D. Ntarlagiannis et al report in Geophys. Res. Lett. 34, L17305; 2007, that ome soil bacteria form networks of tiny wires linking individual bacterial cells into a web-like electrical circuit. The wires allow the bacteria to get rid of electrons generated during metabolism, transporting them to distant 'electron dumps'.
This leads Venter research Institute scientist Yuri Gorby to speculate soil may act as a circuit built by microbes to power their metabolic systems,. As the bacteria consume nutrients for energy, they spit out unwanted electrons into the circuit.
Last year, Gorby and his colleagues discovered that Shewanella oneidensis bacteria can grow 100 nanometer ( 1000 atom wide ) filaments which conduct electricity (Y. A. Gorby et al . Proc. Natl Acad. Sci. USA 103, 11358–11363; 2006). The researchers presented evidence that the microbes use these 'nanowires' to shunt electrons produced during metabolic reactions onto the surface of mineral grains in the soil, to be taken up by metal ions. Without an electron acceptor, the bacteria cannot function properly and die.