Japanese Journal of Limnology (Rikusuigaku Zasshi)
Online ISSN : 1882-4897
Print ISSN : 0021-5104
ISSN-L : 0021-5104
Volume 27, Issue 4
Displaying 1-4 of 4 articles from this issue
  • Tatsuya YAMADA, Masaharu KAWAKATSU
    1966 Volume 27 Issue 4 Pages 135-141
    Published: November 30, 1966
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    In this paper, the vertical distribution of freshwater planarians in the Syakotan Peninsula and Niseko mountainous districts in South Hokkaidô(Lat. 42°45'N. to Lat. 43°25'N. and Long. 140°20'E. to 141°00'E.) is reported. The Syakotan Peninsula is the lower mountainous land (the highest peak, Mt. Yobetsu-dake, is 1, 298 metres above sea level) and runs out to the Sea of Japan. The Niseko mountainous district is situated at the south of the Syakotan Peninsula. The district is characterized by volcanoes belonging to the Nasu Volcanic Zone, such as Mt. Nisekoan'nupuri (altitude, 1, 309 metres), Mt. Iwao'nupuri (1, 554 metres), Mt. Chise'nupuri (1, 135 metres) and Mt. Nito'nupuri (1, 082 metres). There are several hot springs at the foot of mountains. The main river systems of the area surveyed are the Yoichi, the Horikabu and the Shiribetsu. The surveys were made in July 30 to August 1, 1966.
    In the area surveyed, four species of freshwater planarians, Dugesia japonica ICHIKAWA et KAWAKATSU, Polycelis sapporo (IJIMA et KABURAKI), Polycelis auriculata IJIMA et KABURAKI and Dendrocoelopsis lacteus ICHKAWA et OKUGAWA, were found. D. japonica and Den. lacteus were collected only in the stations in the seashore of the Syakotan Peninsula. Pol. Sapporo was common in the stations both in the seashore and the mountainous districts. The altitude of the upper limit of distribution of this species is about 730 metres (inhabitable water temperature range, 7.9-17.2°C). Pol. auriculata was rather common in the stations in the Niseko mountainous district within the altitude range from 220 to 730 metres (7.9-13.0°C). The type of the vertical distribution in the area surveyed is shown as JS-SA-A (J:D. japonica; S:Pol. sapporo; A:Pol. auriculata).
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  • Takeo KATO
    1966 Volume 27 Issue 4 Pages 142-154
    Published: November 30, 1966
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    The Tachiya-gawa River is the second order tributary of the Mogami River. The upper reaches of the drainage system consists of two tributaries, i. e. the Momiji-gawa R. and the Risshaku-gawa R. On the two rivers, the variation of the quality-of-water was observed during the season of rapid thaws. Common to both, between the flow rate and each of chloride ion concentration, calcium ion concentration, hardness and B. C. G. alkalinity, there exists a negtaive correlation respectively.
    Regarding the relation between sulfate ion concentration and flow rate, the circumstance is different in the case of the Momiji-gawa R. On this river, the positive correlation is found to exist. In other words, the dissolution effect from the catchment area exceeds the dilution effect by the freshet. In this drainage basin, is distributed extensively the copper deposit ever mined. The sulfate ion derived from the deposit plays an important role in the phenomenon mentioned above.
    Moreover, the relations between the flow rate and each of silicate and evaporation residue and C. O. D. were studied. In each case, common to the two tributaries the increase of the flow causes the increase of these values.
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  • Yoji ISODA
    1966 Volume 27 Issue 4 Pages 155-161
    Published: November 30, 1966
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    Koyano-ike is situated on the col between Mt. Myoko and Mt. Hiuchi of the Myoko Heights in the western part of Niigata Prefecture, and it consists of several ponds in Sphagnum-bog which is about 2, 100 meters above sea level.
    The writer collected some materials of algae from these bogs on August 8 in 1965.
    In this paper are reported 53 forms belonging to the Chlorophyceae and Flagellata collected in these bogs. The results obtained are as follows:
    1. Chlorophyceae are composed of 20 genera 43 species and varieties, of which 11 genera 32 species and varieties belong to the Desmids, and Flagellata are composed of 8 genera 10 species and varieties.
    2. Among these species, Characiopsis pyriformis, Peroniella minuta and Chrysopyxis bipes are newly recorded in Japan, while Trochiscia Zachariasii, Eremosphaera viridis, Peroniella hyalothecae, Derepyxis amphora, and Lagynion Scherffelii are the species little known in Japan.
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  • Shoji CHIBA
    1966 Volume 27 Issue 4 Pages 162-170
    Published: November 30, 1966
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    Continued to the survey of 1962 (Japanese Journal of Limnology, Vol. 25, No.1), the auther investigated Ono Reservoir limnologically eight times in 1963. It contains the vertical distributions of water temperatures, pH values and amounts of dissolved oxygen.
    The results obtained are as follows :
    No ephilimnion was recognized, and the metalimnion directly touches the water surface, from spring to summer.
    The vertical distributions of the amounts of dissolved oxygen show irregular curves from winter to spring. The surface water contains a large amount of dissolved oxygen, but it decreases remarkably in the hypolimnion, from summer to autumn.
    The variation of pH values from the upper layer to the bottom is not large, but their vertical inclinations get larger from summer to autumn.
    The auther observed these distinctive features of the water temperature, dissolved oxygen and pH values, in 1962 too.
    On February 3rd of this year, the inverse stratification of water temperatures was found, though in 1962 no inverse stratification was seen.
    As to the annual succession of zooplankton, much the similar tendencies were recognized as in 1962:
    Synchaeta pectinata EHRBG. and Asplanchna priodonta GOSSE increase vigorously in winter and the species number as well as individual number of Rotatoria increase greatly in July and decrease in March.
    As to Cladocera, both species number and individual number were less than in 1962, but the period of their appearance is about the same as in 1962. Copepoda also decreased in population, except in June.
    The time and duration of the appearance of Asplanchna priodonta GOSSE, Keratella cochlearis GOSSE, Ploesoma truncatum LAVENDER were similar, but not exactly the same as in 1962.
    As to phytoplanktons, they show the same tendencies as in 1962. The species number and individual number of Bacillariophyceae are abundant from March to June and in November, and Eudorina elegans EHRENBERG is abundant in June.
    The population of the species belonging to Ulothrix, Dinobryon, Oedogonium are less than in 1962. Aphanothece sp., Asterococcus limneticus G. M. SMITH which were not recognized in 1962, appeared in 1963, the former in great number only in June, the latter in June, September and November.
    The fact that Oscillatoria tenuis C. A. AGARDH, Synedra ulna (NITZSCH) EHR., Eudorina elegans EHRENBERG are recognized in this reservoir may suggest that the water of this artificial lake is rich in nutrient salts.
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