- Hi there, I'm Frank Graff.

Could green sand help fight climate change?

Preventing algal blooms, which threaten fish and people and a medical device used to help divers in trouble moves into mainstream science.

Dive into science in the sea, next on "Sci NC" - [Narrator] Quality public television is made possible through the financial contributions of viewers like you who invite you to join them in supporting PBS NC.

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

[gentle music] [gentle music continues] - Hi there, I'm Frank Graff.

Climate change poses the biggest threat to the health of the planet and there is a unique experiment happening along part of North Carolina's coast this summer, testing whether green sand could help fight climate change.

Oh, never heard of green sand?

Producer Rossie Izlar explains.

- [Rossie] There's no escaping the fact that climate change is doing crazy things to the weather.

[thunder banging] Historic heat waves, catastrophic flooding, wildfires, the hits just keep coming and it's all the fault of excess carbon dioxide in the atmosphere from burning fossil fuels.

The US is bedding big on strategies that remove carbon dioxide from the atmosphere to reach its goal of net zero emissions.

The solutions vary from technology that directly captures CO2 from power plants, to planting or preserving carbon sinks like forests.

But right now most of these solutions are either really expensive or take a long time and that's why I ended up visiting a team of scientists here, on the Outer Banks of North Carolina because they're testing another strategy to draw down carbon dioxide and they're using this thing.

We're in what's called an amphibious vehicle with Dr. Jaclyn Pittman Cetiner and a team from the Army Corps of Engineers.

- I grew up in Southern California and going to the beach all the time and playing in the waves and the sand and the mud and incredibly this is still what I get to do is play in the waves and the sand and the mud, for work, which is so fun.

- [Rossie] The Army Corps have been using these surplus military vehicles from the seventies to study the movement of sand along the Outer Banks.

So they're a perfect partner to test out the ambitions of Vesta, a startup that's trying to slow down the carbon crisis with this, yeah, I know it just looks like sand, but this is actually an abundant mineral called olivine.

- [Dr. Jaclyn] It has a slight green hue which is where the name olivine comes from.

- [Rossie] You might know olivine from its gemstone, peridot, which happens to be my birthstone.

Hello, my Leos.

But when you add it to the ocean, it soaks up carbon dioxide.

Here's how it works.

The ocean is already a massive carbon sink.

It stores 40 times more CO2 than the atmosphere, but it can't keep up with our emissions.

That's where olivine comes in.

It transforms CO2 into bicarbonate, a harmless form of carbon, which is ingested by marine animals.

Eventually it becomes shells or skeletons and when those animals die they become part of the sea floor, locking up that carbon for millions of years.

- This is a natural process.

The Earth has been carrying out this exact reaction for billions of years and it's one of the planet's natural mechanisms to stabilizing our climate and all we're trying to do at Vesta is to accelerate this natural process on meaningful timescales for humans.

- [Rossie] Adding olivine to oceans can solve another climate change issue, ocean acidification, which kills corals and other marine life.

Because bicarbonate is basic, it lowers the acidity in the water.

- [Dr. Jaclyn] So we have this like dual benefit here where we're slowing down ocean acidification through the production of bicarbonate and drawing down carbonic acid and carbon dioxide in the ocean.

- [Rossie] Vesta wants to do something that might sound a little wild.

It wants to mine olivine and dump it in shallow tidal areas like this all, over the world.

The wave action breaks down olivine even further which speeds up carbon removal.

- So our current best estimates are that for every cubic yard of olivine, we can capture one metric ton of carbon dioxide.

The scale potential of Vesta's work is very high and we're not limited by much.

There's trillions of tons of olivine on the planet.

There's thousands of miles of coastline where we could deploy it on.

- [Dr. Jaclyn] When you think about it, what Vesta is proposing isn't that unusual.

We've spent billions of dollars dredging and dumping sand along our coast through beach nourishment.

- We have ideas of tacking on to existing beach nourishment programs of like, "Hey, you're already putting down all this sediment, "what if 5% of that sand is carbon capturing sand?"

- [Rossie] There are still a lot of questions that need answering about this strategy, including the environmental impact of mining olivine at the scale Vesta is talking about.

But before they do anything, Vesta wants to see if this can actually work.

So they're trying to get an understanding of the chemistry in the water here at Duck before they add any olivine.

- [Dr. Jaclyn] Any changes we see we can attribute to our olivine and this will help us really evaluate and quantify the amount of carbon that we can capture with this olivine.

- [Rossie] It's clear that we're gonna need more than olivine to solve the climate crisis, but we also need all the tools we can get our hands on and olivine could make a big difference.

- We are working up to a billion ton scale of carbon removal, at that point, would really make a a real difference.

That's why I'm so happy to be with Vesta because I can combine my love of the oceans and also this intrinsic need I have to be part of the climate solution.

- [Rossie] From a green solution to a green problem, algal blooms.

When too much phosphorus from fertilizers gets in the waterways, it creates deadly algal blooms.

As part of our series marking the hundredth anniversary of NC State's College of Engineering, a look at what's being done to save the water.

- Hi, I'm Dr. Nehemiah Mabry.

I'm an engineer and proud graduate of North Carolina State University and this is the Plant Sciences Building.

It's an amazing structure.

For instance, the top floor is an entire greenhouse.

Now there's important work happening here all about phosphorus.

Phosphorus is a critical element.

It's essential to life as we know it.

However, we have too much of it that's running off of our crops into our waterways.

The good thing is that people here are trying to fix all of that in the Step Center.

Let's go check it out.

- So all living things need phosphorus to grow.

It's actually required in our diet.

It's part of our nutrients.

It's stored in our bodies in the form of mostly in bones, but it's also in our DNA.

We also use phosphorus to grow crops.

So it's an essential nutrient in the food system and it's the nutrient in the food system that actually drives agricultural productivity, something we call yield.

In the 1940s, it was recognized that we needed to increase the productivity of the food system and we did that mainly through increasing our mining of phosphates for fertilizers.

Around 1960s and seventies, we experienced the green revolution, which produced plant varieties and crop varieties, which also required more phosphorus to grow and so over the course of about 50 or 60 years, we've significantly increased our dependence on mined phosphates to feed the world's growing population.

So the United States sources most of its phosphorus from Florida and North Carolina, about 75%.

- There's actually a phosphate mine in Aurora, North Carolina just off the Pamlico River where they refine products for animal nutrition and for industrial fertilizer markets.

- But the way that we use phosphorus today is unsustainable.

- You need it to survive.

We need it for all living things to grow.

So we apply it to our fields and then unfortunately it runs off and causes these large algal blooms some low oxygen in the water and fish kills and really disrupts our ability to swim in clean lakes and for recreation purposes, but also for fishermen and women.

People have seen, have driven past lakes or have been in lakes where there's these just large green blobs of stuff and it's unappealing and so you can actually see the problem.

I don't know that there's a connection in people's minds that the fertilizer that we put on fields or the wastewater that we're creating that maybe runs off into these streams causes those large algal blooms.

- We mine the phosphorus from a non-renewable source.

We use it in fertilizer, we put in our agriculture and then 80% of it is lost to our environment.

It's like going in the shower and use a shampoo bottle and then 80% of it goes down the drain.

- [Dr. Nehemiah] The world's population is growing fast.

It's projected that we will have 10 billion people on the planet by 2050.

Scientists and engineers are working to find ways to feed all of these people more efficiently and more sustainably.

- So the vision of Steps is something that's affectionately called 25 in 25.

It's a 25 year vision, within 25 years to have reduced our human dependence on mined phosphates by 25% and reduced losses of phosphorus to soils and surface waters by 25%, increasing resilience of the food system.

- Just said the magic word.

25 and 25.

25 and 25.

Jacob, what is that?

- So Steps was funded as a National Science Foundation Science and Technology Center, or STC, in 2021 with an initial grant of 25 million over five years with an expectation for renewal.

NSF Science and Technology Centers are agency-wide, meaning that the topic sponsored under these centers should span all areas of interest of the National Science Foundation and the challenges underpinning phosphorus sustainability do that.

They reach all the way from material science and chemical engineering and environmental engineering, all the way over to social science and geopolitics and public policy.

And so, we established a team that collaborates in a very significant deep way, across all of those different disciplines, something we call convergence research.

- [Dr. Nehemiah] Darryl Harry is a PhD student in Materials Science and Engineering.

He is looking at metal oxides for phosphorus recovery.

Imani Madison recently completed her doctorate in Molecular Biology.

She's looking at how to measure plants under stress, particularly stress related to phosphorus uptake.

She shows me a 3D printer that uses living material and something called Bio Ink.

- Steps is a partnership with 10 institutions with NC State as the lead.

Some other North Carolina institutions involved include Appalachian State University, UNC at Greensboro and NCANT.

We have about 40 senior investigators and about a 40 postdocs and graduate students that work across all of those different disciplines.

We have a lot of undergraduates working in the center and we also have a summer research experience for undergraduates program that brings in undergraduates from other universities to work within our lead institution and our partner institutions.

- For decades, NC State research stations have been measuring plant production related to the amounts of phosphorus being applied to fields.

The North Carolina Extension Service is a partner with the step center and is working to reach growers with best management practices.

- One of the great things about engineering at NC State is the ability to solve society's grand challenges and I think the Steps Center really exemplifies that.

So taking a problem like phosphorus sustainability, which touches upon agriculture, it touches upon environment, it touches upon public policy and looking at it with engineering eyes while accepting that engineering isn't the only solution, right?

But engineers can bring everyone together and help address the systems level problems associated with that particular issue.

So I think moving forward, seeing engineering do that in other spaces, spaces like climate change for example, I think that's gonna be a wonderful opportunity in the future.

- Scientists are also racing to save oysters.

Oysters are vital to a healthy coastal ecosystem, but they are also a roughly $7 million industry in North Carolina.

But something is causing mass die-offs of the shellfish.

Producer Rossie Izler explains.

- I know the idea of eating an oyster grosses some people out, but I love them.

It's really good.

And lately I've developed a real respect for the people that grow them because farming oysters is not easy [oyster rattling] and something keeps happening to this growing industry.

Oyster farmers will come out to their farms to find that a huge chunk of their crop, like 70%, 80%, 90%, has died.

- We weren't seeing anything one day and the next day we went out and it was just, it was just all dead shell.

- So I came down to Morehead City, North Carolina to talk to some of the people who were trying to figure this out.

Why are so many oysters dying and what can we do about it?

[upbeat music] So we are here to look at the Duke Aqua Farm.

It's basically like a small version of an oyster farm that students can learn from.

- [Employee] This line is kind of, it's connecting all of the bags.

- Is it keeping locked in place?

- Keeping them attached here to the floor.

- [Rossie] A quick primer on how oyster farming works.

Farmers buy what they called seed oyster, basically tiny baby oysters.

- So in this silo here, there's about 17,000 oysters.

- [Rossie] Cuties.

- [Rossie] Farmer, Tyler Chadwick grows his oysters here until they're big enough to stay inside these bags.

As the oysters get bigger, farmers move them into bags with larger holes so they can do what they do best, filter the water for nutrients.

- So it's moving rocks?

Yeah, it's moving rocks.

It's what we do for a living, is move rocks.

[Rossie chuckling] - This one?

- Basically, we put out oysters that were this size, last August, and by now they've grown up to this size and it's May.

- [Rossie] This rapid growth is a very vulnerable time for oysters.

They are pumping so much of their energy into growth that they have less energy for their immune system.

So if they're exposed to pathogens, they're not as able to fight them off.

- But a dead oyster will basically start to gape.

What happens is that the muscle at the end of the oyster, whenever they die, the muscle basically relaxes and so the shell opens and that's that gaping you see.

- How we know when an oyster is dead is when we pull the bag up and [oyster clacking] you hear that sound?

That's what we hear.

- That's the sad sound.

- That's the sad sound.

What we want to hear, what we want to hear, is listen to this.

[oyster thudding] Nope, see that one's dead.

You hear that?

[oyster thudding] So that one's dead.

What we want to hear is [oyster clacking] you hear that?

Sounds like two rocks sitting together.

- [Rossie] Sounds like money.

- Yes, that's right.

- [Rossie] Like in any other farming, sometimes crops die, but these mass mortality events don't seem normal and scientists are trying to find solutions because this is a critical time in this industry.

Many farmers aren't large enough to weather big losses yet.

- We put all this time and all this hard work into it and then it's finally time for us to harvest and we pull 'em up and we gotta dump 'em in the road.

That's what happens with our dead oysters.

They become driveway.

- [Rossie] So there's no single bacteria or disease that's causing all this mortality.

There's a lot of factors involved.

More development on the coast means more potential pollutants, extreme temperature fluctuations due to climate change and also the fact that there's just more oyster aquaculture happening in the area.

But here's what we do know.

North Carolina is known for its really salty waters.

That's partly why oysters here taste so good.

But high salinity causes everything in the water to grow really quickly, including the microbes that kill oysters, which occur naturally in the water.

There's a simple sounding solution to this problem.

- What if we don't grow oysters at high salinity?

Move them up the estuary.

Maybe just move them during the summer when the mortality risk is highest or have nurseries at low salinity and only bring them down to high salinity for a couple weeks to finish them.

They taste better at high salinity.

- [Rossie] There's also a longer term shift that scientists think needs to happen, we need local seed oyster.

Most farmers like Tyler get their seed from Virginia, which means those oysters aren't adapted to live in North Carolina.

But establishing an oyster hatchery is incredibly expensive.

- It's a huge expense and right now the outcome is uncertain.

We have really good initial evidence that our North Carolina derived oyster lines work better.

That's just a few years of study.

- [Rossie] In the short term, the team is growing their own oysters alongside local farmers and bringing them back to the lab to dissect them and identify which bacteria are killing them.

They hope to develop a warning system so that when they see the bacteria they think will kill the oysters, they can give farmers a heads up that it's coming.

- This is a problem for everybody.

We want to make sure that this industry stays resilient in the face of things like climate change and as mortality break out, everybody has the same goal and that's to promote and keep the oysters healthy and alive 'cause they're a great resource.

- Now, I might not have a a PhD behind my name, but I work in the water.

This is my livelihood.

This is something that I deal with every single day.

I'm doing my part to better our water quality.

I'm in it for the long run.

I consider myself a farmer and as long as I can afford to grow oysters, I'll keep doing it.

- Dive deep into the ocean and if you come up too quickly, you will suffer from decompression sickness.

It's better known as the bends.

Producer Evan Howell shows us how hyperbaric medicine which first treated divers is going mainstream.

[water gurgling] - [Evan] Whether it be jumping or diving in a lake or pool or going down to retrieve a toy off the bottom or even pretending you were a creature of the deep, [tense music] well, that just means going underwater is part of your personal experience.

But, if you go too deep, your ears start to hurt from the water pressure and you start to run out of air.

So you swim back to the surface as fast as you can.

- [Medical Professional] 30 seconds.

- [Evan] It's all about pressure and oxygen and that's what they study here at the Duke Department of Hyperbaric Medicine, where researchers look at how oxygen moves through the body, the blood flow and how the environment impacts how tissues react and what's also here is a Duke hyperbaric chamber.

It's the only civilian one of its kind in the country certified by the US Navy and where they study how pressure can be used to treat patients.

It's led by Dr. Richard Moon.

- We treat patients with hyperbaric oxygen, we treat emergencies and also people with chronic problems, certain types of chronic wounds.

- [Evan] These giant tubes can be sealed where staff can regulate pressure to simulate either an increase or decrease of it, depending on the need.

A patient sits inside the chamber, which is basically identical to a hospital examination room.

But how does pressure actually affect you?

[water splashing] You might even think scuba divers haven't made because they take oxygen done with them, but even divers need to be careful.

That water pressure you felt in the pool affects a diver's entire body.

The deeper the dive, the higher that pressure is that their bodies feel under the massive weight of the water.

And if they come up too fast, they can get what's called decompression sickness.

That's when nitrogen builds in the blood and creates bubbles.

In the old days, they used to call it bubble disease, these days, some call it the bends.

More on that in a minute.

- I'm very medicine evolved because of diving.

And back in the 19th century when people were exposed to pressure, either working in tunnels or bridges, in a compressed air environment, or diving, they found that when they came back to normal pressure, they often had illness.

- [Evan] Scuba divers call them safety stops where they hang for three to five minutes every 15 feet on their way back to the surface.

That gives their bodies extra time to release that nitrogen buildup that happened during the dive.

But we're not just talking about water, it turns out the depth alone increases pressure and you can experience that underground too and that's what workers building the Brooklyn Bridge discovered back in the 1870s.

The bridge was so massive, workers needed to settle the foundations of it around 78 feet in the ground under the river.

They used what are called cassons, which were developed in France and where a bottomless chamber was lowered for workers to dig out the mud and sand.

Air was pumped down and that, you guessed it, created pressure.

But when they came up and out after their shifts, many had serious problems, they would bend over in pain.

In fact, that's how the bends became a term.

- Some of 'em couldn't walk and actually there were many people who died of decompression illness.

Many of the many of the men, it was men in those days, who went back into the compressed air environment, found that their symptoms got better and so the notion of using pressure to treat bubble disease came about.

[airplane rumbling] - [Evan] Now, let's think about what happens when air pressure decreases.

Yes, you can get sick going up as well.

Oxygen molecules start to spread out because there's no pressure and that means no usable oxygen to breathe and there's a risk of what's called hypoxia.

- Most people can go to altitudes of 10 to 15,000 feet without really any problem.

At 18,000 feet, you start maybe developing a little symptom of not quite feeling right.

At 25,000 feet there's a potential to lose consciousness.

- [Flight Attendant] Ladies and gentlemen- - [Evan] That's why airplane cabins are pressurized and why flight attendants do that oxygen demonstration every time.

Because if a window were to blow out, while the airplane is at altitude, you only have a short period of time to grab that oxygen mask before losing consciousness.

- [Astronaut] I am halfway in sight of the docking compartment.

- [Evan] Astronauts in particular, need training if something unexpected happens.

In the past, astronauts from the SpaceX program needed a training ground to learn what happens in a low oxygen environment.

So they were taken up to 25,000 feet inside the chamber.

- What we did with them, we had one of those little balls with different shapes in for children, where the child has to pick the right shape and put it in the right shaped hole.

But at 25,000 feet after, a minute or two of hypoxia, each of the individuals we took there was having difficulty.

- [Evan] But treating patients is the primary goal here who were suffering from things like bacterial infections, hypoxia and carbon monoxide poisoning.

It's called oxygen therapy.

- What the oxygen does is it competes with carbon monoxide for all of the proteins that carbon monoxide attaches to and it displaces it so that it's exhaled into the air.

- [Evan] Inside the chamber, the patient receives 100% oxygen through what they call a head tent, like this one.

The patient breathes the oxygen while the pressure increases.

- We have the ability to monitor the patient exactly as they would be in the ICU.

We can connect the patient's arterial line, electrocardiogram, to the hospital monitor, which then collects the data and stores it just as it would as if they were in a normal ICU room.

- It's learning how the human body reacts to different environments that's critical in helping staff understand the doorways and the treatments and a better ability to not just help patients recover from illness, but shed light onto prevention.

- And that's "Sci NC" for this week.

If you want more "Sci NC," be sure to follow us online.

I'm Frank Graff.

Thanks for watching.

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

- [Narrator] Quality Public Television is made possible through the financial contributions of viewers like you, who invite you to join them in supporting PBS NC.