Indexed: 05/27/2023]
Abstract
With annual precipitation less than 20 mm and extreme UV intensity, the Atacama Desert in northern Chile has long been utilized as an analogue for recent Mars. In these hyperarid environments, water and biomass are extremely limited, and thus, it becomes difficult to generate a full picture of biogeochemical phosphate-water dynamics. To address this problem, we sampled soils from five Atacama study sites and conducted three main analyses-stable oxygen isotopes in phosphate, enzyme pathway predictions, and cell culture experiments. We found that high sedimentation rates decrease the relative size of the organic phosphorus pool, which appears to hinder extremophiles. Phosphoenzyme and pathway prediction analyses imply that inorganic pyrophosphatase is the most likely catalytic agent to cycle P in these environments, and this process will rapidly overtake other P utilization strategies. In these soils, the biogenic δ18 O signatures of the soil phosphate (δ18 OPO4 ) can slowly overprint lithogenic δ18 OPO4 values over a timescale of tens to hundreds of millions of years when annual precipitation is more than 10 mm. The δ18 OPO4 of calcium-bound phosphate minerals seems to preserve the δ18 O signature of the water used for biogeochemical P cycling, pointing toward sporadic rainfall and gypsum hydration water as key moisture sources. Where precipitation is less than 2 mm, biological cycling is restricted and bedrock δ18 OPO4 values are preserved. This study demonstrates the utility of δ18 OPO4 values as indicative of biogeochemical cycling and hydrodynamics in an extremely dry Mars-analogue environment.
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Affiliation(s)
- Jianxun Shen
- School of Earth and Environmental Sciences and Centre for Exoplanet Science, University of St Andrews, St Andrews, UK
| | - Andrew C Smith
- NERC Isotope Geosciences Facilities, British Geological Survey, Nottingham, UK
| | - Mark W Claire
- School of Earth and Environmental Sciences and Centre for Exoplanet Science, University of St Andrews, St Andrews, UK
| | - Aubrey L Zerkle
- School of Earth and Environmental Sciences and Centre for Exoplanet Science, University of St Andrews, St Andrews, UK
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