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Early Mars habitability and global cooling by H2-based methanogens


During the Noachian, Mars’ crust may have provided a favourable environment for microbial life1,2. The porous brine-saturated regolith3,4,5 would have created a physical space sheltered from ultraviolet and cosmic radiation and provided a solvent, whereas the below-ground temperature2 and diffusion6,7 of a dense, reduced atmosphere8,9 may have supported simple microbial organisms that consumed H2 and CO2 as energy and carbon sources and produced methane as a waste. On Earth, hydrogenotrophic methanogenesis was among the earliest metabolisms10,11, but its viability on early Mars has never been quantitatively evaluated. Here we present a probabilistic assessment of Mars’ Noachian habitability to H2-based methanogens and quantify their biological feedback on Mars’ atmosphere and climate. We find that subsurface habitability was very likely, and limited mainly by the extent of surface ice coverage. Biomass productivity could have been as high as in the early Earth’s ocean. However, the predicted atmospheric composition shift caused by methanogenesis would have triggered a global cooling event, ending potential early warm conditions, compromising surface habitability and forcing the biosphere deep into the Martian crust. Spatial projections of our predictions point to lowland sites at low-to-medium latitudes as good candidates to uncover traces of this early life at or near the surface.

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Fig. 1: Modelled photochemistry and climate of early Mars.
Fig. 2: Initial and steady-state characteristics of Noachian Mars under the influence of hydrogenotrophic methanogens, for brines freezing at 203, 252 and 273 K.
Fig. 3: Median evolution of the ice coverage of Noachian Mars under the influence of hydrogenotrophic methanogens.
Fig. 4: Steady-state distribution of habitable conditions and ice on the surface of Noachian Mars.

Data availability

The datasets produced and analysed in this study are available in the following repository: (ref. 38

Code availability

The planetary ecosystem model coupling climate, atmosphere, ice coverage and below-ground ecosystem and the datasets produced with it are available in the following repository: (; ref. 38). The photochemical and climate models are accessible on the Virtual Planet Laboratory’s gitlab (; ref. 32); the adapted versions used in this study are available upon request.


  1. Cockell, C. S. et al. Habitability: a review. Astrobiology 16, 89–117 (2016).

    Article  ADS  Google Scholar 

  2. Michalski, J. R. et al. The Martian subsurface as a potential window into the origin of life. Nat. Geosci. 11, 21–26 (2018).

    Article  ADS  Google Scholar 

  3. Fairén, A. G. et al. Stability against freezing of aqueous solutions on early Mars. Nature 459, 401–404 (2009).

    Article  ADS  Google Scholar 

  4. Clifford, S. M. et al. Depth of the Martian cryosphere: Revised estimates and implications for the existence and detection of subpermafrost groundwater. J. Geophys. Res. 115, E07001 (2010).

    ADS  Google Scholar 

  5. Rivera-Valentín, E. G., Chevrier, V. F., Soto, A. & Martínez, G. Distribution and habitability of (meta)stable brines on present-day Mars. Nat. Astron. 4, 756–761 (2020).

    Article  ADS  Google Scholar 

  6. Stevens, A. H., Patel, M. R. & Lewis, S. R. Numerical modelling of the transport of trace gases including methane in the subsurface of Mars. Icarus 250, 587–594 (2015).

    Article  ADS  Google Scholar 

  7. Sholes, S. F., Krissansen-Totton, J. & Catling, D. C. A maximum subsurface biomass on mars from untapped free energy: CO and H2 as potential antibiosignatures. Astrobiology 19, 655–668 (2019).

    Article  ADS  Google Scholar 

  8. Wordsworth, R. D. The climate of early Mars. Annu. Rev. Earth Planet. Sci. 44, 381–408 (2016).

    Article  ADS  Google Scholar 

  9. Liu, J. et al. Anoxic chemical weathering under a reducing greenhouse on early Mars. Nat. Astron. 5, 503–509 (2021).

    Article  ADS  Google Scholar 

  10. Battistuzzi, F. U., Feijao, A. & Hedges, S. B. A genomic timescale of prokaryote evolution: insights into the origin of methanogenesis, phototrophy, and the colonization of land. BMC Evol. Biol. 4, 44 (2004).

    Article  Google Scholar 

  11. Martin, W. F. & Sousa, F. L. Early microbial evolution: the age of anaerobes. Cold Spring Harbor Perspect. Biol 8, a018127 (2016).

    Article  Google Scholar 

  12. Sauterey, B. et al. Co-evolution of primitive methane-cycling ecosystems and early Earth’s atmosphere and climate. Nat. Commun. 11, 2705 (2020).

    Article  ADS  Google Scholar 

  13. Affholder, A. et al. Bayesian analysis of Enceladus’s plume data to assess methanogenesis. Nat. Astron. 5, 805–814 (2021).

    Article  ADS  Google Scholar 

  14. Wordsworth, R. et al. Transient reducing greenhouse warming on early Mars. Geophys. Res. Lett. 44, 665–671 (2017).

    Article  ADS  Google Scholar 

  15. Turbet, M., Boulet, C. & Karman, T. Measurements and semi-empirical calculations of CO2 + CH4 and CO2 + H2 collision-induced absorption across a wide range of wavelengths and temperatures. Application for the prediction of early Mars surface temperature. Icarus 346, 113762 (2020).

    Article  Google Scholar 

  16. Price, P. B. & Sowers, T. Temperature dependence of metabolic rates for microbial growth, maintenance, and survival. Proc. Nat. Acad. Sci. USA 101, 4631–4636 (2004).

    Article  ADS  Google Scholar 

  17. Taubner, R.-S. et al. Biological methane production under putative Enceladus-like conditions. Nat. Commun. 9, 748 (2018).

    Article  ADS  Google Scholar 

  18. Ramirez, R. M. A warmer and wetter solution for early Mars and the challenges with transient warming. Icarus 297, 71–82 (2017).

    Article  ADS  Google Scholar 

  19. Kharecha, P., Kasting, J. & Siefert, J. A coupled atmosphere–ecosystem model of the early Archean Earth. Geobiology 3, 53–76 (2005).

    Article  Google Scholar 

  20. Tarnas, J. D. et al. Radiolytic H2 production on Noachian Mars: implications for habitability and atmospheric warming. Earth Planet. Sci. Lett. 502, 133–145 (2018).

    Article  ADS  Google Scholar 

  21. Yung, Y. L. et al. Methane on Mars and habitability: challenges and responses. Astrobiology 18, 1221–1242 (2018).

    Article  ADS  Google Scholar 

  22. Knutsen, E. W. et al. Comprehensive investigation of Mars methane and organics with ExoMars/NOMAD. Icarus 357, 114266 (2021).

    Article  Google Scholar 

  23. Cockell, C. S. Trajectories of martian habitability. Astrobiology 14, 182–203 (2014).

    Article  ADS  Google Scholar 

  24. Westall, F. et al. Biosignatures on Mars: What, where, and how? Implications for the search for Martian life. Astrobiology 15, 998–1029 (2015).

    Article  ADS  Google Scholar 

  25. Lepot, K. Signatures of early microbial life from the Archean (4 to 2.5 Ga) eon. Earth Sci. Rev. 209, 103296 (2020).

    Article  Google Scholar 

  26. Fastook, J. L. & Head, J. W. Glaciation in the late noachian icy highlands: Ice accumulation, distribution, flow rates, basal melting, and top-down melting rates and patterns. Planet. Space Sci. 106, 82–98 (2015).

    Article  ADS  Google Scholar 

  27. Fassett, C. I. & Head, J. W. Valley network-fed, open-basin lakes on Mars: distribution and implications for Noachian surface and subsurface hydrology. Icarus 198, 37–56 (2008).

    Article  ADS  Google Scholar 

  28. Tanaka, K. L. et al. Geologic Map of Mars: U.S. Geological Survey Scientific Investigations Map 3292, Scale 1000,000 (US Geological Survey, 2014);

  29. Sun, V. Z. & Stack, K. M. Geologic Map of Jezero Crater and the Nili Planum Region, Mars: U.S. Geological Survey Scientific Investigations Map 3464, Scale 1000 (US Geological Survey, 2020);

  30. Ward, P. The Medea Hypothesis (Princeton Univ. Press, 2009).

  31. Chopra, A. & Lineweaver, C. H. The Case for a Gaian bottleneck: the biology of habitability. Astrobiology 16, 7–22 (2016).

    Article  ADS  Google Scholar 

  32. Arney, G. et al. The Pale Orange Dot: The Spectrum and Habitability of Hazy Archean Earth. Astrobiology 16, 873–899 (2016).

  33. Batalha, N. et al. Testing the early Mars H2-CO2 greenhouse hypothesis with a 1-D photochemical model. Icarus 258, 337–349 (2015).

    Article  ADS  Google Scholar 

  34. Stüeken, E. E. et al. Isotopic evidence for biological nitrogen fixation by molybdenum-nitrogenase from 3.2 Gyr. Nature 520, 666–669 (2015).

    Article  ADS  Google Scholar 

  35. Cockell, C. S. et al. Minimum units of habitability and their abundance in the universe. Astrobiology 21, 481–489 (2021).

    Article  ADS  Google Scholar 

  36. Adams, D. et al. Nitrogen fixation at early Mars. Astrobiology 21, 968–980 (2021).

    Article  ADS  Google Scholar 

  37. Fergason, R. L., Hare, T. M. and Laura, J. HRSC and MOLA Blended Digital Elevation Model at 200m v2. Astrogeology PDS Annex (US Geological Survey, 2018);

  38. Sauterey, B. MarsEcosys v.1.0. Zenodo (2022).

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We are grateful for discussion with D. Apai, A. Bixel, Z. Grochau-Wright, B. Kacar, C. Lineweaver, S. Rafkin, A. Soto, V. Thouzeau and members of the OCAV Project at PSL University and of NASA’s Nexus for Exoplanet System Science (NExSS) research coordination network. We thank J. Kasting and his student J. Liu for their help adapting and running the VPL’s photochemical and climatic models. B.S. is grateful to E. Lutz for her open-access codes of beautiful Martian maps ( This work is supported by France Investissements d’Avenir programme (grant numbers ANR-10-LABX-54 MemoLife and ANR-10-IDEX-0001-02 PSL) through PSL IRIS OCAV and PSL–University of Arizona Mobility Program. R.F. acknowledges support from the US National Science Foundation, Dimensions of Biodiversity (DEB-1831493), Biology Integration Institute-Implementation (DBI-2022070), Growing Convergence in Research (OIA-2121155) and National Research Traineeship (DGE-2022055) programmes; and from the United States National Aeronautics and Space Administration, Interdisciplinary Consortium for Astrobiology Research program (award number 80NSSC21K059).

Author information

Authors and Affiliations



B.S., B.C., R.F. and S.M. conceptualized the study. B.S., A.A., R.F. and S.M. were responsible for the methodology. B.S. carried out the investigation and performed the formal analysis. B.S. and R.F. carried out the visualization. B.S. and S.M. wrote the software. R.F. and S.M. supervised the study. B.S. wrote the original draft of the manuscript. B.S., B.C., A.A., R.F. and S.M. reviewed and edited the manuscript.

Corresponding author

Correspondence to Boris Sauterey.

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The authors declare no competing interests.

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Nature Astronomy thanks Michael Wong and Owen Lehmer for their contribution to the peer review of this work.

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Extended data

Extended Data Fig. 1 Simulated depth profiles of (A) temperature and (B) diffusivity in Mars’ Noachian regolith.

Gray areas bounded by dashed lines represent the entire space in which the depth profiles can exist. Each line (here 2,000 in total) represents one specific profile simulated for one set of parameters drawn from the ranges given in Supplementary Table 1.

Extended Data Fig. 2 Ice-free surface fraction, ρ, (A) and average temperature in the corresponding region (B).

Ice coverage and average surface temperature are evaluated across the spatial projection of Mars average temperature distribution (see Methods). The black dotted line in B is the first diagonal corresponding to the planetary averaged surface temperature \(\bar T_{surface}\).

Extended Data Fig. 3 Surface and vertical distribution of a putative hydrogenotrophic methanogenic biosphere on Noachian Mars.

Spatial projection of the median minimum depth of this biomass occurrence for three values of brines’ freezing point of 203 K (A), 252 K (B), and 273 K (C). The white shaded areas correspond to the probability (from 50% to 90% by steps of 10%) of ice-coverage superimposed to the maps by transparency. Open circles indicate the Noachian lakes distributed along the South-North dichotomy. See Methods for more detail.

Supplementary information

Supplementary Information

Supplementary Tables 1 and 2 and refs. 39–47.

Supplementary Video 1

Median evolution through time of of the ice coverage of Noachian Mars under the influence of hydrogenotrophic methanogens assuming that brines freeze at 252 K.

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Sauterey, B., Charnay, B., Affholder, A. et al. Early Mars habitability and global cooling by H2-based methanogens. Nat Astron 6, 1263–1271 (2022).

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