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Volume 42, Issue 1
Displaying 1-7 of 7 articles from this issue
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Seiichi SUEHIRO, Yasuhiko TEZUKA1981 Volume 42 Issue 1 Pages 1-7
Published: January 30, 1981
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThe change in ciliate populations was investigated in bottom sediment at a place 2 km upstream from the Marukobashi Bridge of the Tamagawa River about once a month from April 1976 to May 1978. The numbers of viable heterotrophic bacteria, diatoms and flagellates as foods of ciliates were also counted. A similar pattern of the seasonal change in ciliate populations was observed for two years. In winter Paramecium caudatum, P. trichium, Colpidium colpoda and Chilodonella cucullulus dominated. The number of each species was 103-104 cells per ml of sediment. Perispira ovum increased up to 103 cells per ml at the end of winter. From spring to early summer Spirostomum spp. dominated, and their number increased up to 103 per ml. From summer to autumn Loxodes spp. and P. caudatum were predominant. The number of each species was 102-103 per ml. Frontonia leucas also appeared in summer. Stentor, Metopus es, Litonotus and Acineria did not change seasonally. Interspecific relations, such as predation (of Perispira and Loxodes on Euglena and diatoms, respectively) and competition (between bacteria-feeding ciliates and metazoa such as oligochaetes and diptera larvae), may be some of the important factors controlling the seasonal change in ciliate populations.View full abstractDownload PDF (998K) -
Takeo HAMA, Nobuhiko HANDA1981 Volume 42 Issue 1 Pages 8-19
Published: January 30, 1981
Released on J-STAGE: February 12, 2010
JOURNAL FREE ACCESSGas chromatographic analysis of volatile organic acids dissolved in lake water was conducted by using their benzyl esters, which were well separated and determined in the ng order of magnitude. Thus, only 50-250ml of the lake water was needed for the determination of the volatile organic acids. The identification of benzyl esters of these organic acids was conducted by combined gas chromatography-mass spectrometry. Acetic, propionic, n-butyric and lactic acids were found in the water samples from Lake Kizaki. However, formic acid was identified only by the retention time from gas chromatography. Formic, acetic and propionic acids measured were in the range of 0-30μgC/l, 30-120μgC/l and 0-90μgC/l, respectively, in the various depths of Lake Kizaki.
Gel-filtration using Sephadex G-25 was applied to determine the molecular weight distribution of dissolved organic matter of the water sample from the surface of Lake Kizaki. Volatile organic acids consisting of formic, acetic and propionic acids accounted for 59% of the dissolved organic carbon in the fraction of organic matter with a molecular weight of less than 200. Considering the short residence time as reported by several authors, the volatile organic acids were suggested to be the most ecologically significant materials in the matter cycle in the lake waters.View full abstractDownload PDF (1661K) -
Yoko YAMAMOTO1981 Volume 42 Issue 1 Pages 20-27
Published: January 30, 1981
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSSeasonal and vertical distribution patterns of microbial agents which cause lysis of blue-green algae were investigated in Lake Kasumigaura, about once a month from August 1975 to October 1977. The increases of microbial agents in the lake occur during the summer and fall when phytoplankton are abundant. Their abundance is closely correlated with the abundance of algae in lake waters. The agents most commonly found in Lake Kasumigaura were amoeba. One of them, Nuclearia sp. was isolated from the surface water of the lake in summer, and their responses to a number of environmental conditions were examined.View full abstractDownload PDF (2831K) -
Haruko OTSUKA1981 Volume 42 Issue 1 Pages 28-39
Published: January 30, 1981
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSForms of heavy metals within settling matter collected about once a month for 18 months, at each depth of water in a productive man-made lake, were examined by selective extraction using hydroxylamine-acetic acid (HA), hydrogen peroxide (HO), and hydrofluoric acid-nitric acid-perchloric acid (HF).
The largest portion of the metals was extracted with HA except for Fe, of which more than 80% was with HF. The amount extracted with HO was relatively small except for Cu. These amounts varied seasonally, showing distinctive patterns among fractions or metals.
These results and relationships among parameters suggest that the most important form is “adsorbed or coprecipitated on organic matter and hydrous Fe/Mn oxides.” Zn, Ni, and Cd are more associated with organic matter and Mn oxides, whereas Cu is more associated with Fe and Mn oxides. In case of Cu, firm bonding to organic matter is also significant.
The sedimenting processes of metals were suggested to be closely related to the cyclic behaviors of organic matter, Fe, and Mn within the lake.View full abstractDownload PDF (1662K) -
Masami SAKURAI1981 Volume 42 Issue 1 Pages 40-45
Published: January 30, 1981
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThere have been a few papers concerned with the effect of temporal drought on the life of aquatic insects. In November of 1976, I had an opportunity to investigate an example of insect distribution at dried out and water-flowing areas up a sand arrestation dam of a stream near Kyoto. No individuals of Epeorus sp. were collected alive in the dried-out area. A few individuals of Baetis sp., Ecdyonurus kibunensis, Nogiperla sp., Ephemerella sp. and Paraleptophlebia sp. PA were collected alive in the dried-out area but only in sand and gravel zones; these species were collected mainly on stone surfaces in the water-flowing area. Elmidae and Nemouridae were found alive too, mainly in sand gravel zones. Ephemera japonica, Perla sp., Alloperla sp., Dinarthrodes sp., Chironomidae, Hydropsyche tsudai and Antocha sp. were collected in as many dried-out areas as in water-flowing areas.View full abstractDownload PDF (664K) -
Hideo KURITA, Hiroshi MINEMURA1981 Volume 42 Issue 1 Pages 46-51
Published: January 30, 1981
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThis investigation was carried out by using a new type of bottom sampler with a circular quadrat (0.08 m2) for analyzing the number of replicate samples required to estimate the species number, density and biomass of zoobenthos along a shallow shore of Lake Haruna, Gunma Prefecture, in August 1978.
In the shallow part of stony zone where the samples presented a poor fauna and a large variation, a vast number of replicate samples are required to estimate the total number of taxa and individuals, and total biomass, whereas, in the deeper stony zone (about 2 meters offshore) and aquatic plant zone with an abundant fauna and a smaller variation of samples, about six replicate samples are required to estimate the number and the biomass at 30% level of permissible error and 95% level of confidence of the mean. The species showing a low density and an aggregated distribution requires a large number of samples.View full abstractDownload PDF (788K) -
Midairo MATSUYAMA1981 Volume 42 Issue 1 Pages 52-57
Published: January 30, 1981
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThe neighboring three lakes on the north shore of Kamikoshiki Island, which are all cut off from the sea by a common gravel bar, have a wide chlorinity range from about 1 to 18 ‰. Lake Kaiike, in the middle of these lakes, presents many interesting phenomena due to the stratified condition of the deeper seawater layer covered by less saline water. Comparison with the adjacent two lakes (Namakoike, Kazakiike) suggests that the stratified condition of Lake Kaiike appears only during a limited period of its transition from a freely connected state with the sea to a poorly communicated state with the sea.View full abstractDownload PDF (2955K)
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