Weather Forecast


High temperatures can bring harmful algal blooms

When the summer sun shines and temperatures climb, conditions are ripe for Minnesota lakes to produce harmful algal blooms. The Minnesota Pollution Control Agency (MPCA) is reminding people that some types of algae can harm pets, livestock and even humans.

Algae, microscopic aquatic plants, are a natural part of any aquatic ecosystem. Most algae are harmless, but under the right conditions, certain types of algae can pose health risks.

People or animals may become sick if they touch or ingest affected water. In extreme cases, dogs and other animals have died after exposure to lake water containing toxic blue-green algae.

There are many types of blue-green algae. They are found throughout Minnesota, but thrive particularly in warm, shallow, nutrient-rich lakes.

Not all blue-green algae are toxic. There's no visual way to predict whether a blue-green algal bloom contains toxins, but harmful blooms are sometimes said to look like pea soup, green paint or floating mats of scum, and they often have a bad odor.

An animal that has ingested toxins from an algal bloom can show a variety of symptoms ranging from skin irritation, vomiting, severe disorders involving the circulatory, nervous and digestive systems, and severe skin lesions. In worst cases, the animal may suffer convulsions and die.

Human health effects can include irritation of skin, eyes and nasal passages, and nausea and vomiting. Extreme cases can produce paralysis and respiratory failure.

There are currently no short-term solutions to correct a blue-green algal bloom. Once a bloom occurs, the only option available is to wait for weather changes, such as significant rainfall, wind shifts or cooler temperatures, to disrupt the algae's growth.

Over the long term, the key to solving algae problems is to reduce the amount of phosphorous that is allowed to flow into lakes through runoff.

Some sources of phosphorus include pet waste, lawn clippings and yard debris, and certain fertilizers. Phosphorus-containing fertilizers are now banned in Minnesota under most circumstances.

For more information, visit

us/zihy141d or call 1-800-657-3864.