What you should know

CLWA's Godzilla Algae campaign described harmful algae blooms as a growing threat to people, pets, livestock, aquatic life, recreation, and local economies.

A harmful algae bloom closed Chebacco Lake for 19 days in 2020. Water sampling performed in 2023 reinforced the need for continued monitoring, planning, and public awareness.

Warmer water, more intense rainfall, and increased nutrient runoff can create favorable conditions for cyanobacteria:

• Some harmful cyanobacteria grow faster than other algae at warmer temperatures.
• They can move through the water column to reach nutrients in deeper water and sunlight near the surface.
• Dense surface growth can absorb sunlight and further warm surface water.

Reducing bloom risk requires reliable data, long-term monitoring, and coordinated lake and watershed stewardship.

Related CLWA resources

• Know Your Watershed I: Overview of the Challenge
• Know Your Watershed II: How Healthy Is Our Lake?
• Know Your Watershed III: Managing the Four Human Impacts
• LakeSmart Steps You Can Take
• Algae Blooms

Additional public-health and climate resources

• Climate Change and Freshwater Harmful Algal Blooms — U.S. Environmental Protection Agency.
• Harmful Algae Blooms in Freshwater Bodies — Massachusetts Department of Public Health.
• Guidelines for Cyanobacteria at Recreational Freshwater Locations — Massachusetts guidance.