1935 Volume 4 Issue 3 Pages 183-189
The writer has estimated the amount of nitrogenous compounds of 119 lakes in Japan belonging to the harmonic type since the year of 1929. His data are shown in Table 1 jointly with those of Mr. S. TAKAYASU of 16 lakes in Hokkaidô. He discussed the total amount of nitrogen consisting of ammonia-, nitrate, and albuminoid nitrogen of the surface water. The total amount of nitrogen above mentioned does not show so large seasonal variation that the data, being taken at different seasons of a year, may be compared with each others.
His results show that: -
1. High mountain lakes contain 0.06-0.08mg/lN.
2. Deep caldera or tectonic lakes contain only 0.02-0.1mg/lN.
3. Moderate lakes in the mountains (40-29 meters) contain 0.05-0.1mg/lN.
4. Shallow lakes in the mountains and the moderate lakes on the sea coast include every kinds of amount of nitrogen.
5. Shallow lakes and the swamps on the sea coast and in the cultivated plains contain large amount of N (over 0.2 mg/l).