Destabilization of planktonic ecosystems and blooms of blue-green algae Food Web Management: A Case Study of Lake Mendota by J.F. Kitchell

Blooms of blue-green algae are a serious water quality problem in many productive lakes (Plate 8; Cooke et al. 1986; Paerl 1988). Causes of blue-green blooms involve many factors, including mixing, trace metals, macronutrients, dissolved organic matter, microbial activity, and herbivory (Paerl 1988; Carpenter 1989). Of the many factors implicated, phosphorus loading and grazing are especially pertinent to management of nuisance blue-green blooms (Cooke et al. 1986; Shapiro and Wright 1984). The role of phosphorus is firmly established. Blue-green blooms can be triggered by adding phosphorus ratios favor blue-green dominance (Smith 1983), these nutrients commonly covary (Carpenter et al. 1990) and phosphorus is generally the more critical element for ecosystem dynamics (Schindler 1977).