According to the Great Pond Foundation, harmful cyanobacteria blooms in ponds are the result of rapid growth in single cell algae and seaweed, which can be exacerbated by the introduction of excess nitrogen and phosphorus and increased heat.

Source: https://www.mvtimes.com/2023/08/17/harmful-algal-bloom-advisories-issued-five-ponds/

Over their long history, cyanobacteria have evolved tricks that let them proliferate wildly when shifts in conditions such as nutrient levels or salinity kill off other microbes.

Source: https://www.wired.com/story/the-mystery-of-fish-deaths-in-a-foul-chartreuse-sea/

“The Ministry of Environment operates this page and can help determine if a bloom is cyanobacteria, which may produce toxins.

Source: https://www.100milefreepress.net/news/public-asked-to-report-sighting-of-algae-blooms/

The outbreaks occur when tiny cyanobacteria, also called blue-green algae, suddenly multiply rapidly, stretching out on top of the water for potentially kilometres.

Source: https://www.bbc.co.uk/news/business-64317261?at_medium=RSS&at_campaign=KARANGA

The scientists found that certain combinations of volatile organic compounds (VOCs) released by algae can serve as indicator for microcystin, a produced at varying levels during blooms of cyanobacteria, commonly known as blue-green algae.

Source: https://phys.org/news/2023-08-technique-sniffing-toxic-algae-blooms.html