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At the bottom of the world is miles and miles of desert.
Harsh winds blow over gravelly soil, and the lakes are covered in ice.
This is the McMurdo Dry Valleys—4,800 square kilometers of polar desert situated in the
icy, snowy continent of Antarctica.
It is surreal and majestic and grand.
But we are not journeying to Antarctica for the giant deserts and immense landscapes.
We are journeying to Antarctica for this.
We’re being very generous to ourselves with that “we.”
“We” is actually Ariel Waldman, explorer and president of the San Francisco Microscopical Society.
And today, she is our guest master of microscopes because in 2018, Ariel led a 5 week expedition
to Antarctica.
After being awarded a grant from the National Science Foundation’s Antarctic Artists & Writers
Program, and with additional support from National Geographic, she hopped on a plane
to New Zealand, then boarded a military transport aircraft with 185 pounds of gear to get to
McMurdo Station.
Her goal?
To find and study microbes living in Antarctica.
And not to spoil the mystery or anything, but she found them.
On our journey to the microcosmos, we’ve met so many incredible organisms that have
evolved fascinating lives—lives that are lived in all sorts of strange, strange places.
There’s been ponds, and tanks, and beach sand.
But it’s one thing to imagine microbes being able to survive anywhere.
It’s another thing to actually find an ostracod 74 feet deep on the seafloor in Antarctica,
one of the most extreme climates in the world.
The organisms that live here are dealing with frigid temperatures, dark winters, wind, and
UV radiation.
So you have to wonder…what survives?
It can’t all be penguins and seals.
Throughout the vast continent is an array of tiny, thriving creatures carving out their
own lives in the ice.
And over the past few decades, scientists have been finding microbes in ice, exposed
soils, meltwater ponds, and other pockets of Antarctic geology.
With each discovery, scientists understand a little bit more about how microbes are able
to survive in this harsh climate.
Moreover, the McMurdo Dry Valleys are perhaps the closest we come to replicating a Martian
environment on Earth, making it a useful area for astrobiologists to understand the possibilities
of life beyond our planet.
So with five weeks to search and explore the continent, Ariel set out to find some microbes
of her own.
But how exactly does one find microbes in Antarctica?
Well, any microbe hunt is a function of the environment you are hunting in.
And for our resident master of microscopes James, that means tubes, nets, and careful
monitoring of his freshwater samples.
For Ariel, it meant finding a way under the sea ice.
So, she recruited the help of some divers who gathered around a hole in the ice and dove in.
And if you’ve ever wondered what it looks like underneath an Antarctic ice sheet, Ariel
ventured down a long metal observation tube to watch the divers at work and witness the
hidden life under the ice for herself.
After she brought the samples back to her lab, Ariel used the Antarctic seawater available
on tap to keep them alive and happy as she prepared to watch them under the microscope.
But Ariel didn’t just rely on divers.
She hiked through the McMurdo Dry Valleys, and ventured to Blood Falls to gather microbes
living in the subglacial iron oxide that spills out in bright red colors across the frozen Lake Bonney.
She also hiked up to the top of a glacier to find natural frozen-over holes on its surface.
These are called cryoconite holes, and they form because of dark sediment deposits that
melt the ice around them, creating tiny ecosystems for wandering microbes.
And across the surface of the glacier are these little frozen-over pockets of dirt and
water that microbes are quite happy to live in.
So with some drills and a little help, Ariel collected some dirt-filled ice cores to study.
Under the microscope, she found ciliates and rotifers and tardigrades and cyanobacteria.
And what might be striking to you if you’ve been following our journey for a while is
that these are microbes that we have seen before, and quite frequently.
In some cases, this might not be surprising.
After all, tardigrades are well known for surviving seemingly unsurvivable conditions.
But it is still so remarkable to see a tardigrade in action—to see its legs wiggling and its
body curling—and to know that it came from an icy pocket inside an Antarctic glacier.
And then there are the diatoms, those single-celled algae encased in their own glass shells.
We’ve seen their beautiful jewel shapes before, but these Antarctic varieties can
sometimes reach such high densities that their pigments stain the sea ice brown.
Sea ice might seem like a strange place for these photosynthetic organisms to live.
But frozen seawater is full of channels and pores, creating little salty corridors that
house planktonic creatures (like diatoms) that get trapped in them as the surface water freezes.
The ice then isn’t just something that freezes.
It is something that captures, and something that becomes home.
And the microbes that live in these homes, whether in the ice or in the water—they
all have stories to tell.
In the beginning of the 20th century, Captain Robert Falcon Scott led the Discovery Expedition
through Antarctica.
And among the bits of Antarctica the expedition brought back were mats of cyanobacteria collected
from ponds of melted water.
These samples were carefully preserved and stored in London’s National History Museum,
allowing scientists more than a century later to study their composition and compare them
to the populations of cyanobacteria that exist in Antarctica now.
They found that the populations had stayed roughly the same—that the cyanobacteria
we see now are similar to the cyanobacteria that existed back then.
To some degree, this is a kind of comfort in an era where so much of our ecologies are shifting.
But it may also be that the time we have spent in Antarctica is too short, and that the cyanobacteria’s
future will look quite different from its present.
After all, the cyanobacteria and other microbes that are in Antarctica now may look similar
to organisms we see outside of the frozen continent, but they are still uniquely adapted
to a very particular and harsh way of life.
So the consistency we see over the past century may just be a function of the fact that these
organisms are so well-suited to their environment that new organisms have difficulty finding their way in.
But in a changing world, those well-carved niches may shift, changing the landscape and
the life within it.
Because Antarctica, for all its appearance of a barren land of ice and snow, is not so
barren after all.
It is full of life, found in different corners and unusual pockets.
And life shifts and changes.
But whatever these microbes tell us of our world and our time—or perhaps even a distant
world and a distant time—they are a reminder that even in deeply unfamiliar lands are deeply
familiar friends.
Thank you for coming on this journey with us as we explore the unseen world that surrounds us.
If you want to see more of Ariel’s adventures and microbes, you can watch her Antarctica
video series on her channel, or you can visit lifeundertheice.org.
And before we go, we also need to thank Babbel for sponsoring this episode of Journey to
the Microcosmos.
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It’s really exciting to, every once in a while, to bring you something special here
on Journey to the Microcosmos and I think that this episode is definitely one of those.
We’re so happy to be able to collaborate with Ariel on this, and it was all made possible
by the people whose names are on your screen right now.
They are our Patrons on Patreon and we are so grateful to them because we also very much
want this show to continue existing.
If you want to see more from our Master of Microscopes James Weiss, you can check out
Jam and Germs on Instagram.
And if you want to see more from us, there’s probably a subscribe button somewhere nearby.