When it comes to protecting our valuable salt marsh ecosystems, the most important tool might be one you have enjoyed for years: oysters. A new scientific study from Georgia Sea Grant Fellow, Dr. Sarah Roney, shows that oysters are key to preventing erosion across Georgia’s marshes.
In the wild, oysters grow in reef structures – where oysters growing on top of each other form clumps of shell material. Oyster reefs are an important foundation for salt marsh ecosystems. They are often habitat for fish, crabs, and snails and the oysters making up these reefs filter water of sediment and pollutants, keeping it clean. In addition, oyster reefs form in salt marshes where tall, willowy grasses grow out of soft mud, meaning these oysters provide a solid substrate to protect these muds and grasses from washing away.
Unfortunately, in Georgia and across the globe, oyster reefs have disappeared as a result of overharvesting, storm damage, disease, and more. In some areas of Georgia, as many as 90% of historical oyster populations have been lost. Many conservationists, researchers, and state managers have worked to restore these reefs across Georgia’s coast.
Dr. Sarah Roney, our 2025-2026 UGA Marine Extension and Georgia Sea Grant Fellow, led a research project that restored two oyster reefs in the Savannah River using oyster shell recycled from restaurants across Georgia. The Savannah River is known to experience marsh erosion due to ship wake from commercial vessels travelling to and from the Port of Savannah as well as from recreational boaters. In fact, a majority of the wave energy detected in parts of the Savannah River is directly from ship wake.
After constructing the reefs with partners like UGA Marine Extension & Sea Grant and Georgia Department of Natural Resources, Sarah and her colleagues from Georgia Tech measured wave energy in this area to see how oyster reefs might be breaking up these waves along the marsh edge. What she found was groundbreaking: restored oyster reefs break up wave energy in marshes by as much as 40%! To date, this is the first study in Georgia that quantifies how oyster reefs can reduce waves.
This new study shows that restoring oyster reefs doesn’t just support the flora and fauna in a salt marsh ecosystem, it provides physical protection against erosion. In areas like the Savannah River, restoring oyster reefs throughout means these marshes could be protected against more erosion damage.
These restoration efforts also mean that salt marsh systems could be more resilient to sea level rise. Oyster reefs can trap sediment and raise marsh elevation while also preventing them from being washed away, which supports marshes becoming self-sustaining in the face of rising waters. Prioritizing restoration of this foundation species means increasing ecosystem resiliency, aka the ability to bounce back from storm damage or sea level rise, and ensures we remain good stewards of our coastal resources.
To learn more about how oyster reefs can break up wave energy in the Savannah River, you can read Dr. Sarah Roney’s published study here: https://www.sciencedirect.com/science/article/pii/S0925857425002642
Funding for Dr. Sarah Roney’s study was made possible through UGA Marine Extension & Georgia Sea Grant research traineeship.