As we saw in fall 2023, there are Cyanobacteria (“blue-green algae”) aggregating in “scums” on the lake surface in sheltered locations. Cyanobacteria can appear bright green like the first photo (October 2023), or a more muted color like the second photo (October 2024). They look like pollen on the water surface.

If you see surface scums near your dock, please let the WLA know. From samples collected on October 2, 2024, we know that these scums are producing the toxin Microcystin.

What should you do? Do not ingest water with surface scums in it. Keep children and pets out of water with surface scums. And if you do go into the water where there are scums, rinse off with freshwater afterward. See www.maine.gov/dep/water/lakes/cyanobacteria for more guidelines.

Why is this happening now? The upper layer of lake water is starting to cool and sink, mixing with the bottom layers where nutrients have settled. This mixes nutrients back up into the upper water column where light can penetrate, fueling photosynthesis and Cyanobacteria growth.

How do we fix it? By limiting nutrient inputs to the lake, including controlling erosion, runoff from stormwater, ensuring septic systems are up to date, and disposing of pet waste away from the watershed. The LakeSmart program is a great way to get more information.

Please reach out to the WLA (watchiclakeassociation@gmail.com) with questions and concerns.