WEBVTT - What Can Earth's Deserts Teach Us About Martian Life?

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<v Speaker 1>Welcome to brain Stuff from how Stuff Works, Hey, brain Stuff,

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<v Speaker 1>Lauren Vogel bomb here. When it comes to searching for

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<v Speaker 1>microbes on Mars, sending a robotic rover to the most

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<v Speaker 1>arid environment on Earth is a fine place to start.

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<v Speaker 1>As described in a study recently published in the journal

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<v Speaker 1>Frontiers and Microbiology, a team of researchers explored the extreme

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<v Speaker 1>environment of Chile's Atacama Desert. They wanted to develop strategies

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<v Speaker 1>that future robotic explorers could use to seek out the

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<v Speaker 1>hiding places of Martian microbes. Both NASA and the European

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<v Speaker 1>Space Agency will launch their first life hunting rovers to

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<v Speaker 1>the Red planet, the Mars Exo Mars Rover missions, respectively,

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<v Speaker 1>so mission managers will need to know where to look.

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<v Speaker 1>The Atacama Desert is about as extreme as it gets

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<v Speaker 1>for life to eke out an existence, and not only

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<v Speaker 1>is the region bone dry, the core of the desert

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<v Speaker 1>doesn't get any rainfall for decades at a time, but

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<v Speaker 1>because of its elevation, it also receives high levels of

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<v Speaker 1>damaging ultraviolet radiation. Plus the soil is extremely salty. These

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<v Speaker 1>factors should make the Atacama Desert toxic for life, but

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<v Speaker 1>according to team leader stuff In Pointing, a professor at

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<v Speaker 1>Yale and US College in Singapore, some of the bacteria

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<v Speaker 1>just below the surface quote survive right at the limit

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<v Speaker 1>of habitability, and this is very good news for the

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<v Speaker 1>prospect of finding microbes on Mars. Pointings team deployed an

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<v Speaker 1>autonomous rover mounted drill and sampling device in the Atacama

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<v Speaker 1>Desert to see if it could extract soil samples containing

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<v Speaker 1>microbes down to a depth of eight centimeters that's a

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<v Speaker 1>little over two and a half feet. As a comparison,

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<v Speaker 1>samples were also dug up by hand through DNA sequencing.

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<v Speaker 1>The researchers found that the bacterial life and the samples

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<v Speaker 1>from both methods were similar, confirming that these hardy bacteria

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<v Speaker 1>exist and the autonomous extraction method was successful. This test

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<v Speaker 1>run shores up hope that if similarly hardy microbes also

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<v Speaker 1>thrived just below the Martian surface, a robot could find them. However,

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<v Speaker 1>finding microbial biosignatures on Mars could be very challenging for

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<v Speaker 1>a remotely operated Mars rover. The researchers found that the

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<v Speaker 1>subsurface population of bacteria were extremely patchy, correlating with increased

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<v Speaker 1>salt levels that restricted the availability of water. Pointing put

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<v Speaker 1>it this way, The patchy nature of the colonization suggest

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<v Speaker 1>the rover would be faced with a needle in a

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<v Speaker 1>haystack scenario. In the search for Martian bacteria, previous studies

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<v Speaker 1>have described the ubiquitous population of relatively unremarkable photosynthetic bacteria

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<v Speaker 1>that populate the surface of the desert in Chile. These

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<v Speaker 1>are microorganisms that get their energy from sunlight. Things start

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<v Speaker 1>to get a lot more interesting and indeed more alien,

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<v Speaker 1>just below the surface, Pointing said, we saw that with

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<v Speaker 1>increasing depth, the bacterial community became dominated by bacteria that

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<v Speaker 1>can thrive in extremely salty and alkaline soils. They in

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<v Speaker 1>turn were replaced at depths down to eighty centimeters by

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<v Speaker 1>a single specific group of bacteria that survived by metabolizing methane.

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<v Speaker 1>These specialized microbes have been found before in deep mind

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<v Speaker 1>shafts and other subterranean environment, but they've never been seen

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<v Speaker 1>beneath the surface of an arid desert. Pointing said, the

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<v Speaker 1>communities of bacteria that we discovered were remarkably lacking in complexity,

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<v Speaker 1>and this likely reflects the extreme stress under which they develop.

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<v Speaker 1>Finding highly specialized microbes that can thrive in the extremely dry,

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<v Speaker 1>salty and alkaline Mars. Like soils in the Atacama Desert

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<v Speaker 1>suggest methane utilizing bacteria could also thrive on the Red planet.

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<v Speaker 1>Elevated levels of methane have been observed on Mars by

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<v Speaker 1>various spacecraft over the years, most recently measures made by

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<v Speaker 1>NASA's Curiosity Rover, and that's a big deal. On Earth,

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<v Speaker 1>biological and geological processes generate methane, and in turn, microbes

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<v Speaker 1>can metabolize methane for energy. The discovery of methane in

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<v Speaker 1>the Martian atmosphere could mean there's some kind of active

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<v Speaker 1>biology going on underground. To confirm this, we need microbe

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<v Speaker 1>seeking missions that will drill below the surface, and now

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<v Speaker 1>we have a strategy to track them down. Should microbial

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<v Speaker 1>life be found on Mars, it would undoubtedly be the

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<v Speaker 1>most significant scientific discovery in human history. But in the

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<v Speaker 1>proud human tradition of naming new things, what would we

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<v Speaker 1>call our newly discovered Martian neighbors? Would we just copy

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<v Speaker 1>the system of how we name life on Earth? Pointing said,

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<v Speaker 1>the way we assign Latin names to terrestrial bacteria is

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<v Speaker 1>based on their evolutionary relationship to each other, and we

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<v Speaker 1>measure that using their genetic code. The naming of Martian

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<v Speaker 1>bacteria would require a completely new set of Latin names

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<v Speaker 1>at the highest level, if Martian bacteria were a completely

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<v Speaker 1>separate evolutionary lineage, that is, they evolved from a different

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<v Speaker 1>common ancestor to Earth bacteria in a second genesis event. Granted,

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<v Speaker 1>if we find the genetic code of Mars life to

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<v Speaker 1>be similar to Earth life, it could be that life

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<v Speaker 1>was transferred from Earth to Mars in the ancient past

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<v Speaker 1>via a massive impact, a mechanism known as pan spermia.

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<v Speaker 1>But if we find a truly novel genetic code that

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<v Speaker 1>emerged on Mars, the implications for our understanding of life

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<v Speaker 1>would be profound. Pointing said, if we find truly native

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<v Speaker 1>Martian bacteria, I would love to name one and call

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<v Speaker 1>it planet a desert a supersities, which translates in Latin

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<v Speaker 1>to survive on the desert planet. Today's episode was written

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<v Speaker 1>by Ian O'Neill and produced by Tyler Clain for iHeartMedia

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<v Speaker 1>and How Stuff Works. For more on this and lots

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<v Speaker 1>of other hardy topics, visit our home planet how stuff

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<v Speaker 1>Works dot Com.