Main Content

The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 1128

John Whitaker, Jan Barica, Hedy Kling, and Margot Buckley; Efficacy of Copper sulphate in the suppression of Aphanizomenon flos-aquae blooms in prairie lakes. Environmental Pollution 15:185-194, 1978

Reprint

In File

Notes

Five shallow eutrophic prairie lakes in the Erickson-Elphinstone area of Manitoba were treated with copper sulphate in order to control Aphanizomenon flos-aquae blooms and prevent summer fish kills. Copper sulphate was added at concentrations of 25 to 360 ug/l Cu to lakes and 100 to 3000 ug/l Cu to experimental tubes in early July when A. flos-aquae filaments were about 10 mm in length. Pretreatment chlorophyll-a concentrations were 48 to 55 ug/liter and bloom species compositions were 90 to 98% of A. flos-aquae. Excellent algal control was achieved at all treatment concentrations. Typically chlorophyll-a declined to 2 to 4 ug/liter after 4 days and A. flos-aquae completely disappeared. Algal biomass remained low for 2 to 3 weeks and then gradually increased. Often Chlorophyta, diatoms and chrysophytes dominated the algal community for the rest of the ice-free season, although in two lakes other species of cyanophyta (Microcystis sp.) were predominant. Low concentrations ranging between 25 and 40 ug/liter Cu proved to be effective enough in these lakes. Copper concentration in the water returned to background levels after 8 to 10 days.