Low Pressure Tolerance by Methanogens in an Aqueous Environment: Implications for Subsurface Life on Mars

Astrobiology

DOI: 10.1007/s11084-016-9519-9

Cite this article as:
Mickol, R.L. & Kral, T.A. Orig Life Evol Biosph (2016). doi:10.1007/s11084-016-9519-9

Abstract

The low pressure at the surface of Mars (average: 6 mbar) is one potentially biocidal factor that any extant life on the planet would need to endure. Near subsurface life, while shielded from ultraviolet radiation, would also be exposed to this low pressure environment, as the atmospheric gas-phase pressure increases very gradually with depth. Few studies have focused on low pressure as inhibitory to the growth or survival of organisms. However, recent work has uncovered a potential constraint to bacterial growth below 25 mbar. The study reported here tested the survivability of four methanogen species (Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum, Methanococcus maripaludis) under low pressure conditions approaching average martian surface pressure (6 mbar – 143 mbar) in an aqueous environment. Each of the four species survived exposure of varying length (3 days – 21 days) at pressures down to 6 mbar. This research is an important stepping-stone to determining if methanogens can actively metabolize/grow under these low pressures. Additionally, the recently discovered recurring slope lineae suggest that liquid water columns may connect the surface to deeper levels in the subsurface. If that is the case, any organism being transported in the water column would encounter the changing pressures during the transport.

Keywords

Methanogens Mars Methane Low pressure Survival 

Funding information

Funder NameGrant NumberFunding Note
National Aeronautics and Space Administration
  • #NNX12AD90G
Arkansas Space Grant Consortium

    Copyright information

    © Springer Science+Business Media Dordrecht 2016

    Authors and Affiliations

    1. 1.Arkansas Center for Space and Planetary SciencesUniversity of ArkansasFayettevilleUSA
    2. 2.Department of Biological Sciences, Science and Engineering 601University of ArkansasFayettevilleUSA

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