Seeking Understanding of Life Under Frozen Lakes

Researchers say the seasons are connected – and climate change is playing a role in the changing ecology here.

DULUTH, Minn. – Researchers from the University of Minnesota Duluth are making breakthroughs in how we understand our frozen lakes in winter.

But sometimes there are more questions than answers.

“It’s harder to work in the winter,” explains Dr. Ted Ozersky, Assistant Professor of Biology at UMD. “Things freeze; it’s cold; it’s not as fun as hanging out in the summer on a boat.”

Dr. Ozersky also works for UMD’s Large Lakes Observatory, a consortium of faculty from different science departments.

He’s partnered with his PhD student, Kirill Shchapov and Dr. Andy Bramburger, a Research Associate with the National Resources Research Institute (NRRI) in Duluth.

We meet them on frozen Lake Superior to take a deep dive underneath the ice.

“I think a lot of scientists assumed that things either went dormant or radically slowed down under the ice. But we don’t really know,” Dr. Bramburger said.

Drilling holes in the ice, they collect samples of organisms living in the water and organisms living on the bottom of the lake, trying to understand how the ecology of Lake Superior basically behaves throughout the year: zooplankton, phytoplankton, all sorts of tiny organisms tell the story of life under the ice.

The work they’re doing is part of Shchapov’s thesis project.

“I’m from Siberia,” Shchapov says. “I used to work on Lake Baikal for a while. In the wintertime too. We definitely can say that stuff is going on under the ice. We can definitely say it’s important to have ice for our big lakes.”

Kirill grew up around large frozen lakes just like this.

He’s as curious as his more experienced counterparts as to what life is like in these waters year-round.

“Ecologists are starting to recognize more and more that what happens in the previous season has large effects on subsequent seasons,” Dr. Ozersky explains.

And that’s one of the major breakthroughs of research like this.

The seasons are connected – and climate change is playing a role in the changing ecology here.

“As winter gets shorter and shorter (and in some places further south of here, we’re not seeing ice cover on lakes that used to be seasonally ice-covered), in some areas we’re losing winter,” Dr. Bramburger said. “And we’re at risk of not really having understood what’s going on under the ice before we don’t have any ice to go on and look at.”

Bramburger and Ozersky made some press earlier in march during some field work on Lake Minnehaha.

There, they found that a surprising amount of algae was growing, even under snow-packed ice.

“What we found out in the field a couple weeks ago is there’s actually a fair amount of light going down through the ice,” Dr. Bramburger remembers.

Ozersky explains what it could potentially mean:

“You know, jumpstarting plankton growth, which jumpstarts the growth of small fish, and some those resources that are important to have a healthy fish community and feed those fish come the summertime,” he says.

And some of that is just a guess as to what’s actually happening.

Studying ecology in the winter is difficult, which is why scientists are still unsure as to what happens to life under water in the cold months.

“It’s kind of disconcerting to hear that we don’t really know yet,” Ozersky admits. “But that’s part of the reason that we’re out here. And that’s why other groups are also working on this is to really fill in this gap and make the connection.”

Science is always an on-going process.

These guys know that.

But while facing a public that wants concrete answers, right now, they’ll use their expertise and the tools at hand to brave the elements and seek all the answers they can.

“If we’re patient and we let science have a chance to do it we will figure out some of those answers,” Bramburger said.

Ozersky agrees that it’s an exciting time for their research.

“It’s definitely exciting, because of how little is known,” he says. “It’s kind of this feeling of discovery that I think scientists generally are excited about one of the reasons we work in science.”

These researchers will continue their work in the coming months, studying Lake Superior even as the ice starts to melt.

They are studying the lake at five different points along its shore.

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