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Blue-Gree Algae

Mats of “green slime” often develop on lakes and ponds in Nebraska during the summer. Sometimes these algae blooms can become toxic to humans, pets and livestock. Pay attention to health warnings issued by the Nebraska Game and Parks Commission to avoid problems.

Now that the eclipse is over, it is back to the business of the outdoors. Summer in Nebraska is typically when we begin seeing health alerts regarding blue-green algae blooms. The summer of 2017 has been no different than years before.

So far this summer the Nebraska Game and Parks Commission (NGPC) has issued health advisories in conjunction with the Nebraska Department of Environmental Quality and Health and Human Services for Blue Stem and Pawnee lakes in Lancaster County, Swan Lake in Saline County, Kirkman’s Cove in Richardson County, Rockford Lake in Gage County, Iron Horse Lake in Pawnee County and Willow Creek Reservoir in Pierce County. These types of alerts are cautious and prudent moves.

So what is all the hype about blue-green algae? Where does it come from? Why do these algae blooms occur? These are just a few of the questions I hear. And as a biologist, the cause and effect of these blooms greatly interests me.

There are many types of naturally occurring blue-green algae in Nebraska waters. It’s nothing new. In fact, fossil evidence suggests that blue-green algae have been around for millions of years. There are writings/recordings of blue-green algae blooms dating back 600 years. There are scientific studies documenting the toxic effects on livestock for more than 100 years.

The specific type of algae that can cause the problem is known as a Cyanobacterium. The blooms often occur when the water is warm and enriched with nutrients like phosphorus or nitrogen. Fertilizer runoff is a common cause of these nutrients getting into lakes and ponds.

When the right environmental conditions come together, blue-green algae can grow quickly. It will form clumps that float to the surface and create a scum layer. The result of a blue-green algae bloom can cause discolored water, reduced light penetration, taste and odor problems, dissolved oxygen problems that kill fish, and toxin production. It is the toxin production that prompts the health alerts.

Blue-green algae can cause health problems for humans and animals. This algae is capable of producing several different toxins. People may be exposed to these toxins via contact with the skin while swimming, through inhalation (breathing in water droplets while skiing), or by inadvertently swallowing contaminated water.

You need to use extra caution on any waters that are identified as having a toxic algae bloom. Health officials say you should avoid direct contact with the water during activities like swimming, wading, skiing, jet skiing, etc. Non-contact activities such as boating, fishing and camping are still allowed, but officials suggest minimizing getting wet.

Types of toxins and potential health effects vary widely. Some of the more common toxins produced by blue-green algae that can cause allergic-type reactions such as rashes, eye, nose, throat irritation, asthma, headaches, fever, nausea, stomach cramps, vomiting and diarrhea.

Other toxins can impact internal organs, and can cause gastroenteritis, tissue damage, muscle weakness and paralysis in severe exposure cases. One of the more interesting effects, from a biologist’s perspective, it that some toxins can cause chromosome loss and DNA strand breakage. Still other toxins can attack the central nervous system and can cause seizures, paralysis, respiratory failure or cardiac arrest.

Pets and livestock that drink water with these toxins can become extremely ill. There are documented cases of animals dying from drinking water containing blue-green algae. Nebraska has recorded cases of dogs becoming ill and dying from ingesting water contains toxic blue-green algae.

Fish kills are a problem. When a blue-green algae bloom runs its course and begins to dies off, algae cells begin to break down. This process requires oxygen and can create a biological oxygen demand. If enough oxygen is used in this process, dissolved oxygen in the water can be reduced and that can threaten the fish population.

Are blue-green algae blooms a real threat….YES. Can it be avoided….YES. That is one reason why the NDEQ does its sampling and issues its warnings. Follow the recommendations provided by health organizations. These blooms will run their normal/natural course and be gone as quickly as they appeared. Having this knowledge is the best way to protect yourself, your family, and your animals.


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