Japanese Journal of Limnology (Rikusuigaku Zasshi)

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As is usual in the snowy districts, the melting snow in spring causes the rise of river water remarkably. In the Sake-gawa River, a thaw usually begins early in March and continues for about three months.
Judging from the variations of its flow rate, the snow-thawing season is divided into three stages.
Throughout the thawing season, the concentrations of chloride and calcium ions are kept rather high in spite of being in the large flow rate. Different from the ions, the alkalinity is negatively correlated with the logarithm of the flow rate at the same period.
The observations of the concentration of dissolved minerals show that the amount of transportation (Q_d) is proportional to the 'n'th power of the flow rate (Q), i. e. Q_d=aQⁿ, where 'n' are the constants dependent on the ions and the stage of snow thawing. In the case of chloride ion, the value of 'n'is in the following order : the beginning>the middle stage=the end. At the beginning stage, the atmospheric salt in the fallen snow conveyed by the monsoon in winter is transported rapidly in the river water.
As for the calcium ion, the value of 'n' is in the order : the beginning>the end>the middle stage. The total amount of transported chloride ion during the snowthawing season is about a half of the yearly amount. The same is true of the calcium ion.

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This paper is the report on the distributional pattern and the standing crops of chironomid-larvae which were investigated at Shiozu Bay of Lake Biwa.
We investigated by a bottom sampler four times through the year; April, August, October, 1968 and January, 1969. In our study, Phaenopsectra sp. B, Phaenopsectra sp. C, Procladius sp. B and so on were dominant species next to Chironomus plumosus. Most species lived in the mud, some of them in gravel, and are distributed in the bottoms shallower than 30m. In the sand botom we failed to find any species during this investigation. On the other hand, Phaenopsectra sp. B is very widely distributed from the lake-side to a depth of about 60m.
According to our count, the number of investigations for sampling by a bottom sampler are 2.3 to 3.8 times for Chironomus plumosus and are 46.2 to 66.3 times for Phaenopsectra sp. C, in 50% confidence limits respectively. If we request more correct answer, a large number of investigation are necessary. We presumed that the values of individual numbers and the standing crops in whole Shiozu Bay is as shown in Table 7.
Chironomus plumosus was dissected for the examination of food habit. In the five examples, some algae were recoginized in the alimentary canal.

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