Field determination of the critical nutrient concentrations for Cladophora in streams and their importance in waste load management

Wong, S. L.
Clark, B.
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Ontario Ministry of the Environment

Many streams in Southern Ontario are seriously infested with excessive seasonal growth of aquatic plants such as Cladophora and Potamogeton. A direct relationship, with a regression coefficient of 0.87, was observed between ambient P concentration in the water and P content of plant tissue in six rivers. Critical or growth controlling total P concentration of 60 ?g/L in stream water and 1.6 mg/g dry weight in plant tissue were determined. Unlike P, no significant correlation was observed between N content of plant tissue and N concentration in water. The correlation of total P with plant growth can be used to estimate the waste load which would result in maximum growth rate of Cladophora.

Ontario Ministry of the Environment
Biological Surveys/Investigations Reports
aquatic plants, Cladophora glomerata, Potamogeton pectinatus, phosphorus, plant tissue, nitrogen, plant growth, growth rate, nutrients, nutrient enrichment