This episode is supported by Wren, a website with a monthly subscription that helps fund
projects to combat the climate crisis. Click the link in the description to learn more about how
you can make a monthly contribution to support projects like rainforest protection programs.
[♪ INTRO]
Since almost the beginning of commercial oil production,
engineers have had a problem with things living in the oil reservoirs.
Not around the reservoirs. We’re talking microorganisms
living inside the blob of oil hundreds of meters below the surface.
Until recently, it was thought these critters had just caught
a ride down there from the surface on some drilling equipment. But it appears
that some have actually been down there for a long, long time.
And through a combination of home renovation and a special kind of
digestion, these tiny critters can show us just how hearty life can be.
Now, when I say “oil reservoir,” some people might have a picture that pops in their mind
of like the pumpjack or oil rig, but that’s just the machinery sitting above the reservoir.
The oil reservoir itself is underground,
and formed out of a pocket or series of gaps in the rock.
Sometimes these can be pretty close to the surface,
but many are deep underground…as far as five and a half kilometers.
In addition to oil, the reservoir has a fair amount of water, either as
a separate layer below the oil, or mixed up with the oil in the form of isolated tiny bubbles,
since oil and water can’t mix fully.
And it’s on these borders between oil and the water where microbes can live.
We’re talking bacteria as well as another group of organisms called archaea.
Now, some species definitely arrived after humans breached the ecosystem. Because to free
up the oil, drilling crews sometimes have to pump water or gas down into the wells,
and outside microbes can get swept along for those rides.
But other microbes were likely there before humans even existed.
Oil deposits get their start when dead organisms like algae settle at the bottom
of a body of water, and then get buried under layers upon layers of sediment.
Over millions of years, the molecules in their dead bodies break down and turn into
oil or gas. ~ But if some organisms were buried alive, their descendants could have survived
in those reservoirs anywhere from the 10 to 180 million years it took for humans to dig them up.
This hypothesis might seem a little far-fetched, but scientists have also
discovered microbes living over two kilometers beneath the ocean floor.
On the other hand, species could also have arrived before humans discovered
the oil reservoir, if sea water or fresh water from an aquifer somehow got inside.
Scientists are still working to figure out the origin story of these critters.
And they’re also working on how they manage to survive their toxic,
acidic, high pressure, and pitch black home…which also has very little water.
And thanks to minerals leaching from the rocks,
what water they do have access to is three to six times saltier than sea water.
And being that far below ground, it’s also hot. Deep oil reservoirs can reach
temperatures above 150 degrees Celsius. Even the most heat-loving microbes,
like the ones that live in Yellowstone’s geysers, tend to die when it hits 120 degrees.
But some, if not most of these microbes have figured out a special
way to survive the harsh conditions around them.
Instead of just freely floating around willy nilly,
they’ve actually built their own protective form of housing.
They’re called biofilms…mat-like
structures that microbial colonies create by excreting proteins and other compounds.
It’s basically like if you and your family could just build your own house out of your snot.
These biofilms protect microbes from their environment by keeping excess salt away,
or by forming a kind of heat-shield. They can even create community homes, where
multiple species help each other survive.
And they can also break the oil glob into smaller bits…so that the microbes can eat.
Many of these species produce the energy their single-celled bodies
need by breaking down the hydrocarbon molecules
in oil…those are the ones made up primarily of carbon and hydrogen, like propane or octane.
Meanwhile, other species get their energy by performing chemical reactions
with smaller compounds like sulfates or nitrates.
Sulfate, for instance, is a chemical consisting of one sulfur atom and four oxygens. So while
human cells get their energy by converting sugar molecules into carbon dioxide and water,
these little critters change sulfate into compounds like hydrogen sulfide.
In fact, some microbes eat so much that oil engineers often have to
account for their digestion when setting up a drilling operation.
For instance, they might monitor how much sulfate is in the water they inject into the
reservoir. Because if those sulfate-eating microbes make too much hydrogen sulfide,
it can corrode the oil rig’s steel and even poison human workers.
Or alternatively, they might have a more direct
hand in what microbe populations are allowed to live down there.
They can “disinfect” the reservoir with certain chemicals,
or even stimulate microbe growth by pumping in extra nutrients. That’s because, in some cases,
the chemicals the microbes give off can actually help the oil flow up to the surface more easily.
So depending on the species that’s already in a given well,
engineers might purposefully introduce new microbes to increase oil production!
As for how much humans are messing up these microbial homes, there hasn’t been a lot of
research. But there are hints that our meddling can influence which species thrive over time.
For example, one analysis of the Halfdan oil field off the coast of
Denmark found that after people started drilling there, slow-growing oxygen-shy
species that had once been dominant were pushed out by oxygen-loving hotshots.
Studying these little guys is really fascinating, both because of their incredible backstory,
and because it’s yet another example of an ecosystem affected by humans using fossil fuels.
But it also makes us think a little. Oil drilling can seem so artificial,
such a modern human invention. So when life shows up, we assume it’s interrupting us. But no.
It is actually us who’s interrupting them.
Thanks for watching this SciShow video and thank you to Wren for supporting it!
Wren is a website that helps fund projects that combat the climate crisis,
like protecting the Amazon rainforest.
Wren is currently raising funds to protect biodiversity,
prevent deforestation, and promote Indigenous land rights.
And, of course, that biodiversity includes microbes.
Using satellite and drone monitoring technology,
Indigenous Amazonians in the Ticuna community of Buen Jardín de Callaru in Peru
can detect deforestation early and protect their rainforest before it disappears.
This project provides the technology to combat illegal logging.
That means saving the trees that absorb about 350 million metric
tons of atmospheric carbon dioxide every year.
Once you sign up to make a monthly contribution to projects like this one,
you’ll receive monthly updates on their progress.
You’ll get to see the good you’re doing and what your money is being spent on.
You can start helping today by learning more at wren.co. But you will not be alone in this
effort. We’ve partnered with Wren to plant 10 additional trees for the first 100 people
who sign up using the referral link in the description down below!
[♪ OUTRO]