The Earth.
An inscrutable blue, green and white marble suspended in the vacuum of space and on its
surface, teeming with life.
You and me, countless animals, plants, fungi and bacteria on the mountains, plains, rivers,
and oceans of our planet.
But something is lurking underneath our feet.
According to new research?
A whole other world.
This new world that is slowly being revealed to us is what scientists call the deep biosphere
because it lies many meters below the earth’s surface.
It’s also sometimes called the dark biosphere--just because we like to give you the shivers...and
because, yknow, there’s no light down there.
The Deep Carbon Observatory is a global community of over 1000 scientists who, for the past
ten years, have been exploring this subterranean world and what lives in it.
The latest press release from this research community, as their 10-year long project comes
to an end, reveals just how startling the deep biosphere really is.
The team sampled life forms found at mines and boreholes that had been drilled up to
5 kilometers below the earth’s surface, and up to 2.5 kilometers below the seafloor.
With hundreds of samples, they were then able to model the size and makeup of the deep biosphere...and
it is HUGE.
The DCO estimates that the deep biosphere is probably made up of 2-2.3 billion cubic
kilometers of living organisms, which is almost twice the volume of all of the earth’s oceans.
Just let that sink in a little bit: take the entire water volume of the earth’s oceans,
pour it into a container.
Now double that container.
Now fill that container to the brim with stuff that’s alive--most of it, microscopic.
But the size isn’t the only impressive thing about the deep biosphere.
It’s also incredibly diverse, with the scientists on the project calling it the subterranean
Galapagos or likening it to the Amazon rainforest.
But we’re not talking monsters like the Kaiju from Pacific Rim or a Balrog a la Lord
of the Rings.
The deep biosphere is mostly made up of bacteria and another kind of single-celled organism
called archaea--MILLIONS of distinct types, most of which we’ve never seen before.
We have no idea what they are.
But they’re so plentiful, and so distinct that scientists think that about 70% of all
of earth’s bacteria and archaea probably live in the deep biosphere.
Again, that is INSANE--as of 2016, we estimate that there are around 1 trillion species of
microbes on earth, and scientists think that 99.999 percent of them have yet to be discovered.
And according to this new deep biosphere research, that trillion microbes that we haven’t even
been able to begin to classify?
That’s only 30% of the earth’s bacteria.
The rest are underneath us.
Some scientists even call all of this unclassified life, microbial ‘dark matter’--we know
that it’s there, we just don’t know what it is or how it works
Ok, besides the fact that this is mind-blowingly awesome and kinda freaky, why are these scientists
dedicating 10 years of their life to this research?
Why is this important?
Well, the kind of organisms that live in the deep biosphere are pretty radically different
from those that live above the surface.
They have to be able to survive with no sunlight, withstand massive pressures and extreme temperatures
underneath the oceans or kilometers deep inside the earth.
Some of them apparently have life-cycles on geologic time-scales...meaning they reproduce
and grow in time increments like eras and epochs, rather than minutes or days.
They get their energy from vastly different materials than we’re used to, in some cases
subsisting on nothing more than rock.
All of this is to say--the deep biosphere is a world of extremes.
With the help of advanced deep ocean and continental drilling technologies, and the increasing
accuracy and availability of DNA sequencing, exploring it will expand our understanding
of our own world and its biodiversity.
Hopefully, investigating the deep unknown will help us answer the lingering questions
that this environment poses: did life start below the surface and migrate up?
Or was it the other way around?
How does the deep biosphere interact with and influence the surface biosphere, if at
all?
But, perhaps most intriguingly, the Deep Carbon Observatory has shown us that we have not
yet discovered the limits for life on our planet.
The deeper we dig, the more extreme environments we explore, life is still there, flourishing
and strange.
And if life here can be so different from what we have imagined, what might be waiting
for us on other planets?
By familiarizing ourselves with the organisms of extremes here on Earth, we just might know
a little bit more about what to look for when we go searching for life elsewhere.
Fun fact: the naturally-occurring organism that holds the record for living at the hottest
temperature is Geogemma barossii, a single-celled organism that lives in hydrothermal vents
on the seafloor and can grow and reproduce at 121 degrees celsius.
For more on otherworldly life, check out this video here and thanks for always coming back
to Seeker for your science news fix.