Microcystis bloom create cyanotoxins appropriately name microcystins. The bacteria strains themselves can come either via a single cell or they can come in large colonies. Characteristic traits come from these large colonies that grow as thick as paint, are a bright green coloring, and a smell that is similar to rotting seaweed. Microcystis come in ovoid or spherical shape and are non-filamentous. The bacteria also has a high affinity for phosphorus and uses their gas vesicles to alter their buoyancy to get phosphorus from deeper water than to float back up for sunlight. Fresh waters are also where you will find this plant, preferring places with low salinity.
Microcystins themselves can have altered forms based on the additions of differing amino acids, and the addition or absences of methyl groups. The most common form of microcystin made by cyanobacteria contain the amino acids leucine and arginine which allows the toxin to prevent protein phosphatase. The basic structure seen below adds the arginine in the y position and the leucine in the x position. Overall, the chemical formula is C49H74N10O12.
Microcystin is hepatotoxin, meaning it targets the liver, and with enough exposure will lead to liver failure. Other signs of microcystin poisoning according to the EPA include abdominal pain, headache, sore throat, vomiting, couch, diarrhea, blisters around the mouth and pneumonia.
Oregon Department of Environmental Quality. Microcystis SP. [Image File]. In Harmful Algae Bloom (HAB) Strategy. https://www.oregon.gov/deq/wq/Pages/Harmful-Algal-Blooms.aspx
Rosen, Barry. Brown Microcystic Aeruginosa [Image File]. In Field and Laboratory Guide to Freshwater Cyanobacteria harmful Algal Blooms for Native American and Alaska Native Communities. https://pubs.er.usgs.gov/publication/ofr20151164
Rosen, Barry. Green Microcystic Aeruginosa [Image File]. In Field and Laboratory Guide to Freshwater Cyanobacteria harmful Algal Blooms for Native American and Alaska Native Communities. https://pubs.er.usgs.gov/publication/ofr20151164
Oregon Department of Environmental Quality. Harmful Algae Bloom (HAB) Strategy. https://www.oregon.gov/deq/wq/Pages/Harmful-Algal-Blooms.aspx
United States Environmental Protection Agency. Health Effects from Cyanotoxins. https://www.epa.gov/cyanohabs/health-effects-cyanotoxins
Deaton, Jeremy. Trying to Tame the Klamath River Filled It with Toxic Algae, 2020. Scientific American. https://www.scientificamerican.com/article/trying-to-tame-the-klamath-river-filled-it-with-toxic-algae/