Microbial nanowires: Is the subsurface “hardwired”?
Article first published online: 12 SEP 2007
Copyright 2007 by the American Geophysical Union.
Geophysical Research Letters
Volume 34, Issue 17, September 2007
How to Cite
2007), Microbial nanowires: Is the subsurface “hardwired”? Geophys. Res. Lett., 34, L17305, doi:10.1029/2007GL030426., , , and (
- Issue published online: 12 SEP 2007
- Article first published online: 12 SEP 2007
- Manuscript Accepted: 31 JUL 2007
- Manuscript Revised: 27 JUL 2007
- Manuscript Received: 19 APR 2007
- self potential;
 The Earth's shallow subsurface results from integrated biological, geochemical, and physical processes. Methods are sought to remotely assess these interactive processes, especially those catalysed by micro-organisms. Using saturated sand columns and the metal reducing bacterium Shewanella oneidensis MR-1, we show that electrically conductive appendages called bacterial nanowires are directly associated with electrical potentials. No significant electrical potentials were detectable in columns inoculated with mutant strains that produced non-conductive appendages. Scanning electron microscopy imaging revealed a network of nanowires linking cells-cells and cells to mineral surfaces, “hardwiring” the entire length of the column. We hypothesize that the nanowires serve as conduits for transfer of electrons from bacteria in the anaerobic part of the column to bacteria at the surface that have access to oxygen, akin to a biogeobattery. These results advance understanding of the mechanisms of electron transport in subsurface environments and of how microorganisms cycle geologic material and share energy.