I have been to the Atacama Desert six times already.
We are far from anywhere.
There's no bathroom, there is nothing.
You don't wash for five days.
Comparing what we do to a human mission on Mars, what we do is very easy.
The Atacama Desert in Chile is one of the driest and most surreal places on Earth, and
it is so unique that it may even hold answers to questions about where we might find life
elsewhere in the universe.
The Atacama Desert is very similar to some of the conditions we can find on Mars in terms
of salt chemistry, in particular.
Exposure to UV is much, much higher on Mars than the Atacama Desert.
But this is as close as we can get.
It’s here that Dr. Jocelyne DiRuggiero studies extremophiles, which are microorganisms that
live in extreme environments.
In this instance, she’s studying photosynthesizing extremophiles that live inside of rocks, a
place that you wouldn’t expect light to be able to penetrate.
We are interested in cyanobacteria, and they are found everywhere on Earth.
They are primary producers, very much like plants, so they use energy from the sun, carbon
dioxide, and water, and then they make organic carbon, which is then used by other microorganisms.
They live inside rocks because they're protected from high solar radiation, desiccation, but
it's also a place where water is retained better than in the soil.
We're trying to find out how do they not only survive, but thrive how do they grow, and
how do they evolve in those crazy conditions?
Jocelyne and her team used geological hammers while collecting and opening rocks in the
desert, as well as several other tools to measure weather, temperature, and humidity.
They also used a drill, spectrophotometer, and fiber-optic sensor that measures the intensity
and color of any light penetrating the rock.
We pretended we were those little microorganisms inside the rocks and what do we see?
What do we feel when we're out there in this rock?
We had done experiments in the lab on other types of rocks and we could see that the deeper
in the rock, the less light we had.
It looks like the light they see is a little redder than the light that is outside the
rock, and so this brings the questions, "What are the adaptations to the photo systems that
allow them to capitalize on this red light?"
It was from the bed of a pickup truck in the howling winds that the scientists had to pull
off these complicated experiments.
But it paid off with some striking results.
The light experiments were quite surprising.
With the halite, which are sodium chloride rocks basically, there is a lot of light,
even underneath the rock.
This has to do with the composition of the salt rock and also the fact that the light
is reflected on the ground and bouncing back.
So those microbial communities that are at different spots inside the rocks will see
different type of lights, and we didn't know that before.
The quality of the light that reaches the cyanobacteria could indicate how these organisms
are photosynthesizing from the inside of a rock, compared to other primary producers,
like plants.
In order to figure out this process, Jocelyne and the team want to take a closer look at
the organism's genome, to see if there are any genetic mutations that allow them to live
in these extreme environments.
Back to the lab, where we'll do the molecular analysis to figure out who is there, what the community is
and also count the number of cells and trying to correlate the light
inside the rocks with the microbial community at the molecular level.
But sequencing the genome of these microorganisms is going to take a while.
Once these experiments are complete, Jocelyne and her team hope their data will be useful
to other research missions, like studying how life can adapt to climate change, or thrive
on another planet.
Mars is very dry, so I'm not saying there is life
at the surface of Mars right now.
But you can imagine that Mars became more and more drier over its history.
It's very similar to what's happening in the Atacama Desert right now. It's getting drier and drier.
And so where are the last places where we could find life on Mars, and can we find biosignatures of this life?
Sometimes it's challenging.
But at the same time, it’s very rewarding.
After you work really hard and you're really tired, you sit around the campfire, we drink
a little scotch, brainstorm with ideas.
The skies at night in the Atacama are amazing.
You can see the whole Milky Way.
It's just totally mind-blowing.
This is really the time where you can get new insight about what we do, and we also
talk about why we're doing this, why are we scientists, what is our passion and this is
it.
For more episodes of Science in the Extremes, check out this one right here.
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Thanks for watching.