SEATTLE – A creature that thrives in ice and self-destructs when temperatures inch above freezing sounds like the stuff of science fiction. But as dusk fell on the shoulder of Mount Baker last month, Mauri Pelto had to watch where he stepped to avoid squashing them by the dozens.
“There’s about a hundred per square meter,” said Pelto, a glaciologist from Nichols College in Massachusetts who conducts what might be the world’s sole annual survey of ice worms. That’s right. Ice worms.
Found on glaciers from Alaska to Oregon, these half-inch-long earthworm relatives are one of only two animals known to live exclusively in ice or hard-packed snow. (The other is an animalcule called a rotifer.)
Navigating through cracks and fissures, ice worms dive deep during the day to avoid the sun. At twilight, they rise and graze on algae and other morsels ensnared in the crystalline lattice.
Pelto has documented densities as high as 6,000 per square meter in some places. But he’s also documented a downward trend over the past 21 years, with worm populations appearing to decline in concert with the contraction of their icy home range. “If we lose the glaciers,” Pelto said, “we lose the ice worms.”
The biochemical bag of tricks that enables ice worms to live at temperatures where most life sputters out could prove beneficial to human health someday. That’s why the National Institutes of Health, the National Science Foundation and NASA have all funded research on the creature. “This family of worms is unique in all the world,” said Daniel Shain of Rutgers University.
Through DNA analysis, Shain and his colleagues found that ice worms and their closest relatives exhibit stunning genetic variability that allows them to inhabit a wide range of niches — from warm soil to blue ice. In most creatures, cold temperatures deplete energy stores and slow down metabolic processes. Ice worms actually crank out more ATP — the universal energy source for living things — when the temperature drops.
He has identified the enzyme pathway responsible, and is trying to replicate the effect. Once the mechanism is better understood, Shain hopes it can be used to develop chemicals that extend the storage time of transplant organs, which deteriorate rapidly once they’re harvested and chilled.