Life at the extremes
Frogs that freeze solid in winter - then thaw out and hop away in the spring. Seals that can dive almost a mile deep. Tiny creatures that relish acid strong enough to eat through your shoe. Does this sound like science fiction? It isn't. All kinds of things thrive under conditions that we humans think are impossible. Here are just a few:Skip to next paragraph
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Ancient and extreme
Superman could learn a thing or two from some 3.7 billion-year-old microorganisms. A number of them snack on toxic wastes. Others have no problem swimming in scalding water, or surviving massive doses of radiation.
What's more, they love this lifestyle!
Harold Schreier, of the University of Maryland's Center of Marine Biotechnology in Baltimore, says these tiny beings are "found in environments we thought would not be habitable." Scientists call them "extremophiles" - creatures that love extremes.
Dr. Schreier notes that many extremophiles belong to an evolutionary classification called Archaea (sometimes called Archaebacteria). Archaea (ar-KAY-yuh) means "ancient."
Of all the microorganisms that live in extreme conditions, the most famous is a pink bacteria. Scientists have nicknamed it "Conan the Bacterium." Its real name is Deinococcus radiodurans.
Scientists find "Conan" living in places where the temperature may reach 212 degrees F. (the boiling point of water), in acid baths (in the stomach of a cow, for instance), and even in storage containers filled with radioactive nuclear waste.
D. radiodurans was discovered back in the 1950s during experiments on sterilizing food using radiation.
After zapping meat with high levels of gamma radiation, researchers were startled to see that this bacteria survived. In fact, it thrived. Now scientists are looking for ways to use the bacteria's remarkable talent to break down nuclear and toxic wastes.
Another extremophile, Methanogenium frigidum, was discovered in 1997. A team led by Prof. Davis Boone of Portland (Ore.) State University found the organism in the icy salt waters of Ace Lake, Antarctica. The creature loves the cold so much that it dies when the temperature gets above 64 degrees F. - a little cooler than room temperature.
Not only that, Methanogenium frigidum is "a strict anaerobe," Boone says. That means it can't live where there is any oxygen. "They live on the table scraps of the microbial world," he adds. They aren't fussy eaters, in other words. In fact, they make their own food using such substances as hydrogen and bicarbonates.
They could be an energy source, because they produce methane gas. The methane reacts with water to form methane hydrates. "There is more energy in methane hydrates than in all the petroleum and gas reservoirs known on earth," he says.
Another extreme-loving tiny creature is Bacillus infernus. It likes hot places - 150 degrees F. hot. It was found in an exploratory well in Virginia, two miles underground. It doesn't need oxygen, but uses iron compounds instead.
Halobacterium salinarum can withstand salt concentrations of up to 30 percent. (Most seawater is only 4 or 5 percent salt.) It lives in the Mideast's Dead Sea, along with some salt-loving plants called halophytes. That's all that can live in the Dead Sea, the saltiest place on earth.
Very warm worms