This Humble Mollusk Can Save Shorelines From Rising Seas

As entire islands disappear in Chesapeake Bay, the oyster is enlisted as a first line of climate defense.

The great thing about oysters as a barrier is that they can adapt to waters disturbed by tides, storms, and other stresses, even to rising sea levels. During the Ice Age, oysters increased the height of their reefs as sea levels rose as much as 10 millimeters per year.

Photo by Ivan/Getty Images

In Sudden Spring: Stories of Adaptation in a Climate-Changed South, Rick Van Noy shows what communities are doing to become more climate-resilient and to survive environmental challenges. Here, he tours Chesapeake Bay off the coast of Virginia Beach, where entire islands are disappearing because of rising sea levels. He finds that, in the shadow of the nearby naval base, the best defense against the effects of climate change may come from an unexpected source: the humble oyster.

After touring some flooding in Norfolk, Virginia, we cruised over to nearby Virginia Beach. Captain Chris Moore motored the Bay Oyster, a white skiff, over to a dockside oyster bar. It sat across from a scrappy clump of sand, mud, and marsh grass, shored up by chunks of concrete from an old bridge, called Fish House Island. It used to be 13 acres but dwindled to one or two now. It’s one of the many islands disappearing in Chesapeake Bay because of sea level rise, erosion, and some complicated combination of the two.

I tried some of the local Lynnhaven oysters, a kind of Atlantic or Virginia oyster. They had a briny taste, a little grit and mineral, firm but slippery smooth with a creaminess. The taste is part texture. Some people push them past the taste buds into the back of the throat, like swallowing a lozenge. As connoisseurs will tell you, oysters take on characteristics of where they grow. In the Lynnhaven River, an estuary of the bay, there is salt, a little soil too, and experts tell me they are fatter higher up in the estuaries than close to the coast because there are more minerals to feed on.

Back in Virginia Beach, Christy Everett, Hampton Roads director for the Chesapeake Bay Foundation, gave me a tour of the Brock Environmental Center, one of the world’s greenest buildings. With a combination of solar, wind, and geothermal, a triple threat, the center produces 80 percent more energy than it uses. 

In the foyer, Everett talked about the site, a large, undeveloped tract where some developers wanted to build a set of 11-story apartment towers, but they went bankrupt. The bank had it for $19 million. The Chesapeake Bay Foundation, the Trust for Public Land, and the city of Virginia Beach all partnered and purchased the land for $13 million. 

On the wall hangs a giant sculptured map constructed of wood and glass showing the boundary of the Chesapeake Bay watershed. It cuts through West Virginia, Pennsylvania, and all the way up to Cooperstown, New York. Six states and the District of Columbia, where 18 million live, draining 64,000 square miles of land.

They have no stormwater runoff on the site. Rain is collected into cisterns, where it is filtered and treated to become drinking water, the first project in the United States to receive a commercial permit for drinking filtered rainwater. Toilets are composting, waterless units, using pine shavings to cure odor and absorb waste.

To meet the Living Building Challenge (a design framework committed to sustainability), designers did not use any “Red List materials that include harmful chemicals or materials. Much of the wood was recycled, the flooring coming from a local elementary school that was torn down. The only things that were not salvaged were the triple-paned windows. The decking was treated with something approved by the Forest Stewardship Council and did not have the usual preservatives.

The facility was built at 14 feet above sea level, with 8 feet of clearance from the ground, ready for a rising sea.

I stepped off the deck to join a few of the 40,000 kids that come through each year. On the day I visited, they were learning to identify land-use patterns on the maps spread on picnic tables: marsh, urban, farm/forest, water, beach.

Back on the boat, the crew toured some of the Lynnhaven River and a residential area in Virginia Beach with houses built right up to the water.

In the area, new houses were built up on a slope, creating drainage problems for the neighbors. They were not very far above sea level. In Norfolk, they ask for 3 feet above freeboard for new construction; in Virginia Beach it is 2. Thomas Quattlebaum, the sea level rise expert, stood in front of the steering console, surveying the scene with folded arms. He mentioned some houses needing as much as $6,000 a year in flood insurance, which “kills the deal. Some areas may have to be let go. No one has identified which ones yet.

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In the area we were in, Broad Bay Island, the houses and yachts started getting bigger. The shoreline hardened. I asked Quattlebaum what he thought from a planning point of view. Earlier in the day, Quattlebaum had told me he talks to communities about “opportunities, not wanting to emphasize the negative. Surveying the shoreline and houses on both sides, Quattlebaum shook his head: “It’s a significant challenge. Captain Moore, pointing to another house with landscape timbers at water’s edge, falling in, said, “That is how not to develop a shoreline if you want to protect water quality.

Their answer to the problems we saw was to look for green infrastructure opportunities at every chance. The Chesapeake Bay Foundation would restore wetlands or find ways to capture stormwater so that it did not run directly into the rivers. And rather than harden the shoreline as if with armor, both Moore and Quattlebaum preferred a “living shoreline with natural habitat, such as a wetland or grass buffer with oyster reef. The hardened shoreline can worsen erosion, while the living shoreline traps sand and silt, straining it from the wave action, building up the coast. And a living shoreline further provides the benefit of improved water quality and a healthier estuary.

Oysters must adapt to very changeable conditions, as they are like plants, unable to move.

They showed me another section of living shoreline, “oyster-tecture for some. Moore called it a “spat on shell” operation, in which oyster larvae are cultured on shells in tanks before being introduced into the wild. As they grow, they buffer waves, “chump change compared with conventional barriers. Meanwhile, they will filter and clean the bay.

Oysters must adapt to very changeable conditions, as they are like plants, unable to move. They have developed a wide variety of genes and proteins to respond to changes in temperature and salinity but also different levels of oxygen and pollution. These changes would kill most living creatures. The great thing about oysters as a barrier is that they can adapt to waters disturbed by tides, storms, and other stresses, even to rising sea levels. During the Ice Age, oysters increased the height of their reefs as sea levels rose as much as 10 millimeters per year.

The Chesapeake Bay Foundation recycles shells from restaurants and from drop-off locations. Once the shells are cleaned, they place them in tanks containing oyster larvae, which once attached to shells are called spat, at which point they go to oyster gardeners or somewhere else in the bay to grow and expand reefs.

Chesapeake Bay Foundation’s partner, Lynnhaven River NOW, have installed “oyster castles in other places. These blocks, made of 30 percent oyster shell, can be stacked like Legos to fit the particular depth and contour of the shoreline. Once oysters attach to them, a reef is born. It was amazing to think that, in the shadow of the U.S. naval base at Norfolk and the largest Navy in the world, the lowly oyster is among our best choices at coastal defense.

We maneuvered out into a wider section of the river, Wolfsnare Creek, which contains several oyster farms. Farmers lease land for as little as a $1.50 an acre. The state leases 150,000 acres, 2,500 in the Lynnhaven. We drove up close to a conveyor belt tumbler on a dock. Oysters could be fed into it and the machine cracked off the pointy end, making a nice 3-inch-sized oyster, what the restaurants prefer to shuck. Each oyster filters 50 gallons of water a day, cleaning out nitrogen, phosphorous, and other pollutants. And since oysters are a keystone species, when they clean the bay the grasses grow, which brings in tiny fish and crabs, and pretty soon things get back to how they once were. Oysters bring life.

A century ago, oyster harvesters in the bay gathered 15 million bushels a year. In 2005, they were down to 1 percent of that. At one time, harvesters would find 1,000 oysters per square meter in the Lynnhaven. Now they find one or two. The bay floor was once covered with them, oysters growing on top of one another like a coral reef. They used machines to dredge reefs so high they would strand ships. Over the past 300 years, bay oysters have suffered from overharvesting, pollution, and diseases. But scientists have found ways to grow oysters resistant to disease, and the bay is healthier. Regular rain helps, but too much increases algal blooms. Over the past 25 years, surrounding states have spent billions to clean up the bay.

A century ago, oyster harvesters in the bay gathered 15 million bushels a year. In 2005, they were down to 1 percent of that.

One oysterman was out tending to his cages, holding hundreds of oysters each. His area was marked by poles, like the kind in driveways to guide snowplows. A Jet Ski cruised past, kicking up a wake. The oysterman raised a fist. Or maybe a finger. The recreational boater stopped. Words were spoken, ones we could not hear. It seemed like some kind of Western standoff, “I can ride my horse wherever I want. Moore and Quattlebaum told me such conflicts were becoming more common. The harvesting of oysters was not something residents had quite gotten used to, even though it was a normal course of life for generations. Residents wanted to keep the area a private watery playground. For some, those markers and their cages, visible at low tide, marred the view. Looking at the homes on the shore, I sensed a lot of power and money that could work to protect that view.

We were now off the coast of First Landing State Park, named for the English colonists who arrived in 1607. When John Smith roamed the shores, he famously found oysters as big as dinner plates and said they could feed a family of four. Though his writing was often full of false swagger and self-promotion, he was apparently not bragging. Locals have found shells as big as hubcaps.

After our tour of the Lynnhaven, Captain Moore guided us back to the dock at the Brock Environmental Center. The kids had been released from the picnic table lesson and were scavenging the shore for shells. We had been off the shore of First Colony State Park, the most visited state park in Virginia. Nearby is also the least visited, False Cape State Park, accessible only by boat, bike, or foot. It was called False Cape because sailors mistook it for Cape Henry, the mouth of the bay. Rather than a safe harbor from the turbulent Atlantic, they were lured into the shallow waters where they often ran aground.

Drifting into the dock, I glanced up at the center, built on a point. I thought of it as a kind of lighthouse or beacon, guiding the way for the 64,000 square miles of land that drained into this bay. As a center for education, the Brock aimed to be a guiding light. From the moment the kids step off the bus and step onto the permeable pavers in the parking lot, they receive a whole systems education: about the connections between stormwater and the health of the bay, energy use and its effect on a warming planet and rising seas, the way a watershed connects us, unites us, how what happens upstream affects those down.

I poked around with the kids along the shore for a little while, thinking of what it would take to restore the bay to its former state, to how John Smith found it, how the Powhatans knew it. With the right policies, future generations would be able to enjoy it. Then I said goodbye to the Bay Oyster crew.

As I walked back to my car, I caught up with a 10-year-old boy, Jackson, whom I had seen at the day’s lesson. When asked to find “the important parts on the land-use map, in terms of filtering the bay, he pointed to the marsh. Other kids were trying to find their house. Developmentally, it can be a hard lesson to learn: that the world does not radiate out from me.

By the driftwood gateway arch that welcomes visitors, I asked him if he enjoyed his day. He told me he did. He asked me where I was going.

“Home, I said. Though I felt the need to offer that I lived in a different watershed.

“I live in this one he told me, making clear he had absorbed the days lesson. “This is my home. He was referring to the ground he stood on, at the mouth of the bay, the ocean beyond it, under driftwood from near and far, a piece in a much bigger ocean universe. An oyster.

Edited Excerpt from Sudden Spring: Stories of Adaptation in a Climate-Changed South by Rick Van Noy (2019) published by permission of University of Georgia Press.