Abstract
A report about microorganisms adhered to a river bed in the spring and the summer seasons run on Japanese Journal of Water Treatment Biology, Vol, 29, No.1 (1993) .This time microorganisms adhered to river bed were investigated during the autumn and the winter seasons at every points. A cycle of a year about microorganisms adhered to river bed was round off.The dominant species of the microorganisms adhered to the river bed were also investigated separately.The saprobity in the surface water in terms of saprobic index of the species was following;
autumn winter
Points 1, 2, 4, 6 1, 2, 3, 4, 8 : oligo-saprobity s=1.0±0.5
Points 3, 5, 8, 9, 10, 12 5, 6, 7, 9, 11, 12 : β-meso-saprobity s=2.0±0.5
Points 7, 11 10 : α-meso-saprobity s=3.0±0.5
About 10 species were observed at every points in the four seasons. At the same time, discript the result of the investigation on microorganisms quantities. Microorganisms indicate the past career of water quality for a fairly long time. But because of the differences in temperature, environment of a river bed, the water current and the time of the year the dominant species assume a different aspect. So a deeper understanding of the water environment is the best measure to prevent water pollution. Needless to say, the origin of water pollution should be managed and controlled. Cleaning and putting a river side in good condition is very important. And is necessary to care for the change of a river bed by bridging work.
