It turns out that bacteria may have figured out the whole electricity thing way before
we did, you guys.
In fact, there are bacteria deep in the ground and under the ocean right now that are acting
as living electric cables, and scientists are coming up with all sorts of cool new ways
to study them…and maybe even use them.
Electron-transporting bacteria were a mystery up until a couple decades ago and what makes
them unique is that some of them may not need anything but electrons to survive.
See, every living thing needs a source of electrons to survive, but the difference is that we
can’t just lick an electrode for all the energy we need.
Both Shewanella and Geobacter species, for example, breathe rock.
When no oxygen is available, these species use their pili, or little electrically
conductive ‘nanohairs’ to transport electrons to nearby rocks, putting their electrons into
metals like iron in the same way we put our body’s electrons into oxygen.
One team at the University of Southern California is now attempting to grow bacteria directly
on an electrode without giving it anything else, just to see if they can survive on pure electrons.
Delving into this whole world of electric bacteria has made scientists think, ‘Hey!
What else out there is like this.’
And in recent years they observed something very strange.
Electric currents were detected in the seafloor, but we didn’t know what the source was.
And when we took a closer look?
Surprise, bacteria!
But these work a little differently: they’re called “cable bacteria”, and they’re
remarkable, maybe one of the most striking discoveries of the last few decades in microbiology.
They also live in areas with little to no oxygen, like far down in the sediments at
the bottom of a body of water.
They can connect deep layers of the soil—where there is no oxygen to breathe—with surface
layers, where oxygen is present.
And how they do it is maybe the most remarkable piece of all.
Cable bacteria are actually multicellular microorganisms—which is pretty rare in the bacterial
world.
And what you’re looking at right now is not little nanohairs grown by the bacteria, as
is the case with other electrically conductive microbes...these structures are the bacteria
themselves.
They are the cable!
They can span up to a few centimeters, which is a huge distance for a microorganism like
a bacterium, shuttling electrons like a little snorkel.
That’s how they carry out their respiration process, which is what generates their energy and
which also generates an electric current. These electrically conductive ‘cables’ can even
connect to each other, forming extremely dense networks of what is essentially living electricity.
Which you can imagine, opens up a whole world of possibilities.
Researchers across the world believe they’ve identified at least six new species of cable-connected
bacteria that live in places like tidal pools, mud flats, and salt marshes.
And a new study that measured the properties of this kind of bacteria for the first time
showed that these biocables can sustain an electric that's current comparable to the current density
in copper wiring that we use in our everyday lives!
Think about it—this could give us electricity that you can grow.
I mean, some scientists think that these bacterial mats could be forming networks that extend
for hundreds of meters—and we didn’t even know about these bacterial biocables
until recently.
So imagine what else we’ll uncover about them as we continue to explore!
But there are lots of other big implications too.
Scientists think that these interconnected mats of complex microorganisms could be involved
in the regulation of Earth’s soil and ocean biogeochemistry, which is something we’d never
considered before.
Other non-cable electric bacteria could be incorporated into machines called self-powered
useful devices.
These SPUDs could be sent into places that have some kind of chemical that needs to be
cleaned up, full of microorganisms that could be genetically engineered to adhere to or
absorb that pollutant, while also creating the electricity needed to power the machine
just by cycling electrons from their surroundings.
Bacteria that exhibit these electric properties often live in extreme places where there’s
not a lot else to breathe—that’s what drives ‘em to the electric life, so to speak.
This is important because it provides a model for life in other places with no other things
for living stuff to eat...like, I dunno, other planets?
So bacteria like Geobacter species, that can survive basically just with access to metal,
could give us helpful clues about what kinds of organisms could be living out there in
the rest of the universe.
These organisms give us important insight into what the bare minimum required for life
really is, letting us guess not only about life out in space, but about the origin of
life here on Earth too.
Tiny but mighty, and changing the world, one electron-conducting bacterial appendage at
a time.
Gotta love ‘em!
If you want more on the amazing things that bacteria can do, check out this video here,
and let us know down in the comments what crazy bacterial species you want to learn
about next.
Make sure you subscribe to Seeker to stay up to date with all your microbial news and
as always, thanks for watching.