Last of two parts

BEAUFORT– As more people move toward the coast, estuaries are increasingly under stress. If not correctly managed, North Carolina’s estuaries may see the same fate as other overwhelmed estuarine systems in the country.

The Chesapeake Bay, for example, was once a thriving estuary with unmatched oyster harvesting. According to the National Oceanic and Atmospheric Administration, numbers have fallen to less than 1 percent of historic populations because of overfishing, poor water quality, habitat degradation and disease.

North Carolina is home to the country’s second-largest estuarine system behind the Chesapeake Bay, the Albemarle-Pamlico estuary. As with the Chesapeake Bay, national and state agencies have both worked to protect the resources and livelihoods the areas provide. Despite these efforts, over the years both areas have lost habitats, suffered from poor quality and seen increasing development nearby. Restoration efforts in both states are now focused on improving water quality and growing the oyster economy.

This week is National Estuaries Week, as designated by the nonprofit group, Restore America’s Estuaries. In this second installment of a two-part special report, we will look at the types of threats North Carolina’s estuaries face and what their futures may look like.

Coastal Living

In 2010, NOAA reported that about 40 percent of the United States’ population lived directly on a shoreline. This percentage is projected to increase, along with the risks estuaries face. North Carolina also has the fourth most beach visits in the country, adding more pressure to its coastal region.

Joel Fodrie, an assistant professor at the University of North Carolina at Chapel Hill’s Institute of Marine Sciences in Morehead City, said coastal development presents estuaries with many different challenges at one time.

“Those local impacts, because they happen everywhere, those may be the real dangers,” Fodrie said.

Boating, as one example, can result in cumulative deterioration as thousands of vessels transit estuaries annually, disrupting ecosystems, Fodrie said. Construction of bridges and causeways can also add pressure to the various habitats in estuaries, including oyster reefs, mud flats and sea grass beds.

Lexia Weaver, a coastal scientist at the North Carolina Coastal Federation, said waterfront property owners who install bulkheads and seawalls are among the biggest offenders. The hardened shorelines cause the salt marshes along properties to disappear.

“Whenever they put a bulkhead in, it takes away all of that habitat in front of it,” Weaver said.

Stormwater runoff from development also affects estuaries.

After heavy rainfalls, chemicals, sediment and bacteria are carried by stormwater into estuarine systems. The Division of Marine Fisheries will temporarily close waters to oyster fishing and clamming if bacterial concentrations are high enough to keep consumers from eating contaminated shellfish. During these closures, it is unlawful to take or sell oysters, clams and mussels from the polluted areas.

Just this week, heavy rainfall and runoff associated with Tropical Storm Julia caused the division to close waters in Carteret, Craven and Pamlico counties, and continue closures of waters in five other coastal counties.

Continued coastal development can make this problem worse as roads and other impermeable surfaces prevent stormwater from filtering through soil naturally.

Pollution carried by stormwater has also affected the Chesapeake Bay. The bay has some of the most documented cases of dead zones, or low-oxygen waters, in the country. In July, an update from the Maryland Department of Natural Resources showed that 20 percent of the Chesapeake Bay suffered from dead zones. These areas can develop when runoff mixes fertilizers and other nutrients into the water, promoting algae growth. Algal blooms then draw oxygen out of the water, often leading to fish kills.

Both the Albemarle and Pamlico sounds are at heightened risk of low-oxygen waters because of their proximity to North Carolina’s industrial farming areas.

Poor water quality also puts the state’s commercial fishing economy at risk by disrupting habitats like sea grasses. Commercially important species of flounder, black bass and blue crab rely on North Carolina’s sea grasses for part or all of their life cycles.

Disease is another threat to estuarine habitats. In the Chesapeake Bay, disease and overfishing nearly wiped out once-thriving oyster populations. It is estimated there used to be enough oysters to filter the entire bay in a single week, but now it could take the remaining populations a year to do the same work.

The same trend of decline is visible in North Carolina’s oyster reefs, which were once rich fisheries. According to the North Carolina Coastal Federation’s 2015 State of the Oyster report, oyster harvests have declined 15-20 percent since 1889. The culprit is dermo, a disease that kills oysters before they reach a certain size.

Anne Deaton of the Division of Marine Fisheries habitat-assessment program said that there has been a historic loss of oysters, causing the fishery’s status to be “concern” because of disease, poor water quality and habitat loss.

“We’ve improved the regulations,” Deaton said, “but they just haven’t come back to what they used to be.”

Climate Change

Fodrie said the threat of climate change is not as immediate as development along the coast. Species, he said, have for the most part experienced climate changes over geological time and may be able to adapt.

“In the historical record from 15,000 years ago to 5,000 years ago, they basically averaged a meter rise every century, so the animals and plants in the estuaries have seen that before,” Fodrie said. “They can handle that in a vacuum.”

Fodrie said the more interesting question is how estuaries will adapt to climate change while also dealing with humans.

“The new player is going to be us,” he said, “and so it’ll really be how we respond, how adamant we are to tow the line or how easily we are able to retreat away from a moving seashore. The plants and animals will be responding to us and to that change.”

Estuaries may be able to adapt to human-induced climate change if other, local threats are well managed.

“They’re certainly resilient as long as we don’t screw up too badly,” he said.

The Future of North Carolina’s Estuaries

If the future of North Carolina’s estuaries looks anything like the Chesapeake Bay, it is concerning. However, Fodrie said it’s difficult to predict what the future will look like for the state’s estuaries.

Restore America’s Estuaries, a nonprofit that works to protect the country’s estuarine systems, said on its website that as individuals, people can help protect the future of estuaries by recycling and minimizing vehicle emissions.

Weaver is optimistic about the future of the state’s estuaries. She said North Carolina is doing more than other parts of the country to protect its estuarine systems.

“I think here in North Carolina, because of all the efforts that are happening with respect to oysters and living shorelines and all the research that’s going on because all the marine labs are here, that its promising,” she said.

Funding and grants aimed at improving and restoring the state’s estuaries and fish habitats are also available, Weaver said. The federation uses this type of funding to restore living shorelines, salt marshes and oyster reefs.

It is difficult to know how the continued effects of human encroachment and rising sea levels will change estuaries and the organisms that will rely on them.

Estuaries’ blessing is also their curse. The calm, productive waters inspire people to protect them, while also fishing, recreating and living near them.

“The challenge,” Fodrie said, “is to make sure we don’t love the estuaries to death.”

To Learn More

• Restore America’s Estuaries
• North Carolina Coastal Federation

Read Part One

First of two parts

BEAUFORT — The products of North Carolina’s estuaries are found on dinner plates up and down the East Coast. Peek into a restaurant in New York, and you may see a blue crab that once lived in the sea grasses of Bogue Sound. Stroll into an oyster bar in South Carolina, and you may dine on oysters harvested from Pamlico Sound. Many of the creatures that make up North Carolina’s fishing industry at some point in their lives, depend on the humble, shallow waters of an estuary — waters that are facing increasing pressures from human activities.

This week is National Estuaries Week, as designated by the nonprofit group, Restore America’s Estuaries. In this two-part series that begins today, we will explore what estuaries are, the role they play in the state’s economy and environment, the problems they face and their future.

Danielle Keller, a doctoral candidate at the University of North Carolina at Chapel Hill’s Institute of Marine Sciences in Morehead City, studies these unique areas. On a cool summer morning, she’s releasing flounder into the estuarine waters near the Rachel Carson Reserve, across Taylors Creek from the Beaufort waterfront.

As she tosses in the first flounder, Keller points out a small, red surgical spot on the juvenile fish. She explains she’s implanted tracking devices in 20 flounders and 20 gag groupers, and will follow their movements as they travel through the estuary.  She is hoping to understand what changes in estuarine sea grass habitats, which are influenced by water quality and climate change, will have on local fish populations.

Studying these waters, she said, is important, because our health is linked with the health of estuaries.

“Everyone is in some way connected to the ocean,” Keller said.

What are estuaries?

Estuaries are shallow, partially enclosed areas usually found in sounds, inlets or bays. The freshwater flowing to the sea from inland rivers mixes here with the salty ocean, creating brackish waters. Their shallow nature creates the ideal environment for marine grasses and plants that can easily capture sunlight. On this day, the deepest waters Keller wades in only reach her chest.

One of the nation’s largest estuarine systems is found here in North Carolina in the Albemarle-Pamlico region that includes Core, Croatan, Back, Bogue, Currituck and Roanoke sounds.

There are probably few places on earth as productive and mysterious as estuaries. On any given day, these shallow, productive areas appear calm and quiet. However, below the water’s surface, estuarine systems are teeming with organisms ranging from worms, rays, baby fish and shrimp. Species including red drum, black sea bass and stone crabs rely on the habitats within estuaries.

According to the Fish and Wildlife Service, about 90 percent of commercially important fish in North Carolina live in estuarine habitats, such as mud flats, salt marshes and the water column itself, at some point in their lives.

“Every parcel of water, every acre of habitat out there is valuable to some species,” said Joel Fodrie, a professor at the institute who studies estuaries and is also Keller’s faculty adviser.

North Carolina’s estuaries

North Carolina’s estuaries are particularly notable due to their size and biodiversity.

Fodrie said warm water coming up from the Gulf Stream mixes here with the colder waters of the Labrador Current to create a unique environment. The result of this is a variety of species, including the sea grass Keller studies.

Eel grass, a northern species that likes cooler waters, has its southernmost range in North Carolina, and shoal grass, a southern species that prefers warmer waters, has its northernmost range here, too.

Keller is observing to see if animals use the two grasses differently, and if any shift in the grasses’ ranges would affect the animals. This is especially concerning as the range of eel grass may pull out of North Carolina as waters warm because of climate change.

That’s not the only reason why the state’s estuaries are unique.

North Carolina has more sea grass than all other East Coast states, except Florida, combined. It is also home to the Albemarle-Pamilco estuary, which is the second-largest system in the lower 48 states. The area is one of the only remaining places the endangered Atlantic sturgeon still goes to breed annually.

“North Carolina is just replete with resources and issues to consider our role, the role of estuaries, and our balance with estuaries,” Fodrie said.

Congress in 1987 established the National Estuary Program as an amendment to the Clean Water Act after the importance of estuaries was realized. The non-regulatory program created 28 regional organizations across the country. In North Carolina, the Albemarle-Pamlico National Estuary Partnership, or APNEP, was created to research, restore and protect the area.

In addition, the North Carolina National Estuarine Research Reserve was created through the National Oceanic and Atmospheric Administration and the state to protect more than 10,500 acres across four sites in Currituck Banks, Rachel Carson Reserve, Masonboro Island and Zeke’s Island.

The North Carolina Coastal Reserve, managed by the state’s Division of Coastal Management, protects six more sites, including Bird Island in Brunswick County and Permuda Island in Pender County.

What do estuaries provide?

Summing up the importance of estuaries is not an easy task. They provide a variety of “ecosystem services,” according to Keller, or resources important to both humans and wildlife. Fodrie said their role is extensive, from nutrient cycling to fish production to wave-energy absorption.

The list goes on.

One of the most important services estuaries provide, in terms of the state’s economy, is as a nursery to marine life, promoting the state’s $1 billion fishing industry.

“All the birds that you enjoy looking at when you’re on your boat, all of the fish and crabs,” Keller said, “all of them really grow up in the estuaries.”

The fish Keller studies, gag grouper and flounder, are born in estuaries and take refuge amongst the sea grasses and gentle waters. Keller says one reason for estuaries’ popularity with wildlife is because the area is full of the nutrition larger organisms need to survive, including phytoplankton.

“There’s a lot of food at the bottom of the food chain that other baby fish and crabs can consume,” Keller said.

She added that estuaries are just as productive as rainforests with a variety of habitats and species that call them home. The waters are so nutrient-rich that taking pictures underwater is virtually impossible during Keller’s day of field work, with green phytoplankton creating murky waters.

“People don’t realize that because they don’t see it, essentially because it’s all underwater,” Keller said. “But, estuaries have so many different habitats and provide homes for so many different organisms.”

Habitats like oyster beds and sea grasses filter the water, keeping it clean and fresh for humans and marine life. An oyster can filter water at a rate of up to 50 gallons per day. The areas, along with salt marshes, also buffer storm surges and stabilize shorelines as the spiky beds absorb wave energy.

Estuaries also serve in the frontlines against climate change.

Ian Kroll, another doctoral student at the institute who joined Keller on the water, said estuaries are also known to store carbon. The plants that call estuaries home photosynthesize, meaning they absorb carbon dioxide, a greenhouse gas. Over time, these plants die and are covered by sands, along with the carbon they absorbed.

“Instead of coming back to the atmosphere,” Kroll said. “It floats to the bottom of the ocean, deposits there and builds up.”

Fodrie said the unique nature of estuaries is what makes them special.

“Estuaries are just tremendously important both because people are living right around the edge of estuaries,” he said, “but also because they’re pretty dynamic given their nature and the interface between and land and sea.”

To Learn More

• Restore America’s Estuaries
• Albemarle-Pamlico National Estuary Partnership

Wednesday: Threats facing our estuaries