Japanese Journal of Limnology (Rikusuigaku Zasshi)
Online ISSN : 1882-4897
Print ISSN : 0021-5104
ISSN-L : 0021-5104
Volume 29, Issue 2
Displaying 1-4 of 4 articles from this issue
  • Kiniti SHIMIZU
    1968 Volume 29 Issue 2 Pages 1-10
    Published: July 28, 1968
    Released on J-STAGE: October 16, 2009
    JOURNAL FREE ACCESS
    Followings were found after the balneogeological study of hot springs around Lake Togo.
    1) The geology around Lake Togo consists of alluvium (deposit of Lake Togo) diluvium (deposit of drowned valley) and substratum of Tertiary deposit and granite.
    2) Though the presumption of substratum in the distance of Asazu hot spring, Nagae and Kadota was succeeded by the electric prospecting, that is difficult in the sides of Matsuzaki and Togo hot spring.
    3) The ground water bearing layers around Lake Togo consists of deposits of Lake Togo and drowned valley, containing its considerable continuity. But the hot water bearing layer is a part of drowned valley deposit, only having a partial extension.
    4) The heat energy of hot spring groups is magmatic water. It is considered that the hot water bearing stratum have been constituted after this heat or hot water raised along cracks of failures cutting bed rocks and then mixed with ground water in the coarse sand layer of drowned valley deposit.
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  • Takeo KATO
    1968 Volume 29 Issue 2 Pages 11-18
    Published: July 28, 1968
    Released on J-STAGE: October 16, 2009
    JOURNAL FREE ACCESS
    The Su-kawa River, which starts from the Zao volcanic region, has ever been famous for poisonous acid water. The author has continued the investigations on this river with the aim at elucidating the hydrological features. The results of these have been often published by him for these ten years. In this paper, some remarks are presented on the transportation of dissolved minerals of this river.
    Regarding sulfate and chloride ions, each mineral discharge is the function of flow rate. The functional form is expressed as follows : Qd (SO42-) =928Q0.665
    Qd (Cl-)=183Q0.680
    where Qd is mineral discharge and Q flow rate.
    Moreover, the total discharge of sulfate ion is estimated to be 23, 000 tons per year. Such a large amount of the ion is transported to the river with thermal water gushing from the Zao spa.
    Similarly, the total discharge of chloride ion is determined to be 4, 500 tons per year.
    The annual observation of the acidity reveals that the Su-kawa River transports about 20, 000 tons of free sulfuric acid in a year.
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  • Toshiharu WATANABE
    1968 Volume 29 Issue 2 Pages 19-26
    Published: July 28, 1968
    Released on J-STAGE: October 16, 2009
    JOURNAL FREE ACCESS
    Zooplankton of Lake Nikuru-numa, Hokkaido collected on 25th October 1966 were studied. The results obtained are as follows.
    1. Zooplankton was very rich. It consists of only 7 species, Acanthodiaptomus pacificus, Diaphanosoma brachyurum, Daphnia rosea and Keratella cochlearis var. macracantha being abundant.
    2. It is noticeable that the individuals of Acanthodiaptomus pacificus, Daphnia rosea and Keratella cochlearis var. macracantha were markedly reddish brown colored.
    3. The most abundant zooplankton was Daphnia rosea. More males were found than females.
    4. The male of Alonella excisa was found for the first time in Japan.
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  • Satoshi INOUE, Kenkichi ISHIGAKI
    1968 Volume 29 Issue 2 Pages 27-36
    Published: July 28, 1968
    Released on J-STAGE: October 16, 2009
    JOURNAL FREE ACCESS
    1. The biology of juvenile masu salmon (Oncorhynchus masou) during winter was investigated in the Chihase River which enters into Japan Sea, in southern Hokkaido, from the 13th to the 15th of December, 1967.
    2. In the Chihase River system, juvenile masu salmon exhibited a tendency to gather in the tributary (Hiyamizunosawa) in which the water temperature is comparatively high during winter.
    3. As the result of the examination of stomach contents, it appeared that juvenile masu salmon ate larvae and nymphs of aquatic insects including Ephemeroptera, Trichoptera, Plecoptera and Diptera during winter.
    4. The feeding behavior of O-year fish was more active than that of 1-year fish. Therefore, the ecology of juvenile masu salmon during winter seemed to differ by age group.
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