Here is a good article on Harmful Algal Blooms (HABs) by Corinna Parnapy
A freshwater Harmful Algal Bloom (HAB) is any excessive amount of algae that causes negative or harmful impacts on other organisms, water quality, recreation or the economy. HABs are an indicator of nutrient enrichment, primarily phosphorus within that given body of water, however scientific documentation has proven that nitrogen including ammonia can trigger HAB’s in the form of a cyanobacteria bloom. This can be compounded by the addition of road salt, heavy metals and increased water temperature.
read the entire article at: https://www.linkedin.com/pulse/toxic-waters-corrina-parnapy