Veteran Antarctic researchers make another discovery- Water!

John Priscu has been to Antarctica more than a dozen times, but perhaps he never shivered more than in 1996 on Lake Vida.

by Annette Trinity-Stevens MSU News

"It was my coldest experience in Antarctica," the Montana State University ecology professor recalls. "We spent two weeks at -40 degrees Fahrenheit with little shelter and no heat. We had to eat fast or the food would freeze on the plate. The wind was so strong that it flattened our mountain tents."

Now that biting field season is breaking new scientific ground. The results of the studies appear in the Dec. 16 issue of the prestigious Proceedings of the National Academy of Sciences.

Priscu, MSU civil engineering associate professor Ed Adams and former MSU postdoctoral student Chris Fritsen are three of the authors. The lead author is Peter Doran at the University of Illinois.

The scientists report a unique aquatic system where water seven times saltier than seawater is capped by 20 yards of ice that’s nearly 3,000 years old.

What’s more, they found freeze-dried microbes throughout the ice column that were revived in the presence of liquid water. Priscu calls these deeply frozen lakes "ice museums" because they harbor ancient DNA that is well preserved by the cold, salty and arid conditions.

"The ice covers of these lakes represent an oasis for life in an environment previously thought to be inhospitable," Priscu said. "These organisms may possess novel ice-active substances such as antifreezes and ice nucleation inhibitors that allow them to survive the freeze-thaw cycles and come back to life when exposed to liquid water."

More than three miles long, Lake Vida is one of the largest in the cold Antarctic desert region known as the McMurdo Dry Valleys in the Transantarctic Mountains. The area receives less than four inches of snow per year and the average annual temperature hovers around -22 F.

Scientists previously thought Lake Vida, like several Antarctic lakes, was frozen to its bed year-round. However, using ground-penetrating radar, ice core analysis and long-term temperature data, the researchers now show that Vida has a thick ice cover, a vast amount of ancient microbial biomass, and a cold, super-salty, liquid pool underlying the ice that remains liquid at temperatures below 14 F.

Priscu said studying the microbes from Lake Vida might help scientists draw implications about the type of life that may exist in Lake Vostok, a much larger body of water that lies more than 2.5 miles beneath the East Antarctic Ice Sheet.

Priscu and Adams are studying Vostok ice cores drilled close to where the ice layer meets liquid water, and Priscu heads an international team of scientists concerned with how to sample the ancient water without contaminating it.

The researchers think Lake Vida may also offer clues for how to look for simple life forms in outer space.

"Mars is believed to have a water-rich past, and if life developed, a Lake Vida type ecosystem may have been the final niche for life on Mars before the water bodies froze solid," Doran said.

Priscu first went to Antarctica in 1984 as a specialist on freshwater lakes. Since then, he has become an expert on microbial life in the extreme Antarctic environment and the author or co-author of several key scientific papers.

Priscu’s most recent writings focus on the need to think about the earth’s biosphere, or life zones, as encompassing icy systems such as sea ice, glacial ice and permafrost.

"The Lake Vida results are only a small part of a much larger and more globally important, multifaceted story," Priscu said. "The earth’s biosphere is larger than we had ever imagined, and the microbial world has few limits on our planet and, possibly, others."

The Lake Vida studies were funded by the National Science Foundation.

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Josh Chamot of the National Science Foundation contributed to this report.

Contact: John Priscu, (406) 994-3250 or [email protected]

http://www.montana.edu/commserv/csnews/nwview.php?article=659