Radiolysis via radioactivity is not responsible for rapid methane oxidation in subterranean air

This is a Preprint and has not been peer reviewed. This is version 3 of this Preprint.


Download Preprint

Supplementary Files

Arndt Schimmelmann, Angel Fernandez Cortes, Soledad Cuezva, Thomas Streil, Jay T. Lennon


Atmospheric methane is rapidly lost when it enters humid subterranean critical and vadose zones (e.g., air in soils and caves). Because methane is a source of carbon and energy, it can be consumed by methanotrophic methane-oxidizing bacteria. As an additional subterranean sink, it has been hypothesized that methane is oxidized by natural radioactivity-induced radiolysis that produces energetic ions and radicals, which then trigger abiotic oxidation and consumption of methane within a few hours. Using controlled laboratory experiments, we tested whether radiolysis could rapidly oxidize methane in sealed air with different relative humidities while being exposed to elevated levels of radiation (more than 535 kBq m-3) from radon isotopes 222Rn and 220Rn (i.e., thoron). We found no evidence that radiolysis contributed to methane oxidation. In contrast, we observed the rapid loss of methane when moist soil was added to the same apparatus in the absence of elevated radon abundance. Together, our findings are consistent with the view that methane oxidizing bacteria are responsible for the widespread observations of methane depletion in subterranean environments. Further studies are needed on the ability of microbes to consume trace amounts of methane in poorly ventilated caves, even though the trophic and energetic benefits become marginal at very low partial pressures of methane.



Earth Sciences, Geochemistry, Life Sciences, Physical Sciences and Mathematics


methane, cave, methanotrophy


Published: 2018-10-29 06:39

Last Updated: 2018-10-29 10:11

Older Versions

CC BY Attribution 4.0 International

Add a Comment

You must log in to post a comment.


There are no comments or no comments have been made public for this article.