Read the full article at https://www.pca.state.mn.us/water/blue-green-algae-and-harmful-algal-blooms from the Minnesota Pollution Control Agency.
What are blue-green algae?
Blue-green algae are not algae at all, but types of bacteria called cyanobacteria that are normally present in many lakes. This type of bacteria thrives in warm, nutrient-rich water. When conditions are right, the bacteria can grow quickly forming “blooms.”
What do blue-green algal blooms look like?
Blue-green algal blooms are often described as looking like pea soup or spilled green paint. However, blooms aren’t always large and dense and can sometimes cover small portions of the lake with little visible algae present. Blooms can also produce a swampy odor when the cells break down.
When do harmful algal blooms occur?
Blue-green algae prefer warm, calm, sunny weather and water temperatures higher than 75 °F. Blooms usually occur during summer and early fall, but can occur other times of the year, if conditions are right.
Where are harmful algal blooms found?
Harmful algae can be found everywhere in Minnesota, but thrive in warm, shallow, nutrient-rich lakes. They will often be found on the downwind side of a lake or in a secluded bay or shoreline.
What are the possible health effects?
You can become sick if you swallow, have skin contact with, or breathe in airborne water droplets while swimming, boating, waterskiing, tubing, bathing, or showering in water that has harmful algae or if you drink water that contains algal toxins. If you become sick, you might experience vomiting, diarrhea, rash, eye irritation, cough, sore throat, and headache. Symptoms generally begin hours to two days after exposure.
Can animals be affected?
Pets, especially dogs, are susceptible to harmful algae because they swallow more water while swimming and doing activities like retrieving a ball from the water. They are also less deterred by green, smelly water that may contain harmful algae. Animals can experience symptoms within minutes of exposure to the toxins. Symptoms they might experience include vomiting, diarrhea, weakness, difficulty breathing, and seizures. In the worst cases, animals have died. If your pet experiences these symptoms after exposure to algae, contact your veterinarian.
How can we get rid of harmful algae blooms?
We can't eliminate blue-green algae from a lake -- they are an inherent part of the overall algal community. What we really want to do is control their overall intensity and the frequency of the blooms. Since we can't control the water temperature, the best thing we can do is to reduce the amount of nutrients getting into the lake. This can best be accomplished by reducing the amount of phosphorus and nitrogen from man-made sources such as lawn fertilizer, and runoff from cities, cultivated fields, feedlots, and a myriad of other sources. Though a reduction of nuisance algal blooms will not be immediate, it is the best long-term solution to minimizing the frequency and intensity of algal blooms.
Find out how to report adverse health effects of exposure to contaminated water, when to seek medical attention and photos of blue-green algae at https://www.pca.state.mn.us/water/blue-green-algae-and-harmful-algal-blooms