The standing crop of the plankton and benthos was studied in two ponds, Arasakaike and Nakaike, near Neyagawa, Osaka Prefecture. Both ponds were fertilized with hen excrements, and only Nakaike was aerated. 1) In both ponds, blue-green and green algae were very rich in the biomass and diatoms ranked next to them. Seasonal change of the dominant species of algae is shown in Figure 2. Zooplankton was rich in species number but the biomass was small. As to the standing crop of plankton, Nakaike was richer than Arasakaike(Table 1). 2) Nakaike had more standing crop of benthic fauna than Arasakaike.(Table 2).
