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Volume 21, Issue 1
Displaying 1-5 of 5 articles from this issue
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Kyuémon GOSÉ1960 Volume 21 Issue 1 Pages 1-8
Published: March 30, 1960
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe effect of river pollution by the Ashio Copper-Mine, near Nikkô in Tochigi Prefecture, upon the aquatic insects was examined. The insect samples were collected quantitatively at ten stations in the Watarase-gawa system, which receives the effluents of the Mine at Station 3. The amounts of copper and zinc dissolved in the river water increase rapidly at St. 6, where there were found two kinds of insect larvae, a caddis worm, Polycentropits sp. and a stonefly nymph, Acroneltria stiginatica. The effect of river pollution is distinct the aquatic insects decrease markedly in both the number of species and of individuals. In St. 9 and 10, 27 km and 38 km respectively, distant from the effluents of the Mine, it seems to recover the aquatic fauna to a certain extent.View full abstractDownload PDF (993K) -
Kyozo KIKKAWA1960 Volume 21 Issue 1 Pages 9-16
Published: March 30, 1960
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSA large number of hot springs in Beppu City are discharged through bored wells. In former times, thermal water was found under water-table condition in some inland area in that city over 1000 m distant from the sea-shore, where temperature and water level of a well have been observed once a day during the past 35 years by Geophysical Laboratory, Kyoto University. Its temperature has gradually lowered and is now about 25°C. This shows the decrease of hot water leakage through semi-impervious bed from deeper confined aquifer, in which the water pressure has lowered owing to the increase of withdrawals in the city.
It is observed that the other artesian well of 50 m deep in Beppu shows the obvious rise of temperature under the effect of heavy draft from nearby area and recover after the end of draft. It means that more thermal water rises from the deeper bed with the drawdown of water pressure in the upper aquifer by the pumping effect.
It is found that each aquifer layered vertically is not perfectly bound by confining bed but interchanges water in accordance with pressure gradient through the semi-impervious stratum.View full abstractDownload PDF (1182K) -
Shizuo SUZUKI1960 Volume 21 Issue 1 Pages 17-24
Published: March 30, 1960
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe ecological studies on the aquatic Phycomycetes were carried out in the Arakawa River during the period from December, 1956 to August, 1957.
The zoospores of aquatic Phycomycetes in that river were scarce in its upper course and increased in its lower part. They became a maximum amount at the middle course near the city of Kumagaya, and diminished in the lower stream with the increase of industrial and urban pollution. The difference of distribution of species was observed in the stream between the upper and the lower courses. Leptomitus lacteus, which was considered as a sewage fungus, was found only in the lower stream.
The zoospores of aquatic fungi showed considerable variations in amount, with one maximum occurring in winter and one minimum in summer. The seasonal fluctuation of fungi differed according to species, i.e. Saprolegnia monoica, Achlya racemosa, A. flagellata, and Leptornitus lacteus flourished in winter, while Saprolegnia diclina and Pythiurn sp. were obtained throughout the year.
The zoospores of aquatic fungi were distributed uniformly from the surface to bottom layers, and in particular Saprolegnia monoica was found mostly in the surface layer and Leptomitus lacteus was seen in the bottom layer.View full abstractDownload PDF (955K) -
Shizuo SUZUKI1960 Volume 21 Issue 1 Pages 25-31
Published: March 30, 1960
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe genus Aphanomyces (aquatic fungi) is distributed widely in Japanese lakes, occurring not only in the water but also in the bottom mud. The researches have been carried out to clarify their ecological nature. So far as the writer's observations are concerned, the following ecological specificity may be given in regard to the distributing conditions of fungi.
1. The amount of zoospores of Aphanomyces changed seasonally. The seasonal fluctuation differed according to various species, e. g., Aphanomyces laevis reached its maximum in summer, while sterile species of Aphanomyces of Lakes Naka-numa and Shinsei-ko showed their maximum in winter.
2. The vertical distribution of zoospores of Aphanomyces differed also seasonally. They occurred only in the deeper layer during the circulation period. Their distribution seems to have relation to the amount of oxygen dissolved in the water.
3. The distribution of the genus Aphanomyces seems to have close relation to the lake types. They were distributed abundantly in both harmonic and dystrophic lakes, while they were very rare in acidotrophic ones. The difference in the occurrence of Aphanomyces was also seen within the harmonic lakes, i. e., it was very abundant in eutrophic lakes, but was scarcely found in both mesotrophic and oligrotrophic ones.View full abstractDownload PDF (1242K) -
1960 Volume 21 Issue 1 Pages 44
Published: 1960
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSDownload PDF (117K)
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