Abstract
The Opalinus Clay formation will host geological nuclear waste repositories in Switzerland. It is expected that gas pressure will build-up due to hydrogen production from steel corrosion, jeopardizing the integrity of the engineered barriers. In an in situ experiment located in the Mont Terri Underground Rock Laboratory, we demonstrate that hydrogen is consumed by microorganisms, fuelling a microbial community. Metagenomic binning and metaproteomic analysis of this deep subsurface community reveals a carbon cycle driven by autotrophic hydrogen oxidizers belonging to novel genera. Necromass is then processed by fermenters, followed by complete oxidation to carbon dioxide by heterotrophic sulfate-reducing bacteria, which closes the cycle. This microbial metabolic web can be integrated in the design of geological repositories to reduce pressure build-up. This study shows that Opalinus Clay harbours the potential for chemolithoautotrophic-based system, and provides a model of microbial carbon cycle in deep subsurface environments where hydrogen and sulfate are present.
| Original language | English |
|---|---|
| Article number | 12770 |
| Journal | Nature Communications |
| Volume | 7 |
| DOIs | |
| State | Published - Oct 14 2016 |
Funding
The work conducted by the U.S. Department of Energy Joint Genome Institute (JGI) is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. K.C and R.L.H. acknowledge support from U.S. Department of Energy's Genomic Science Program. JGI is acknowledged for providing resources for the sequencing analysis through the grant CSP 1505 to R.B.-L. A.F.A. is supported by a grant from the Swedish Research Council VR (grant 2011-5689).