Spring bloom in a hypereutrophic lake, Lake Kasumigaura, Japan—V : Factors controlling natural population of phytoplankters

Temperature was the limiting factor controlling the multiplication rate and standing stock of natural population density of phytoplankters in the lake of Tsuchiura Harbor during the spring bloom of 1980. The temperature relationship of the multiplication rate could be expressed as an Arrhenius equation during the spring bloom. The species composition of the natural phytoplankton community, on the other hand, was affected chiefly by combination of the ambient nutrient concentrations of ammonium, nitrate, phosphate and silicate. Although many phytoplankton species occurred, one temperature relationship appeared to hold for mixed species of the natural community from 4.4 to 24.9° C.