Oklahomans need to get used to the idea of blue-green algae as a growing threat involved with pond and lakeside recreation.
People are also encouraged to be aware of the possibility of blooms of what is actually cyanobacteria every year when the weather turns warm, according to an expert at the University of Oklahoma.
In recent days, news reports about the sudden deaths of two dogs in Texas, three in North Carolina and one in Georgia after exposure to blue-green algae in swimming waters raised alarms among pet owners nationwide. With the closing of a pond at a dog park in Edmond and the city of Moore issuing a message about its city ponds, the message hit closer home Friday.
Limnologist Dave Hambright, a biology professor who is leader of a global research team looking at blue-green algae as an environmental problem on four different continents, shared a basic message of awareness for Oklahomans when it comes to the potential threat. If you have any doubts, just stay out of the water.
“This is the time of year we’re going to get these blooms and there’s really no way around that,” he said.
Hambright said blue-green algae, actually a bacteria called cyanobacteria, is almost always present in all kinds of water and is among the oldest living organisms on the planet. The problem in some waters, especially in Oklahoma and other southern states, comes when waters overloaded with nutrients see the hot, calm, dog days of summer.
Internationally, climate change is creating a greater need to learn more about cyanobacteria, why instances of blooms are increasing in frequency and to discover new ways to identify and mitigate blooms, he said. Nonpoint source pollution (typically fertilizers in agriculture or on yards, or concentrations of livestock or geese) is a problem hard to isolate and battle, he said.
“We have a greater pattern of heavy spring rains that wash these nutrients into the water and hot summers that lead to blooms, he said.
The problem for the average person is to know the good algae from the bad, or to know if the amount of algae in a pond or lake is at a level that could be toxic.
Some signs of a bloom are fairly obvious and widely publicized by state agencies, but the danger is not always visibly obvious, he said. Sometimes it’s impossible to know for sure without tests done in a laboratory.
“Any fisherman will tell you they catch the biggest fish in the greenest lakes,” he said. “That’s because there is algae and plenty of zooplankton for the fish to eat.”
Cyanobacteria is not healthy, however, and with enough nutrients in the right conditions it will out-compete other bacteria, sometimes even floating to the surface to shade out other algae.
“And it can make hundreds of different toxins. It’s probably something that has evolved as a mechanism to deter zooplankton,” he said. “It can be things that are toxic to pets and humans and make them sick or possibly kill them.”
Some toxins hit the blood stream, some are neurotoxins and yet others may cause an allergic reaction, he said.
Cyanobacteria can be present and not be harmful because the toxins are contained within the cells, but as the bacteria die off — or when ingested — the toxins are released.
“For dogs, what happens is it coats the fur and when they lick themselves clean then they ingest massive amounts of the toxins,” he said. A dog that has recently been swimming and suddenly develops diarrhea or is lethargic may have been gotten a mild dose that made it sick, he said.
A preventative measure for a dog that takes a dip in a suspect pond is to wash it thoroughly with soapy water and if necessary use a veterinary cone or other device to keep it from licking itself until after it is thoroughly dry, he said.
James Roberts, an award-winning amateur retriever trainer in Tulsa, said he has long been cognizant of the threat and that his crew simply does not train their water dogs in some local ponds after the weather turns warm.
“I wish there was some kind of a kit, like a pH test, you could use sometimes,” he said. “But we err on the safe side. It’s the protected ponds, where there isn’t any flow and there are trees or houses that block the wind that seem to turn first.”
Until such a kit test can be developed or large public resources are devoted to the topic, Hambright said the key is to just be aware.
“With the number of reservoirs and cattle ponds and retention ponds, it’s in the millions and there aren’t enough scientists and agencies to monitor them all,” he said. “Use common sense and don’t jump into water that looks like it has a green oily paint film on top, call the (Department of Environmental Quality) or local officials and say ‘hey, I think we may have a problem here.’ ”
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