Note: This article is currently in 'Proposed Content'
Cable bacteria are filamentous bacteria that conduct electricity across distances over 1cm (or more) in sediment and groundwater aquifers.They couple the reduction of oxygen or nitrate at the sediment's surface to the oxidation of sulfide in the deeper, anoxic, sediment layers.
“Long-distance electrical conductance in sediment was first observed in 2010 as a spatial separation of sulfide oxidation and oxygen reduction in marine sediment that was interrupted and re-established at a rate faster than could be explained by chemical diffusion. It was later found that this electrical conductance could be observed across a non-conductive layer of glass microspheres, where the only possible conductive structures were filamentous bacteria belonging to the family Desulfobulbaceae.”
The exact mechanisms by which the chains of bacteria conduct electricity are under investigation. How they evolved is unexplained. Their electrical activity is predicted to have profound impacts on mineral deposition - they very probably play an important role in maintaining marine ecosystems in coastal areas - but the scale is currently unknown.