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[piano intro] - Hi there, I'm Frank Graff.

Sunday day flooding is a nuisance.

It's getting worse.

Algae blooms threaten nature and people, and what you can learn from water insects.

It's time to put your water shoes on, on Sci NC.

- [Narrator] Funding for Sci NC is provided by the North Carolina Department of Natural and Cultural Resources.

[upbeat music] ♪ - Hi again, and welcome to Sci NC.

Flooding is something you normally think of happening during a rainstorm, even a hurricane, but as our climate changes and sea levels rise, flooding is a lot more common.

In fact, streets along the coast can flood even on sunny days.

As we continue our state of change project, producer Rossie Izlar, explains the phenomena of sunny day flooding.

[birds chirping] - So there are days when like today it's pretty sunny, there's no rain, but you see a big puddle right around your storm drain.

What's happening is ocean sea water is actually coming in through the pipes and up and out onto the street.

So even if you don't see the water coming in from the side, it's because it's coming up and under from underneath.

- [Rossie] A puddle of water in the street might not seem like a big deal, but this isn't rainwater, it's salty ocean water and it's incredibly corrosive to cars, pipes, and infrastructure generally.

It's called sunny day flooding and it's a problem all along the east coast, where the number of these floods has doubled in frequency since 2000.

- Climate change has caused sea levels to rise.

And with that, our storm water infrastructure, which was built decades ago is not behaving as intended.

With rising seas, water can go up through storm drains and overflow onto streets.

- The challenge is really the frequency.

So even just in the past couple of decades, we've seen places that used to only flood a few times a year.

Now, they're seeing flooding 20, 30, 40 days a year.

And we know that that frequency is going to go up really quickly as sea levels rise.

You hit these tipping points where all of a sudden, every high tide or a high tide every three weeks is above that threshold that you're worried about.

When it happens that frequently, we start to worry because it's disrupting people's commutes to work.

It's forcing school buses to operate on a different schedule 'cause they can't get to certain neighborhoods at the time they need to get to.

It's preventing customers from getting to businesses, right?

If the entire parking lot is flooded, you're not gonna get as many people coming in as you would've before.

And so it goes from being something that was maybe a concern once a year to something that's a really disruptive weekly occurrence.

- [Rossie] Miyuki, Katherine and their team are trying to discover the extent of the problem in Beaufort and other North Carolina towns so these communities can better understand how to manage these floods.

- And what we have come up with here for the town at Beaufort and some other towns in Carolina is to create a really cheap sensor that we can put in storm drains and get the data in real time, but it's hard to sometimes tell how far that water has traveled on the road.

So we have a camera so you don't have to drive through a salty lake.

You can check our website and see if water is actually coming up through the drain.

- Having that information will be very powerful.

And I don't think we're the only community that's dealing with it all throughout the coast.

So we can also partner with those communities.

What have you done?

What has been successful?

What have you struggled with?

So we don't always have to reinvent the wheel.

[water burbling] - These are really really important places.

I get lots of questions about long term futures of coastal communities.

And the question I'll get is, well, what option do they have besides moving?

There's no way, the only thing they can do is move.

And nobody ever says that to be around Miami.

Our imaginations of what's possible are really big in some places and really small in others.

The answers to this type of flooding are gonna be different from place to place.

So in some places they might choose to invest in their storm water infrastructure that might also involve elevating some of the buildings that are most exposed.

And in others, they might just say, this stretch where we're really concerned about how often it's flooding, maybe the best use of that land is a park, right?

A place where it can flood, the water can recede and it's not going to put anyone in danger or put any buildings into any type of physical damage.

- We know that our boardwalk the sub structure is starting to crumble a little bit so we've gotta be able to fix this.

Can we work with UNC and the experts there and then determine when we repair the bulkhead, how do we do this in a way that'll help protect our community?

- [Miyuki] The most important thing is that we're trying to preserve what the community values in the long term.

And that means that people from outside of the community, aren't going to know what's best.

- We can do our part at a local level, but this is a national problem, this is a global problem as well.

And we need the US to be a national leader in reversing the effects of climate change.

- Our ecosystem is becoming off balance.

It is really beginning to talk back to us in a very different way.

So we're gonna have to listen to it.

- Algae, are simple plants that live in seawater and fresh water and it's all fine until pollutants, usually fertilizers get into the water and algae growth explodes.

Creates what's called algae blooms, massive bursts of algae that turn the water green and those green blooms can be toxic to animals and people.

Producer Evan Howell, explains how researchers at UNC Wilmington are taking a new look at algae blooms.

[upbeat music] - [Evan] Brazil fame for its beaches, it's lush beauty, it's diverse ecosystems deep within the Amazon rainforest, and of course, it's parties.

- Last time I was in Carnival?

- [Evan] Last time you were at Carnival.

- That was five years ago just before I accepted the position here.

- [Evan] Rio native Dr. Catharina De-Souza, says she came to the United States to make a contribution.

Now, she's a research professor at the Center for Marine Science at the University of North Carolina, Wilmington.

It's here where they study things like coastal ecology, Marine mammals, and what they eat like plankton.

- Microalgae are part of the plankton.

So basically the microalgae are tiny plants.

- [Evan] Microalgae get their food mainly from nutrients, like nitrogen and phosphorus.

So the more food in the water the more microalgae reproduce, supporting that food chain.

But sometimes there's an excess of it.

And that often comes from things like fertilizer runoff from farms, that's called eutrophication.

And that's when the microalgae reproduce exponentially, leading to what are called algal blooms.

Why can algal blooms be bad?

Among other things they can consume oxygen and block sunlight from underwater plants.

Fish and other life can't find food causing entire populations to leave or even die.

On top of that, a bloom that's thick muck, can impact recreation and even bring down property values.

- You have lots of different microorganisms in the plankton, good and bad.

Most of the time you have the good ones.

They are the predominance, but you have also some bad species.

And under certain conditions these bad species they proliferate.

The bad ones inside their cells they produce the toxins.

- [Evan] So the bad blooms, the toxic blooms are the basis for De-Souza's work.

- In the left, the cells are passing and then you see is more squares around the cells.

- [Evan] De-Souza and her team study individual species of algae with devices like this and actually take pictures of them in order to find out what's inside.

- Those are new.

- [Evan] They're building a microalgae collection, thanks to a $600,000 grant from the National Science Foundation.

And while field samples are widely used to study algae in their components, what De-Souza is doing is actually growing cultures of microalgae in her lab to catalog which are toxic, which are harmful or both.

- Once you find a culture that can produce a toxin, then the chemists they need a lot so they can do their jobs and describe the molecule.

- [Evan] Call it a library that currently holds around 500 species, some from as far away as New Zealand.

And she wants to get that number to a thousand.

- And then you take a little bit of this then you put it like that.

- [Evan] De-Souza is working to make this collection available to other researchers around the state and the country.

- Now, it is the source of information.

For example, the agencies that perform the monitoring, perhaps they're looking at species in the microscope and they have no idea that the species can be toxic.

- It's a step down freezer.

- [Evan] But building a library requires too much space.

And that's where this device comes in.

- So what it does is over a short period of time, goes from 20 degrees down to negative 40.

What that allows us to do is not completely instantly freeze the samples that we're putting in there.

This helps us in that we can bring these back to life and the way it helps the overall lab is we don't have to keep everything in large cultures so that we can keep things in small amounts and basically freeze their evolution at any particular time.

- [Evan] She says the library can be seen as a public health tool, particularly as some species can cause paralysis, damage a liver, and impact the community.

In the summer of 2019, three dogs were playing in pond near downtown Wilmington and died from an algal bloom.

De-Souza's team visited the pond the next day and took field samples, but they couldn't find the species or even see it, but the toxin they determined was a neurotoxin called Anatoxin.

Anatoxin can come about during periods of warm water temperatures.

- They're so strong that the dogs they just were playing there and that was enough to cause their death.

And so that's the other thing.

Some toxin micrology they don't need to be in very high concentrations to have an effect.

- [Evan] So how do some micrology for some reason, spontaneously produce toxins?

De-Souza says they're not sure yet and says that might be more of a philosophical question.

Whatever the reason she hopes that with the expansion of this library, she and her colleagues will have created a better defense and greater understanding of what dangers lurk in the microscopic world.

- Mostly what we can do right now is to detect them that they're in the water because they affect people.

We need to know our enemy.

- Now, to the science of the insects living above the water.

It turns out describing new species can tell you a lot about the quality of the water below.

Adrian Smith, at the North Carolina Museum of Natural Sciences explains.

- [Adrian] This is what a day on the job looks like for biologist, Chris Verdone.

- I'm gonna gonna beat that, that looks really good.

That holly right there overhanging the stream.

It's kind of short and that looks appealing.

- [Adrian] He's looking for this, the adult form of an aquatic insect known as a stonefly.

This one you're seeing here is a new species, one he's describing and naming for the first time.

- If I were a stonefly, I might hang out someplace like this.

So right now we have 11 undescribed species of stoneflies statewide.

Two of them occur in this creek.

Each species has a different pollution tolerance, but for these ones that are undescribed, those are all unknown, but those are all pieces to the puzzle.

And if we can identify those then our picture gets a little bit clearer.

- Chris is part of a team of biologists charged with monitoring water quality across the state of North Carolina.

They do that by collecting and cataloging insects that live in the water.

They also happen to be taxonomic experts.

So they're finding and describing new species all the time.

I think what they do is a really interesting mix of basic and applied biology.

So I spent a few days with them learning about how and why they do what they do.

- All right, so to collect adult stoneflies, I like to use what's called a beating sheet.

Put your sheet underneath the vegetation, knock it.

And if you're lucky, you might find something.

[object clattering] But sometimes it's easier said than done.

When they're hard to find, you can always flip over rocks.

They don't call them stoneflies for no good reason.

The stoneflies live in the interstitial spaces, but what I'm gonna do is disturb that with my feet and just lodge them and then they will flow into the net.

So we've got a new species of Isoperla right here next to my index finger.

So now we're gonna get a ripple kick using a kick screen.

So he's going to disturb the substrate.

Everything's gonna flow into this and then we can wash it into a bucket and sort it.

So I see we've got a crayfish climbing up here, stonefly.

All right, so now we'll wash this into a bucket.

This bucket has a screen on the bottom of it so all the excess water can wash out.

I think we're good.

Whenever we conduct a bent sample, this is how we pick the sample.

We do it on site, in the stream, in lawn chairs.

- This represents a stream right here.

At the end of the day, this is what we come back with.

All of these or many of these aquatic insects, we have developed what is known as a tolerance value.

The tolerance values are essentially a proxy for how that organism can withstand pollution.

If you look back here, we have the historical record of water quality in North Carolina from 40 years ago to the present.

We can track North Carolina's water quality with this wall of bottles.

And we'll show you what's going on in here.

And if you come back here, these are rearing units.

The purpose of rearing these or the purpose of putting the bugs in here is to give them a setting that is similar to the stream setting out in the field in nature.

We'll dump those in there and you can see, oh, those larva swimming around here.

They go in then I will take this and essentially just put it in here where they will live until they emerge.

We now have one larva that has emerged as an adult and it appears to be a male.

So the really important part of this is that the larval skin is still in here, which means that we can now take the larval pattern that we didn't know what species it was, but we also now have an adult.

And this adult is what we need to look at to figure out what species it is.

For me water quality is about the biological end.

It's about how the pollution or the chemicals affect the stuff living in the water.

What we do is important because it allows us to actively try to protect the water quality and to also protect and conserve many species that would be lost through human activity.

- By documenting insect biodiversity, this group of researchers is protecting water all across the state.

As a bonus, they're also giving names to some incredible undescribed insect species.

Here's one.

This is an undescribed stonefly in the genus Isoperla.

We collected it as a larva from the field when I filmed the first part of this video.

And then they raised it into an adult in the rearing units you saw on the second half.

And to end this video, this is its flight captured at 6,000 frames per second.

- Now, to one of North Carolina's largest lakes, Lake Waccamaw.

It is home to species of aquatic life found nowhere else.

Now, the lake is facing many of the challenges we've talked about, algal blooms, rising water levels, but one of its biggest threats from the invasive hydro plant is now under control.

Students from the UNC Hussman School of Journalism and Media explained.

- [Instructor] State biologists consider Lake Waccamaw, a jewel of biodiversity.

Two rare species of mussels live here as well as three species of fish and two species of snails found nowhere else in the world.

Wildlife biologist, Brena Jones, monitors these species annually to track their numbers.

She knows just where to look.

- The silver side is it prefers open water.

However, the kelly fish and the darter are usually found closer to shore.

The darters really like these emergent maiden cane beds.

They hide in there among all the stalk and the kelly fish just move into any cover they can find.

The mussels can be found throughout the lake in all depths of water.

They settle in the bottom and feed on organic material and algae and bacteria down there.

And the snails too can be found anywhere in the lake.

- [Instructor] Lake Waccamaw is what's known as a Carolina bay and not because it's an inlet to this sea.

- It actually comes from three bay trees, loblolly bay, sweet bay and red bay are the common bay trees you'll find in and around a Carolina bay.

- [Instructor] Lake Waccamaw is the largest bay lake in North Carolina, but that's not all that sets it apart.

The water in most bay lakes is acidic.

The water in Lake Waccamaw is not.

- So what you see here is the limestone bluff that's located on the north shore of Lake Waccamaw.

There are four creeks that feed into the lake that are highly filled with what we call tannic acid.

That's what gives the lake it's dark tea color.

This acidity is neutralized by this bluff here, which gives the lake a neutral pH.

That is for the extreme biodiversity that you see out here in the lake.

As far as total species in the lake that we have is 15 mussel species.

Two of them only being native for Lake Waccamaw 54 fish in this lake with three fish only found in Lake Waccamaw.

And then we have 11 species of freshwater snails, two fresh water snails only native to this lake.

- [Instructor] But in 2012, that biodiversity faced a foreign invader, an aquatic plant called hydrilla native to Asia and Africa.

- Hydrilla was one of those things that kept me up a lot of nights.

It was a very scary situation.

- [Instructor] Hydrilla robs the lake of oxygen.

North Carolina state researchers found the plant covered more than 10% of Lake Waccamaw, putting the lake seven unique species in danger.

- So it certainly would've choked out all the lake habitat.

It would've just been solid hydrilla, the entire water column, solid flatbed across the surface.

- We are almost sure that the hydrilla came because people brought their boats from other lakes.

- [Instructor] Boats can carry the invasive plant from one body of water to another, says Julie Stocks, a volunteer for Coastal Carolina University, who checks water quality in Lake Waccamaw.

- And the hydrilla it's very difficult to get rid of 'cause they have tubers that settle in the bottom of it's like a potato tuber in the bottom of the lake and it stays there.

And if you can kill off the top, but then the tubers still there.

- [Instructor] After hydrilla's discovery in 2012, officials were unsure how to cope with the invader.

- Should we use chemicals?

Should we use a kind of a carp like a big goldfish to eat it?

Should we drain the lake?

[ducks quacking] - [Instructor] Officials chose to use a chemical called Fluridone that they felt wouldn't hurt the Lake's native species.

- We didn't want to use anything that was a copper-based product.

Copper is a big one that we were worried about that would be infused into the soils that would affect the mussel species here, but this herbicide has been successful in just attacking hydrilla to make sure it's fully eradicated.

- [Instructor] The town of Lake Waccamaw, Columbus County and the state paid for a 10 year treatment plan that started in 2013.

Over the past six years, Fluridone treatments have cost more than $3 million.

- We were a little nervous about how it might affect our samples.

And we could not tell even the day that they put the Fluridone in the water, we could not tell any difference in the samples that we had the year before.

- [Instructor] Officials say they found no hydrilla in the lake in 2019.

That makes former town manager, Harry Foley, happy.

- When it comes to the treatment of hydrilla, I think there's been one of the best things that the state of North Carolina was able to do for Columbus County in Lake Waccamaw.

It's working.

I think that the test results speak for themselves.

- [Instructor] State biologists and park officials, say there's a lesson to learn here.

Hydrilla can threaten any lake in the state.

To prevent that from happening, boaters must wash their boats before entering and after leaving new bodies of water.

Boaters must also empty and wash holding tanks they use for fish catches.

Just one tiny piece of hydrilla can multiply to infest an entire lake.

That didn't happen in Lake Waccamaw, but a return of hydrilla still is a threat.

- So we have mussels, fish, and snails that are native only to this lake.

They're found nowhere else in the world.

So it's very very important to protect these species 'cause when they're gone, they're gone.

- So since we've talked about water for this entire show, it's time for a quick review about the system, the natural system that powers all of this, the water cycle.

- [Narrator] This water molecule may not look like much, but it's been around the world and back again in a process called the water cycle.

The water cycle has two main parts, water goes up, water comes down, but it happens in weighs slightly more complicated than that.

First, the up part.

Heat from the sun causes the liquid water in our ponds, lakes, oceans, glasses of lemonade and even sweat to turn into a gas and rise into the atmosphere through a process called evaporation.

Plants play a part too.

Water released through tiny holes in their leaves, a process called transpiration, also evaporates into the atmosphere.

Once up and Earth's atmosphere, gases water eventually loses energy and condenses back together as clouds, then comes the down part.

When this water gets heavy enough, gravity takes charge and it falls back down as snow, sleet, rain or fog into lakes, oceans and onto land.

And the water cycle begins again.

So next time you have that glass of lemonade, just imagine where that water has been.

[upbeat music] - And that's it for Sci NC for this week.

If you want more Sci NC please, check us out online.

I'm Frank Graff, thanks for watching.

[upbeat music] ♪ - [Narrator] Funding for Sci NC is provided by the North Carolina Department of Natural and Cultural Resources.

[upbeat music] ♪