New anti-algal bloom technology being tested in Maryland has implications for the whole Chesapeake Bay region.
The Maryland Department of Natural Resources say the so-called “robots”, buoys equipped with ultrasonic transmitters, use the power of sound to disrupt harmful algal blooms before they form.
On Labor Day weekend in 2023, the Cunningham Falls State Park swimming hole, Hunting Creek Lake, was forced to shut down for all swimming because of a cyanobacteria bloom. This type of algae can be harmful to people and animals in high concentrations.
“That’s what prompted us to push to get these buoys,” says Ranger Mark Spurrier. “We want to control it the best we can.”
This June, the state park in Frederick County installed two new buoys with “sonicators” into the water, then waited to see if they worked. It appears they are working. There is usually a notable cyanobacteria bloom in the fall, but there haven’t been any harmful blooms this year at Hunting Creek Lake.
The sonicators work by putting a low-power, ultrasonic pulse into the top layer of the water that receives sunlight. The ultrasonic pulse creates a pressure barrier that blocks cyanobacteria from coming up to photosynthesize near the surface.
The buoys are monitored remotely and the ultrasonic waves can be changed based on current water quality trends and which algae species is present.
The sonicator buoys also proved successful in the swimming hole at Camp Todd, a Girl Scout camp in Caroline County just outside the Choptank River. Before it was put into place, scientists from DNR and the University of Maryland Center for Environmental Science’s Institute of Marine and Environmental Technology confirmed the sonicators wouldn’t be harmful to fish. They operate on a frequency comparable to fishfinders. The buoys cost just over $50,000 each.
Of the more than 1,454 species of algae in the Chesapeake Bay, only about 2 percent are toxic. Cyanobacteria blooms can create skin irritants, liver toxins, and powerful neurotoxins, including the one disturbingly known as “Very Fast Death Factor.”
The natural resources department worries that climate change could up the occurrences of these harmful blooms. “With climate change, there’s the potential for this to get worse and become more than one in September or one in November. That was the fear,” Spurrier said. “That prompted us to say we have to get ahead of this sooner rather than later.”
DNR asks residents to report algal blooms on the Eyes on the Bay website and to look out for “foamy, scummy water of unusual color that may smell like rotting plants.” People and pets should take caution and stay away from potential blooms.
