Three years ago researchers from Aarhus University in Denmark discovered something completely unpredicted, measurable electrical currents running through a completely undisturbed seabed. At the time of discovery, it wasn’t completely clear what was conducting the current, but the theory was that electric currents could possibly be traveling through different bacteria “via a joint external wiring network.”
The mystery has now been uncovered, though — the entire process is occurring inside of bacteria that are only one centimetre long. These create a sort of living electric cable. This discovery opens up all sorts of potential applications in different fields of electronics and energy technologies.
Every one of the ‘cable bacteria’ possess a ‘bundle of insulated wires’ that is conductible, allowing an electrical current to travel from one end to another.
Aarhus University writes: “Electricity and seawater are usually a bad mix. And it was thus a very big surprise when scientists from Aarhus University a few years ago discovered electric currents between biological processes in the seabed. Since then they have been searching for an explanation and together with partners from the University of Southern California, USA, they now present sensational results in Nature.”
“Our experiments showed that the electric connections in the seabed must be solid structures built by bacteria,” says PhD student Christian Pfeffer of Aarhus University.
The electrical currents could be interrupted simply by moving a thin wire horizontally across the seafloor. In the same way that our electric cables can be interrupted by damage.
“The incredible idea that these bacteria should be electric cables really fell into place when, inside the bacteria, we saw wire-like strings enclosed by a membrane,” says Nils Risgaard-Petersen, Aarhus University.
The new bacterium is about 100 times thinner than a human hair. The whole bacterium is essentially an electrical cable, possessing a quantity of insulated wires inside of itself — nearly in the same way that the common electric cables we use everyday are built.
“Such unique insulated biological wires seem simple but with incredible complexity at nanoscale,” says PhD student Jie Song, Aarhus University, who mapped the electrical properties of the cable bacteria using nano tools.
“In an undisturbed seabed more than tens of thousands kilometers cable bacteria live under a single square meter seabed. The ability to conduct an electric current gives cable bacteria such large benefits that it conquers much of the energy from decomposition processes in the seabed.”
In contrast to every other known form of life, these cable bacteria are able to “maintain an efficient combustion down in the oxygen-free part of the seabed. It only requires that one end of the individual reaches the oxygen which the seawater provides to the top millimeters of the seabed. The combustion is a transfer of the electrons of the food to oxygen which the bacterial inner wires manage over centimeter-long distances. However, small disturbances can lead to fatal ‘cable breakage’ in the fragile bacteria.”
Already, a number of international entities have shown interest in the research of the bacterium. Not only could the bacterium alter our understanding of bioelectronics, and revolutionize that field; but the bacteria really stand out in their uniqueness — there is much that is unknown about the role they or similar bacteria may have played in the development of life on Earth.
As of now, any potential applications are theoretical, but it would seem unlikely that these bacteria wouldn’t be used in some capacity in the development of new technologies.
Source: Aarhus University
Image Credits: Mingdong Dong, Jie Song and Nils Risgaard-Petersen;
For the fate of the sons of men and the fate of beasts is the same; as one dies, so dies the other. They all have the same breath, and man has no advantage over the beasts; for all is vanity. - Ecclesiastes 3:19