Cyanobacterial Blooms in the Wetlands of the Perth region, Taxonomy and Distribution: an overview
The distribution pattern (spatial and temporal) of cyanobacterial blooms in Perth wetlands and the Canning River in Western Australia has been investigated sporadically over a span of 20 years. The major bloom-forming species have been identified as Microcystis aeruginosa, M. flos-aquae, Anabaena circinalis, A. spiroides and Nodularia spumigena. Blooms of potentially toxic Anabaena spp. have occurred in the Canning River since 1993, and in many Perth wetlands for several years. For the first time, the Swan River estuary itself experienced a prolonged toxic bloom of Microcystis flos-aquae in February 2000. The two species of Anabaena and Microcystis aeruginosa blooms have occurred under salinity of less than 3 ppt, whereas blooms of Microcystis flos-aquae occurred in salinity above 3 ppt. Microcystis blooms were most common and persistent in most of the alkaline, shallow, mostly mesotrophic to eutrophic lakes but rarely in oligotrophic lakes. Both species of Microcystis were often found together, although M. flos-aquae appeared to be dominant in late summer and autumn, when salinity levels were at maximum. Shape and size of colonies and cells were the stable morphological features differentiating the two species of Microcystis. Microcystins associated with these blooms ranged from < 0.5 to 1 645 µg L-1 in wetlands and 0.05 to 124 µg L-1 in the Swan River estuary. Nodularia spumigena blooms were confined to two freshwater lakes with salinity slightly below 3 ppt. This is the first time N. spumigena blooms are reported in freshwater lakes. The hepatotoxin nodularin was also detected in these wetlands, but at low levels.
John, J., & Kemp, A. (2006). Cyanobacterial blooms in the wetlands of the Perth region, taxonomy and distribution: An overview. Journal of The Royal Society of Western Australia, 89(2), 51-56.