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Cyanobacteria guide Fact Sheet Blue-green algae cyanobacteria a guide WHAT ARE THEY Despite their name blue-green algae are actually photosynthetic bacteria also called ? cyanobacteria ? that rely on sunlight for energy Blue-green algae are present in alm

Fact Sheet Blue-green algae cyanobacteria a guide WHAT ARE THEY Despite their name blue-green algae are actually photosynthetic bacteria also called ? cyanobacteria ? that rely on sunlight for energy Blue-green algae are present in almost all aquatic ecosystems including creeks rivers lakes and wetlands Individual cells are very small so blue-green algae can be present in a water body without being visible As environmental conditions become favourable algae numbers start to increase rapidly or ??bloom ? and scums may become easily visible on the water surface Blooms range in colour from dark green to yellowish-brown and develop a paint-like consistency as they dry out at the water ? s edge A blue pigment may also be seen as they dry A BIG PROBLEM Algal blooms can cause major problems Some species of blue-green algae produce chemical compounds that taint drinking water with musty or earthy tastes and odours These o ?-tastes and odours are not hazardous to health but require extensive treatment to remove and in severe cases make the water undrinkable This can place signi ?cant strain on the water supply system Algal bloom on Murray near Robinvale photo courtesy of Vanora Mulvenna HIGHLY TOXIC More signi ?cantly some species produce toxins that can be hazardous to animals and people if they are consumed inhaled or possibly contact the skin Blue-green algal toxins are colourless odourless and can remain present in the water weeks after the blue-green algae have disappeared They are not destroyed by boiling a ected water With an unsightly appearance and often also a pungent smell cyanobacteria can make a ?ected water unappealing for recreational activities such as swimming boating or ?shing Water a ?ected by a bloom is unsuitable for agricultural use When blooms form in drinking water storages such as reservoirs or dams they can cause serious di ?culties for drinking water suppliers Blue-green algae produce toxins that can a ?ect us in three main ways ? Hepatotoxins damage the liver and may also increase the risk of certain types of cancer ? Neurotoxins damage nerves and at high doses can cause numbness and muscle tremors especially in the muscles animals and people need to breathe ? Allergens are thought to produce a range of reactions in sensitive individuals including skin rashes irritation of the eyes and possibly gastroenteritis Although human poisoning and illness from exposure to these toxins is rare it can be severe and even fatal The only documented case of human deaths occurred in in Brazil where dialysis patients died after direct exposure to Water Research Australia Water for the wellbeing of all Australians March Page Ctoxins in their dialysis uid However people from Palm Island Australia in were hospitalised after drinking water from the local reservoir which had a bloom NOT NEW Algal blooms are not a new phenomenon The ?rst scienti ?cally documented case of an algal bloom causing deaths was in South Australia ? s Lake Alexandrina in where cattle pigs and sheep died within hours of