Certain algal bloom bacteria not as toxic as previously thought

MAINE PUBLIC • October 2, 2026

A certain type of algal bloom on Maine lakes may be less harmful than previously thought according to a study from Bigelow Labs and others. Climate change and environmental degradation have led to a rise in algal blooms in Maine lakes in recent years. Toxic cyanobacteria bacterium can cloud clear water and interfere with swimming, fishing and other recreational activities. But one variety of cyanobacteria may not be toxic to humans, as originally thought. Gloeotrichia echinulata tends to bloom in clear lakes, forming thick mats of visible green or white puff balls in otherwise clean water. "There have been reports that this is producing toxin, but now through this new way of looking at it through the genetic lens, we are not seeing any way that these could be producing things like microcystin," said Bigelow Labs research scientist Robin Sleith. Microcystin is known to be harmful to the liver.