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Evidence from fluid inclusions for microbial methanogenesis in the early Archaean era

Nature volume 440, pages 516519 (23 March 2006) | Download Citation



Methanogenic microbes may be one of the most primitive organisms1, although it is uncertain when methanogens first appeared on Earth. During the Archaean era (before 2.5 Gyr ago), methanogens may have been important in regulating climate, because they could have provided sufficient amounts of the greenhouse gas methane to mitigate a severely frozen condition that could have resulted from lower solar luminosity2 during these times. Nevertheless, no direct geological evidence has hitherto been available in support of the existence of methanogens in the Archaean period, although circumstantial evidence is available in the form of 2.8-Gyr-old carbon-isotope-depleted kerogen3. Here we report crushing extraction and carbon isotope analysis of methane-bearing fluid inclusions in 3.5-Gyr-old hydrothermal precipitates from Pilbara craton, Australia. Our results indicate that the extracted fluids contain microbial methane with carbon isotopic compositions of less than -56‰ included within original precipitates. This provides the oldest evidence of methanogen (> 3.46 Gyr ago), pre-dating previous geochemical evidence by about 700 million years.

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We thank M. Terabayashi, Y. Kato, K. Okamoto, T. Ota, T. Kabashima, K. Kitajima and K. Shimizu for assistance in field work, A. Thorne, K. J. McNamara and A. H. Hickman for field collaboration, H. Nara, Y. Matsui and M. Nishizawa for assisting in the construction of the vacuum line, and R. Buick and J. F. Kasting for comments on early versions of this manuscript. This research was supported by the 21st Century COE Program ‘How to build habitable planets,’ Tokyo Institute of Technology, sponsored by the Ministry of Education, Culture, Sports, Technology and Science, Japan. Y.U. thanks the Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists.

Author information


  1. Research Center for the Evolving Earth and Planet, Tokyo Institute of Technology,

    • Yuichiro Ueno
    • , Naohiro Yoshida
    •  & Shigenori Maruyama
  2. Department of Earth and Planetary Science, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan

    • Shigenori Maruyama
  3. Department of Environmental Science and Technology and

    • Yuichiro Ueno
    •  & Naohiro Yoshida
  4. Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, Midori-ku, Yokohama 226-8503, Japan

    • Keita Yamada
    •  & Naohiro Yoshida
  5. SORST project, Japan Science and Technology Corporation (JST), Kawaguchi, Saitama 332-0012, Japan

    • Yuichiro Ueno
    • , Keita Yamada
    •  & Naohiro Yoshida
  6. Department of Earth Science and Astronomy, University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan

    • Yukio Isozaki


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Competing interests

Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Corresponding author

Correspondence to Yuichiro Ueno.

Supplementary information

Word documents

  1. 1.

    Supplementary Figures

    This file contains Supplementary Figures 1, 2 and 3 with legends, which show sample locality map, more detailed photomicrographs of the fluid inclusions, and Universal Tree of Life with age constraints, respectively.

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  1. 1.

    Supplementary Notes

    This file contains Supplementary Methods, Supplementary Figures 3 and 4 with legends, and Supplementary Tables 1 and 2, which describe methods and results of the laser Raman and carbon isotope analyses. Supplementary Data includes the list of modern hydrothermal vent sites compiled in Fig. 2c of the main text with data source used for the compilation.

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