The hot, dry weather has set the stage for toxic blue-green algae blooms throughout Minnesota.
The Minnesota Pollution Control Agency (MPCA) issued an algae warning this week, saying the persistent drought is increasing the potential for these toxic blooms to occur. Blue-green algae can potentially kill dogs and other animals who come into contact with it, and may sicken humans.
The blooms are often compared to spilled green paint or pea soup in the lake, and are commonly found in warm, shallow waters during the summer. But the MPCA says the warming climate is making blue-green algal blooms more widespread.
“Hot, dry conditions are ideal for growing algae," said Lee Engel, surface water monitoring supervisor for the MPCA. "We are experiencing higher temperatures due to climate change, and that means warmer lakes, even in Northern Minnesota. We are seeing harmful algal blooms in more places, some of which persist throughout the season.”
The agency is reminding people to be cautious and look out for the dangerous blooms.
Unfortunately, while most blooms are not toxic, you can't tell just by looking at it. While there is a simple overnight test anyone can do using a mason jar, the agency's general advice is caution.
"When in doubt, stay out!" the MPCA says.
While dry, hot conditions stoke the possibility of an algae bloom occurring, there is another culprit: phosphorus. The MPCA says the mineral is one of the leading pollutants of lakes in Minnesota, and "fuels the growth of algae."
"Preventing phosphorus pollution is even more important in lakes warming as a result of climate change," the agency notes.
Anyone who has property on or near a lake should take steps to reduce phosphorus pollution, including:
- Using rain gardens, rain barrels and other measures to limit the amount of urban storm water runoff that reaches the water
- Responsible lawn management, such as the use of phosphorus-free lawn fertilizer, preventing grass clippings and lawn waste from reaching storm drains, and picking up after pets
- Establishing cover crops increasing organic matter and reducing tillage
- Planting deep-rooted native plants along ditches, lakes, and streams, in order to slow down and filter runoff
- Managing manure responsibly to prevent it from entering lakes and streams