Growth Characteristics of Dictyosphaerium pulchellum v. minutum isolated from a bloom which occurred in the Reservoir Sagami, Kanagawa Prefecture

—The effects of pH and temperaturen the growth of Dictyospaerium pulchellum v. minutum—

Abstract

The growth characteristics of Dictyosphaeriumpulchellum v. mitum a micro green alga were studied under several experimental conditions. The alga wesisolated from a bloom which occurred in the Reservoir Sagami Kanagawa prefecture on June 23 1987. The effects of pH and temperature on growth of the alga were investigated and the optimum growing conditions were estimated. The optimal growth of the alga was obtained at a temperature of 20°C on pH 9.0-9.5 with growth rate=1.00-1.06/day, doubling time 15.2-15.7 hours, number of generation 6.1-7.6 and maximum cell concentration 1.3×10⁶ cells/ml. The optimal temperature of the alga was about 10-15°C lower than Microcystis aerugtinosa.