- [Announcer] Coming up on "Great Lakes Now," journey to the deepest point in the Great Lakes.

- They are these incredible magical worlds that just don't get explored enough.

- [Announcer] Find out what lives 1,300 feet beneath the surface.

- It's adapted to live in such a extreme place.

It's basically 39 degrees Fahrenheit year round.

- [Announcer] And what it took to get there for the first time in decades.

- There still are a lot of questions facing the Great Lakes.

(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.

(light music) - Welcome to Great Lakes Now.

I'm Rob Green.

The deepest point in the Great Lakes is more than 1,300 feet, or 400 meters beneath the surface of Lake Superior.

For 40 years, it's gone unexplored, but in June of 2026, a team of filmmakers set out to change that.

(water gurgling) - [Narrator] This is the view from the deepest part of the Great Lakes, Superior Maximus.

Natural light doesn't touch it.

The pressure is about 40 times the pressure on the surface.

And for 40 years, only a handful of people had ever laid eyes on it.

- It's super hard to believe that the deepest spot in the world's largest lake was visited like a couple of times before in the mid-1980s, and then that was it.

Like that was the end of the age of exploration, really, in the Great Lakes.

- [Narrator] In 2026, Canadian filmmakers, Zach Melnick and Yvonne Drebert set out to change that and to live stream their exploration for anyone to watch.

- We really wanted to shine a spotlight on this freshwater world, show people what's beneath the waves, and we really see that as our job to show people what's down there.

- [Narrator] Despite being in our own backyard, the deepest depths of the Great Lakes have gone largely unexplored.

- They are these incredible magical worlds that just don't get explored enough.

Okay.

We just hit the bottom.

See a cloud of silt rising in front of the sub.

Also visible in the back.

- [Narrator] In 1985, NOAA's National Undersea Research Program brought a state-of-the-art research vessel and submersible to the Great Lakes, giving scientists the chance to see the lake bed up close.

Over the next several years, they would explore the depths of Lakes Superior, Huron, Michigan, and Ontario.

Ivar Babb was the last director of the National Undersea Research Center at the University of Connecticut, which helped coordinate the dives.

- We call them in situ technologies, that allows an investigator to actually get on the site and look at things in really fine scale.

The ability to precisely sample an image is really a very important aspect to a lot of research questions that we faced not only in the oceans, but in the Great Lakes as well.

- [Narrator] The research vessels Seward Johnson and its submersible, the Johnson Sea Link II were top of the line for underwater research.

The dives provided valuable opportunities to gather samples and observe some of the creatures that live in the deep, like burbot, sculpin, and hydra, small stationary animals that use waving arms to capture zooplankton for food.

- [Ivar] So over the course of a three-hour dive, you could be transiting the lake floor covering kilometers and be able to sample and get a really good picture of what was happening on the sea floor, were there transitions in terms of anything living there or contaminants that might be there.

- [Person] The water temperature here is 4.5 The trasnsponder is 890.

- [Person] The life line is in, the swimmer holds on and the submersible is now winched out for the water.

- [Narrator] One of the scientists on board was a limnologist from the University of Wisconsin-Milwaukee named Val Klump.

On July 30th, 1985, about 35 miles north of Munising, Michigan, he led the first descent to the deepest point in the Great Lakes, more than 1,300 feet beneath the surface of Lake Superior.

- Our interests were understanding the biogeochemical mass balance in lakes or the elemental economy of lakes, if you will.

How much of the material that bombs out of the water column and hits the sediment is actually sequestered and remains permanently buried in the sediment.

To actually be able to see the environment you're sampling was a huge plus.

- [Narrator] One way to gather that data was to visit the deepest point in the lake.

- One, sediments tend to sift their way down to the bottom, right to the deepest portion of the lake.

So if you want to find high accumulation rates, it typically would go to the deepest point in the lake.

And two, simply because it was the deepest point.

Let's face it.

That was kind of cool.

- [Narrator] On July 27th, 1986, almost a year later, the submersible went back.

And this time, it wasn't just to take samples.

They left something behind.

A time capsule.

- [Person] Apparently this is going to be search for and located in 50 years.

- [Narrator] That was the sub's last visit to Superior's deepest point.

And after 1992, the JSL-2 left the Great Lakes entirely with unmanned remotely operated vehicles emerging as a cheaper and safer alternative.

But for 40 years, neither a sub nor an ROV returned to Superior Maximus.

- It is my opinion that the Great Lakes research community is vastly underfunded.

There still are a lot of questions facing the Great Lakes.

(gentle music) - [Narrator] Even though no one else has seen Superior Maximus, that hasn't stopped people from studying it.

For decades, Shawn Sitar, a fisheries biologist with the Michigan Department of Natural Resources, has been researching the ecosystems of Lake Superior.

- We're about three miles southeast of the deepest spot in the Great Lakes, Superior Maximus.

- [Narrator] For nearly 20 years, much of that work has been done aboard the research vessel Lake Char, a floating fish laboratory.

- Exploring deep water areas, the first thing is, as a scientist, when there is unknown, that's always something that we seek, is the unknown.

- [Narrator] It's a drive that, for Shawn, originates with a fictional group of explorers that boldly go where no one has gone before.

- My interest in science started from watching "Star Trek," as well as coupled with my interest in nature and being outdoors.

Their view of exploration.

I feel very fortunate to be able to carry some of those concepts in my work and in Lake Superior.

(machinery rattling) - [Narrator] Using indirect methods of observation, like gillnets that capture fish from the lake bed, Shawn and his colleagues have pieced together a snapshot of life in Superior Maximus.

- [Shawn] It's a very extreme environment and, you know, very little productivity's out there.

So there's only five species of fish that exist out there.

- [Narrator] There are the predators, like the burbot and the siscowet, a large fatty type of lake trout.

- It's adapted to live in such a extreme place where they can't see and there's very high pressure.

And basically the temperature's constantly cold.

It's basically 39 degrees Fahrenheit down there here around.

- [Narrator] Then there are the prey fish, food for the predators, like the alien-looking deep water sculpin, and the kiyi, a fish believed to be found only in Lake Superior.

It's so rare that it has never been observed in its natural habitat.

- It's related to the Cisco and Lake Whitefish, and that's what we call a pelagic predator.

It moves up and down the water column, feeding on small invertebrates.

- [Narrator] They've also discovered that, even with its crushing pressure and harsh conditions, Superior Maximus is home to at least one invasive species.

- The fifth fish would be the sea lamprey, which is an invasive.

We do see impacts from sea lampreys even at Superior Maximus.

- [Narrator] In recent years, the Lake Char has been looking into zombie fish.

Extremely emaciated siscowets.

Why are they emaciated?

That remains a mystery.

There's a lot they still don't know about life in Superior Maximus.

And actually seeing it, something Shawn has never done, could help answer some important questions.

- Fortunately, with modern technology and more resources, we have that capability to go out, I guess, and boldly go where no one has gone before.

- [Narrator] That's where Zach and Yvonne come in.

- Okay, here we go.

Getting ready for the deep dive.

(bright music) - [Narrator] As part of their work making a documentary about the hidden worlds of the Great Lakes, they wanted to be the first in 40 years to explore Superior Maximus.

- If you're doing exploration in the Great Lakes and you want to get people interested in it, there's really only one place you got to go.

You got to go to the deepest spot.

Everybody loves the deep.

- We do hope to catch some really high resolution footage of the underwater world, that deep water world that really will help our scientific partners learn more about this really hard-to-reach ecosystem.

- [Narrator] They'll do it using Kiyi, an ROV.

- [Yvonne] This is our robot.

We've named it kiyi after a Great Lakes fish that has never before been caught on film, so we're really hoping to do that this week sometime.

- [Narrator] The descent to Superior Maximus will be the deepest Kiyi and its operators have ever attempted.

And they're spending the days before the dive testing their gear in shallower waters.

- We are going to test a new really deep, really strong tether and getting used to working at the extreme depths that we need to work at.

- It's about 750 meters long.

And this is the first time we're plugging it in, so here we go.

- We'll be adjusting the weighting of the drone to try to make sure it's perfectly neutrally buoyant down there.

We have just passed 250 meters, which was our previous maximum depth.

Farther is the Kiyi ever gone.

Hopefully there's kiyi down here.

We are now at 300.

- [Narrator] Preparing the gear is only part of the challenge.

They also want to attract some of the creatures that live at these depths, which means working with the crew of the Lake Char to bait the waters near Superior Maximus with frozen hunks of fish guts that they call meatballs.

(water splashing) But Lake Superior makes the rules, and there's no guarantee that the dive to Superior Maximus will go as planned.

(boat engine rumbling) (people laughing) The day before the big descent, the crew sets out to check on one of the meatballs in shallower waters near Superior Maximus.

- Let's get this robot in the water.

- Yay.

Yeah.

- [Yvonne] So we shall see.

We see a big ball of fish guts.

- [Zach] Let's hang out here for a little bit.

- [Yvonne] What's that?

- This is our meatball.

- [Yvonne] That's the meatball?

- That's the meatball.

- [Yvonne] Oh my gosh.

- [Zach] Can't find it.

Look at that beautiful ball of fish guts.

- [Yvonne] It's beautiful.

It's so shiny.

- Alrighty.

So we have found the meatball.

So mission accomplished, recon done.

It's good that we were able to find it, but there's nobody around.

We will just skip it just a little bit.

Or it's hog.

- [Yvonne] Straight down.

- [Narrator] But no one shows up.

And there's still more to do.

The next task of the day is to choose a precise location for the dive.

Mapping the lake bed with sonar to find interesting features that could attract wildlife.

But before they can finish mapping, reports of a storm come in.

So the crew heads back to land.

- [Yvonne] I mean, that's kind of the nature of making documentaries.

And that's just the nature of the beast when you're outside working with nature.

So such is life.

- [Zach] I guess we'll go a little bit blind on the exact location where we're going to drop down into Superior Maximus.

(birds chirping) - [Narrator] On the day of the dive, the weather doesn't look any better.

- The conditions have worsened, so we're not sure if we'll be able to do it today or not.

We're going to get in our little boat and we're going to head out and see what it's like out there and make the call whether or not we can do it today or not.

- [Narrator] And with that, they set out for Superior Maximus.

Not far behind, the Lake Char carries the rest of the crew.

Along with Shawn Sitar, who will be featured on the livestream.

The crew is optimistic it will work out, but eventually the call is made.

- [Zach] Hi, folks.

So we're out here around the deepest spot, around Superior Maximus.

And unfortunately, we're getting 20 knot gusts out here and the waves are just too big to deploy the robot and keep our boat in the, in the same spot.

So unfortunately I think the safest and ultimately most enjoyable thing for everyone to do is to give this a shot tomorrow instead.

- [Yvonne] I think there's always disappointment when you're hoping things are going to go a certain way and you can't do it.

Really, we're always going to make the choice to scrap a mission if the weather is against us and it's not safe.

- [Zach] We've done some work on an Arctic lake called Great Bear Lake, and the people there say that Bear Lake is the boss.

I would say that Lake Superior is also the boss.

So we're working for it right now.

(birds chirping) - [Narrator] Despite the fog, the next day's forecasts are looking much better.

- Broadly going here.

- [Narrator] So once again, they take a small crew to scout the location.

(light music) And just like the day before, the Lake Char is not far behind.

- I'm excited to actually visualize an area that I've been studying for 20 years that I've not been able to ever see, but just to collect information from indirectly.

So that's exciting to me just to see this maximum extent of the Great Lakes.

And hopefully, we'll see some life forms swung around.

- [Narrator] When they burst out of the fog, the lake is still as glass.

And when the Lake Char catches up with Zach and Yvonne, everyone kicks into gear.

- Yes, the star is here!

(team cheering) - All right, you're not getting them back.

He's ours now.

- [Narrator] And soon enough, it's time to begin.

- Welcome.

And thanks for joining us for this historic dive.

Today, we'll attempt to send an underwater robot to the deepest point in the Great Lakes, a place not explored in 40 years.

Okay.

How are you guys feeling out there?

- [Teala] Good.

Ready to launch when you are.

- Okay.

Everything looks good here.

One more final check.

Sensor power on.

And we can go ahead and launch away.

(light anxious music) - [Teala] Okay.

And you are good to start your motors.

- Okay.

I am starting thrusters.

- [Narrator] The descent alone takes about 12 minutes.

And at first, the bottom looks barren.

- [Zach] We are coming up on the bottom here.

Let me get a focus.

Get us in focus.

And yeah, we have, we have a rock.

Exciting.

So we are on the bottom, folks.

So we are at 350 meters right now.

And I'm going to try to go west, southwest as we do sand... Oh, we got a bunch of deepwater sculpin down here.

And let's see if we can can get these little guys on camera here.

So we got some deepwaters.

They're moving around.

Gonna keep on keeping on.

- [Narrator] As they make their way deeper to Superior Maximus, they stop to investigate interesting features on the lake bed.

Like rocks in what most people assume is a sandy lake bottom.

- [Zach] Well, this is sort of an interesting sort of rock pile in the middle of nowhere.

So Shawn, what are your thoughts about having come upon this pretty interesting rock pile way down here as we descend to the very deepest part of the lake?

- So yeah, there have been questions like the value of doing this.

And this right here is a great example of the value.

So a lot of assumptions are in deep water that the bottom is just muddy or sandy.

And here we're seeing a rocky substrate.

And this is the type of rock that is necessary for lake trout to lay eggs in.

So this is verifying that there is a spawning habitat down here.

And it's also cover for sculpins and probably burbot - There's a hoppy sculpins.

You know what?

That sculpins is trying to mow down on some, just having dinner down here.

Let me try to get... You trying to eat a mysis, buddy?

Is that what you're up to down there?

I think the answer is yes.

Maybe we're providing a little bit of extra light for little dude down here.

(light music) Seems to be hunkered down now.

Probably because there's a large robot thing hovering over it.

See you later, buddy.

We're going to keep on keeping on into the deepest realms here.

(bright music) - [Narrator] They encounter small forests of colorful hydra first observed at these steps in the 1980s.

- [Zach] You can just see the rock has some fur on it.

And that's not fur.

That's a really cool little creature that eats zooplankton in the water.

- [Narrator] And even at these depths, they find signs of human impact.

- Oh, hold on here.

Whoa.

Yeah.

Okay.

Now I got to.

What are we saying?

Oh, no.

I thought it was a burbot.

But you know what?

I think this is the... What do we got here?

We have a can.

(Jocie laughing) We have a rock and some kind of a can.

There is hydra on the rock as well.

Let's see if I can stay in place enough here too.

And so this is a little habitat made by, I think, a beer can and a beer can and a rock, folks.

So you know.

- [Jocie] Someone was having a good time.

- [Zach] Here you can get a better view of the hydro.

- [Yvonne] They've got these arms that are kind of waving out in the water.

So that's the only way they can get food is by using the currents and their arm motions to pluck little life out of the water.

- [Narrator] They even play with a sculpin using lasers typically used for taking measurements.

- [Zach] Are you interested in that, in the- - [Yvonne] In the lasers?

- [Zach] Lasers.

We'll see.

- [Yvonne] Oh, I think the sculpin is chasing the lasers.

- [Zach] Yeah.

See?

- [Yvonne] Oh, there's a cat.

- [Zach] Earlier, Shawn mentioned that the burbot were the cats of the... Maybe sculpin are.

Yeah.

That's a even bigger sculpin, I think.

- Yeah, these are very good.

Hefty.

Yeah.

I'm pretty surprised to see this many sculpin.

So that's something we're learning.

I think my colleagues that sample and work with sculpins will have a lot of things to think about, especially at this extent.

- [Narrator] By the end of the live stream, they had spent over an hour exploring the lake bed.

- So I think we've just about made it to the deepest spot.

And we're spending a few more weeks out here exploring this deep zone for hidden below.

So, you know, we'll let you know what we find.

Thanks so much for joining us today.

And as I say, we're gonna keep on exploring down here, so go away.

Leave us alone.

(group laughing) - [Person] Bye-bye.

(engine rumbling) (upbeat music) - [Narrator] For viewers at home, the live stream may have been the main event, but for Zach and Yvonne it was just the beginning.

- I think the overall density of life was actually a little bit higher as far as the number of sculpin and mysis and all the other creatures down there.

So it shows that even in the deepest parts of the Great Lakes, there is life.

So we're gonna keep looking around in this deepest hole, see what other life we can find down there, look around the edges of it, try to get a better picture, and then really contribute to the knowledge and understanding of this ecosystem.

- [Narrator] They didn't find a time capsule, and they didn't find the elusive kiyi.

But to Zach and Yvonne that just means there's more to explore.

(light music) - Doing this kind of work, you know, you never really know what you're gonna see when you put the robot down.

(light music continues) Each one of those moments feels pretty special to know that you're kind of the only human in the world that's had this experience.

It's pretty magical.

And then to be able to share that with other people, like there's nothing better than that, right?

Everyone's excited about discovery.

(light music continues) - You can see the full expedition to Superior Maximus that we streamed live at greatlakesnow.org/hiddenbelow.

When you get there, you can follow us on social media and subscribe to our newsletter to get updates about our work, including the next live-streamed expedition.

This time, we'll take you to the Middle Island sinkhole at the bottom of Lake Huron, which contains an ecosystem so unusual that researchers study it to learn what life on earth might have been like 2.5 billion years ago.

(bright 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.

(bright music)