Cable bacteria

[7] Within a 15 cm thick top layer of sediment, cable bacteria densities providing total length of up to 2 km per square centimeter of surface have been observed.

They consist of proteins that are rich in nickel and sulfur, are electrically insulated, and run the entire length of the cell filament.

[11][12] Cable bacteria have been identified in a diverse range of climatic conditions worldwide,[13] including Denmark,[2][6] the Netherlands,[14] Japan,[15] Australia,[16] and the United States.

[17] Cable bacteria lack flagella, but are capable of motility in the form of gliding[18] by propelling themselves forward through the excretion of substances.

[18] Although motility is important for other microorganisms, once cable bacteria are located in a place that connects oxygen to sulfide, they no longer need to move.

The transfer of electrons through cable bacteria allows the sulfate reduction that occurs in inundated soils to be balanced by sulfide oxidation.

[24] In the future, cable bacteria may play a role in increasing the efficiency of microbial fuel cells deployed in sedimentary environments.

Cable bacteria have also been found associated with a bioelectrochemical system that enhances the degradation of marine sediment contaminated by hydrocarbons [25] and thus may play a role in future oil spill cleanup technologies.

Cable bacteria in between two layers of sediment split apart inside a glass cylinder.
Diagram demonstrating cable bacteria metabolism in surface sediment. Hydrogen sulfide (H 2 S) is oxidized in the sulfidic sediment layer, and the resulting electrons (e − ) are conducted up through the cable bacteria filament to the oxic layer and used to reduce molecular oxygen (O 2 ).