Occurrence and possible causes of a severe cyanobacterial bloom in Lake Cargelligo, New South Wales

摘要: Although smaller cyanobacterial blooms had occurred in Lake Cargelligo previous summers, a severe bloom of Anabaena circinalis the lake November 1990. Cell numbers exceeded 100 000 cells m L -1 , and toxicity tests revealed to be highly hepatotoxic. This resulted first known closure town water supply due cyanobacteria New South Wales. Blooms Microcystis aeruginosa, Aphanizomenon issatschenkoi, Oscillatoria rnougeotii Cylindrospermopsis raciborskii also at similar very high cell during summer autumn 1990-91. All five species persisted until May 1991, although there was no detectable from January onwards. Severe flooding Lachlan River valley upstream winter 1990 led nutrient enrlched inflows lake. These elevated concentrations would have been major factor contributing bloom. However, other physico-chemical factors were suitable for growth.