Short Wave - Behold! The Mysterious Ice Worm

Episode Date: January 12, 2023

Inside the mountaintop glaciers of the Pacific Northwest lives a mysterious, and often, overlooked creature. They're small, black, thread-like worms that wiggle through snow and ice. That's right, ice worms! Little is known about them. But one thing scientists are sure of? They can't really handle freezing temperatures. In this episode, NPR science correspondent Nell Greenfieldboyce talks to Emily about how ice worms survive in an extreme environment and why scientists don't understand some of the most basic facts about them. See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, everybody. Emily Kwong here with a rerun episode featuring Nell Greenfield-Boyce, NPR Science correspondent, on some of the coolest worms on planet Earth. Hey, Emily. So, you used to live in Alaska, right? I did. I just got back from a little vacation there. I did a lot of swimming, a lot of hiking, a lot of staring at glaciers from the airplane. They are beautiful. They're pretty.

Did you see any ice worms? I did not see any ice worms. Also, I only know a little bit of what ice worms are, but not really. Yeah, I didn't know about them either, but I just got a crash course. I met with a few researchers, including Peter Wimberger. He's a biologist at the University of Puget Sound. And he told me he, like a lot of people, used to think that ice worms were fictional, like a joke that people might. And so a while back when one of his students said that he wanted to study ice worms, Wimberger

thought it was a prank. And he realized they didn't believe him. And all of a sudden he pulled out this little small stack of papers. And he said, damn it, they're real. I love this reaction. So now, breaking news, ice worms are real. What do they even look like? So they're small black worms that live inside mountaintop glaciers in the Pacific Northwest and

your beloved Alaska. And they're like little tiny. tiny earthworms, but instead of soil, they live in snow. And they live there in vast numbers. If you were going to put a biological mascot on glaciers of the northwest, it's an ice worm. That's Scott Hotaling. He's a biologist with Washington State University. Ice worms essentially changed my life from the first time I saw them. He's kind of an iceworm evangelist. I have no shame in promoting ice worms.

So these guys took me up to the glacier where they study these worms. and I can understand why he found them so striking and why he thinks they are way more than just some curiosity. So today on the show, we head up a glacier in the Pacific Northwest to explore the mysterious world of ice worms, how they survive in an extreme environment, and what these warmy denizens of the ice can tell us about one of the most rapidly changing parts of the world. This is Shortwave, the Daily Science podcast from NPR.

So, Nell, where did you go to see these ice worms? So we went up Mount Rainier, and that's this massive snow-capped mountain outside of Seattle in a national park. And you can just sort of drive up to this parking lot there with the visitor's center. And that's where I met Peter Wimberger and Scott Hotaling and a grad student, Jordan Borsma. The Visitor's Center was actually closed because of the pandemic, but Hotaling has been there a bunch. And he says, there's a display in there on mountain wildlife that has stuff like birds, and the snowshoe hair. And there's somehow nothing about ice worms.

And it is a source of frustration for me. Probably no one else that comes here. He says it's surprising how many people work and play on this mountain. And yet they have never seen or maybe just didn't notice an ice worm. They're very obvious once you notice them, but it's so beyond your expectation when you're in a glacier environment that there will be worms. Plus they only come up onto the glacier surface.

at certain times, like in the summer in late afternoon. Yeah, it's easy to think of a glacier as just a block of snow and ice. But if you look closely, there's a lot going on in there. Yeah, hoteling says glaciers used to be seen as these sort of sterile, lifeless places. But, you know, as ice worms show, this view is just completely wrong. I mean, he studies the worms on Paradise Glacier. It's one of the many glaciers on Mount Rainier. So we started walking up there.

And so basically, you're just going straight up through the snow. snow, it's just kind of a trudge. Yeah, Mount Rainier is a serious peak. Now, how high did you go? So only about 7,800 feet, so not that high. On the contrary, that is actually quite high. Well, not on Mount Rainier. Mount Rainier is like 14,000 feet high. So, you know, it was a steep trudge. Like, don't get me wrong. We were trudging straight up through the snow for several hours. But, you know, it was beautiful weather. I mean, it was just like blue sky, white snow. It was, you know, It was nice. So what percent of the world's iceworm researchers would you reckon we got here on the side of this mountain right now?

Active iceworm researchers? Might be it. This might be all of them. Hotaling says over the years, a few scientists have done studies, but it's not like this is a huge research enterprise. And whenever we stop for a break, I'd naturally ask questions about ice worms. And their answer was almost always, like, who knows? Well, they must know some things, right? Like, what do ice worms eat?

So scientists think they eat bacteria and algae, but how far down they burrow and what they do over the winter? I mean, hoteling really wishes he knew. What's going on below all that snow? Are they just staying at the old snowline? Below all the seasonal snow? Are they going to, like, the bed of the glacier? Yeah, right. I mean, do they have some kind of hibernation or, like, suspended animation state they go into?

So he doesn't think so. He and Wimberger say there's research showing that when winter ends, the ice worms are actually like more lipid rich, fatter than they are later in the summer. So that's weird, right? Like a hibernating bear is like skinny at the end of winter because it's used up all its energy stores. But ice worms are fatter. So maybe winter is their best time when living is easy. Hoteling says they don't seem to need much. I've kept them in my fridge in my home for physiology experiments for a year or more

without adding anything to their system. And they're fine. So they could have lived at least a year or, you know, maybe they reproduced in there. He doesn't know. So peculiar. All right. And how exactly do they reproduce? Well, the researchers assume it's like other worms, like earthworms,

but Wimberger says, you know, that's just a guess. Early in the summer, you tend to see more smaller iceworms, suggesting that at some point before that, their little eggs hatched and baby ice worms popped out, but we don't know. Emily, here's one thing they do know about ice worms, and to me, this was totally unexpected. They can't handle even the slightest bit of freezing. Hotelling told me that the worms live at zero degrees Celsius, so 32 degrees Fahrenheit. But he and a colleague did some lab tests showing that if their body temperature dips even slightly below that, like just a half a degree. Celsius or 1 degree Fahrenheit, the worms die, at least ice worms collected in the summertime.

So they're living pretty close to their limit in terms of low temperatures. Yeah, that is super surprising, Nell. I mean, given that they have ice in their names, you'd think these worms could handle below freezing, but apparently not. Yeah. So, you know, what they can withstand is shockingly high levels of harsh ultraviolet light. Hotaling says their lab test show that the worm's UV-tolerance. is amazing, which is a good thing for them because the sun up at the mountaintop is intense.

I actually think they are coming, looking for the sun a bit, because they want to have some of that heat energy to drive their biochemical reactions. But I thought you said that these worms come out in the late afternoon. So if they want the sun, clearly they don't want the sun at its most intense, like at high noon. Yeah, they don't know why late afternoon, but that's when they come up. And as we walked on and on, it got later in the day. So, you know, we started looking for the worms. And, you know, we were higher up. So as we sort of gazed at the scene around us, you know, we could see other snow-topped peaks in the distance like Mount Adams and Mount Hood and Mount St. Helens.

You could see the scar from that eruption back in 1980. And, you know, you could see why someone would just totally overlook a tiny worm. The scenery is overwhelming. You know, but we're all looking at the ground. and eventually hoteling found, you know, a quarter. People say there's no money in iceworm research. So then he reached down and he scooped up a bit of snow. Here's an ice worm.

It looked like this short piece of black thread, like maybe half an inch long. I would never have guessed that was a worm. Yeah. Eventually you get good at spotting them. It was really beautiful. Yeah, beautiful for a worm or just plain old beautiful, beautiful, beautiful. Well, I think beautiful, but you know I have a weakness for the, lowly and misunderstood creatures of the world. I mean, I think it was, you know, objectively beautiful.

It was jet black and wet and sort of shimmery. And it had this way of kind of snaking around individual ice crystals, really gracefully. You know, so you've got this like handful of really white, clear, glistening snow and this surprisingly quick and lively little black, you know, sort of snake-like thing moving around in there. I mean, it's just such a contrast between this creature and. And, you know, the whole thing was glistening in the sun. And it was beautiful, at least to me.

This is so captivating, Nell. And was it just there, like right on the surface? Yeah. I mean, they come up from underneath the snow in the afternoon in huge numbers. And Hotaling said it was hilarious that we were so excited to find one worm because of the way they come out. He's like, in a minute, you'll see. They'll be everywhere. And as we went over a ridge and onto this white expanse of Paradise Glacier, it's happening.

And so now you can start to look out a little further and you can start see them just dotting. They were like all over the whole glacier and there were just more and more and more. And like I didn't want to step on them, but it was impossible to walk on the glacier and avoid them. I mean, one minute they were not there and then suddenly they were all coming out. And it was amazing to see. And hoteling told me if you dig down in the hours before they appear, you know, you might find a few, but not the thousands and thousands that show up later on. So are they just moving? a large area. Like, are they just coming from much deeper? But, yeah, there's, there are more mysteries than there are

solved things with ice worms. That's amazing, Nell. How many ice worms would you say were on the glacier? There's been estimates that a single glacier can contain five or seven billion ice worms, so billion with a bee. And that's part of why hoteling thinks these things have got to be having some kind of impact on the world around them. There are so many. Like from where we're standing right now, I can see five, six, ten glaciers. And if everyone hosts that density of ice worms, like, that is just a massive amount of biomass that's in a place that is generally biomass poor.

Yeah. I mean, they have to be doing something. So what does studying ice worms tell us about their environment? Like, what kind of research questions are they trying to answer here? The main thing they did when I was there was put out some wildlife. cameras around this glacier to see, you know, like, for example, what might be eating the worms. I mean, they already know that some high altitude birds eat the worms and they might be really important for their life cycle. More generally, they just want to understand the extent to which

wildlife come to mountaintop glaciers at all and to see, you know, how they use whatever resources are there because really not much is known about this kind of environment. These glaciers are hard for scientists to get to usually. It's a very harsh place. And, you know, there's been this assumption that they're just lifeless and sterile. So, you know, as the iceworms show, that's not true. And there's actually some urgency in understanding this because this is a rapidly changing habitat. Absolutely. Glaciers are melting. Right. Hotaling even wonders if the ice worms might contribute to that. How is that? Well, their bodies are dark. So they darken the surface of the glacier. And we know from studies of snow algae that that algae can absorb heat and drive

melting. And, you know, he thinks it's worth thinking about this with ice worms. It's just like one of the many, many things that are open for scientific investigation when it comes to ice worms. This is pure research at its finest, Nell. I mean, you've convinced me that ice worms are not just some curiosity. They're a real scientific question. Hoteling thinks they've got to be the most abundant creature living in glaciers of the northwest. And he says, well, other critters like birds and marmits live near the glaciers. They aren't living in the actual ice that is like the embodiment of the glacier. And so to me, you can't get any closer to glacier biology than an iceworm.

Well, I know I will be thinking about ice worms whenever I see one of those Pacific Northwest Mountain Tops. Nell, thank you so much for coming by and talking about these critters. And maybe the next time you go on vacation in Alaska, you know, you can put this on the agenda. Yeah, maybe I'll look down instead of up. Find an ice worm. Amazing. All right.

Thank you so much, Nell, for this story. Take care. Bye-bye. This episode was produced by Thomas Liu, edited by Giselle Grayson and Viet Leigh. and fact-checked by Indy Kara. The audio engineer for this episode was Josh Newell. I'm Emily Kwong. Thanks for listening to Shortwave,

the Daily Science podcast from NPR.