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On a sunny day this fall, two Georgia Southern grad students stood waist-deep in the North Newport River near St. Catherine’s Island while their professor and a team from the Georgia Department of Natural Resources used a winch to lower pallets full of oyster shells into the water.
The students guided the pallets into place on the muddy river bank. Those pallets, piled with shells, will provide a hard surface for baby oysters to latch onto.
“We are creating a foundation which wild oysters can populate and grow into an independent reef,” said Cameron Brinton, a marine biologist with DNR.
Oysters used to be abundant here — Georgia led the nation in oyster harvesting in the early 20th century, according to the University of Georgia. But by the 1930s, they’d been overharvested.
Scientists are trying to bring them back, and not just because they’re a popular food. Oysters are also important for healthy coastal ecosystems. And researchers are studying how creating new oyster reefs could help fight climate change by sequestering carbon.
Oysters, Brinton explained, are a keystone species. That means they create habitat for other critters, from small shrimp and crabs to fish like red drum and spotted sea trout that are popular for fishing.
“The majority of commercially and recreationally important species of fish and shellfish will spend a portion of their life associated with oyster reefs,” Brinton said.
And scientists are studying two ways that oyster reefs suck up and store carbon. First, they keep the sediment in the river from washing away.
“There’s lots of organic matter in this sediment in the rivers here,” said John Carroll, a professor of biology at Georgia Southern. “So some of that organic matter gets buried behind the reefs.”
Organic matter has carbon in it, so the oyster reefs can store that carbon and keep it from warming the planet.
Second, by stabilizing the shoreline, oyster reefs also help marshes expand — and marshes themselves are very good at storing carbon.
“As the marsh grasses grow toward the reefs, they’ll also trap a lot of carbon,” Carroll said.
So Carroll and his students are helping DNR build these reefs. Then, they’ll track how the shoreline changes and how much carbon it’s storing.
The project is funded by the environmental arm of Yamaha, the boat engine maker. The company, whose U.S. manufacturing is headquartered in the Atlanta area, is looking for ways to offset its carbon impact, and a project on Georgia’s coast made sense, said sustainability program manager Josh Grier.
“It’s something that our customers who are out using our products can see,” he said. “Not only are we investigating how we could potentially sequester CO2, but also providing habitat for fish, you know, kind of giving back into the communities where our customers are using our products.”
Once his team is able to quantify the carbon storage, Carroll said, he’s hopeful Yamaha and other companies will want to fund more oyster reefs in Georgia.
“There’s lots of need,” he said. “It just boils down to having enough of the materials.”
