Rock-crushing derived hydrogen directly supports a methanogenic community: significance for the deep biosphere
|Author(s)||Parkes Ronald John1, Berlendis Sabrina1, Roussel Erwan1, Bahruji Hasiliza2, Webster Gordon1, 3, Oldroyd Anthony1, Weightman Andrew J.3, Bowker Michael2, Davies Philipp R2, Sass Henrik1|
|Affiliation(s)||1 : School of Earth and Ocean Sciences; Main Building, Park Place, Cardiff University; Cardiff CF10 3AT Wales, UK
2 : Cardiff Catalysis Institute, School of Chemistry; Cardiff University; Cardiff, CF10 3AT Wales, UK
3 : School of Biosciences; Sir Martin Evans Building, Cardiff University; Museum Avenue Cardiff CF10 3AX Wales, UK
|Source||Environmental Microbiology Reports (1758-2229) (Wiley), 2019-04 , Vol. 11 , N. 2 , P. 165-172|
|WOS© Times Cited||10|
Microbial populations exist to great depths on Earth, but with apparently insufficient energy supply. Earthquake rock fracturing produces H2 from mechanochemical water splitting, however, microbial utilization of this widespread potential energy source has not been directly demonstrated. Here, we show experimentally that mechanochemically generated H2 from granite can be directly, long‐term, utilized by a CH4 producing microbial community. This is consistent with CH4 formation in subsurface rock fracturing in the environment. Our results not only support water splitting H2 generation as a potential deep biosphere energy source, but as an oxidant must also be produced, they suggest that there is also a respiratory oxidant supply in the subsurface which is independent of photosynthesis. This may explain the widespread distribution of facultative aerobes in subsurface environments. A range of common rocks were shown to produce mechanochemical H2, and hence, this process should be widespread in the subsurface, with the potential for considerable mineral fuelled CH4 production.