On June 27, we identified a Cyanobacteria outbreak on Matthews lake. We noticed 2″ round spheres of algae floating in the water last weekend along with a “fishy” smell. Dick today observed the following:
I just got up at the lake, examined our shoreline and found two smaller examples that appear to me to be Cyanobacteria or “blue green algae”. These are blue and dark green in color with a sheen that looks like an oil spill. I did not detect any odor but they do produce a smell like something rotting or dead fish. This is only a small amount and in an area out of the wind. This is not a threat to humans unless ingested but could be toxic to dogs in larger quantities (acids in their stomach dissolve the cell walls and release the toxin into the blood stream producing gastrointestinal and liver damage). It blooms best in more stagnant waters. Have you seen any large amounts on shorelines that might be concerning? The amount on my shoreline is less than 6 sf. I will look more as I go around the lake
Needless to say this can be very harmful to pets, so please keep them out of the water, and be careful while swimming to not swallow water. In addition to our low lake level not allowing the water to run out the outlet, other contributing factors may include dead plant matter decomposition (which feeds algae), stirring up the lakebed, and runoff of fertilizer into the lake. We will hope for the lake level to rise so we can see some turnover, but meanwhile while boating, please try not to disturb healthy plants by going slower in areas that are shallow.
We wanted to advise that from what we can tell we do not have the same evidence of a Cyanobacteria outbreak as we did last week.
- Lake does not have “fishy” smell
- No observed green algae floating on surface
However given the lower lake levels, heat, and disturbance of the bottom sediment in shallow areas, this could easily change.
If you suspect you see this at your shore, a simple test of gathering a sample in a mason jar and letting sit overnight in the fridge will give you an answer. If the algae floats, its bad. If it sinks its good.
How You Can Help Keep Matthews Lake Healthy
We all play an important role in protecting our lake, and there are plenty of easy, practical ways that, as a community, can make a big impact. Here are just a few ideas:
- Be mindful of wake activity in shallow areas — it stirs up bottom sediments and affects water quality. Minimum 100′ from docks and swim rafts.
- Skip the fertilizer near the shoreline — even “phosphorus-free” blends can contribute to runoff.
- Let nature thrive! Keep a buffer zone of native plants along the shoreline to reduce erosion.
- Take care of your septic system to prevent nutrient leakage into the lake.
- Pick up leaves, grass clippings, and pet waste to prevent them from washing into the water or ditches.
Thank you for all you do everyday to protect Matthews Lake! It’s thanks to your care and stewardship that our lake remains such a treasure. Together, we can keep our lake clean, clear, and beautiful for years to come.