Have you heard the one about the potato and the oyster? It’s not a joke, but a game-changing technology -- a three-dimensional grid made from potato starch -- that has the potential to help reverse the decline of the world’s oyster reefs. It might not have the sexiest of names and it hasn’t even been fully tested yet, but Biodegradable EcoSystem Engineering Elements (otherwise known as BESE-elements) is already making waves in the world of coastal conservation.
As part of the experimental design, recycled oyster shell was placed between the BESE layers on half of the test units. Monitoring will determine if the addition of shell affects the recruitment of live oysters on the material. © Anne Birch / The Nature Conservancy
To understand how, we must first step back and consider the outsize importance of the humble oyster.
Eighteen months after installation, oysters are growing well on the reefs. © Anne Birch / The Nature Conservancy
Most of us meet them only at the raw bar -- coarse on the outside but, once you get to know them, seduction on the half shell, so delicious they have been compared to angels dancing on your tongue. But coastal conservationists are not like you and I. Their job is to look beyond the capers, cocktails and spicy horseradish cocktail sauce and see the oyster in an entirely different light.
“It’s the quiet, unsung hero of our estuaries,” says Anne Birch, Marine Program Manager for The Nature Conservancy in Florida. In many places around the world, including Florida, oyster reefs play a vital role in keeping our coasts healthy.
© The Nature Conservancy
Muddy and sharp, these reefs might not be much to look at, but they improve water quality, with each oyster filtering up to 50 gallons per oyster per day.
© The Nature Conservancy
They provide nursery areas, food and shelter for countless species such as fish, crabs, shrimp and birds. They stabilize shorelines. And yes, oysters are also an economic boon, bringing upwards of $10 million (dockside valuation) into Florida alone. “I can think of few other species that combine such great ecological and economic benefits,” says Birch, scarcely containing her enthusiasm for these gray and gritty bivalves.
© The Nature Conservancy
“Let there be you, let there be me,
Let there be oysters under the sea”
NAT KING COLE
The problem is that, as vital as they are, oyster beds are in serious decline. Like the balding, gray-suited film directors at the Oscars, oysters don’t get as much press as the colorfully coutured stars (coral reefs). But they are equally endangered. Over the last two centuries, 85% of the world’s oyster habitat has disappeared. Coastal run-off, natural predators, disease and over-harvesting have taken a toll. Oyster reefs that once grew 100 feet deep in some areas have been all-but eradicated by oyster dredges. “The health of our estuaries hangs in the balance,” says Birch. “The importance of restoring oyster reefs cannot be over emphasized.”
Our partners from the Charlotte Harbor National Estuary Program and Charlotte Harbor Aquatic Preserves were also onsite to help with the material assembly and installation. © Anne Birch / The Nature Conservancy
Birch has been a part of the solution since 2005 when she began managing the Conservancy’s Indian River Lagoon Restoration project. Charged with replenishing the lagoon’s oyster reefs, she was struck by the community support she received. “Until then I had no idea how charismatic oysters are. In the seven years I worked in the lagoon,” she remembers, “we attracted over 25,000 volunteers. Adults, school children, the disabled…people from all walks of life and abilities came out to help replenish the lagoon’s oyster beds, making and deploying oyster mats (a mesh with oyster shells attached, designed to attract baby oysters and become the foundation of a reef).”
TNC ecologists prepare oyster mats that will be the foundations of new oyster reefs to be built in Charlotte Harbor near Punta Gorda, Florida located on the Gulf of Mexico. © Carlton Ward Jr.
Why did the ugly duckling of the reefs inspire such a passionate response? “People are captivated by the sea and crave opportunities to help,” she says. “While most marine conservation is literally out of reach, oysters live in intertidal waters. You can walk up to them at low tide. And if you ‘plant’ the right material in the right location you’re rewarded with healthy oyster reefs. It’s like gardening in the sea.”
Project volunteer clips excess material off reef made of mats with recycled oyster shells attached. © Anne Birch / The Nature Conservancy
And this is where BESE fits in. Oysters need hard surfaces on which to settle and grow. Many oyster restoration projects use plastic oyster mats or bags as the substrate (foundation) for new reefs. Serendipitously, The Nature Conservancy in Florida was already knee-deep in a pilot project in Charlotte Harbor, experimenting with oyster mats, bags filled with oyster shells, and loose fossilized shells to see which method produces the best “larval recruitment.” “I got a call in February, asking if we would be interested in adding BESE elements as a fourth method,” explains Birch. “Interested? You bet we were. We had it in the water less than two months later.” Deploying this material is a privilege – U.S. testing is only underway in Florida, and the Charlotte Harbor project is one of just a few test sites.
Metal rods are used to secure the material. © Anne Birch / The Nature Conservancy
Why are Birch and other marine conservationists so excited about BESE?. Made from the byproduct in potato chip manufacturing, BESE elements have clear ecological benefits over the traditional forms of plastic substrate. It’s a three-dimensional solid grid (similar in design to an egg carton) that snaps together into sheets. It’s not labor intensive. It doesn’t leach chemicals. It’s digestible and, best of all, it biodegrades in 5 to 10 years (depending on the glue used to bind the potato starch). “It’s the ideal starter kit for an oyster reef,” she enthuses.
“It could be a miracle solution,” agrees Dr. Christine Angelini, a professor of Environmental Engineering Sciences at the University of Florida, who is working with the Conservancy in Charlotte Harbor. This and three other test sites in Florida will show which variables -- high or low tidal zone, temperature, salinity, prevalence of seabirds and fish, etc.-- produce the best results. “By the fall we will be able to measure the rate of settlement,” says Malenthe Teunis, a marine biologist at the Bureau Waardenburg, the Netherlands-based company that is one of the inventors of BESE and the third member of the Charlotte Harbor monitoring team. “The results could have a big impact on all forms of coastal conservation,” she continues. “Today so much of the work relies on plastic. How much better would it be if we could substitute it with a biodegradable material that leaves nothing but nature behind.”
Sixteen units of the BESE materials were installed, each measuring 19" x 19" x 8". © Anne Birch / The Nature Conservancy
Now this is where things get really interesting. If BESE works for oyster beds, maybe its use could be expanded. Maybe, with the proper adaptions, it could take the place of plastic in all sorts of coastal and deep-water applications. “It’s early days,” cautions Boze Hancock, Senior Marine habitat restoration Scientist for TNC, who works on a broad range of coastal restoration projects all around the world. “At the moment BESE has some restraints, starting with its shape, durability and rigidity. But if it can be tailored to suit different applications, then its potential is enormous.” BESE could take the place of PVC piping in mangrove planting. It could provide a stabilizing framework for growing sea grass. It could be used as a structure for coral reef restoration. Bags made of BESE could be weighted down in intertidal areas to reinforce shorelines.
The volunteer oyster habitat monitoring program, led by the Charlotte Harbor National Estuary Program, engages citizen scientists in helping to monitor the progress of the test reefs. © Anne Birch / The Nature Conservancy
“We don’t yet know if BESE can do what we want it to do,” says Hancock “but one thing is certain: the last thing we want to do is to put yet more plastic in the oceans. Conservationists have been searching for a natural substitute for years, trying everything from coir (coconut fiber) and burlap to recycled toilets but, so far at least, nothing has performed the way we want it to. If BESE, is the answer,” he adds, “it would be the conservationist’s equivalent of finding the Holy Grail.”