Home Glaciers It’s summer, and it means the mysterious return of the ice worms from the glaciers

It’s summer, and it means the mysterious return of the ice worms from the glaciers


Iceworm researchers Scott Hotaling and Peter Wimberger led a trip to study life on the glaciers of Mount Rainier in June. For a long time, Hotaling says, biologists called high-altitude glaciers barren and lifeless places. But it is no longer. (Jordan Boersma)

High on Mount Rainier in Washington, there are stunning views of the other white-topped peaks of the Cascade Range. But Scott Hotaling looks down at his feet, studying the snowy ground.

“It’s happening,” he said, gesturing to Paradise Glacier.

Small black spots suddenly appear on the previously blank expanse of white. The glacier’s surface is changing rapidly as more and more tiny black creatures emerge. The ice worms returned, snaking between the ice crystals and shimmering in the sun.

These thread-like worms, each about an inch long, wriggle in droves over the summer, in the late afternoon, to do – what? Scientists don’t know. This is just one of the many mysteries surrounding these worms, which have barely been studied even though they are the most abundant creature living out there in snow and ice.

Scientists are unsure why the segmented worms, each less than an inch long, squirm on the glacier’s surface at the end of the day, although they believe it may be for food or to soak up the sun’s rays. Sun. (Scott Hotaling)

Billions upon billions of inch-long black creatures

“There is so muchWashington State University researcher Hotaling explains. It is estimated that 5 billion ice worms can live in a single glacier.

“From where we are now, I can see five, six, 10 glaciers,” he says. “What if everyone harbored this density of ice worms?” It’s just a huge amount of biomass in a place that is generally low in biomass. “

For a long time, he says, biologists viewed high altitude glaciers like these as fundamentally barren and lifeless places. Ice worms, however, show that this fragile environment – where glaciers are vulnerable to climate change and recede – is potentially much more complicated.

“If you were to put an organic mascot on the glaciers of the Northwest,” Hotaling says, “it’s an ice worm.”

And yet, with the possible exception of the annual Cordova Iceworm Festival in Alaska, these bizarre worms have generally been ignored or treated as mere curiosity.

The National Park Service visitor center near Paradise Glacier, for example, has a nice display of alpine wildlife, says Hotaling, “and there’s kind of nothing about the ice worms. And that’s a source of frustration for me.

He admits that it bothers “probably no one else coming here.” Many people who hike, ski or work on these mountains have never seen an ice worm despite their abundance, in part because the beasts only come to the surface at certain times of the year. , at certain times of the day.

Although they are called ice worms, the creatures Hotaling (right) and his colleagues study on the glaciers of Mount Rainier cannot stand the slightest frost. If temperatures drop even slightly below zero degrees Celsius (32 degrees Fahrenheit), Hotaling says, the worms die. (Pierre Wimberger)

“Damn, they’re real! “

“They’re very obvious once you notice them, but it’s so beyond your expectation, when you’re in a glacial environment, that there will be worms,” Hotaling explains.

His colleague Peter Wimberger at the University of Puget Sound says he became interested in worms years ago when a student said he wanted to study them. Wimberger thought the guy was pulling his leg and that was some kind of prank. “He realized I didn’t believe him,” Wimberger said, “and all of a sudden he pulled out this little stack of papers and he said, ‘Damn, they’re real! “

The pile of scientific papers was small because only half a dozen researchers have ever studied worms, Hotaling says.

The worms ignore the incredibly high levels of hard ultraviolet light, according to Hotaling, which is a good thing, as the summer sun on the treeless, snow-covered mountainside can be intense. (Scott Hotaling)

They thrive in a glacier but die if they freeze

No one knows how these worms survive harsh winters, or how far they sink into the snow. Hotaling thinks that sometimes they probably live under 30 feet or more of snow, where the annual seasonal snow meets the older snow on the glacier.

Winter can be the best season for them and a time when they can increase their energy stores, says Hotaling, because the worms are bigger when they first come out, in early summer, than they are. not later.

Worms are thought to eat algae and snow bacteria, but they may not need much. “I’ve kept them in my refrigerator, in my house, for physiology experiments, for a year or more, without adding anything to their system, and they’re doing fine,” Hotaling says.

In fact, however, he notes that he’s not sure if these particular worms survived the year, or if they recurred. This is because the reproduction of the ice worm is also a big black box.

“In early summer you tend to see more of the smaller ice worms, which suggests that at some point before that their little eggs hatched and young ice worms appeared,” explains Wimberger, “but we don’t know.”

What is clear, from lab tests, is something quite surprising for an animal that has “ice” in its name: “They can’t stand any freezing,” Hotaling says.

Worms can live at zero degrees Celsius (32 degrees Fahrenheit), but if temperatures drop even slightly below, he says, the worms die.

Ultraviolet light does not bother them

Other tests, meanwhile, show that the worms ignore incredibly high levels of hard ultraviolet light, according to Hotaling. Which is a good thing for them, as the summer sun on the tree-less, snow-covered mountain side can be intense. No matter what pushes them to the surface, they seem to wait until the last hours of the day, when the sun isn’t so ruthless.

“I actually think they come for the sun a bit,” Hotaling says, “because they want to have some of that thermal energy to drive their biochemical reactions.”

Hotaling sets up an animal camera. The natural history of ice worms and their predators, which is only now revealed, underscores that the fragile environment of retreating glaciers is potentially much more complicated than initially thought. (Nell Greenfieldboyce / NPR)

Hotaling, Wimberger and a graduate student – Jordan Boersma – worked together to install wildlife cameras around Paradise Glacier this summer. They want to understand the extent to which wildlife use these glaciers and depend on ice worms for food.

Already, researchers have spotted birds eating ice worms. Those known to peck worms include pink-crowned finches, American pipits, common ravens, larks, semipalmated plovers, and snow buntings.

Boersma says they want to know “if alpine breeding birds use them to feed their young and if it is an essential part of their life history.”

Birds can also have an impact on the natural history of ice worms. Genetic research shows that ice worms may have traveled a long distance from Alaska to Vancouver Island, possibly sticking to the paws of migrating birds and hitchhiking.

A pink-crowned finch catches an ice worm. (Scott Hotaling)

So many fundamental questions remain unanswered. “There are more mysteries than solved with ice worms,” Hotaling says.

He even wonders if ice worms could affect the rate at which a glacier melts, as their black bodies have to absorb heat. It is known that the presence of dark-colored glacial algae can accelerate melting, and ice worms clearly change the surface of a glacier.

“What happens when a mountain glacier is lost? I don’t think we have a good answer to this question, ”Hotaling says. “Ice worms are an amazing example of a little biodiversity on our planet that most people don’t know about. And in this case, Seattle and the Northwest, it’s in the backyards of millions of people. “

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