Summary
Aquatic plant, Elodea nutallii from Lake Biwa was decomposed under different temperature conditions and weight loss was measured. After 90 days, decomposition was nearly complete at 20 and 30°C under dark condition. It released nitrogen and phosphorus as ammonia at 10°C or nitrite at 20 and 30°C and as phosphate. The water taken from a small inlet covered by drifting aquatic plants was measured for nutrients in Lake Biwa. High concentrations of dissolved organic carbon and carbohydrates were observed in the water samples taken from the pool surrounded with aquatic plants.