"What if I told you that beneath this silent, frozen surface, fish are still swimming, plants are still growing, and nature hasn’t stopped at all?"

In this episode, we explore the quiet yet vibrant world of lakes during winter. Though a frozen lake may appear silent and lifeless, there's an entire ecosystem at work beneath the ice. From slow-moving fish and dormant plants to persistent microbes and crackling ice sheets, winter in a lake is a carefully balanced, structured, and active time of year. This episode takes you under the surface—literally and figuratively—to reveal how life adapts and thrives in extreme conditions, offering a beautiful metaphor of resilience and quiet survival.

Top Topics:

1. Ice as Protector, Not Enemy

We kick off by dispelling the myth that ice suffocates lake life. Ice forms a protective lid on the lake, preserving a liquid environment beneath it. This frozen surface insulates the lake, shielding it from the bitter cold and allowing life to carry on in a slower but steady rhythm.

2. Life Beneath the Ice

Fish don’t hibernate. They shift gears. Perch and trout remain relatively active, while bass and sunfish conserve energy in deeper waters. Aquatic plants store energy in roots and rhizomes, and some even stay green, producing oxygen. Insect larvae like dragonflies and mayflies feed slowly, providing vital nutrition for fish.

3. Microbial Magic and Nutrient Recycling

Microbes remain tirelessly at work in near-freezing waters, breaking down decaying material and recycling nutrients. Their activity is so significant, they release gases that become trapped in bubbles under the ice—a visible sign that life continues, even unseen.

4. Amphibians and Bottom Dwellers

Frogs and salamanders overwinter in lakebed mud, barely moving, relying on oxygen exchange through their skin. Alongside them, snails, worms, and crustaceans contribute to a slow but ongoing ecological process, helping keep the system in balance.

5. The Lake’s Organized Layers

Winter doesn’t bring chaos—it brings structure. The lake layers into zones: the icy lid, a freezing cold upper layer (epilimnion), a shifting middle layer (thermocline), and a life-rich lower refuge (hypolimnion). Each plays a role in protecting and organizing life below.

6. Cracking Sounds and Ice Acoustics

One of winter’s wonders is the eerie, musical cracking of lake ice. These sounds—booms, groans, and pops—are the result of pressure shifts and temperature changes. Far from dangerous, they are a sign of the ice adjusting and holding strong, transmitting sound like a natural amphitheater.

Takeaways:

Winter lakes are not lifeless—they’re marvels of adaptation and resilience. From the surface, it might seem like everything has stopped, but underneath, life reorganizes, endures, and prepares for spring. It’s a reminder that in times of stillness, growth continues in quiet ways. Understanding this hidden activity deepens our appreciation for nature’s complexity and strength. So next time you're near a frozen lake, remember: it’s not asleep. It’s alive and waiting.

Whether you're a nature enthusiast, a hiker, or someone just looking for a deeper connection to the natural rhythms around you, this episode invites you to see winter not as an end—but as a powerful pause filled with quiet determination.

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By choosing to watch this video or listen to this podcast, you acknowledge that you are doing so of your own free will. The content shared here reflects personal experiences and opinions and is intended for informational and inspirational purposes only. I am not a licensed healthcare provider, psychiatrist, or counselor. Any advice or suggestions offered should not be considered a substitute for professional medical or mental health advice. You are solely responsible for any decisions or actions you take based on this content.

Is winter a big pause button for a lake? Or is there something more active going on that we can't see? That's what we're going to talk about today.

Hi, this is Jill from the North Woods, talking about nature right outside your front door. Right outside my front door—winter. It is cold, blowy, and we have been having lots of ice and snow.

When winter settles in and a lake freezes over, it's easy to assume that the story is over then. The surface is solid. The water is hidden. In fact, it was funny—I was out hiking at a lake last weekend, and the wind had pushed the lake away from the shoreline just a bit because the wind was so strong in one direction. The ice layer itself was above the ground of the lake, and I could actually see in Waka’an some of what had been and look under the ice into the lake. And it was wild.

But it looks quiet and still. And the question is: what happens when a lake freezes? Is anything really alive in there? And what is happening with the lake all winter long?

Because in the end—and here's the end of it—the lake hasn't stopped. It's reorganized. The fish are slowed in their movements and gathering deeper into water. The plant's energies are stored and waiting for action. Insect larvae keep feeding in the dark, and microbes are recycling what it is that's going on in the lake. And the lake itself—the water, the ice, the layers—has become carefully structured.

The ice forms a lid of cold water near the surface. Slightly warmer water settles at the bottom, creating a refuge for life. And sometimes that ice expands and contracts and snaps. And that's what we're going to be doing today—walking through this hidden winter world that's going on in a lake.

Now, I do walk by a number of lakes, and so I was kind of curious what's going on in there. I even bought a GoPro because someday I'm going to take it and shove it into that lake and see what's down there. But the idea is, like I said, the water is still going on, even though the surface is sealed.

And it sounds very quiet when you walk around the lake in winter. It feels very quiet, like winter had just shut down the entire system. So we're going to talk about what is going on.

Ice Is Not the Enemy

So the first thing to understand is that ice is not the enemy of lake life. You think it is, and I think it is. But water freezes from the top down, so the ice floats on the very top and then forms a solid lid over the lake, sealing the water—but also protecting it from the most bitter winter air around the outside of it.

Under that ice, the water stays liquid—usually just above freezing. And with the water being liquid, it means that cells don't rupture. You know, like if we get frostbite, that's what happens: our cells rupture. Gills can still extract oxygen, and life continues, even though it's a little bit slower than it was before.

Snow, if it forms on top of the ice, often makes things even better. The snow acts as insulation, trapping some of the heat underneath the water, and so the ice and the temperature become more and more stable.

The frozen surface you see is actually what makes winter survival possible for what's going on in the lake.

Fish in Winter

The fish themselves, like I said, don't freeze. They don't sleep through winter either. They just downshift.

As the water cools, the fish metabolism slows down. Their bodies need less food. They become less active and need less oxygen. Oftentimes, you'll find them in deeper parts of the lake where the temperature is a little bit more stable.

If you ever watch those survival shows, like Alone in Alaska kind of thing—once the lake freezes over, what do they do? They go walk out into the middle of the deep part of the lake and drop a line in—because that's where all the fish are.

You’ll often see perch and trout remain relatively active and even feeding occasionally. The bass and sunfish move very little and conserve more energy. Many fish are just hovering around, barely moving their fins, making it through the winter.

A fish won't chase prey like they might in the summertime because they're trying, in the wintertime, to conserve energy and conserve their movements. Everything costs in wintertime.

So winter is about survival for a fish, and it's about efficiency—not strength or dominating all the other fish.

Aquatic Plants in Winter

If you have aquatic plants, they're waiting. Again, they don't go. They don't die—they die back. But they are off the lake surface.

Down at the bottom, the roots and the tubers and the rhizomes—those are the things that go under. Like if you have anything invasive above land and they spread through roots, they remain alive in the sediment of the lake itself.

Plants like pondweed and water lilies, which we think of as being on top of the lake—their leaves decay, the stems collapse, and all the energy is stored underground.

Some of those plants will stay even green underneath the ice, especially in more clear lakes where light can penetrate through. They're still getting enough to do photosynthesis, and so they will remain green and still produce small amounts of oxygen.

These plants are one of the reasons that the fish can survive all winter long and still be breathing. So they’re just hanging out and waiting.

Insect Larvae and Bottom Life

The insect larvae are winter specialists in this part of the woods. We know that. Because the lake just below has all sorts of insect larvae in there—juvenile forms of insects that are waterborne and someday will fly.

Things like mayflies, dragonflies, midges—annoying things—all live in the soft mud. These insects spend months of the year just waiting, never seeing the outside. And in wintertime, they're feeding on decayed plant matter, moving very slowly.

They provide fish with food as well, and they're perfectly adapted for the cold.

I think I told you before in past editions—where I go camping, we camp regularly at this one particular lake. We are on this island in the lake. One night, it was like 10 o'clock at night, and all of a sudden we hear this—it sounded like an alien invasion.

My friend and I were like, “What is that?” So we start walking around on the path trying to figure out what kind of noise that was. It sounded like a hundred little drones flying over the lake. And what it was were all the mayflies being birthed out of the water.

It finally got warm enough where one night they spawned, and the next day they were everywhere. It was amazing. And I forgot—I had a stat when I did a podcast about it—how many tons, millions of tons of food that is to birds and everything else. But they're waiting inside that lake for that day, and, like I said, providing a little bit of food for the fish.

There's snails, worms, small crustaceans, crawfish and crayfish, and all the things that you have at the bottom. And they're still continuing too. The snails will kind of scrape around along the algae from surface to surface. The worms tunnel through the sediment, and the tiny crustaceans drift slowly around in the water.

These creatures are constantly recycling nutrients, turning dead material—dead plants and microbes—so they can use it again and eat them. And it just doesn't get much attention, but the system that is active in the summertime is still active in the wintertime. And it really depends heavily on these small little lives to recycle.

Microbes, Amphibians, and Oxygen

And then we think too about microbes. Microbes are the invisible workforce, right? Even in near-freezing water, microbes are still active. The bacteria break down the dead plants and animals, releasing nutrients back into the system.

As they release material, they release gases like methane and carbon dioxide. A lot of times you might see bubbles in the lake ice. That's evidence that life is still going on right up to the moment where the lake sealed over with ice.

So they don’t stop either. They are just patient and persistent and doing their job.

Then the last thing is you think about amphibians and other bottom dwellers. Small frogs and salamanders overwinter underwater. They tuck themselves into the mud or leaf litter around the sides of the lake. But they barely move for months.

Oxygen goes in and out through their skin and the surrounding water. So their survival depends on all the other pieces—the stable temperature, the oxygen that's going on. This is a real winter retreat.

Cold rarely kills lake life. Oxygen loss, if it happens greatly, could kill lake life off—but that doesn’t usually happen to that degree. When the ice is thick and the snow blocks the light, the plants stop producing oxygen, and the microbes keep consuming it. The fish and amphibians could suffer because of the plants' lack of oxygen.

But usually, it's not quite so bad. Certainly, a really tough winter can lead to fish kill, but it's because the system runs out of oxygen.

So winter is a very careful balance, and certainly, there's no guarantees living outside in the wintertime.

I think when I was a kid, I thought winter was the absence of life. Instead, it’s everything using its advantage in the most harsh conditions and just waiting it out. And I think that shows a lot of resilience from nature.

So that’s the idea. I go every year—once it gets a little bit more cold, because I don’t trust the ice—once it gets thick enough, I usually walk out onto a lake because it’s kind of fun and exciting to do.

And you’ll see bubbles. You’ll notice patterns in the snow. And sometimes, I need to take a deeper look to see what I can see deep down inside. One of the lakes I go walking on is crystal clear.

Winter Is Not Chaotic—It’s Organized

The next point I want to make is that winter is not chaotic. It’s very, very organized. And I want to talk about the lake layers.

The ice, like I said, seals off the top, and the water itself sorts into various layers underneath. Temperature has a lot to do with the various layers.

First of all, we get the top layer: ice. Sometimes it has snow on it. It’s not just frozen water—it also protects everything that’s going on below it. The ice blocks the worst of the air, prevents the heat from escaping too quickly, and stops the wind from stirring the waters and making them even colder.

But once we have that ice, there are a couple of layers below it.

Lake Layers: Epilimnion, Thermocline, Hypolimnion

One of them is called the epilimnion, and it’s the coldest water—just below the ice layer. In the summertime, that layer is usually warm and lively and active. But in wintertime, it’s the coldest liquid in the entire lake. It’s usually somewhere right at the freezing point because the water above it is frozen, so it is very close to being frozen.

Fish avoid it, and movement is really minimal. Life at that particular level is very sparse because it is so cold. It’s the boundary zone for the cold buffer between the ice and the rest of the lake.

Then there’s something called the thermocline—and that’s the transition zone. Below that first layer is the thermocline, and it is a place of change. It’s where the temperature shifts from very, very cold—almost freezing—to slightly warmer.

Just because it is slightly warmer, it is not so harsh. It’s much more stable, and it also has slow mixing of water. Remember, temperature is what mixes things. We talked about air: warm air rises and cold air sinks. There’s a little bit of mixing in there. So it stays organized within that particular layer.

Then the last one is called the hypolimnion, and that is really the refuge. That is the most important layer when we’re talking about the lake, because the temperature down there—the water—is the most dense, and it sinks to the bottom. Life gathers there. That’s where the fish are, the amphibians, the insect larvae—everything that’s going on is in that very bottom layer.

It tends to be very stable, doesn’t move around much, and it’s very dark. So it also makes it very energy-efficient for things to hang out there. Everything is really in those particular layers, and that’s what’s going on below the lake level when you’re taking a look at it.

The Sounds of Ice: Cracks, Groans, and Vibrations

The last thing to talk about when it comes to what’s going on in a lake is the incredible cracking—or even almost like a weird guitar sound—it can make.

My friend and I were walking, like I said, around the lake, and all of a sudden we heard this sort of… it sounded like a guitar string going flang! But it was very deep, and it was very loud. It made this incredible noise.

What can happen is that ice is very brittle. Suddenly there’s pressure that can crack the ice. It can snap. It can crackle. It can groan. And the sound is the pressure being released.

And it was, like I said, a very loud crack. I thought, "Oh my gosh, the ice is cracking!" So we ran down to the shore to look—and saw no cracks.

Obviously, there are many layers we just talked about. So what’s happening is it’s releasing tension, kind of adjusting shape a little bit and redistributing some of the stress across the surface. Maybe a little bit like what an earthquake does—but just on a smaller scale.

There may be cracks that open and then seal up directly again—because obviously, the water would fill in and freeze again. These ice crystals form along a network and lock together, but they don’t all expand and contract at exactly the same rate.

Cracks, like I said, can form. Fractures. Pressure ridges can form inside the sheet ice itself. And then suddenly there’s the ice—which transmits sound very well, by the way.

Cold Carries Sound Far

If you don’t live in a cold area, one of the most amazing things about very super cold winters is: you can hear everything. The noise—because there’s less moisture in the air—can travel farther than you can normally hear.

I don’t live that terribly far from a highway. I don’t hear it in summertime. But in wintertime, I can hear it crystal clear, even through my closed windows—because vibrations move better, sound waves move better in the cold.

Same thing with the lake. Vibrations move quickly through a lake. The surface of the lake acts like a giant soundboard, and sounds can echo across a long distance.

You’ll also hear these types of noises at different times of the day—sunset, when the temperature is dropping fast. Or even late at night, when the deepest cold settles in for the evening.

In this particular case, when I heard the noise, it was early morning. That’s when the temperatures are slowly rising, and the ice starts tightening.

The different types of environments can produce different kinds of sounds. Sharp cracks might be a sudden fracture. The long groans—like I guess I heard—come from that pressure shift. And booming sounds can happen right when it’s releasing that stress in the ice.

Closing Thoughts

So it’s kind of an interesting thing—because the ice itself will remain solid, even though there’s liquid underneath. Whenever there are surface cracks, they almost self-repair. And when this happens, it’s just adjusting and readjusting the stress so that everything can just stay level with the lake itself.

I hope that helps you understand winter lakes a little bit more. I love winter lakes. And if you get a chance, go take a walk around a nice winter lake.

In my area, we have a lot of lakes. And I’ve probably been around, oh, probably about a dozen small lakes in this area in wintertime. Each of them kind of has their own nature to it.

So I hope that helps. I hope you enjoy knowing a little bit more about nature.

One of the things that I do with this podcast is that the idea is that it’s not a deep dive into anything—it’s just giving you the idea that something’s going on outside in nature.

You know, a little bit like the oceanic conveyor or something like that—you can go find a book. You like bears? Go find yourself a bear book. You’re interested in the oceanic conveyor? There are books about that too.

And if you love lakes, there’s a really fantastic book about water.