Laboratory studies on the viability of life in H2-dominated exoplanet atmospheres


Theory and observation for the search for life on exoplanets via atmospheric ‘biosignature gases’ is accelerating, motivated by the capabilities of the next generation of space- and ground-based telescopes. The most observationally accessible rocky planet atmospheres are those dominated by molecular hydrogen gas, because the low density of H2 gas leads to an expansive atmosphere. The capability of life to withstand such exotic environments, however, has not been tested in this context. We demonstrate that single-celled microorganisms (Escherichia coli and yeast) that normally do not inhabit H2-dominated environments can survive and grow in a 100% H2 atmosphere. We also describe the astonishing diversity of dozens of different gases produced by E. coli, including many already proposed as potential biosignature gases (for example, nitrous oxide, ammonia, methanethiol, dimethylsulfide, carbonyl sulfide and isoprene). This work demonstrates the utility of laboratory experiments to better identify which kinds of alien environments can host some form of possibly detectable life.

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Fig. 1: The simplified schematic of the cell culture growth experiment for E. coli or yeast S. cerevisiae.
Fig. 2: Growth curves of E. coli.
Fig. 3: Growth curves of yeast.
Fig. 4: Spectral features of gases produced by E. coli with existing data.

Data availability

We supplied the source data for Figs. 2 and 3, which you can find as supplementary files as well as at The other data that support the plots within this paper and other findings of this study are available from the authors on request.

Change history

  • 14 May 2020

    An amendment to this paper has been published and can be accessed via a link at the top of the paper.


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We thank A. Babbin for use of his laboratory and S. Smirga for assistance. We thank M. Slabicki and C. de Boer for providing us with a sample of yeast Saccharomyces cerevisiae S288C. We also thank J. Petkowska-Hankel for help with Fig. 1 and Z. Zhan for Fig. 4. Seed funding for this work came from the Templeton Foundation Grant ‘The Alien Earths Initiative’, ID 43769. Funding for this work came from the MIT Professor Amar G. Bose Research Grant Program.

Author information




S.S. conceived the original idea and wrote the paper with the help of J.J.P. and M.P. M.P. designed and implemented the experimental set-up. S.S. and M.P. planned the experiments with the help of J.J.P. J.H. and M.P. performed the experiments with the help of J.J.P. All authors analysed the data.

Corresponding author

Correspondence to S. Seager.

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Supplementary information

Supplementary Information

Supplementary Materials and Methods, Figs. 1–3 and Tables 1–3.

Source data

Source Data Fig. 2

E. coli culture OD measurement data.

Source Data Supplementary Fig. 2

Oxygen partial pressures in E. coli experiments

Source Data Fig. 3

Composite photos of yeast cells in hemocytometer used for cell counting.

Source Data Fig. 3

Yeast hemocytometer cell counting data.

Source Data Supplementary Fig. 3

Oxygen partial pressures in yeast experiments.

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Seager, S., Huang, J., Petkowski, J.J. et al. Laboratory studies on the viability of life in H2-dominated exoplanet atmospheres. Nat Astron (2020).

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