Have you heard the one about the potato and the oyster? It’s not a joke, but a game-changing technology—a 3-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 been fully tested yet, but Biodegradable EcoSystem Engineering Elements (otherwise known as BESE-elements) is already making waves in the world of coastal conservation.
Recycled oyster shell is 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
First, consider the outsize importance of the humble oyster. In many places around the world, including Florida, oyster reefs play a vital role in keeping our coasts healthy. Muddy and sharp, these reefs might not be much to look at, but they are essential to improving water quality: Each oyster filters up to 50 gallons of water per day.
So far, oysters are growing well on the reefs. ©Anne Birch
“It’s the quiet, unsung hero of our estuaries,” said Anne Birch, marine program manager for The Nature Conservancy in Florida.
©The Nature Conservancy
Oyster reefs provide nursery areas, food and shelter for countless species of fish, crabs, shrimp and birds. They stabilize shorelines. And oysters are 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,” Birch said.
© The Nature Conservancy
Vital as they are, oyster beds are in serious decline. Over the last two centuries, 85 percent 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,” Birch said. “The importance of restoring oyster reefs cannot be overemphasized.”
©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 said, “we attracted over 25,000 volunteers. People from all walks of life and abilities came out to help replenish the lagoon’s oyster beds.”
Partners from the Charlotte Harbor National Estuary Program and Charlotte Harbor Aquatic Preserves help with material assembly and installation. © Anne Birch
Birch understands why the ugly duckling of reefs inspires such a passionate response.
“While most marine conservation is literally out of reach, oysters live in intertidal waters,” she said. “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.”
TNC ecologists prepare oyster mats that will be the foundations of new oyster reefs in Charlotte Harbor near Punta Gorda, Florida. © Carlton Ward Jr.
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. The 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” when Birch was asked if she would be interested in adding BESE-elements as a fourth method.
“Interested? You bet we were,” she said. “We had it in the water less than two months later.”
Project volunteer on a reef made of mats with recycled oyster shells attached. ©Anne Birch
Made from a byproduct of potato chip manufacturing, BESE elements have clear ecological benefits over traditional plastic substrates. It’s a 3-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.
Metal rods are used to secure the material. ©Anne Birch
“It could be a miracle solution,” said Dr. Christine Angelini, professor of environmental engineering sciences at the University of Florida, who is working with the Conservancy in Charlotte Harbor.
Sixteen units of the BESE materials were installed. ©Anne Birch
This and three other test sites in Florida will show which variables—high or low tidal zone, temperature, salinity, prevalence of seabirds and fish—produce the best results.
Malenthe Teunis, 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, said the results could have a big impact on all forms of coastal conservation.
“Today, so much of the work relies on plastic,” Teunis said. “How much better would it be if we could substitute it with a biodegradable material that leaves nothing but nature behind?”
If BESE works for oyster beds, 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. 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.
“It’s early days,” said Boze Hancock, senior marine habitat restoration scientist for the Conservancy. “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.”
Citizen scientists help monitor the progress of the test reefs. © Anne Birch
Hancock said scientists have been searching for a natural substitute for plastic for years.
“If BESE, is the answer,” he said, “it would be the conservationist’s equivalent of finding the Holy Grail.”