About
About cyanobacteria and Cyano Community
So, what exactly is a cyanobacterium?
A cyanobacterium is a microorganism capable of photosynthesis, just like plants. They occur in aquatic environments but also in a wide variety of terrestrial ecosystems, including extreme environments such as deserts. Despite their common name “blue green algae,” cyanobacteria are not algae but bacteria.
Benthic and planktonic cyanobacteria
Benthic cyanobacteria
Benthic cyanobacteria grow on submerged surfaces: rocks, pebbles, sand beds, aquatic plants, logs, and roots. Benthic cyanobacterial blooms appear as dark, brownish, dense, foul smelling masses that may float to the surface or wash up on shore. These masses can contain very high concentrations of neurotoxins and are particularly dangerous to dogs, which are attracted to their smell.
Planktonic cyanobacteria
Planktonic cyanobacteria are found in lakes, floating in the water column, either near the surface or deeper down. Planktonic blooms color the water blue green, green, or sometimes red. When the bloom is extensive, colored scums may accumulate along the shore. As they decompose, these blooms can deplete dissolved oxygen in the water and cause mass die offs of aquatic animals (and plants). Some planktonic blooms also produce toxins that may affect swimmers or contaminate the water.
Cyanotoxins
A small number of cyanobacterial species—whether planktonic or benthic—are capable of producing toxins that are dangerous to humans and pets. The most common and hazardous cyanotoxins affect the nervous system (neurotoxins) or the liver (hepatotoxins). Neurotoxins can act extremely rapidly (death within minutes), while hepatotoxins cause symptoms several hours later.
Six dogs die in Neuchâtel in less than 24 hours
In summer 2020, at the mouth of the Areuse River, at least six dogs died after ingesting mats of toxic cyanobacteria. Symptoms appeared only minutes after ingestion. The toxic cyanobacterium responsible was identified by the Microbiology Laboratory at the University of Neuchâtel as Microcoleus anatoxicus. This species grows on the riverbed substrate, including in the Areuse river. Its mats contain large amounts of an anatoxin a derivative, highly toxic to dogs that ingest it. Anatoxin a interferes with a natural neurotransmitter (acetylcholine) required for normal muscle function. In cases of anatoxin a poisoning, paralysis of the diaphragm leads to asphyxiation.
Understanding the extent of the cyanobacteria problem through citizen science
Cyanobacteria capable of producing anatoxin a appear to be widespread in rivers and lakes across the Swiss Plateau: they are found from the shores of Lake Geneva in the canton of Vaud to the banks of the Rhine in the cantons of Schaffhausen, and in areas in Ticino. The Cyano Community citizen science project aims to improve our understanding of toxic cyanobacterial blooms and to create a direct link between authorities, citizens, and scientists. Within the project, participants learn to recognize and document potentially toxic blooms. During the initial training session, they learn more about cyanobacteria and their toxins, become familiar with the data collection platform, and are introduced to sampling procedures. Citizen scientists receive a kit enabling them to carry out sampling safely. Thanks to Cyano Community, they can submit key information about their observations and send cyanobacterial mat samples to analytical laboratories.
Want to participate in the project? Register for our training sessions