- [Rob] Coming up on "Great Lakes Now," diving for algae samples in a frozen lake.

- It's a dangerous thing.

- Dale gives one of these.

That's the symbol to abort the dive.

No questions asked.

It was time to get out.

- [Rob] And can Lake Huron help us see into the distant past?

- Imagine you were going back two to three billion years ago.

That's what you are likely to see in Middle Island.

(upbeat music) - [Announcer] This program is brought to you by Richard C. Devereaux Foundation for Energy and Environmental Programs at Detroit PBS, Polk Family Fund, DTE Foundation, and contributions to "Great Lakes Now" from viewers like you.

Thank you.

- Welcome to "Great Lakes Now."

I'm Rob Green.

In our last episode, we showed you part one of a documentary called "Under the Ice" about a team of divers and researchers trying to learn more about the ecosystems in frozen lakes before our lakes stop freezing like they used to.

You met filmmaker and diver Andrew Budziak, lead diver Dale McKnight, and Andy Bramburger, a research scientist with Environment and Climate Change Canada.

- [Andy] If you take lake ice away from a lake that's always had lake ice, what happens to the food webs?

What happens to the lake itself?

We really don't know.

- [Rob] In 2024, their research project took them to Kenora, Ontario and Lake of the Woods at the intersection of Ontario, Manitoba, and Minnesota.

- This is extreme citizen science.

We are going to go diving under the ice and collecting algae samples.

- [Andy] Algae is a primary producer.

It's the point where that sun's energy becomes entrained into something that can be eaten by larger and larger and longer and longer-lived organisms.

So if you don't have algae at the base of your food web, chances are you don't have much of a food web.

If all the algae of the world disappeared tomorrow, everything would be dead, including us.

- [Rob] But almost immediately, they had a problem.

- The weather is not our friend.

It's getting warm.

Like, really warm.

- [Rob] And now, part two of "Under the Ice."

(upbeat music) - The planning and infrastructure that has to go into a dive under the ice is leaps and bounds more complicated than just a simple dive in open water.

It's even more compounded by the fact that you're underneath an overhead environment.

There's no direct route to the surface.

Dale literally did write the book under those conditions.

I can describe Dale as the Michael Jordan of ice diving.

- Hello.

When I was younger, I really had a drive for exploring and wanting to go places that maybe not many people have been to before.

This is very scary.

So I'll try this at home.

I don't know what it was that really attracted me to it, outside of the fact that I just found the idea of exploring and going to an unknown world that's in our world fascinating and exciting.

I just was naturally attracted to it and just decided when I was very young this is what I wanted to do.

Well, I don't really get into talking numbers too much because so many people talk stuff like that, but done, you know, probably in excess of 12,000.

(soft music) So when I hear people talk about what they've done, especially in today's day and age where you can put something on Facebook or on the internet and you can have instant fame in 15 minutes, I've always shied away from that.

I was never driven by any of that.

I was just driven by the pure challenge of seeing what I could do or not do and taking myself to that edge without going over that edge.

And sometimes that worked out well and sometimes it didn't.

(upbeat music) (zip zipping) - [Andrew] In addition to the ice-bottom algae samples that we're going to get while we're diving, Andy and his team are also doing a whole bunch of other cool under-ice experiments.

These people love doing this.

They love the process, and they love the results.

- I'll come back.

So a log coming back, and I'll just pull it in, sort of hand over hand, and trying to be about, like, a meter every five seconds or so.

- Celine is my direct report back at the lab.

She's a technician who's been working for us, and I have the good fortune to have her working in my lab.

It's fun in that there is a sense of anticipation that we're going to find something new, and it's tedious in that you want to be doing the science, but you have to still take the time to make sure the lab is set up properly and everything is clean so that we can get good data.

I'm curious to see what's happening this winter in that the ice cover is so much less than what we would typically see, and the temperatures up topside here are a lot warmer.

So what that means as far as the algae doing whatever they're doing under the water and under the ice, it's kind of a new situation for us.

So it'll be really interesting to see.

In the experiment that we're going to do, we add a small amount of radiolabeled carbon solution to the water.

So it's basically like baking soda, except the carbon is carbon-14 radioactive isotope.

So the algae, when they're photosynthesizing, are going to take up carbon.

And then we can go back afterwards with detectors and actually detect how much radiation there is.

And that'll tell us how much carbon those algae took up over the period of time that they're under the water.

It is five minutes to four.

So these will straddle four o'clock.

The other one's pretty quick.

(soft music) - See how this is all broken up in here underneath?

I don't like walking on this.

We've lost a lot of ice.

This is amazing.

Beautiful yet terrifying.

- The blocks that we took out are like decaying.

- I believe that, we've lost inches of ice last night.

- Today, the global average ocean temperature is the highest it's ever been today as we film this.

And typically, then the highest point of the year globally is in July.

So we're at the hottest the oceans have ever been today.

And we're nowhere near what it gets to later in the year.

- We couldn't screw into this.

- No way.

No.

- No.

We wouldn't be able to screw into that.

- It was just a mess under there.

- That's bad ice.

- That's really bad ice.

- A little closer to home, freshwater is directly related to our health and survival.

We need it.

Within this country, we have a lot of access to it.

We take it for granted.

But because we have so much of it, we really need to be good custodians of it.

We can't think about changing it tomorrow.

And I think a lot of people have a sense of hopelessness.

I don't know how people who have kids do it, because it's so alarming.

We're not going to be able to turn back time.

We're not going to be able to change the way things are, probably in our lifetime.

But if we can start making better decisions, we may be able to slow it down at least.

We may be able to make it so that we can keep up with the rate of change.

It's going to result in the change that means that humanity can keep existing on the planet.

The planet will go on without us.

But we don't want to take everything else down with us.

You're okay.

Look, you're all right.

I know.

Some tasty grass, isn't it?

You don't usually get to eat that at this time of year.

Hello.

Hello.

(machine whirring) - Hello.

How are you?

Good.

Lovely to meet you.

I'm Andrew.

- Hi, Andrew.

Mona.

- So nice to meet you.

We've been working with Grand Council Treaty #3.

- Nice to meet you.

- Andy, our science lead.

The traditional caretakers of this area, of this land.

We told them what we were up to.

And Mona came out.

Representing the Women's Council, she wanted to do a ceremonial blessing.

- In anything we do with science, we want to make sure that we acknowledge and take care of spirit first to ensure that everything that is to happen happens in a good way.

And the safety of the divers and everybody involved.

For everybody from the Western science world and Anishinaabe spiritual world.

And for us to be coming together today is a very special thing.

And it's my ask today that we can learn to reestablish, strengthen, and renew, and heal, and correct our relationship with the water, and to correct ourselves as humans, to correct how we carry ourselves, how we walk on Mother Earth.

Water is life.

(dramatic music) Water gives us life.

Water sustains us.

Water sustains our Mother Earth.

Water sustains all of creation.

Humanity as a whole has taken that relationship for granted.

The effects that that's going to have on our nation and our relatives, those that fly, those that swim, the four-legged, the two-legged, those that fall closest to our Mother Earth.

Mother Earth will heal herself and renew herself, whether we are here or not, that we are being given a chance to do what's right for all of creation, for life on Mother Earth.

- Thank you.

- That was lovely.

(people chattering) - [Andrew] This is going to happen.

This dive's going to be a good dive.

- We're going to get you more samples today than you can shake a stick out.

All right, so I'm going to give you an on-site briefing here about what we're going to do, how we're going to do it.

The assigned-out rules, Sophie, you're going to be handling our interactions on the surface with regards to the bags.

Andy, you're just going to be doing your scientific stuff, and you'll kind of be around if we need you.

And Dave's going to be tending us, specifically tending with me, and he's going to be priming the pump as that goes on as well, and Andrew and I will be doing our thing.

(soft music) Okay.

And once we've got that plan put together, we're going to get ourselves systematically dressed.

We're going to zip up, get ourselves into our systems, working as a team.

We're going to come down here.

We're going to take a breather right over there.

- Okay.

About an inch of water now coming over the hole, which we didn't have yesterday.

- When's the last time you lubricated these?

- What are those?

The ice screws?

- They're totally seized.

- What?

- Seized.

- It was clear when we started setting up that our gear had taken a beating on the drive up.

We traveled a really great distance.

We had to drag it across this province.

I think we're both feeling a little tense at this point.

(tense music) (people chattering) (people chattering) (tense music continues) - A couple minutes into the dive, Dale looks at me and gives one of these.

That's the symbol to abort the dive.

No questions asked.

It was time to get out.

When we hit the water, things weren't okay.

- Watch out.

- Yep.

- Okay?

- Yep.

- All right.

- Out, out.

Yep.

- Oh.

Done?

- Copy.

Yep.

- Good.

- Dale and I don't dive with tethers when we do this kind of diving.

We do a more advanced version of this, but we thought, hey, here's the opportunity.

Let's be a little bit safer.

That was a mistake.

It just completely screwed up how we did everything.

It screwed up our standard operating procedures.

It's that little change to our plan, plus these little alterations in gear and these little problems that we were having.

- Well, that was a real (censored) wasn't it?

- [Andrew] Just kind of cascaded, cascaded, cascaded.

- I haven't done one of those dives in a couple years.

- Okay.

I don't know why we decided to change up our routine.

We had practiced and we were so dialed in, and I guess this nice opportunity came in to be a little bit safer, but it just completely screwed up how we did everything.

- Never again.

- Yeah.

We came out alive, which is the most important thing.

But man, it was frustrating.

(soft, tense music) - We're going to do this dive flawlessly because that's what we trained on.

We're going to be successful and do something that probably hasn't been done before.

- [Andrew] And I'm watching him and I'm like, oh no, this is not good.

He's not moving.

The bubbles have stopped.

- That'll be in our next episode.

Sign up for our newsletter at greatlakesnow.org/newsletter, and we'll remind you to watch.

In September of 2026, we teamed up with underwater explorers and filmmakers to livestream a dive to one of the strangest areas of the Great Lakes, Lake Huron's Middle Island Sinkhole.

(soft music) - [Narrator] This might look like the landscape of some alien world, but believe it or not, this footage was recorded in Lake Huron.

The Middle Island Sinkhole is one of the strangest ecosystems in the Great Lakes.

And in September of 2026, underwater filmmakers Yvonne Drebert and Zach Melnick used a high-tech, remotely operated vehicle, or ROV, to livestream from this strange underwater world.

- Everything looks pretty good.

Good.

So let's go.

So what we're gonna do is, so we're coming to the edge of the sinkhole right now.

We get a couple other things in focus.

(soft music) - We've all seen footage of ocean deep-sea vents where there's water just coming out of the ground, and then there's all these alien-like creatures.

And we were pretty excited when we found out, hey, there's kind of places like this in the Great Lakes.

And because we were pretty surprised, we suspected most folks living around the lakes would be pretty surprised by it.

And we were so happy that other folks could join us for that adventure.

(upbeat music) - [Narrator] Located in northern Lake Huron, the massive sinkhole is about 80 feet deep and was formed by groundwater eroding away the limestone geology of the lakebed.

- [Yvonne] It's freshwater pouring out of these weird holes in the earth.

We have a lot of karst-like structures in the lower Great Lakes because it's limestone, so that means there's lots of holes and crevasses and caves where water can get in and do some weird things and then come up through the earth.

- [Narrator] While far from the deepest point in Lake Huron, the Middle Island Sinkhole is nevertheless an extreme environment.

This groundwater is high in sulfur and low in oxygen, so you won't find many fish here.

It's too inhospitable.

But it's the perfect environment for a different kind of life: microbes that create the psychedelic patterns carpeting the bottom.

(upbeat music) Scientists believe conditions in the sinkhole are similar to what the Earth's oceans were like billions of years ago.

And these microbial mats likely resemble early life on the planet, long before plants and animals existed.

- Imagine you were going back two to three billion years ago, how the shallow seas might have been and how the biosphere might have been just a thin film of life clinging to the shallow sea bottom.

That's what you are likely to see in the Middle Island.

(light music) (people chattering) - [Narrator] Dr.

Bopi Biddanda, an aquatic microbial ecologist from Grand Valley State University, has been studying the sinkhole for years.

He says it could help us understand how life first evolved on Earth, making it a window into life's distant past.

- It goes to our deep desire to seek our roots, just like human ancestry.

Similarly, we want to know how life got going and how it then set up the stage for the, you know, very vivacious, diverse biosphere we have today.

- [Narrator] In many ways, we might owe our very existence to microbial mats like the ones found in the Middle Island Sinkhole.

The vibrant purple mats are cyanobacteria that grow by photosynthesis, the same oxygen-producing process that plants use today.

- [Bopi] Over longer days, late afternoons, they can start emitting small amounts of oxygen that over a long geological span might have oxygenated our planet.

That's one of the things we are finding out, that they might have had a significant role in oxygenation of the planet.

- [Narrator] Unlike the purple cyanobacteria, the white microbial mats with long strands grow or produce through chemosynthesis.

- [Bopi] They use hydrogen sulfide in the process of producing or fixing carbon dioxide.

These might have been the first and original primary producers on the planet.

Scientists think they might have been in shallow springs or in deep seas thermal vents where they prevail even today.

- [Narrator] The mats are constantly shifting throughout the day, with the purple cyanobacteria trying to maximize its exposure to sunlight from the surface.

And the white chemosynthetic microbes becoming more dominant at night.

- These migrations happen in under submillimeter ranges.

You have to change the color when the purples come out during the day to make it all mostly purple.

At night, really dark nights, you will get nearly white coloration at night because the chemosynthetic white mats are marching up.

(upbeat music) - But our own distant past isn't the only thing this sinkhole can help us understand.

Environments like this one could provide clues about what life may look like on other planets.

- [Bopi] There are many planets and there are satellites that have hydrospheres.

Think of Jupiter's moon Europa or Saturn's Enceladus.

This kind of life could be one of the trends of life we may likely encounter.

- [Narrator] Plus, the sinkhole is within the boundaries of NOAA's Thunder Bay National Marine Sanctuary, which collaborates with researchers to collect samples of the microbial mats.

Stephanie Gandulla is the sanctuary's resource protection coordinator.

- It is a really special place to dive and one of my favorite places to scuba dive in the sanctuary.

I will say what probably contributes to that is also how enthusiastic our visiting scientists are when we're collecting samples for them and they're undertaking all this research that I just know very little about.

And they're very excited to get these samples.

- [Narrator] And because the sinkhole is within sanctuary boundaries, it's accessible to the public.

- We have a mooring buoy, a sanctuary mooring buoy there at the Middle Island Sinkhole.

So anybody can come tie up to that buoy, and certified divers can explore it themselves.

You do have to be an advanced diver.

So any dive charter company would confirm your certification.

But it's a really fun place to explore.

- [Narrator] The Middle Island Sinkhole isn't the only sinkhole in the Great Lakes or even in Lake Huron.

But to those who have seen it, Middle Island stands apart.

(people chattering) - [Bopi] Nobody can visit the past, but we have these current models that we can study and try to explain the past.

- It really is a special place.

I suspect anywhere in the Great Lakes.

I think the Middle Island Sinkhole is a pretty special spot that can help us learn more about, you know, what else might be out there in the Great Lakes.

(upbeat music) - Thanks for watching.

For more about any of the stories in the show, visit GreatLakesNow.org.

When you get there, you can follow us on social media or subscribe to our newsletter to get updates about our work.

(upbeat music continues) (upbeat music continues) - [Narrator] This program is brought to you by Richard C. Devereaux Foundation for Energy and Environmental Programs at Detroit PBS, Polk Family Fund, DTE Foundation, and contributions to "Great Lakes Now" from viewers like you.

Thank you.

(upbeat music)