Effect of Carbohydrates on the Symbiotic Growth of Planktonic Blue–Green Algae with Bacteria

Abstract

PHOSPHORUS and nitrogen have been suggested to be limiting agents in the unwanted growth of Cyanophyta. Removal of phosphorus from sewage effluents is being considered as the preferred method to control eutrophication. The significance of organic matter in lake water has been largely disregarded, although carbonaceous material is always found in productive lakes, for example, from 22 mg to 99 mg/l. of dissolved organic matter in the Great Lakes¹. Massive growths of blue–green algae have been documented before the use of industrial phosphates, and they probably occurred always after a heavy influx of organic matter. Maximum growth of phytoplankton does not require high concentrations of phosphorus. As little as 0.02 mg of phosphorus/l. in natural lake water may sustain it². Additional phosphorus alone does not increase growth because algal growth will depend on the presence and availability of not less than fifteen essential elements³.