Development of an alkaline layer and its disappearance caused by heavy rain at Lake Noziri

Abstract

At Lake Noziri, the writers made the observations of the vertical distribution of the hydrogen ion concentration etc. on July 25, September 9, and September 22 of 1965.
On July 25, when the rainy season just ended, the writers observed no layer where the lake water is more alkaline than that of any other layer. After the day, sunny summer weather lasted, and on September 9, they observed an alkaline layer (pH=8.1) conspicuously developed as hitherto observed, in the thermocline of the lake. The writers think the development of the alkaline layer to be attributed partly to the enough radiation of the sun.
On September 22, however the disappearance of the alkaline layer was observed, the writers consider this phenomenon to be attributed to the circulation, though imperfect, of the lake water caused by heavy rainfall accompanied with the typhoons which had passed before the time of the last observation, near the lake.