Next Steps Forward in Understanding Martian Surface and Subsurface Chemistry

Carrier, Brandi

doi:10.1002/2017je005409

Cited by 10 publications

(6 citation statements)

References 18 publications

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“…We used calcium perchlorate as the source of perchlorate ions, as it is presumed to be the dominant parent salt at Rocknest 37 ; but perchlorate salts dissolve readily in water and we do not expect the parent salt to have a large effect on the toxicity of the perchlorate ions. On the other hand, concentrations vary with location, and how concentration changes with depth in the regolith is not known 38 . Besides, the regolith (or the water to which it has been added) could be processed to decrease perchlorate concentrations; a variety of methods have been developed on Earth 39 , where perchlorates are widespread contaminants.…”

Section: Discussionmentioning

confidence: 99%

On the growth dynamics of the cyanobacterium Anabaena sp. PCC 7938 in Martian regolith

et al. 2022

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The sustainability of crewed infrastructures on Mars will depend on their abilities to produce consumables on site. These abilities may be supported by diazotrophic, rock-leaching cyanobacteria: from resources naturally available on Mars, they could feed downstream biological processes and lead to the production of oxygen, food, fuels, structural materials, pharmaceuticals and more. The relevance of such a system will be dictated largely by the efficiency of regolith utilization by cyanobacteria. We therefore describe the growth dynamics of Anabaena sp. PCC 7938 as a function of MGS-1 concentration (a simulant of a widespread type of Martian regolith), of perchlorate concentration, and of their combination. To help devise improvement strategies and predict dynamics in regolith of differing composition, we identify the limiting element in MGS-1 – phosphorus – and its concentration-dependent effect on growth. Finally, we show that, while maintaining cyanobacteria and regolith in a single compartment can make the design of cultivation processes challenging, preventing direct physical contact between cells and grains may reduce growth. Overall, we hope for the knowledge gained here to support both the design of cultivation hardware and the modeling of cyanobacterium growth within.

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Section: Discussionmentioning

confidence: 99%

On the growth dynamics of the cyanobacterium Anabaena sp. PCC 7938 in Martian regolith

et al. 2022

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“…One example is the absence of perchlorates in the former, which have been detected and quantified at several locations on Mars (Hecht et al, 2009 ; Kounaves et al, 2014 ; Sutter et al, 2016 ). Perchlorates are likely ubiquitous at the surface, and how their concentration changes with depth is unknown (Carrier, 2017 ). Concentrations of perchlorates that would result from using 0.2 g ml −1 of regolith with perchlorate contents roughly similar to those found at the Phoenix landing site (Kounaves et al, 2014 ; Fang et al, 2015 ) affected, but did not prevent, the growth of Anabaena sp.…”

Section: Discussionmentioning

confidence: 99%

A Low-Pressure, N2/CO2 Atmosphere Is Suitable for Cyanobacterium-Based Life-Support Systems on Mars

et al. 2021

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The leading space agencies aim for crewed missions to Mars in the coming decades. Among the associated challenges is the need to provide astronauts with life-support consumables and, for a Mars exploration program to be sustainable, most of those consumables should be generated on site. Research is being done to achieve this using cyanobacteria: fed from Mars's regolith and atmosphere, they would serve as a basis for biological life-support systems that rely on local materials. Efficiency will largely depend on cyanobacteria's behavior under artificial atmospheres: a compromise is needed between conditions that would be desirable from a purely engineering and logistical standpoint (by being close to conditions found on the Martian surface) and conditions that optimize cyanobacterial productivity. To help identify this compromise, we developed a low-pressure photobioreactor, dubbed Atmos, that can provide tightly regulated atmospheric conditions to nine cultivation chambers. We used it to study the effects of a 96% N2, 4% CO2 gas mixture at a total pressure of 100 hPa on Anabaena sp. PCC 7938. We showed that those atmospheric conditions (referred to as MDA-1) can support the vigorous autotrophic, diazotrophic growth of cyanobacteria. We found that MDA-1 did not prevent Anabaena sp. from using an analog of Martian regolith (MGS-1) as a nutrient source. Finally, we demonstrated that cyanobacterial biomass grown under MDA-1 could be used for feeding secondary consumers (here, the heterotrophic bacterium E. coli W). Taken as a whole, our results suggest that a mixture of gases extracted from the Martian atmosphere, brought to approximately one tenth of Earth's pressure at sea level, would be suitable for photobioreactor modules of cyanobacterium-based life-support systems. This finding could greatly enhance the viability of such systems on Mars.

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“…− ) was first detected on Mars by the Wet Chemistry Lab (WCL) on the Phoenix Mars Lander at concentrations of 0.6 wt% 1,2 , by the Sample Analysis at Mars (SAM) instrument on the Curiosity Rover 3 , and subsequently in two martian meteorites 4,5 . These discoveries confirmed its planet-wide coverage and spurred questions about the role of oxychlorines (ClO x ) in the alteration and/or fragmentation of organic molecules on the surface of Mars [6][7][8][9][10] .…”

Section: Perchlorate (Clomentioning

confidence: 99%

Permeation of photochemically-generated gaseous chlorine dioxide on Mars as a significant factor in destroying subsurface organic compounds

Newmark,

Kounaves

2024

Sci Rep

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It has been shown that ultraviolet (UV) irradiation is responsible for the destruction of organic compounds on the surface of Mars. When combined with the photochemically-driven production of oxychlorines (ClOx) it can generate highly reactive species that can alter or destroy organic compounds. However, it has been assumed that since UV only penetrates the top few millimeters of the martian regolith, reactive ClOx oxidants are only produced on the surface. Of all the oxychlorine intermediates produced, gaseous chlorine dioxide [ClO2(g)] is of particular interest, being a highly reactive gas with the ability to oxidize organic compounds. Here we report on a set of experiments under Mars ambient conditions showing the production and permeation of ClO2(g) and its reaction with alanine as a test compound. Contrary to the accepted paradigm that UV irradiation on Mars only interacts with a thin layer of surface regolith, our results show that photochemically-generated ClO2(g) can permeate below the surface, depositing ClOx species (mainly Cl− and $${\text{ClO}}_{3}^{ - }$$ ClO 3 - ) and destroying organic compounds. With varying levels of humidity and abundant chloride and oxychlorines on Mars, our findings show that permeation of ClO2(g) must be considered as a significant contributing factor in altering, fragmenting, or potentially destroying buried organic compounds on Mars.

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Next Steps Forward in Understanding Martian Surface and Subsurface Chemistry

Cited by 10 publications

References 18 publications

On the growth dynamics of the cyanobacterium Anabaena sp. PCC 7938 in Martian regolith

On the growth dynamics of the cyanobacterium Anabaena sp. PCC 7938 in Martian regolith

A Low-Pressure, N2/CO2 Atmosphere Is Suitable for Cyanobacterium-Based Life-Support Systems on Mars

Permeation of photochemically-generated gaseous chlorine dioxide on Mars as a significant factor in destroying subsurface organic compounds

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