Diving Into a Volcano
Nowhere to Hide
Scientists from NASA, the SETI Institute and other institutions will study microscopic life forms in some of the highest lakes on Earth atop a South American volcano to learn what life may have been like on early Mars.
From Oct. 27 to Nov. 23, scientists will conduct field tests to examine life forms in several lakes, including the Licancabur volcano crater lake, at nearly 20,000 ft. in the Andean Altiplano on the border of Bolivia and Chile. The expedition hopes to learn how the organisms that live in the lakes have adapted to the thin atmosphere and damaging high-UV environment some 6000 meters (19,700 feet) above sea level.
"Studying life in these lakes not only provides critical information about the habitability potential of early Mars and other planets in the solar system, it also opens a window into our own past to reveal how life survived on Earth 2 billion years before the ozone layer formed," said the project's principal investigator and expedition lead, Dr. Nathalie A. Cabrol of NASA Ames Research Center, Moffett Field, Calif., and the SETI Institute, Mountain View, Calif.
|Click here for larger image. Expedition leader Nathalie Cabrol with Edmond Grin, the current record-holder for the oldest person ever to summit Licancabur.
Credit: Seth Shostak
Intense ultraviolet (UV) radiation, low oxygen, low atmospheric pressure and cold temperatures make the environment a close analog to martian lakes 3.5 billion years ago. Despite the extreme conditions at Licancabur, scientists say microscopic life is present and diverse. Its survival strategy might be very ancient, according to Cabrol.
During their first expedition last year to the same area, Cabrol's science team discovered that very small plankton-like algae called diatoms had 10 times more deformities than similar algae in other lakes. UV is believed to be the 'prime suspect' that may have triggered the malformed algae, according to Cabrol.
One of the scientists' goals is to identity the species living in the high lakes and to learn how these living things cope -- or do not cope -- with UV and other stresses. "Most of the lakes we study there are shallow and do not provide substantial protection to living organisms. They have nowhere to hide from UV," Cabrol said. "We want to understand if these diatoms have developed some sort of 'sunscreen.' If not, they are probably on their way to extinction," she added.
|The Licancabur team place UV filtering plates in Laguna Blanca (above) to study how the UV affects the lake's biology.
"Either case represents potentially an immense source of knowledge," Cabrol said. "On the one hand, we might learn more about life strategy against UV with all its implications for early planets' habitability and future astrobiological mission exploration strategies, and on the other hand, we might possibly be on our way to identifying a limit to life's adaptation on Earth," Cabrol explained.
Most of the Earth is covered by a protective ozone layer that screens out higher-energy UV radiation, which is particularly damaging to life. "The best way to get high UV," explains Chris McKay, a planetary scientist at NASA's Ames Research Center in Mountain View, CA, and a member of earlier Licancabur expedition, "is to go to high elevations. The equatorial regions are particularly interesting because the Sun is higher in the sky," so the radiation is stronger than in regions closer to the poles.
The team will set up data-collection stations with instruments and experiments to measure UV and its effect on life in the area. The stations also will measure temperature, water properties and other conditions. The instruments are the first element in a planned large network of stations that the team will position in coming years at high-altitude lakes up to 20,130 feet. Commonly used in marine and lower altitude lake environments, these stations have never been taken to such high altitude; scientists believe they will record unprecedented data for years.
Cabrol and several other scientists also will 'free' dive to collect biological samples and sediments at various locations in Licancabur Lake that are not accessible by boat. During their dives, scientists plan to take underwater pictures and video to document the lake's biology and its habitats.
|Viking image of Gusev Crater, an ancient proposed lakebed that will be targeted in the January 2004 Mars Exploration Rover mission. Cabrol has a key role to play in peaking scientific interest in the Gusev landing selection.
Divers will wear 'LifeGuard' devices to monitor the divers' conditions including real-time vital signs (ECG, heart rate, respiration, oxygen saturation, temperature and human activity) from the expedition site. A satellite will relay this data to NASA Ames. Members of the ascent team also will wear the LifeGuard telemedicine monitors. The 'Astrobionics' team at NASA Ames developed the monitors for use on Earth and in space.
Learning how the Licancabur organisms protect themselves from UV may help researchers understand how life survived on early Earth - and perhaps on early Mars as well. Cabrol, who can be found poring over images of ancient Martian lakebeds when she's not busy climbing terrestrial volcanoes, sees important similarities between present-day conditions at Licancabur and conditions on early Mars. Cabrol likens the harsh, isolated environment of Licancabur to what was perhaps the final era of Martian habitability. "High UV, low oxygen, low atmospheric pressure: These must be the conditions that were on Mars 3.5 billion years ago, when the atmosphere was not completely gone, when there was still a little bit there, when local ponds were still possible," says Cabrol.
As Mars became more and more inhospitable, Cabrol adds, life would have survived only in "very isolated ecoystems, basically seeing their world shrinking year after year after year," much as Licancabur's summit lake is believed to be slowly shrinking. Studying Licancabur, Cabrol hopes, will help scientists to understand how life behaves under such conditions and help to focus their search for evidence of ancient Martian life.
Orbital projections of where the Mars Exploration Rovers are right now, can be continuously monitored over their half-year journeys, which culminate in their landing around January 2004.
NASA and the National Geographic Society funded the project, with additional support from the SETI Institute and other organizations.
Related Web Pages
Extreme Environments: Licancabur Site
Michael Endl's Journey to Licancabur
What's Living in the World's Highest Lake? (Licancabur Expedition Journal: Part I)
Licancabur Expedition Journal: Part II
Hot Springs in the Andes (Licancabut Expedition Journal: Part III)