Life on the Edge
January 13, 2008: NASA scientists are joining forces with researchers from the Center for Astrophysical Research in Antarctica and the University of California's White Mountain Research Station to conduct a unique educational activity in microbiology. It's a hands-on experiment designed for students of all ages to investigate life in extreme environments and to learn about the possibilities for life elsewhere in the Solar System.
In recent years scientists have begun to recognize that certain life forms on Earth can thrive under very extreme conditions. Viable microorganisms have been found living in acidic hot springs, buried under ancient permafrost, and even inside volcanic rocks.
Perhaps the most astonishing survivor of extreme living conditions is the common bacteria Streptococus mitis. Unknown to mission planners in 1967 a small colony of Streptococus bacteria traveled to the moon aboard Surveyor 3, stowed away inside the spacecraft's TV camera. Three years later when Apollo 12 astronauts returned the camera to Earth, scientists were astonished to find that the bacteria were viable. They had survived 3 years of hard vacuum, with no food or water. In 1991 Apollo 12 commander Pete Conrad commented "I always thought the most significant thing we ever found on the whole...Moon was that little bacteria who came back and lived...."
The discovery of things living in extreme environments has clearly changed our understanding of life and where it might be found. Places like the polar caps of Mars or oceans on Jupiter's moons were once thought to be too extreme for life, but many scientists are now reexamining that conventional wisdom. Extreme-loving bacteria and other organisms ("extremophiles") are showing scientists that there is a surprising range of conditions where basic life forms can set up housekeeping.
This month scientists will launch a program called Life on the Edge designed to bring the concepts of life in extreme environments to classrooms everywhere. "The basic idea," says Dr. David Noever, a member of NASA/Marshall's astrobiology research group, "is to expose a collection of microorganisms to some of Earth's harshest environments, including geothermal vents, high mountain peaks, and even the South Pole. We plan to distribute the microbes to US classrooms where students can perform experiments to see how well they fared. The microbes would come with an 'Extremophiles Experimenter's Kit' containing all the basic ingredients a student might need to investigate how well the microbes survived their experience."
LIFE ON THE EDGE FAQ
What is Life on the Edge? Why study life in extreme environments? How do I become involved?
The answers to these and many other questions about Life on the Edge may be found on our Frequently Asked Questions web page.
Students would apply simple laboratory protocols to assess the effects of severe conditions on their microbe samples, and to learn how these conditions compare with environments elsewhere in the solar system, such as Europa, the Moon, and Mars. "The exact contents of the Experimenter's Kit are still up in the air," continued Noever, "and there are many candidate micro-organisms for this experiment, including yeasts native to Antarctica, bacteria from Russian volcanoes, and others. We have to decide which microbes are going to work best in the field and in the classroom. That's the purpose of the White Mountain activity."
STEP 1: THE WHITE MOUNTAIN SUMMIT
The first phase of Life on the Edge begins next week when Dr. Tony Phillips and a team of 8 Siberian Huskies will transport a 50 lb container of test microbes to the summit of the White Mountain Range in central California. Conditions there are severe. At 14,249 ft., the air pressure is only 600 millibars, and the sustained temperature during winter is a frigid -20 C. Annual precipitation is less than 12 inches, most of which arrives as snow in winter. The temperature, pressure, and low humidity are similar to conditions at Earth's south pole during the austral summer.
"The White Mountain summit is just the first of many extreme environments we plan to explore through Life on the Edge. This first run is a test to help us validate some of our basic assumptions," explained Dr. John Horack, director of science communications at the NASA/Marshall Space Sciences Lab. "Do the microbe containers work as expected? Which microorganisms survive the bitter cold? What lab protocols are best? You don't know unless you do the experiment, and we'd like students to help us figure these things out. That's why we're inviting educators to become involved now. By joining they'll be eligible to receive microbe samples from the White Mountains and to help us develop classroom protocols that we'll use with microorganisms from other extreme environments."
The microbes will be situated at the White Mountain summit during the 3 harshest months of the Northern winter, and then returned for testing in early May 1999. Most of the micro-organisms will be members of the family saccharomyces cerevisiae, better known as baker's yeast. Saccharomyces cerevisiae is one of the half-dozen microbes on Earth whose genetic script has been comprehensively deciphered. Notable in the yeast gene is a host of signals called thermal shock proteins that trigger the microbe to protect itself against extremes in heat and cold.
Two types of containers will be used. One will place the microbes in thermal contact with the environment, but isolate them from other factors like wind, snow, and competing life forms. A second type of container will expose the microbes as fully as possible to their surroundings, without actually releasing them into the environment. These "full exposure" vessels will provide the most realistic test of life in extreme conditions.
Joining baker's yeast in the microbe containers will be a collection of other benign, but extremophilic microorganisms:
- Aquaspirillum arcticum: a bacteria found under snow and ice in the Canadian Northwest territory that produces cold-shock proteins and cold-acclimation proteins
- Candida Antarctica: an alkali-tolerant yeast hailing from Lake Vanda, Antarctica
- Desulfurella acetivorans: an anaerobic bacterium discovered in the Russian volcano Uzan on the Kamchatka Peninsula.
- Saccharomyces cerevisiae Hansen: a radiation-tolerant strain of Baker's yeast that can survive in the core of a nuclear reactor.
- Shewanella benthica: a high pressure bacteria discovered living in the Puerto Rico trench.
- Halobacterium halobium: a salt-loving extremophile from the Owens Dry Lake in California
All of the organisms listed above have the best possible biosafety rating as determined by the American Type Culture Collection.
After the microbes are recovered in May they will be flown to the NASA/Marshall Space Sciences Laboratory. There, researchers will evaluate the design of the microbe containers and examine the microbes themselves to see how well they endured winter conditions at the summit. The experience gained at the White Mountain summit will be invaluable for planning future Life on the Edge expeditions to Alaska, the South Pole, and other frigid, high altitude environments.
NASA Science News will cover the expedition to the White Mountain summit as it progresses. The journey is set to begin this week.