Japanese Journal of Limnology (Rikusuigaku Zasshi)
Online ISSN : 1882-4897
Print ISSN : 0021-5104
ISSN-L : 0021-5104
Volume 50, Issue 2
Displaying 1-9 of 9 articles from this issue
  • Munetsugu KAWASHIMA, Takashi NISHIYAMA
    1989 Volume 50 Issue 2 Pages 93-104
    Published: April 28, 1989
    Released on J-STAGE: October 19, 2009
    JOURNAL FREE ACCESS
    Concentrations of Na+, K+, Mg2+, Ca2+, Cl-, SO42- and alkalinity in water samples from the Tibetan Plateau were analyzed. The samples were from 27 lake waters, 82 river waters, 19 snows, seven hot spring waters and one groundwater. Almost all the snows and rivers were fresh (<0.5 g· l-1 in salt concentration), while most of the lakes and spring waters were saline. In the north of the plateau, where the climate is more and than in the south, the river waters tended to have a higher salt concentration than in the south. Almost all the lakes investigated were closed and saline. The chemical type of the lake waters was Na-Cl and/or Na-SO4 in the northern and Na-HCO3 in the southern part of the plateau, whereas the type of the fresh river waters and snows was Ca-HCO3.
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  • Yu ISHITOBI, Hiroshi KAMIYA, Kyoichiro HAYASHI, Manabu GOMYODA
    1989 Volume 50 Issue 2 Pages 105-113
    Published: April 28, 1989
    Released on J-STAGE: October 19, 2009
    JOURNAL FREE ACCESS
    The tidal exchange in Lake Shinji, an inner coastal lake connected to a lower one by a long narrow channel, was investigated under low discharge conditions. Fixed point observations at the cross-section in the uppermost reaches of the channel were carried out. Evaluation from the analysis of the velocity and salinity profiles showed that the tidal exchange was the dominant component responsible for the inward salt flux under normal tidal conditions. Moreover, longer term variations of water level with an amplitude superior to the tidal one were recognized in Lake Shinji, and were considered to be another factor of the water exchange between this inner lake and a lower one.
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  • -A Particle-Fluid Two-Phase Flow Model Using a Finite Amplitude Wave Theory-
    Yosuke KISHI, Tadao KAKINUMA, Kunimitsu INOUCHI, Motoo HASAI
    1989 Volume 50 Issue 2 Pages 115-128
    Published: April 28, 1989
    Released on J-STAGE: October 19, 2009
    JOURNAL FREE ACCESS
    The behavior of suspended matter in the gravity wave field is investigated by using a finite amplitude wave theory, under the assumption that the mixture of suspended matter and fluid behaves like a sort of fluid (fluid mixture) with density varying linearly with suspended matter concentration.
    Based on the governing equations for suspended matter and fluid mixture, which is inviscid and irrotational, a numerical analysis is carried out to obtain the flow velocity of the fluid mixture, suspended matter concentration and suspended matter transport rate for various non dimensional parameters. The main results are as follows : 1) The amplitude of flow velocity is nearly equal to that for the case in which the density of the fluid mixture is assumed to be constant (ρ=constant), the difference being within 5%. 2) Mean suspended matter concentration averaged over a wave period decreases exponentially with the height above the bottom. 3) Amplitude of the variation of suspended matter concentration is larger near the bottom when the non-dimensional diffusion coefficient Dz is smaller, and it is larger near the water surface when Dz is larger. 4) Mean suspended matter concentration is almost equal to that for ρ=constant, and the amplitude of the variation of suspended matter concentration is smaller than that for ρ=constant by 10% at most near the bottom. 5) Suspended matter transport rate in the horizontal direction averaged over a wave period increases rapidly as ws/Dz (ws : non- dimensional falling velocity) becomes smaller and is smaller than that for ρ=constant, by 20% at most for smaller values of ws/Dz. 6) Computed results with respect to mean suspended sediment concentration agree well with the experimental data of HOM-MA et al. (1964) and NODA and IWASA (1971) except for those in close proximity to the bottom.
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  • Toshiharu WATANABE, Noriko SUZUKI
    1989 Volume 50 Issue 2 Pages 129-137
    Published: April 28, 1989
    Released on J-STAGE: October 19, 2009
    JOURNAL FREE ACCESS
    When the biological assessment of water pollution using attached algal corn munitiesis done, it is an important problem whether or not the algal floras are same on different substrata. This investigation was carried out to make it clear in an artificial water way. Following facts have been clarified through the research.
    In the beginning of succession process, the diatom assemblages were considerably different with each other between different substrata in their species components, and also the variation of their values of diatom assemblage index to organic water pollution (DAIpo) was large. However, the difference among the assemblages disappeared and DAIpo values became almost equal, in a mature stage of succession.
    From the results, it seems to be suggested that samples collected from various substrata in addition to stones or rocks are useful to provide the proper judgement to water pollution, so far as we use the samples in the mature stage of succession under the prearranged condition.
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  • Osami YAGI, Norio OHKUBO, Noriko TOMIOKA, Mitsumasa OKADA
    1989 Volume 50 Issue 2 Pages 139-148
    Published: April 28, 1989
    Released on J-STAGE: October 19, 2009
    JOURNAL FREE ACCESS
    Determination of water quality, Algal Growth Potential (AGP) and limiting nutrients in Ushiku Marsh and related rivers ; lnari, Higashiyata, and Nishiyata were carried out using Microcystis flos-aquae, M. aeruginosa, and Selenastrum capricornutum in order to clarify the difference between Ushiku Marsh where water bloom occurs very rare and Lake Kasumigaura where high density of water bloom occurs every year. T- P concentration of Ushiku Marsh was the same level of Lake Kasumigaura. However, T- N content in Ushiku Marsh was significantly higher than in Lake Kasumigaura. AGPs of the filtrated samples in Ushiku Marsh were very lower values than those of autoclaved ones. Autoclaving was done at 121°C and for 15 min. The limiting nutrients in Ushiku Marsh and related rivers were P and EDTA through the year for M. flos- aquae and M. aeruginosa. However, Lake Kasumigaura water did not need the EDTA for the growth of M. flos- aquae and M. aeruginosa in summer season. Lake Kasumigaura contained more chelate compunds which were growthstimulating than Ushiku Marsh. This may be one of the important reasons why the water bloom did not occur in Ushiku Marsh.
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  • Yasuhiko TEZUKA
    1989 Volume 50 Issue 2 Pages 149-155
    Published: April 28, 1989
    Released on J-STAGE: October 19, 2009
    JOURNAL FREE ACCESS
    Microcystis and Anabaena were collected from their natural environments and decomposed under aerobic conditions in the laboratory. They had low C : N : P ratios (74 : 13 : 1 for Microcystis and 58 : 8 : 1 for Anabaena, by weight) and released both dissolved inorganic nitrogen (DIN) and phosphorus (DIP) by decomposition. Thus, it was demonstrated that the phytoplankton with low C : N : P ratio release both DIN and DIP by decomposition, whereas those with high C : N : P ratio (e.g., 200 : 20 : 1 in summer), like the phytoplankton in the euphotic zone of Lake Biwa during the stagnation period, release only DIN (TEZUKA, 1985b, 1986).
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  • Naoshi C. WATANABE
    1989 Volume 50 Issue 2 Pages 157-161
    Published: April 28, 1989
    Released on J-STAGE: October 19, 2009
    JOURNAL FREE ACCESS
    Seasonal and diurnal changes in emergence of P. kamonis were studied using a light trap and emergence traps in a stream of central Japan in 1978-1980. The main emergence period was from mid-July to the end of September. Most of the winged adults collected were subimagos. Subimagos gradually decreased in size during the emergence periods in 1979 and 1980, but this tendency was not so clear in 1978. The emergence continued from sunset to sunrise each day in the middle of the emergence period, but it ceased far earlier before sunrise on the early and later days of the period. The daily emergence time of females was somewhat earlier than that of males, and the proportion of males to females gradually increased toward sunrise.
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  • 1989 Volume 50 Issue 2 Pages 163-171
    Published: April 28, 1989
    Released on J-STAGE: October 19, 2009
    JOURNAL FREE ACCESS
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  • [in Japanese], [in Japanese]
    1989 Volume 50 Issue 2 Pages 173-175
    Published: April 28, 1989
    Released on J-STAGE: October 19, 2009
    JOURNAL FREE ACCESS
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