British Columbia

These ice worms thrive on B.C. glaciers and now we might know why

A Washington state scientist and his team believe they've figured out how ice worms move from glacier to glacier along B.C.'s coast.

Worms may move from glacier to glacier thanks to the gray-crowned rosy finch

North American ice worms are found along the Pacific Northwest coast. A team of Washington state scientists believe they've figured out how the critters get around. (Rachel Mallon)

A Washington state scientist and his team believe they've figured out how ice worms move from glacier to glacier along B.C.'s coast.

The elusive critters are found in tangled masses in the melting ice of Pacific Northwest glaciers, from Oregon to Alaska, and around Vancouver Island and the Sunshine Coast.

How the North American ice worm has managed to spread along such an expanse is the subject of a new study published on Wednesday in the Proceedings of the Royal Society scientific journal.

"They're fascinating little creatures," said Washington State University professor Scott Hotaling, lead author of the study.

"They're globally rare, but when you actually go to a glacier where they're present, they can be really abundant."

North American ice worms are hard to find, but once you do they're found in great numbers. (Jon Ridel)

So abundant that there will be hundreds present per square metre. The animals are annelids, distant relatives of the earthworms found in a garden.

Because they're tiny worms with limited mobility, scientists have been baffled as to how they've proliferated across vast distances. Now, Hotaling thinks he might have found the answer. 

The worms survive on an abundant diet of microbes blanketing the glaciers. The worms also may be the primary food source for the gray-crowned rosy finch, the highest nesting bird in North America.

Hotaling believes the worms are carried by the finches between glaciers. In an effort to prove his hypothesis, Hotaling travelled across glaciers trying to capture an image of the finches interacting with worms. He then successfully captured the first ever photo of a bird eating an ice worm.

Scott Hotaling says this is the first ever image of a bird — a gray-crowned rosy finch — interacting with an ice worm. (Scott Hotaling)

Hotaling said the worms appear to be a key link in the glacial food web between algae and vertebrates such as birds.

Part of the excitement in studying the dark-coloured worms, said Hotaling, is that they're very mysterious. Scientists don't know much about how they work or much about glacier ecosystems. Hotaling suggested that they may be able to live on the freezing glaciers by ramping up their metabolisms as the temperature gets colder.

"But we haven't really proven that," said Hotaling, smiling. "We don't really know. There could be an anti-freeze protein circulating in their blood."

Hotaling added that climate change is causing glaciers to melt and rapidly destroying many of the worms' habitats.

With files from On the Island

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