A new ultrasonic algae remediation device has been installed in Barnwell’s Lake Edgar Brown to control blue-green algae without harming fish populations and beneficial plants.
The S.C. Department of Natural Resources (SCDNR) manages Lake Edgar Brown primarily for fishing, and a certain amount of algae is desirable in a fishing lake. Phytoplankton–microscopic aquatic plants–and other green algae form the base of the food chain, add oxygen to the water, and give the water a greenish appearance. Without them, fish populations cannot survive.
However, excessive growth, or “blooms,” of blue-green algae, also known as cyanobacteria, can be harmful. The new remediation device uses sound waves to specifically target blue-green algae.
Blue-green algae cells contain gas vesicles, which are small, air-filled compartments that allow them to float. The new remediation device emits sound waves at a specific frequency that causes the walls of these compartments to burst–much like an opera singer shattering a wine glass. The blue-green algae then sinks to the bottom of the lake and dies, leaving fish and beneficial aquatic plants unharmed.
SCDNR Freshwater Fisheries Section staff will continue to monitor water quality at Lake Edgar Brown into the fall to determine the full extent of the device’s effectiveness.
The new device is not believed to be linked to a recent fish kill at Lake Edgar Brown. SCDNR biologists believe high water temperatures were the likely cause. The fish kill affected only threadfin shad, a species known to be sensitive to changes in temperature and water quality. The biologists investigating the kill observed that dead fish appeared to be older, post-spawn individuals, and that mortality coincided with a period of extreme heat.
Many factors, such as disease outbreaks, low dissolved-oxygen levels, or sudden changes in water quality, can result in fish kills. Out of an abundance of caution, samples have been sent for testing to Auburn University’s Southeastern Cooperative Fish Parasite and Disease Laboratory.
SCDNR stocks threadfin shad into Lake Edgar Brown as forage for bass populations. Despite the fish kill, biologists continue to observe live threadfin shad and other forage species in Lake Edgar Brown, and more threadfin shad stockings are planned for this fall.
SCDNR is moving forward with plans to repave the Wellington Road parking lots and boat ramps at Lake Edgar Brown. This work should be out for bids later this summer, with construction hopefully complete by the end of the year.
Lake Edgar Brown is a 100-acre lake providing largemouth bass, bluegill, shell-cracker and catfish fishing. A portion of the lake is used for boating and water skiing. Lake Edgar Brown offers a boat ramp, fishing pier and is handicapped accessible.