The Physicochemical Characteristics of the Water at the Community Habitats of Waterhyacinth (Eichhornia crassipes oprt.) Solms)

摘要

Waterhyacinth (Eichhornia crassipes (Mart.) Solms) is known as one of the most troublesome aquatic weeds in the world. The plant naturally grows in eutrophic freshwater habitats of both tropical and temperate regions. The nutrient status of various habitats offers a much wider range and the plant multiplies so rapidly that it often forms dense stands covering a large surface area of the habitats. In this work, 20 community habitats of the plant in Kagoshima Prefecture were investigated with regards to the reproduction of the plant and physicochemical characteristics of the water in these habitats. The reproduction of the plant and the development of the habitats were related with the concentrations of pollutants (NO_3-N, PO_4-P) in the water. The origin of NO_3-N in water at the habitas was considered to be N of polluted with mainly animal waste, because N values of animal waste in Kagoshima Prefecture is several times higher than the values in other prefectures.