Snow Wrigglers
Fragile friends of glacial ecosystems face extinction amid climate change
Ice worms wriggling across the frozen surface, a rare glimpse into life thriving in glacial extremes. // Photo by Scott Hotaling
Story by Jasmine Rosado
December 14, 2024
As evening falls over Mount Rainier, the glacier stirs with life. Ice worms, no thicker than a pencil lead, move to the surface drawn by the cool air and fading sun. They wriggle across the snow, feeding on algae.
Above them a researcher crouches with a large cooler, scooping them with their hands into the bucket. As the researcher collects them, he is amazed at their ability to thrive in this freezing world.
He pauses, looking towards the glacier’s edge, where he can see the slow retreat of ice. With each passing year, his research becomes more urgent. These tiny survivors, so perfectly adapted to their icy home, are running out of time.
Ice worms thrive only in specific glaciated regions of the Pacific Northwest, Alaska and parts of Canada, where temperatures and ecosystems remain stable enough to sustain them. Unlike many creatures that cope with freezing environments by going dormant, ice worms are remarkably active, weaving through snow and ice to feed.
Their entire existence depends on the unique stability of glaciers, making them highly vulnerable to warming temperatures and habitat loss.
“If you're standing on a glacier, you can have tons of ice worms,” Mauri Pelto, a glaciologist and director of the North Cascade Glacier Climate Project, said. Researchers like Pelto's work is crucial for these creatures, especially as climate change advances.
Ice worms sound otherworldly; even scientists who study them admit how little is understood about their biology. Shirley Lang, a biologist and lab instructor at Haverford College who has studied ice worms in her lab, calls them “very mysterious.”
Basic questions about their life cycle still need to be answered. Where do they lay eggs? How long do they live in the wild? Researchers suspect ice worms breed deep within glaciers, but no one has ever observed their cocoons or young.
A study from Rutgers University highlights how ice worms survive in extreme conditions. Their ability to produce energy in the cold is tied to a unique genetic extension, which enables their cells to remain active even when freezing temperatures would immobilize most organisms. These cellular mechanisms help ice worms thrive where few species can, but their adaptation has limits.
“They live at zero degrees Celsius, but they can't survive -0.1 degrees Celsius,” explains Scott Hotaling, a glacial ecologist.
Similarly, they are sensitive to heat; even a slight temperature rise can cause their proteins to denature, leading to death. Their survival depends on glaciers staying precisely within their narrow thermal comfort zone.
Though small, ice worms play an outsized role in their ecosystems. Feeding primarily on snow algae, they act as nutrient recyclers, benefiting the microbes, algae and other organisms.
“The best way to think about what ice worms are doing on a glacier is to imagine earthworms in a compost pile,” Hotaling says. “They’re moving around through the snow matrix, but they're just taking in whatever's in front of them, passing it through their gut, taking nutrients out and excreting it.”
Ice worms are also a key food source for high-elevation birds like the gray-crowned rosy finch, North America’s highest-nesting species. These birds rely on ice worms when other food sources are unavailable during their breeding season. Their disappearance could disrupt this delicate balance, cascading through the ecosystem.
The glacier research project that Pelto directs highlights that ice worms, which once thrived in abundance on glaciers such as Mount Rainer and Mount Baker, are now struggling due to the shrinking snowpacks. From 2003 to 2005, the population faced difficulties as the glaciers experienced less snow cover, making it less conducive for ice worms to survive.
Despite some recovery in snow cover between 2007 and 2008, their habitats have continued to shrink, exacerbating the population decline.
The effects of glacier loss extend beyond ice worms. Glaciers store water, regulate temperatures, and sustain species adapted to these environments. Their disappearance signals broader disruptions to ecological systems and human communities alike.
“As the glaciers go, so go the ice worms,” Hotaling said.
For researchers, the urgency to study ice worms before they vanish is growing. Insights from ice worms could advance cryopreservation techniques, including organ preservation for transplants, according to a study by Rutgers University.
Studies on cryopreservation in extreme organisms, including ice worms, suggest that understanding their unique cellular processes could lead to breakthroughs in preserving human tissues in freezing conditions.
Public awareness about ice worms remains limited, but events like Alaska’s Iceworm Festival aim to raise interest in these enigmatic creatures. Meanwhile, digital platforms like Hotaling’s YouTube channel, Mountain Futures, seek to educate the public about the broader implications of glacier loss.
The story of ice worms is both a cautionary tale and a call to action. These tiny creatures, so perfectly adapted to their frozen world, symbolize the fragility of ecosystems under threat. They remind us that even the smallest species play vital roles in maintaining the balance of nature.
As glaciers recede, ice worms provide a stark warning about the urgency of addressing climate change. Their survival depends on our collective efforts to protect the icy habitats they call home and to recognize the interconnectedness of all life on Earth.
“For every glacier that goes away, for every acre of ice that we lose, we not only lose the water resource that's stored in the mountains that's buffering ecosystems and agriculture and drinking water,” Hotaling emphasizes. “But we also lose habitat, and we lose habitat that we have a very poor understanding of.”