Cyanobacteria blooms, also knows as blue-green algae, have made the news in recent weeks due to the death of an estimated 12 family dogs in North Carolina.
The water of Lake Gaston, however, flows quickly enough to prevent toxic blue-green algal blooms from becoming an issue, experts say, though care should be taken around ponds and stagnant coves in the area.
Brent Silk, PLM Lake and Land Management Corp. senior regional manager, said that algal blooms are more of a concern in small bodies of water that are lacking in a regular moving water source or aeration.
“Algal blooms can happen anywhere, but are more likely in hot, nutrient rich areas,” Silk said. “Toxic cyanobacteria is very localized and very specific.”
According to the National Ocean Service, a nutrient rich area suffering from nutrient pollution can be caused by water runoff carrying lawn fertilizers, farm waste, and other manmade inputs. Nutrients can also be introduced naturally as a result of weathering of rocks and soil in a watershed.
According to Silk, Lake Gaston is constantly moving, and toxic blooms are of little concern. Water in ponds and coves can be stagnant, but the warning signs of a problem are normally visible long before it occurs.
“I’ve never seen evidence of blue-green algae on Lake Gaston,” Silk said. “It is possible, anything can happen. Out of all of the cases that I’ve seen on the East Coast, none of them happened in a large body of water.”
One case of a pet’s death was listed around Lake Norman, but the algae was reported to be in a small pond nearby.
“Blue-green algae is thick and normally dark green or blue in color,” said Silk. “It makes a thick film all over the water that looks like pea soup, and sometimes it has an odor.”
According to N.C. Division of Water Resources, blooms are most common in freshwater during summer months, in bright sunlight, warm temperatures, and increased nutrients. Cyanobacterial blooms are not always dangerous, but sometimes produce cyanotoxins, which are harmful to both humans and animals.
The DWR warns that algal blooms can also form below the water’s surface or along the bottom. Blooms that form on the surface can cause water discoloration, surface scum, or appear as a floating clump or mat. Blooms can be bright blue, green, red, or brown. As the blooms begin to die, they often produce a strong and foul odor.
Silk’s advice to pet owners around any body of water is: “Be smart and watch the surroundings. If the water is discolored and has an odor, keep pets away and absolutely avoid it.”
Silk stressed how rare a toxic bloom would be on the lake. He also mentioned that he is not a scientist, but is well versed in lake ecology.
The N.C. Department of Environmental Quality provides an interactive algal bloom map and additional information on their website dep.nc.gov. From the main page, search for algal bloom map.