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.

"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.

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.

"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.

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.

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.

NASA and the National Geographic Society funded the project, with additional support from the SETI Institute and other organizations.