Microbial activity in Martian analog soils after ionizing radiation: implications for the preservation of subsurface life on Mars

Vladimir S. Cheptsov; Elena A. Vorobyova; George A. Osipov; Natalia A. Manucharova; Lubov’ M. Polyanskaya; Mikhail V. Gorlenko; Anatoli K. Pavlov; Marina S. Rosanova; Vladimir N. Lomasov; Vladimir S. Cheptsov; Elena A. Vorobyova; George A. Osipov; Natalia A. Manucharova; Lubov’ M. Polyanskaya; Mikhail V. Gorlenko; Anatoli K. Pavlov; Marina S. Rosanova; Vladimir N. Lomasov

doi:10.3934/microbiol.2018.3.541

AIMS Microbiology

2018, Volume 4, Issue 3: 541-562. doi: 10.3934/microbiol.2018.3.541

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Research article Topical Sections

Microbial activity in Martian analog soils after ionizing radiation: implications for the preservation of subsurface life on Mars

1.
Soil Science Faculty, Lomonosov Moscow State University, Moscow, Russia
2.
Space Research Institute, Russian Academy of Sciences, Moscow, Russia
3.
International Analytical Center, Interlab, N.D.Zelinsky Institute of Organic Chemistry, Moscow, Russia
4.
Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg, Russia
5.
Peter the Great St. Petersburg State Polytechnic University, St. Petersburg, Russia

Received: 30 April 2018 Accepted: 04 July 2018 Published: 09 July 2018

At present, the surface of Mars is affected by a set of factors that can prevent the survival of Earth-like life. However, the modern concept of the evolution of the planet assumes the existence more favorable for life climate in the past. If in the past on Mars had formed a biosphere, similar to the one that originated in the early Earth, it is supposed that it is preserved till now in anabiotic state in the bowels of the planet, like microbial communities inhabiting the ancient permafrost of Arctic and Antarctic. In the conditions of modern Martian regolith, this relic life seems to be deprived of the possibility of damage reparation (or these processes occur on a geological time scale), and ionizing radiation should be considered the main factor inhibiting such anabiotic life. In the present study, we studied soil samples, selected in two different extreme habitats of the Earth: ancient permafrost from the Dry Valleys of Antarctica and Xerosol soil from the mountain desert in Morocco, gamma-irradiated with 40 kGy dose at low pressure (1 Torr) and low temperature (−50 °C). Microbial communities inhabiting these samples showed in situ high resistance to the applied effects, retained high number of viable cells, metabolic activity, and high biodiversity. Based on the results, it is assumed that the putative biosphere could be preserved in the dormant state for at least 500 thousand years and 8 million years in the surface layer of Mars regolith and at 5 m depth, respectively, at the current level of ionizing radiation intensity.
- astrobiology,
- Mars,
- gamma radiation,
- microbial communities,
- radioresistance
Citation: Vladimir S. Cheptsov, Elena A. Vorobyova, George A. Osipov, Natalia A. Manucharova, Lubov’ M. Polyanskaya, Mikhail V. Gorlenko, Anatoli K. Pavlov, Marina S. Rosanova, Vladimir N. Lomasov. Microbial activity in Martian analog soils after ionizing radiation: implications for the preservation of subsurface life on Mars[J]. AIMS Microbiology, 2018, 4(3): 541-562. doi: 10.3934/microbiol.2018.3.541

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Abstract

At present, the surface of Mars is affected by a set of factors that can prevent the survival of Earth-like life. However, the modern concept of the evolution of the planet assumes the existence more favorable for life climate in the past. If in the past on Mars had formed a biosphere, similar to the one that originated in the early Earth, it is supposed that it is preserved till now in anabiotic state in the bowels of the planet, like microbial communities inhabiting the ancient permafrost of Arctic and Antarctic. In the conditions of modern Martian regolith, this relic life seems to be deprived of the possibility of damage reparation (or these processes occur on a geological time scale), and ionizing radiation should be considered the main factor inhibiting such anabiotic life. In the present study, we studied soil samples, selected in two different extreme habitats of the Earth: ancient permafrost from the Dry Valleys of Antarctica and Xerosol soil from the mountain desert in Morocco, gamma-irradiated with 40 kGy dose at low pressure (1 Torr) and low temperature (−50 °C). Microbial communities inhabiting these samples showed in situ high resistance to the applied effects, retained high number of viable cells, metabolic activity, and high biodiversity. Based on the results, it is assumed that the putative biosphere could be preserved in the dormant state for at least 500 thousand years and 8 million years in the surface layer of Mars regolith and at 5 m depth, respectively, at the current level of ionizing radiation intensity.

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