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Microbial nanowires: Is the subsurface “hardwired”?
Author(s) -
Ntarlagiannis Dimitrios,
Atekwana Estella A.,
Hill Eric A.,
Gorby Yuri
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl030426
Subject(s) - shewanella oneidensis , nanowire , microorganism , nanotechnology , bacteria , materials science , microbial fuel cell , electrical conductor , electron transfer , scanning electron microscope , shewanella , chemistry , chemical engineering , electrode , geology , anode , composite material , paleontology , organic chemistry , engineering
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.