It can erupt suddenly and be deadly. Pets and livestock have been known to die within hours of exposure. It is cyanobacteria, better known as blue-green algae, and it is present in many bodies of water in the state.
Algae blooms are typical in North Dakota sloughs, lakes and rivers during the hot days of July and August, often giving water a "pea soup" appearance. However, common green algae differs from blue-green algae. Blue-green algae resembles spilled paint, usually cyan in color, but other pigments are possible. Unlike green algae, blue-green algae might also contain deadly toxins.
"Ninety-nine percent of green algaes are harmless, a nuisance and ugly, but harmless. Not all blue-green algae is harmful. Sometimes they are, sometimes not. Certainly caution is advised," said Mike Sauer of the North Dakota Department of Health's Water Quality Division.
Kim Fundingsland/MDN • Blue-green algae is sometimes toxic, so precautions should be taken with pets and livestock when the presence of blue-green algae is suspected. It can also affect humans.
Botulism outbreaks are almost always associated with blue-green algae. Waterfowl and shorebirds can die within hours of exposure. Blue-green algae can also lead to rapid death for pets and livestock drinking or swimming in blue-green algae contaminated water.
"We haven't heard anything yet this year," said Sauer. "We had several cases of cattle and dogs dying around the state last year. The time is about right."
Algae blooms can be prolific, particularly during warm weather. Algae consumes nutrients in the water, so much that the amount of algae in the water can double daily. When blooming algae consumes the available nutrients, it dies and releases more toxins into the water.
"Some are neurotoxins. Some get into the liver. Neurotoxins can kill within a few hours. Dogs are particularly vulnerable," said Sauer.
Last year the State Health Department confirmed deaths from dogs that visited Lake Josephine, a fishing lake located two miles north of Tuttle in Kidder County.
Hot weather, calm winds and shallow water produce an ideal environment for blue-green algae outbreaks. With the most recent weather forecast calling for very high temperatures, the likelihood of an outbreak increases too. According to Frank Durbian, acting Souris River Basin Complex manager, the shallows at the upper end of Lake Darling are a possible trouble spot. Blue-green algae has been associated with waterfowl botulism on that portion of Lake Darling in previous years.
Farther downstream, at J. Clark Salyer NWR, Durbian said the shallow marshes are particularly susceptible to outbreaks of blue-green algae.
"This is normal up to now. We've got some green algae blooming here and haven't noticed any serious blue-green blooms," said Durbian. "Blue-green is not good for critters. People should take some concern, especially if they have a dog out. We'll start getting on the water more and doing a little more searching to try and head it off as best as possible."
Durbian was referring to a possible botulism outbreak where the removing of dead or dying waterfowl is a common procedure to try and eliminate the spread of avian botulism believed to be triggered by blue-green algae.
Moving water is less likely to produce an algae bloom than calm water. Approximately 25 cubic feet per second of water is currently being released into the Souris River from Lake Darling Dam. Although a minimal flow, it is hoped it is enough to deter a serious blue-green algae bloom in the river.
Coming off a particularly warm winter, the region also experienced an early spring. With higher than normal temperatures in June and July, bodies of water have also warmed up earlier than usual and there is still plenty of summer remaining. It is not a very favorable scenario to keep blue-green algae at bay.
"I think we are in unknown territory for another week or so," said Gene Van Eekhout, North Dakota Game and Fish Department fisheries biologist in Jamestown. "We could suffer through a whole month of this stuff yet. What helps, even though we hate it, is the wind that breaks that stuff up."
Although blue-green algae can be suspended throughout a body of water, it is usually not detected until it gathers on the surface. There it takes the appearance of spilled paint and produces an unpleasant odor.
Lisa Otto, with the First District Health Unit in Minot, said she has not yet received any reports of problems with blue-green algae. However, she added, the first requests for testing for blue-green algae were received this week.
North Dakota is not alone in having concerns over blue-green algae outbreaks. The Wisconsin Department of Natural Resources urges people with concerns over symptoms of blue-green algae exposure displayed by their pets to contact a veterinarian immediately. Symptoms include seizures, vomiting or diarrhea after contact with surface water.
The Kansas Department of Health also warns pet owners to be aware of the symptoms of blue-green algae exposure, but also says humans can be affected. Common symptoms in humans includes sore throats, coughs, congestion, itchy skin and abdominal pain. According to the Kansas Dept. of Health, "Health effects could occur when surface scums or water containing high levels of blue-green algal toxin are swallowed, through contact with the skin or when airborne droplets containing toxin are inhaled while swimming, boating and skiing."
Because little is known about what causes blue-green algae to become toxic, precaution remains the best defense. Livestock and pets should be prevented from drinking water suspected of containing blue-green algae. People should also restrict their contact with water contained blue-green algae. Algae blooms generally subside when temperatures moderate in early fall.