ABSTRACT
Cyanobacterial toxins first came to attention as a cause of poisoning of domestic animals. Poisonous lakes, ponds, and waterholes have long been known, but the first careful investigation of the cause of a series of livestock deaths to be reported in the scientific literature was that of George Francis in 1878 (Francis 1878). Francis was employed by the South Australian government as an analyst and was asked to report on cases of farm animal poisoning occurring on the shoreline of Lake Alexandrina, a large shallow coastal lake close to the mouth of the Murray River in South Australia. This lake connected to the sea through the river entrance and at that time would have contained partially brackish water. Francis noted that the water level that year was very low, with very slight inflow from the river, and that the water was unusually warm at 74°F (23.3°C). He described a “conferva” (a slimy mass of freshwater algae) in excessive quantities in the lake, floating on the surface and “wafted onto the lee shores, where it was forming a thick scum like green oil paint, some two to six inches thick, and as thick and pasty as porridge.” He also noted the rafts of scum that passed out through the Murray Mouth and accumulated on the beach as beds of “green stuff” up to 12 in. (300 mm) thick. The decomposing scum was said to make a “most horrid stench like putrid urine” and exude a fluorescent blue pigment. The toxic organism was correctly identified by Francis as Nodularia spumigena, a common worldwide species found in the eutrophic brackish waters of the Baltic Sea and in coastal lakes in the present day.
