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.
In the Beaufort Sea in the northwest Canadian Arctic, the sun rose Jan. 23 after a long polar night of round-the-clock darkness that had begun in late November. At this latitude (71 degrees north), the sun will be shining 24 hours a day by mid-May. With the wind blowing at more than 20 m.p.h. it feels like 53 degrees below zero F.Skip to next paragraph
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The bright-red bow of the 320-foot Canadian Coast Guard research icebreaker Amundsen looms above the frozen sea. While armed crewmembers stand on guard nearby, ready to fire a warning shot in case we encounter marauding polar bears, scientists snowmobile around on the three-to-15-foot-thick ice surface collecting ice and snow samples.
“It turns out the sea ice of the Canadian Arctic is not that dead after all,” says Jody Deming, an astrobiologist from the University of Washington in Seattle and chief scientist on one of several three-week legs of the Amundsen’s year-long Circumpolar Flaw Lead Project.
The $20 million project, led by Arctic climatologist Dave Barber of the University of Manitoba, is part of Canada’s contribution to International Polar Year, a multinational effort aimed at researching the polar regions. Atmospheric chemists, physicists, oceanographers, and marine biologists from Asia, North America, and Europe are studying the place where the Arctic Ocean’s multiyear sea ice meets one-year, land-fast ice in the Canadian Arctic archipelago.
With funding from the US National Science Foundation, Ms. Deming has been focusing on the nepheloid layer – clouds of water-borne particles above the ocean floor – as well as halophiles, tough, “salt-loving” microorganisms that thrive in superchilled liquid brine channels within the ice.
Microbes on Europa?
Deming believes the bacteria and viruses in these channels in polar sea ice could provide clues about possible life on Jupiter’s ice-covered moon Europa.
“When we think astrobiologically, we think of the initial microbes, similar to ones that gained a foothold on Earth 3.8 billion years ago,” she says. “Europa is a very promising situation because all the evidence points to an ocean under the ice cover and heat under the ocean.”
Astrobiology is a decades-old scientific discipline bringing together astronomy, biology, and geology. It examines whether microorganisms living in extreme heat and cold on Earth could tell us what kind of life forms might exist on other celestial bodies.
“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.