These ice-loving algae may play a big role in lake health. But time is ticking to learn more
Abby Hughes | CBC Radio | Posted: March 7, 2025 8:57 PM | Last Updated: March 7
Researchers are studying algae samples from just under the ice surface with the help of a diving team
On top of the ice, lakes in the winter don't look like much. They're barren and seemingly lifeless, a white expanse stretching out as far as the eye can see.
But the view from below is something entirely different and magical, according to journalist Andrew Budziak.
"It's as if somebody has taken a cathedral and turned it on its side … the ceiling is stained glass, and the light comes through the ice in a way that is completely surreal," Budziak told The Current host Matt Galloway. "It's all very calm and very still."
Budziak says he's always loved diving, but in the past few years he's been taking the plunge into freezing-cold waters across Ontario in the name of science.
While the world under the ice might seem still, it's actually alive with microorganisms such as algae year round, both in the water and inside the ice.
With the help of Budziak and the diving team, researchers are getting a new look at a specific community of algae that hangs out on and around the bottom of the ice during the winter through samples the divers bring topside. And researchers say they're racing against time to understand this group of algae before climate change thaws the ice they call home — possibly threatening the algae and harming the ecosystem.
How to study under ice algae?
Researchers have known that certain kinds of algae live in and around ice for years. But in the mid 2000s, some scientists on a ship noticed that the underside of chunks of ice bobbing in the wake of the boat were completely brown with algae.
Andrew Bramburger — a research scientist with Environment and Climate Change Canada — says when that group tried to pull the ice out of the water to check out the algae underneath, the fragile microorganisms slipped right off, making it impossible to get a good sample.
Those researchers were able to determine from residual bits left behind on the ice that the algae were diatoms — a kind of single celled algae that photosynthesize, or make energy out of sunlight.
"We know that [diatoms are] a really important food source that's at the base of the entire aquatic food web in the Great Lakes," Bramburger said. "So we started thinking, you know, if we lose ice and lose the ice-attached algae, what does that actually mean?"
WATCH | Trailer for Andrew Budziak's documentary about collecting samples from under the ice:
But because pulling the ice out of the water disturbed the algae, answering that question remained difficult.
That's when Budziak came in. He was talking to Bramburger for a different documentary project when the two started discussing this algae Bramburger was hoping to study.
Budziak asked if a diving team would work to retrieve the samples, and Bramburger thought it was worth a shot. Within weeks, the two began building a mechanism to collect the algae and assembling a dive team. Budziak has been filming the process for a documentary.
How it works
Put simply, the collection device looks like a plexiglass dome with two bags connected to either side by tubes. Each bag — one filled with air and one that's empty — has a one-way valve.
The plexiglass dome suctions to the bottom surface of the ice. Then, the diver lets air from the first bag into the plexiglass dome. The air bubbling inside the dome is enough to gently knock the algae off the ice and into the water. That water is collected in the empty bag, creating a clean, scientifically-relevant sample full of ice-loving algae.
Budziak, Bramburger and an ice diving expert first tested the process in the winter of 2023 on Lake Simcoe. In the winters since, Bramburger says they've perfected their technique and begun collecting samples from Lake of the Woods near Kenora, Ont.
In all, accounting for weather, planning for disasters, getting equipment to the site and more all take weeks to months of preparation.
The divers themselves fight cold conditions with a laundry list of equipment including dry suits, long underwear, heated vests and gloves.
But Calum Cawley say it's worth it.
"The feeling of being underwater and especially under ice is special on its own," the diver said. "But … being able to deliver things that the scientific community finds interesting, I thought it was really cool."
What they've found
The 33 samples they've collected so far this winter are being studied by at least a few dozen researchers across North America, according to Bramburger.
He says no research has been published yet, but adds the first studies will likely be submitted in the next few months.
Andrea Kirkwood, an algal ecologist and professor at Ontario Tech University, who is not involved in this diving and gathering project, says the research Bramburger and the team are undertaking is really exciting because it will help fill a knowledge gap about what microorganisms live in this space just below the ice.
Bramburger also says he's made an interesting initial observation — that the algae in these samples constitute a distinct community, unique from the kinds of algae living elsewhere in the water.
The discovery of this unique community is especially important due to climate change, Bramburger says — as ice starts to disappear, the algae that call it home will likely be impacted in some way.
He says it's possible that some of these algae types will die out in an iceless future, while others may find ways to float near the surface and survive.
"I suspect they'd still be alive, but they just wouldn't be terribly happy," Bramburger estimates.
But whether or not the algae are "happy" could have serious consequences on the ecosystem around them. Because many of these algae types release oxygen and are a critical base of the food chain, their survival could have impacts on carbon dioxide levels coming from lakes as well as the ecosystems in them, Bramburger hypothesizes.
Kirkwood agrees that the initial discovery opens up more questions about how global warming will impact this population. If these good oxygen-producing algae were to suffer from a loss of ice, it's possible that bad algae — like the toxic blooms that grow in the summer — would have more resources to thrive, Kirkwood says.
Already, she says algae blooms that used to die off by August or September are lasting well into the fall.
Melting ice poses a painful irony for the team, too. While it will take more sample collection and more research to understand how valuable the ice is, warmer winters are making it an even more difficult task.
Some of the samples collected will be cryogenically frozen at the Canadian Museum of Nature. That way if the ice cover disappears and microorganisms die, at least a record of them will remain, according to Roger Bull who runs the museum's National Biodiversity Cryobank.
For Budziak, he hopes the insurance is never necessary, and that the ultra-Canadian endeavour will help protect our lakes.
"[Canadians are] adventurous people … we love winter," Budziak said. "We love our lakes and we should be working hard to understand and protect them."