Exploring Earth- Extremophiles

In the 1980s and 1990s, biologists found that microbial life has great flexibility for surviving in extreme environments—niches that are acidic or extraordinarily hot, for example—that would be completely inhospitable to complex organisms. Some scientists even concluded that life may have begun on Earth in hydrothermal vents far under the ocean's surfaceAccording to astrophysicist Steinn Sigurdsson, "There are viable bacterial spores that have been found that are 40 million years old on Earth—and we know they're very hardened to radiation."[4] Some bacteria were found living in the cold and dark in a lake buried a half-mile deep under the ice in Antarctica,[5] and in the Marianas Trench, the deepest place in Earth's oceans.[6][7] Some microorganisms have been found thriving inside rocks up to 1,900 feet (580 m) below the sea floor under 8,500 feet (2,600 m) of ocean off the coast of the northwestern United States.[6][8] According to one of the researchers, "You can find microbes everywhere—they're extremely adaptable to conditions, and survive wherever they are."[6] A key to extremophile adaptation is their amino acid composition, affecting their protein folding ability under particular conditions.