Surface accumulations of Lemna or Spirodela (Duckweeds) and/or Wolffia (Watermeal) are unsightly and are frequently a symptom of excessive nutrients. These tiny-floating leaf plants are sometimes confused with harmful Cyanobacteria, but one can tell the difference up close because the tiny floating leaves are visible to the naked eye. Cyanobacteria scums tend to look more wispy, fine, or paint-like. It is also common to see both Cyanobacteria and Duckweeds/Watermeal accumulated together along shores of polluted water bodies so it is always good to take photos and verify what you see with a professional. Tag us in any photos that you’d like a response for!