Scientists urge the public to be on the lookout for harmful algal blooms in Lake Superior

As warmer summer temperatures approach, Lake Superior researchers are urging the public to be on the lookout for harmful algal blooms, commonly referred to as blue-green algae.

This type of algae often grows in inland lakes, including those in the Boundary Waters Canoe Area Wilderness, with abundant nutrients and warm water, but they have also been seen on the shores of Lake Superior in recent years.

Cyanobacteria, also known as blue-green algae, can grow into accumulations called harmful algal blooms. Cyanobacteria have the potential to make toxins and can degrade environmental health when they grow in high numbers. HABs pose a threat to the environment because they can block sunlight and use up oxygen needed by other plants and animals. Blooms can also create undesirable recreation conditions including unsightly scums, foul odors, and health risks.

Reports of blooms in Lake Superior began in 2012. Since 2012, blooms have been reported in most years. The majority of the blooms have been small, isolated events. In 2018, a widespread bloom led to many individual observations. Current data indicate that bloom frequency has increased in recent years, but this may be due to increased awareness.

Kait Reinl is a research coordinator at the Lake Superior National Estuarine Research Reserve. She spoke with WTIP’s Joe Friedrichs about recent algal blooms in Lake Superior and what to expect for the rest of 2023 on the Big Lake. Audio below.

Joe Friedrichs July 16, 2023