Low Pressure Tolerance by Methanogens in an Aqueous Environment: Implications for Subsurface Life on Mars
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.
KeywordsMethanogens Mars Methane Low pressure Survival
The authors thank Dr. Chris McKay for his helpful suggestions during the review process. The authors would like to acknowledge Walter Graupner at the Arkansas Center for Space and Planetary Sciences for his research assistance. The authors would also like to thank Larry Joe Steeley Jr. (Rainbow Technology, Pelham, AL) for his donation of duct seal putty. This research was supported by a grant from the National Aeronautics and Space Administration (NASA) Astrobiology: Exobiology and Evolutionary Biology Program, grant #NNX12AD90G and by grants from the Arkansas Space Grant Consortium.
- Atreya SK, GU ZG (1994) Stability of the Martian atmosphere: Is heterogeneous catalysis essential? Journal of Geophysical Research: Planets 99(1991–2012):13133–13145Google Scholar
- Lyons JR, Manning C, Nimmo F (2005) Formation of methane on Mars by fluid-rock interaction in the crust. Geophys Res Lett 32Google Scholar
- Martín-Torres FJ, Zorzano M-P, Valentín-Serrano P, Harri A-M, Genzer M, Kemppinen O, Rivera-Valentin EG, Jun I, Wray J, Madsen MB, Goetz W, McEwen AS, Hardgrove C, Renno N, Chevrier VF, Mischna M, Navarro-González R, Martínez-Frías J, Conrad P, McConnochie T, Cockell C, Berger G, Vasavada AR, Sumner D, Vaniman D (2015) Transient liquid water and water activity at Gale crater on Mars. Nat Geosci 8:357–361CrossRefGoogle Scholar
- Rennó NO, Bos BJ, Catling D, Clark BC, Drube L, Fisher D, Goetz W, Hviid SF, Keller HU, Kok JF, Kounaves SP, Leer K, Lemmon M, Madsen MB, Markiewicz WJ, Marshall J, McKay C, Mehta M, Smith M, Zorzano MP, Smith PH, Stoker C, Young SMM (2009) Possible physical and thermodynamical evidence for liquid water at the Phoenix landing site. Journal of Geophysical Research: Planets 1991–2012:114. doi: 10.1029/2009JE003362 Google Scholar
- Schirmack J, Böhm M, Brauer C, Löhmannsröben H-G, de Vera J-P, Möhlmann D, Wagner D (2014) Laser spectroscopic real time measurements of methanogenic activity under simulated Martian subsurface analog conditions. Planetary and Space Science 98:198–204. doi: 10.1016/j.pss.2013.08.019 CrossRefGoogle Scholar
- Sears DW, Chittenden JD (2005) On laboratory simulation and the temperature dependence of the evaporation rate of brine on Mars. Geophys Res Lett 32Google Scholar
- Smith PH, Tamppari LK, Arvidson RE, Bass D, Blaney D, Boynton WV, Carswell A, Catling DC, Clark BC, Duck T, DeJong E, Fisher D, Goetz W, Gunnlaugsson HP, Hecht MH, Hipkin V, Hoffman J, Hviid SF, Keller HU, Kounaves SP, Lange CF, Lemmon MT, Madsen MB, Markiewicz WJ, Marshall J, McKay CP, Mellon MT, Ming DW, Morris RV, Pike WT, Renno N, Staufer U, Stoker C, Taylor P, Whiteway JA, Zent AP (2009) H2O at the Phoenix landing site. Science 325:58–61CrossRefPubMedGoogle Scholar
- Sowers KR, Schreier H (1995) Archaea: A Laboratory Manual: Methanogens. MethanogensGoogle Scholar
- Spiga A, Forget F, Dolla B, Vinatier S, Melchiorri R, Drossart P, Gendrin A, Bibring JP, Langevin Y, Gondet B (2007) Remote sensing of surface pressure on Mars with the Mars Express/OMEGA spectrometer: 2. Meteorological maps. Journal of Geophysical Research: Planets 112(1991–2012)Google Scholar
- Tortora GJ, Funke BR, Case CL (2015) Microbiology: An Introduction, 12th Ed.Google Scholar
- Webster CR, Mahaffy PR, Atreya SK, Flesch GJ, Mischna MA, Meslin P-Y, Farley KA, Conrad PG, Christensen LE, Pavlov AA, Martín-Torres J, Zorzano MP, McConnochie TH, Owen T, Eigenbrode JL, Glavin DP, Steele A, Malespin CA, Archer PD Jr, Sutter B, Coll P, Freissinet C, McKay CP, Moores JE, Schwenzer SP, Bridges JC, Navarro-Gonzalez R, Gellert R, Lemmon MT, Science Team MSL (2015) Mars methane detection and variability at Gale crater. Science 347:415–417Google Scholar