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High Lakes May Yield Clues to Life on Mars

John Roach
for National Geographic News
October 27, 2003
 
Next month Nathalie Cabrol and colleagues hope to slip into drysuits, don masks, and dive, without the aid of an oxygen tank, into a lake tucked into the crater of a 19,734-foot (6,014-meter) tall volcano on the border between Chile and Bolivia.

If they succeed, they will tie a world record for the highest "free dive."


"I'm less interested by the record than by what we will be wearing," said Cabrol, a planetary scientist with the NASA Ames Research Center and SETI Institute in Moffett Field, California.

The researchers will be wearing CPODS, specially-outfitted suits that will record their vital signs and transmit them, in real time, back to NASA Ames.

"It's the first time we've done real-time," said John Hines, manager of the astrobionics group at NASA Ames, which is developing the technology.

The suits, also known as LifeGuard devices, are prototypes of technology that the space agency is developing to monitor astronauts' health as they float around the International Space Station and, eventually, explore distant planets.

When the opportunity arose to field test the real-time transmission feature of the devices on researchers probing a lake in an ancient, Mars-like environment, Hines and his group jumped at the chance.

"I'm pretty confident everything should go OK, but we did accelerate the development process," said Hines.

Cabrol and her international team of scientists depart for the Licancabur Volcano today (October 27, 2003), where they will spend the next five weeks studying life and designing strategies for exploring distant planets in one of Earth's most extreme—and Mars-like—environments.

"We are trying to understand the environment and life in a very similar environment to ancient Martian lakes," she said.

Mars Analog

The seemingly lifeless borderland between Bolivia and Chile is bombarded by ultraviolet radiation and has half the oxygen and atmospheric pressure as sea level. And it's chilly: Temperatures range from —40 to 27 degrees Fahrenheit (—40 to —3 degrees Celsius).

Such an environment, say the researchers, is similar to what Mars was like 3.5 billion years ago when, according to morphological evidence, icy lakes and rivers covered the red planet.

"This is probably the best analog in the world," said Cabrol, who with her colleagues performed a preliminary reconnaissance of the region in 2002. The scientists will visit the lakes each year through 2008.

On the 2002 trip, the researchers discovered abundant and diverse life-forms thriving in the lakes in and around Licancabur, raising speculation that life could have existed on ancient Mars.

In addition, two billion years ago, there was no ozone layer protecting Earth from harmful ultraviolet rays. Thus the life forms that thrive in these lakes are like a window back into time when life first evolved on Earth.

"We are looking at our own past to see how we made it," said Cabrol.

Extreme Environment

These high lakes on the altiplano, a high-altitude desert that is one of the world's driest regions, are what scientists refer to as extreme environments and the microbes that live in the lakes are called extremophiles—organisms that love living on the edge.

Such life-forms fascinate scientists. To survive in extreme environments the organisms must evolve unique traits and scientists keep looking in more and more extreme environments—hydrothermal vents, underwater caves, volcanoes—to understand the limits of life on Earth.

"So far, we have not found a limit of life," said Cabrol. "But these lakes might show a limit."

Last year, the researchers discovered very small plankton-like algae called diatoms that had ten times more deformities than similar algae in other lakes. The researchers believe that the intense ultraviolet radiation on the altiplano is finally catching up to the organisms.

These lakes lie on the eastern edge of the world's driest desert, the Atacama, and they are evaporating. The deformed diatoms were found in a lake at the foot of Licancabur that is now just 1.5 feet (50 centimeters) deep. Harmful ultraviolet rays can penetrate water up to 3 feet (1 meter).

"The question is now, are these deformations mutations towards adaptation or are they the sign that life cannot cope in the environment and they are going into extinction," said Cabrol.

The team will set up data collection stations with instruments and experiments to measure ultraviolet radiation and its effect on life in the area. Whether the diatoms are on the road to extinction or evolving a sort of UV sunblock, Cabrol's interested.

"On the one hand, we may see how life may be able to adapt itself against UV and strategies for UV on other planets. On the other hand, we may be finding a real limit of life on Earth," she said.

The Licancabur Expedition is funded by grants from the National Geographic Society, NASA, the SETI Institute, and the support of other organizations.
 

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