Thanks to the alert investigation of Shawn MacPherson and the help of Ben Peterson, Timothy Clark (of King County) measured an algae bloom and discovered the following:
The bloom is a blue-green algae:Aphanizomenon. Aphanizomenon may produce several algal toxins. We measured the level of one the toxins, microcystin, in the algal scum, and it was found to be 4.3 µg/L, which is below the state recreational guideline of 6.0 µg/L. That’s good, but there is still concern that the lake may reach toxic levels if the bloom persists.
He further recommends that to avoid making the bloom worse, we clean up after pets, avoid fertilizer, and don’t feed the waterfowl.