津軽十二湖の湖沼學的研究績報

概要

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Since previous studies (KOKUBO & KAWAMURA 1940a, 1940b, 1940c, 1941) limnological observations in Lake Zyuniko have been continued from August to March (1940-1941). In these observations attention has been directed to the seasonal change of the physical and chemical conditions of the lakes, taking into account the former observations. The results show that the temperatures of these lakes subject to the routine change of general cases except the hypolimnion whose temperature is influenced by the underground water. The hypolimnion of these lakes manifests such particular changes as dichotomous or poikilothermous stratification, yet the general tendency submit to the seasonal change that its temperature decreases from autumn to winter. As to the stratification of dissolved oxygen it was found that the “O2-Sprungschicht” which ascended from below by August again sinks with the partial circulation of autumn, situating deeper than 15 meters or thereabout. Probably “02-Sprungschicht” m ?? ght exist still closer to the bottom just after the autumnal circulation, hinting that it is developed from socalled microstratification. The thickness of anerobic layer attained to 10 meters in August in Lake Otikuti. The highest percentage of saturation was 140•2% of Lake Koikuti in August in 2 meter layer.