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Algal blooms on the rise in Michigan lakes; climate change impacts part of the problem

green algal bloom on water surfaceIt may still be winter but the interest in harmful algal blooms in Michigan is still high. Aaron Parker, EGLE senior aquatic biologist, recently addressed the Tip of the Mitt Watershed Council, on harmful algal blooms in Michigan's recreational waters.

Since Michigan began tracking algal blooms in 2016, confirmed cyanobacteria blooms - the scientific name for the organism that can produce toxins -- in Michigan have increased dramatically. Last year, there were 79 different waterbodies with confirmed blooms, compared to 21 in 2016.

In general, blooms develop when

  • High amounts of nutrients are in the water.
  • Surface water conditions are calm.
  • Water temperatures are high.
  • Zebra or quagga mussels are present in low nutrient lakes.

Parker notes that changes in the Great Lakes region's climate contribute to algal blooms. From 1951 to 2017:

  • The average temperature has increased by 2.3 degrees Fahrenheit.
  • The frost-free season has increased by 16 days.
  • Total precipitation has increased by 14%.
  • Heavy precipitation events have increased by 35%.

Higher temperatures have contributed to longer seasons for cyanobacteria, Parker notes. He cites 2021, when the first confirmed cyanobacteria bloom occurred in March and had some blooms last into late November.

He cautions, however, that you can't tell if an algal bloom is toxic just by looking at it; that requires testing. Since 2014, the State of Michigan has been testing for harmful algal blooms.

The State also established an email address - -- that allows residents to send concerns and photos of suspected algal blooms.

Check out the video presentation for more information on algal blooms.

Caption: Most cyanobacteria blooms appear on water surfaces and are green.

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