An Aug. 1 Science article about life in Antarctica incorrectly described the publication in which Eugene Domack and his colleagues recently published a study. The publication is Eos, a weekly newspaper of the American Geophysical Union.
Beneath Ice Shelf's Remains, Life Blossoms
Monday, August 1, 2005
Bacteria live everywhere: in the acidic pit of your stomach and in the hot springs of the Galapagos Rift. Now, scientists have discovered them in another unlikely location -- at the bottom of the near-freezing waters of Antarctica.
In March, researchers accidentally discovered a vast community of bacteria and clams on the ocean floor while exploring Antarctic waters that opened up after the vast Larsen B Ice Shelf collapsed in 2002.
The area had been isolated under the ice for at least 10,000 years, and the discovery means that "the chance of life happening in other places that are even more restricted is increased," said Eugene Domack, a professor of geosciences at Hamilton College in Clinton, N.Y., who led the international team to Antarctica earlier this year.
Bacteria are the simplest and most ancient life forms, and with their ability to break down organic matter, they are essential to keeping the cycle of life going.
Their presence at a depth of 2,800 feet, in an environment Domack called the "coldest of the cold," may be the reason life has been possible under a 600-foot layer of ice. The bacteria form a white, rug-like sheet as thick as one centimeter (a third of an inch). On top of the mat lie clusters of clams.
Similar communities have been found around the world, but "never in such an extreme region," said Jim Barry, a deep-sea ecologist at Monterey Bay Aquarium Research Institute. Barry has studied these so-called cold-seep communities in the Monterey Bay area, but the recent discovery "gives us the ability to see what these communities look like at the end of the spectrum," he said.
"This is yet another place on our planet where we found something we didn't expect," David Karl, a professor of oceanography at the University of Hawaii who studies bacteria in extreme environments, said in an interview. "It's as if we were back 100 years ago and we found the first deep-sea organisms."
Many mysteries remain. Researchers are not sure what species the microbes and the clams are, or where and how they get their food and energy.
Cold-seep communities are usually found deep in the oceans where there is no sunlight, and the bacteria obtain their energy from sources other than the sun. The new finding "could take us a step further to understanding life where there's no photosynthesis," Domack said.
The bacteria under the Larsen B ice shelf evolved in far colder conditions than other known cold-seep communities, thriving in near- or below-freezing temperatures, and may have unique properties. Studying them could lead to discovery of "enzymes that could be used in different aspects of industry," said Barbara Methe, assistant investigator at the Institute for Genomic Research in Rockville.
Methe's team recently sequenced the genome of a different type of bacterium that thrives in extremely cold environments, but at this point, scientists can do little more than speculate about the properties of the organisms Domack found.
"We don't know if these bacteria are the same as the ones we have found in [Monterey Bay], because the Antarctic ocean is the most isolated ocean on Earth," Barry said.