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| Drilling for life: Crispin Halsall, an environmental chemist, checks air and ice samples on the Beaufort Sea. Researchers
aboard a converted icebreaker, the Amundsen, have been combing the Canadian Arctic for microscopic organisms. George Tombs |
Beneath Arctic ice pack, teeming life holds extraterrestrial clues
Microscopic organisms thrive in polar-ice 'brine channels' whose conditions mirror some of those found in space.
from the April 24, 2008 edition
Page 2 of 3
"Humans have always thought that icy environments are 'harsh' and 'inhospitable'," says Jere Lipps, an astrobiologist at the University of California, Berkeley, who has done fieldwork in Antarctic sea ice and authored several scientific articles on possible life on Europa. In fact, he says, the diversity of the "sea-ice community" demonstrates that an icy environment can play host to a complete and complex ecosystem.
The ecosystem of polar sea ice includes larger halophile zooplankton – such as nematode worms – that are able to survive in brine channels so saturated with salt that they rarely freeze.
Maike Kramer, a marine-biology doctoral student at the Institute for Polar Ecology at the University of Kiel, in Germany, has been braving the extreme cold, taking ice cores from the ocean surface back onboard the Amundsen. She scrutinizes them under a microscope for signs of life.
High-stakes endeavor
Studying life in polar sea ice requires a major investment. The icebreaker Amundsen had to be retrofitted with innovative design features and state-of-the-art laboratories for polar research. Still, the ship has limits. According to the Amundsen commander, Lise Marchand, the ship has rammed a few times this winter into pressure ridges – where plates of sea ice ride up on top of one another. "We occasionally get stuck," says Captain Marchand. "The way to break loose again is to send ballast and fuel from one compartment to another, to lighten the ship's stem." Crew members and scientists then use gas-powered ice augers and chain saws to loosen the ice jam.
Deming has been doing fieldwork in the Arctic for more than a decade. Her work before this project was aboard a Canadian icebreaker off Greenland.
"We were focusing on organic polymers, a kind of gelatinous material released by microbes into the brine pores that acts like antifreeze," she says. "When temperatures are very cold, liquids become thin films. As the microbes produce this stuff to protect themselves, they change the physics of the ice, keeping the pores liquid. This is an unusual case where biology affects physics."
A eureka moment
Then, on returning to Seattle, she had her "eureka" moment. She was struck by images of Europa captured by the National Aeronautics and Space Administration's Galileo spacecraft mission, showing a lunar-ice surface full of lines, domes, and streaks. It reminded her of the Arctic and made her wonder about parallels. "If you allow life to have extraordinary capabilities of living in tiny patches of ice," Deming says, "then some astrobiologists would say that the moon and Mercury, as well as comets, have a likelihood of life."
If there is life out there, Mr. Lipps says, it could well be carbon-based. "Carbon is the only element that is interactive and will make long molecules under those conditions…. The elements of carbon-based life are everywhere in the universe," says Lipps, who thinks the possibility of "hydrothermal seeps" on the floor of Europa's oceans means that hot conditions could also exist there, raising the prospect of originating life.
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