Live cables explain enigmatic electric currents

Oct 24, 2012
This shows cable bacteria in the mud of the sea bottom. Credit: Credit: Mingdong Dong, Jie Song and Nils Risgaard-Petersen

Researchers at Aarhus University, Denmark, made a sensational discovery almost three years ago when they measured electric currents in the seabed. It was unclear as to what was conducting the current, but the researchers imagined the electric currents might run between different bacteria via a joint external wiring network.The researchers have now solved the mystery. It turns out that the whole process takes place inside bacteria that are one centimetre long. They make up a kind of live electric cable that no one had ever imagined existed. Each one of these 'cable bacteria' contains a bundle of insulated wires that conduct an electric current from one end to the other.

Cable bacteria explain electric currents in the seabed

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 . 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 Christian Pfeffer, Aarhus University.

He could interrupt the electric currents by pulling a thin wire horizontally through the . Just as when an excavator cuts our electric cables.

In microscopes, scientists found a hitherto unknown type of long, multi-cellular bacteria that was always present when scientists measured the .

Live cables explain enigmatic electric currents
A small cavity in the seabed reveals a number of cable bacteria that conducts electric currents between the red surface and the deep, black, anaerobic sediment layers of the seabed. Credit: Credit: Nils Risgaard-Petersen

"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. Kilometers of living cables

The bacterium is one hundred times thinner than a hair and the whole functions as an electric cable with a number of insulated wires within it. Quite similar to the we know from our daily lives.

"Such unique insulated biological wires seem simple but with incredible complexity at nanoscale," says PhD student Jie Song, Aarhus University, who used nanotools to map the electrical properties of the cable bacteria.

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.

Unlike all other known forms of life, cable bacteria 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 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.

Biological innovation

"On the one hand, it is still very unreal and fantastic. On the other hand, it is also very tangible," says Professor at Aarhus University, Lars Peter Nielsen, who is in charge of exploring the natural electrical currents.

Along with a number of international cooperation partners, several scientists at Aarhus University already address the new and exciting questions that arise. Right from the understanding of bioelectronics at the molecular level to the role of cable bacteria in the history of Earth.

The future will tell whether this wondrous result of the biological evolution can also be used in new types of electronics.

Explore further: Cell division speed influences gene architecture

More information: Nature DOI:10.1038/nature11586

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Sanescience
1 / 5 (1) Oct 24, 2012
I wonder where in the scheme of things this kind of development would be related to the nerves in larger organisms?
jscroft
1 / 5 (2) Oct 24, 2012
One wonders if this could be a basis for consciousness... and, if so, what the sea floor wonders.
christ_jan
3.7 / 5 (3) Oct 24, 2012
Maybe Gaia theory is correct.
hemitite
not rated yet Oct 24, 2012
As there seem to be no nerve signals just DC current, these microbes appear to function as a sort of battery to free up O2 from water (or something else) to oxides their food.
jay_kaye_568
1 / 5 (1) Oct 24, 2012
A bio-computer the size of an ocean? hmm...
Jonseer
2 / 5 (4) Oct 24, 2012
Maybe Gaia theory is correct.


I'd agree with that.

I'd have to add however, that instead of being separate from it, we humans are an integral part of it even if we currently seem to be a rather dysfunctional part of the whole LOL

The day when technology makes connections between human minds doable with neural receiver implants wirelessly connected we will see what Gaia was up to ;)

We'll still be individuals, but on the subconscious level we will all function as one as her brain and be utterly unaware of it.

Once implementation reaches a critical mass of interconnectivity, irresponsible human behavior will suddenly grind to a rapid halt. (irresponsible = bad for the planet)

We will say to ourselves our civilization has finally matured, but the truth will be otherwise. ;)
cantdrive85
1 / 5 (7) Oct 25, 2012
"The combustion is a transfer of the electrons of the food to oxygen which the bacterial inner wires manage over centimeter-long distances."?!?!?
Excuse me?
Am I to understand the hypothesis is that these bacteria are digesting "food" which dislodges electrons from the "food" which in turn attaches to Oxygen?

Could another scenario be these are more like "antenna bacteria", that collect the electrical energy flowing from the Earth and water currents?

nuge
not rated yet Oct 25, 2012
This is absolutely incredible. The diversity of life and the power of evolution never cease to amaze me.
vidar_lund
1 / 5 (1) Oct 25, 2012
Maybe Gaia theory is correct.

Guess it depends on your definition of Gaia theory but humans are made entirely of material from the earth. We come from dust and will return to that when we die. In this respect the human mind is the concious mind of the earth itself.
jscroft
1.7 / 5 (3) Oct 25, 2012
Still getting my head around this. So now the ocean floor is riddled with networks of living electrical cables.

In an undisturbed seabed more than tens of thousands of kilometers of cable bacteria live under a single square meter of seabed.


By way of contrast, the total length of the "wiring" in a human brain is about 3 million km, or the equivalent of 300 square meters of seabed. The regions where these things live cover on the order of 300 million square km of ocean floor, so the total length of this living network is on the order of one TRILLION human-brain equivalents!

Once again we find the Universe to be somewhat stranger than we imagined.

P.S. For those unaccustomed to dealing with large numbers: that's around a hundred times more wiring than all human brains COMBINED. Does all that wiring necessarily imply processing power or intelligence? No... but it COULD.
Tausch
1 / 5 (2) Oct 25, 2012
Wiring?
Are the analogies aiding or impeding our understanding?

And Humans? Don't humans want a no-moving-parts, wireless existence or at least gadgetry that meets such criteria?

Are analogies superseded or obsolete once such a stage of human progress is as common as the wheel?

Wonderful discovery.

jscroft
1 / 5 (1) Oct 26, 2012
Tausch, I'm going to go with the idea that English isn't your native language. For "wiring", substitute "conductive neural connections," and the analogy might make more sense to you.

Within the context of neuroscience and related studies, it's a fairly common one. And since it obviously can't be true unless you can find it on Wikipedia, here: http://en.wikiped...igametre
Tausch
1 / 5 (1) Oct 27, 2012
@jscroft
Raised bilingually.

"conductive"? "Cables" have no 'choice' but to 'conduct'.
In fact a holy grail for 'conduction' is superconductivity.
Not so neurons.

If you were to create your own neuron, you need an ionic biochemical representation for the poorer analogy of 'resistance'.

The fairly common notion falls short and fails as soon as the word 'life' is mentioned.

The eel is a fine example where 'life' 'defines' - within the scope of human understanding - what is meant by 'live wires'.
'Microscopic' 'eels' - if you will.

The mimicry coming from humans is a failed understanding.
The electric chair.
Torbjorn_Larsson_OM
5 / 5 (3) Oct 27, 2012
This isn't totally unprecedented. The world's largest biomass, a bacterial bed outside of Chile, is using similar sheet filaments to close a sulfur redox process between anoxic sediments and oxygenated sea water. The difference is that it is only one bacteria per sheet. [ http://rd.springe...2-0443-3 ]

Re nerve analogs: Not only isn't there any signalling involved, there is no branching. It is no more a nerve than a solar cell is.

@ christ_jan:

No. Gaia has been rejected in tests (and it was seen as a woolly headed idea from the start). There are mass cycles but no overall feedback that protects from, say, extinctions.

@ cantdrive:

No, you are not to understand redox processes as electric currents. Redox processes are mainly concerned with wet state ionic currents. No "PU/EC" religion can change the actual physics.
jscroft
1 / 5 (3) Oct 28, 2012
Re nerve analogs: Not only isn't there any signalling involved, there is no branching. It is no more a nerve than a solar cell is.


Do we know that? I'm not so sure; the article certainly doesn't say. If there is more than one layer of these things, then you could certainly envision them arranged in branching networks.

Look, I'm not asserting that anybody has discovered Gaia. I'm just pointing out that here lies at least some POTENTIAL (pun intended, sorry) for the presence of Mind. Is that sort of a specious observation? Maybe... but at least to me it is also a VASTLY entertaining one! :)
LorentzFactor
5 / 5 (1) Oct 29, 2012
Re nerve analogs: Not only isn't there any signalling involved, there is no branching. It is no more a nerve than a solar cell is.


Do we know that? I'm not so sure; the article certainly doesn't say. If there is more than one layer of these things, then you could certainly envision them arranged in branching networks.

Look, I'm not asserting that anybody has discovered Gaia. I'm just pointing out that here lies at least some POTENTIAL (pun intended, sorry) for the presence of Mind. Is that sort of a specious observation? Maybe... but at least to me it is also a VASTLY entertaining one! :)


The article doesn't exclude it, because it felt no need to. Does one mention that no "nerve" signaling occurs when writing a research paper on their breadboard power AC->DC power converter they made for an electronics 101 class? No. Why? Because there is no reason to consider it given the context of the subject matter.

Seriously, all this pseudo-science posting is annoying.
BikeToAustralia
not rated yet Oct 29, 2012
Entertaining Gaia theory - Hitchhiker's Guide to the Galaxy proposed Earth, and everything on the planet, as a computer constructed to discover the meaning of 'Life, the Universe and Everything'.

Consciousness or the soul is our greatest prize. We use it to prove we are better than all of God's other children or all other life on Earth. But, what is it? Consciousness in a root mystery at the foundation of many of our proofs. "I think, therefore I am."

How much electricity does each bacteria produce and how much electricity does a string of bacteria conduct? It sounds like the bacteria work together.
BikeToAustralia
not rated yet Oct 29, 2012
Could DC electrical currents be part of another form of consciousness? I assume the bacteria exchange chemical signals with their neighbours. Isn't that exchange the basis of communication?

I think western science and mind set have not developed enough to detect intelligences and consciousnesses different from our own. Any sufficiently different intelligence is indistinguishable to us. (taking poetic license with Arthur C. Clarke quote)
jscroft
1 / 5 (2) Oct 29, 2012
Seriously, all this pseudo-science posting is annoying.


I know, I know... photon torpedoes don't work that way in real life.

Sheesh.
christ_jan
1 / 5 (1) Nov 06, 2012
@ christ_jan: No. Gaia has been rejected in tests (and it was seen as a woolly headed idea from the start). There are mass cycles but no overall feedback that protects from, say, extinctions.


Since when does gaia theory say extinction events are impossible? Give me one book reference. Plus link me the test that disporves gaia theory. For your information gaia theory has been proved by all environmental sciences, in fact without the author we wouldnt have environmental sciences to begin with. Now go back to the ignorance closet.
Tausch
1 / 5 (1) Nov 06, 2012
Maybe Gaia theory is correct. - cj


All good and well.
All good and finite.
If it were not for the decay of all condense matter.

All life - as presently defined - is finite.
All life - as presently defined - goes extinct.
All matter decays.

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