The combination of freshwater pollution and repeated warmer and prolonged heat waves provokes intense cyanobacteria blooms in French streams, rivers, ponds & lakes.
Toxic for animals and humans and degrading water quality they are the object of many concerns for citizens and public authorities.
CYANOBACTERIA ARE AT THE HINGE BETWEEN BACTERIA AND ALGAE
Cyanobacteria are bacteria (microorganisms present in the water) that naturally occur in all worldwide surface water systems (oceans, lakes, rivers, wetlands) for several billion years. They are also called blue-green algae, unless not algae, because of their blue-green color. Noteworthy, they were the first organisms to emit oxygen on Earth and thus are at the origin of human life.
Cyanobacteria developed morphologic advantages allowing them to grow in aquatic environments faster than algae and thus to proliferate significantly. They perform photosynthesis like algae, but in addition they have the ability to float within the water thanks to gas vacuoles, and above all they can fix nitrogen directly from the atmosphere.
CYANOBACTERIA PRODUCE TOXINS
Cyanobacteria can produce cyanotoxins that are dangerous for aquatic organisms, livestock and wildlife and even threaten human health. Indeed, numerous dog’s death have been reported following ingestion of cyanotoxins within the water.
Typical health problems in animals and humans include fever, vomiting, weakness, liver, kidney, heart, brain, and skin damage, neurological disorders, and even death.
Beyond the possibility of human contamination through the water supply, there is also a risk of contamination through the food chain as bioaccumulation of cyanotoxins and their transfer into the food chain has been demonstrated in several studies.
CYANOBACTERIA BLOOMS HAVE INCREASED DUE TO CLIMATE CHANGE
Nowadays, cyanobacteria blooms have increased in intensity and duration due to the combination of water pollution and climate change, in particular water warming. The increase in cyanobacteria blooms has therefore become a worldwide public health issue.
Accordingly, in France, cyanobacteria are now monitored in many surface water systems by water bodies managers. And consequently , during the last few years, several french water bodies have been temporarily closed by local authorities during summer conditions because of too high cyanobacteria concentration