Japanese Journal of Limnology (Rikusuigaku Zasshi)
Online ISSN : 1882-4897
Print ISSN : 0021-5104
ISSN-L : 0021-5104
Volume 59, Issue 4
Displaying 1-7 of 7 articles from this issue
  • Koichiro KAWAI, Eiso INOUE, Hiromichi IMABAYASHI
    1998 Volume 59 Issue 4 Pages 367-381
    Published: December 01, 1998
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    Seven new chironomid species belonging to three subgenera of the genus Polypedilum were described on the basis of adult male morphology. Among these, five species, P. akisplendens, P. albiventris, P. crassistyla, P. fuscovittatum and P. paranigrum were members of the subgenus Polypedilum. P. pseudomasudai and P. bingoparadoxum were members of the subgenera Tripodula and Uresipedilum.
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  • Takao NOZAKI, Tomiko ITO
    1998 Volume 59 Issue 4 Pages 383-389
    Published: December 01, 1998
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    The larva and the pupa of Lenarchus fuscostramineus SCHMID are described here for the first time. The general morphology of the larva mostly agrees with the character of the genus provided based on North American species by WIGGINS (1977). The larvae live in small shallow springs and seeping areas and feed on highly decomposed plant material. We established that the larvae described as Lenarchus sp. LA from Honshu by TANIDA (1985) were a misidentification of Nothopsyche sp. NA.
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  • Naoshige GOTO, Osamu MITAMURA, Hisayoshi TERAI, Noriko ISHIDA
    1998 Volume 59 Issue 4 Pages 391-408
    Published: December 01, 1998
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    The photosynthetic rates of phytoplankton and microphytobenthos were measured with a combustion method of 14C in a tidal flat of the Wakaura estuary, Central Japan. In addition, chlorophyll a concentra-tion and a set of environmental factors (water temperature, salinity, nutrient concentrations) in the water and the sediment were measured in order to investigate factors affecting their photosynthetic rates. The chlorophyll a concentration of microphytobenthos (average 20 mg chl a m-2) was several times as high as that of phytoplankton (average 3.0 mg chl a m-2). The photosynthetic rate of microphytobenthos, which showed a significant positive correlation only with chlorophyll a concentration in the sediment, ranged from 1.1 to 19 mg C m-2 hr-1 (average 8.7 mg C m-2 hr-1), which was equal to or greater than the photosynthetic rate of phytoplankton at that same time. The photosynthetic activity of microphytobenthos (average 1.5 mg C mg chl a-1 hr-1) was lower than that of phytoplankton (average 2.3 mg C mg chl a-1 hr-1). During the observation period, the chlorophyll a concentration, photosynthetic rate and photosynthetic activity of phytoplankton dropped with decreasing water temperature, whereas those of microphytobenthos were almost unchanged. From these results, it was considered that microphytobenthos, particularly in winter, greatly contributed to primary production at the Wakaura tidal flat due to the large amount of biomass, though the growth rate of microphytobenthos was small.
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  • Yoshihiro YAMADA, Takaaki UEDA, Tadatoshi KOITABASHI, Eitaro WADA
    1998 Volume 59 Issue 4 Pages 409-427
    Published: December 01, 1998
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    Nitrogen and carbon isotope ratios of organisms were measured in order to elucidate and illustrate the food web structure in Lake Biwa. Samplings of particulate organic matter (POM), zooplankton, and fish were performed at the north basin from 1993 to 1994. The food web structure of Lake Biwa (north basin) was divided into five parts judging from carbon and nitrogen isotope ratios. A clear trophic effect of ca. 3‰ was found as δ15N for the pelagic food chain in the following order : small POM (2.7 to 40 μm) →Eodiaptomus japonicus → Plecoglossus altivelis altivelis, Hypomesus transpacificus → Salmo masou macrostomus, and Silurus biwaensis (euphotic zone food chain - 1). This was considered the major food chain and was manifested in the surface layer. The other food chains in the euphotic zone, hypolimnion, lake bottom and coastal zone were described as follows ; POM with low δ15N → Daphnia galeata (euphotic zone food chain -2), sinking large POM (40 to 150 μm) and organic matter in mud →Jesogammarus annandalei (hypolimion food chain), organic matter in mud → oligocheata (lake bottom food chain), and attached algae →Sarcocheilichthys variegatus and Rhinogobius sp. (coastal zone food chain). The above mentioned food web structure seems to reflect physical environment at factors such as vertical and horizontal water movements, the sinking of particulate organic matter, and the geographical setting of Lake Biwa.
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  • Yaeko FURUYA
    1998 Volume 59 Issue 4 Pages 429-441
    Published: December 01, 1998
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    I investigated the downstream distribution and annual changes in densities of net-spinning Trichoptera in the Yoshino River, Shikoku, Japan from 1973 through 1996. I found that 13 species of caddis larvae, and Stenopsyche marmorata, Hydropsyche orientalis, H. setennsis and Cheumatopsyche spp. were abundant taxa in the main stream. Macrostemum radiatum had been restricted to the lower reaches of the river, but from 1985 it became abundant and expanded its distribution to the middle reaches just down-stream of a reservoir, Sameura Dam, constructed in 1973. I compared the gut contents of the fifth instar larvae of M. radiatum and S. marmorata, and found that the former species ingested more plankton algae, probably from the reservoir, than the latter. The construction of the reservoir and the rich supply of plankton algae from it probably enhanced the colonization and settlement of Macrostemum larvae.
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  • Ryoji NAKAZATO, Kimio HIRABAYASHI, Tokio OKINO
    1998 Volume 59 Issue 4 Pages 443-455
    Published: December 01, 1998
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    The abundance and seasonal trend of chironomid emergence and the horizontal distribution of larvae were studied in Lake Suwa from April 1990 to December 1991. A total of 18 species of chironomid adults were captured with a light trap set up on the eastern shore of the lake, and 11 species with bottom-type emergence traps at 2.5 m water depth. Abundant species in the light trap were Chironomus plumosus, Einfeldia dissidens, Propsilocerus akamusi, Procladius choreus, and Glyptotendipes tokunagai. In particular, the former three species constituted 86% of all adults captured with the light trap. E. dissidens was first reported from this lake in the present study. C. plumosus had three emergence periods in 1990, but only two in 1991. The emergence of P. akamusi took place during October to November in both years. The emergence periods of E. dissidens, P. choreus and G. tokunagai occurred during May to October in both years without a marked emergence peak.
    In a grid survey of 68 points located at intervals of ca. 250-500 m, C. plumosus larvae were mainly distributed in the profundal zone. P. akamusi larvae had the widest distribution with high densities at all stations. E. dissidens was more abundant in the littoral zone, showing significant negative correlations with water depth and loss on ignition.
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  • Sang-Ho JUN, Jeong OK BAE
    1998 Volume 59 Issue 4 Pages 457-464
    Published: December 01, 1998
    Released on J-STAGE: December 11, 2009
    JOURNAL FREE ACCESS
    The fractional composition of dissolved copper in the Nakdong River, Korea was investigated. The dissolved copper was classified into "labile", "bound" and "inert" fractions. The total dissolved copper concentration increased gradually toward the lower reach of the river. In general, the inert fraction was most abundant, followed by the bound fraction. The labile fraction was a minor part of the total dissolved copper. The high ratio of labile fraction in the upper part of the Nakdong River water may be caused by high levels of ionic substances and low levels of dissolved organic carbon. A close relation was observed between the labile fraction and the dissolved organic carbon concentration in the upper reach of the river.
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