巻号一覧
48 巻, 1 号
選択された号の論文の8件中1～8を表示しています
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安田 香, 沖野 外輝夫1987 年 48 巻 1 号 p. 1-8
発行日: 1987/01/30
公開日: 2009/11/13
ジャーナル フリーTen species of aquatic Oligochaeta were identified in Lake Suwa. Limnodrilus hoffmeisteri and Limnodrilus claparedeianus were obtained from every station and were most abundant among all species. Their density tended to be high as the depth was greater. The second abundant species, Rhyacodrilus sp., was collected in the region shallower than 4 m depth. The study on the seasonal changes in the density of Limnodrilus spp. (L. hoffmeisteri and L. claparedeianus) and Rhyacodrilus sp. exhibited clearly a decrease in summer and an increase in winter and spring.
Lake Suwa was divided into three regions in terms of the depth distribution of aquatic Oligochaeta, namely, the region deeper than 5 m depth, the transitional region from 3 to 4 m depth, and the region shallower than 2 m depth. The seasonal changes in the density and depth distribution of aquatic Oligochaeta were discussed from the environmental condition of the lake bottom and the reproductive state.抄録全体を表示PDF形式でダウンロード (890K) -
須川 明1987 年 48 巻 1 号 p. 9-17
発行日: 1987/01/30
公開日: 2009/11/13
ジャーナル フリーLake Kanna is a reservoir. The dam intake moves up and down with the lake surface, and the surface water is discharged through the intake. In this case vertical distribution of water temperature is similar to that of a natural lake.
When a large amount of water is supplied rapidly into Lake Kanna, the lake water is discharged not only through the intake, but through the dam gate. The gate is usually situated below the lake surface. In this case eddy diffusion in the lake water is affected by the discharge, and vertical distribution of water temperature is different from that of a natural lake.
Degree of eddy diffusion is expressed by eddy diffusivity K. If Qi, ti, and T are defined in Section 6, the relation between the values of K in the hypolimnion and _??_Qiti/T is roughly linear as shown in Fig. 9. In Fig. 9 the values of K and _??_Qiti/T are plotted with logarithmic scale.抄録全体を表示PDF形式でダウンロード (1000K) -
五百井 正樹, 串部 宏之, 北田 忠義, 建部 渉, 前田 礼造, 人見 宗男1987 年 48 巻 1 号 p. 19-24
発行日: 1987/01/30
公開日: 2009/11/13
ジャーナル フリーUsing dissolved conservative constituents in river waters, the mixing of flowing waters was studied between 13 km downstream and the junction where the River Kizu from left side, the River Uji from the middle, and the River Katsura from the right side, converge to form the River Yodo.
The concentrations of ammonium, phosphate, sodium and potassium in river waters on the right side of the River Yodo were always higher than those found on the left side to about 13 km downstream. The amounts of silica, sodium and potassium calculated from their concentrations and flow volume in the River Yodo were in good agreement with the sum of their amounts from the three tributaries. Using each flow volume estimated from the concentrations of silica and sodium (or potassium) in tributaries, the contribution ratio of ammonium and phosphate loading to the River Yodo was calculated and found to be in good agreement with the measured loadings.
The present results suggested that the removal of ammonium and phosphate during flow downstream might not occur, and silica can be used as a conservative tracer of flowing water mixing as well as sodium and potassium.抄録全体を表示PDF形式でダウンロード (857K) -
岡田 浩美1987 年 48 巻 1 号 p. 25-32
発行日: 1987/01/30
公開日: 2009/11/13
ジャーナル フリーInvestigation on water balance, water temperature, dissolved oxygen and other chemical analyses were made for Lake Saino-ko, Nikko, from May 1980 to April 1983.
The results are as follows :
(1) As estimated by electric prospecting of geology around the lake, the lake was dammed by coarse gravel from the river. Because of this permeable material in the downstream section, the water level of the lake shows a wide seasonal variation. The level falls by about 11m in winter compared with early summer, then the water surface area and the water volume decrease to 1/2 and 1/6, respectively, in winter.
(2) The rate of leakage from the lake is estimated from water balance in winter when noticeable inflows are not observed. A high rate of leakage is obtained at a high water level and vice versa.
(3) In summer, water balance calculated including the effect of water level has a close relationship to the effective precipitation. The equilibrium water level in summer is estimated to be 13.3m.
(4) Water circulation is effective in shallow layers as deduced from dissolved oxygen and water temperature. This may be influenced by the position of leakage. A phenomenal circulation was observed during and after floods.抄録全体を表示PDF形式でダウンロード (1333K) -
-那賀川河口および喜木川河口における分散長-柿沼 忠男, 岸 洋介, 井内 国光, 都築 克明1987 年 48 巻 1 号 p. 33-39
発行日: 1987/01/30
公開日: 2009/11/13
ジャーナル フリーA three-dimensional steady state hydrodynamic dispersion model with the velocity-dependent dispersion coefficient was used to simulate seawater encroachment in the confined aquifers in the estuaries of the Naka River, Tokushima Prefecture, and the Kiki River, Ehime Prefecture. The main results are as follows: 1) The longitudinal and lateral dispersivities are 1, 000 to 1, 250 m and 100 to 125 m in the estuary of the Naka River, respectively. In the estuary of the Kiki River, the corresponding values are 200 m and 200 to 20 m, respectively. 2) Examining the local distribution of the dispersion coefficient values computed from the dispersivity and velocity fields of groundwater, the same value as estimated in the analysis with the constant dispersion coefficient (KAKINUMA et al., 1985) is located in the middle layer of the aquifer. 3) In the estuary of the Naka River, the piezometric surface predicted using the dispersion model with the velocity-dependent dispersion coefficient in almost the same as the one predicted with the dispersion model with the constant dispersion coefficient. They are 5 to 10% lower than the one predicted with the interface model (KAKINUMA et al., 1984), but about 1.3 times the observed one.抄録全体を表示PDF形式でダウンロード (1182K) -
青谷 晃吉, 横山 宣雄1987 年 48 巻 1 号 p. 41-58
発行日: 1987/01/30
公開日: 2009/11/13
ジャーナル フリーThe life cycles of the two net-spinning caddisflies, Stenopsyche marmorata and S. sauteri, were compared in the Mamigasaki River in Yamagata, Tohoku District. S. marmorata had a slow-growing overwintering generation pupating from May to June with a long flight period, and a fast-growing summer generation with pupating in August with a short flight period. The mean individual weight of the overwintering generation was heavier than that of the summer generation in fifth instar larvae and adults, probably because pupation and emergence of the overwintering generation were suppressed by low spring water temperature, although larval growth continued. S. sauteri was a clearly univoltine life cycle. The development of S. sauteri was overtaken by that of S. marmorata in May when S. sauteri did not begin to pupate, although water temperature was high enough. S. sauteri began to pupate in July when the overwintering generation of S. marmorata finished pupation. We speculated that the staggered life cycle might facilitate the coexistence of the two species from July to September.抄録全体を表示PDF形式でダウンロード (2134K) -
Kazuko MORIKAWA1987 年 48 巻 1 号 p. 55-65
発行日: 1987/01/30
公開日: 2009/11/13
ジャーナル フリーThe bacterial generic composition in the Periphyton at an oligotrophic region in the Tamagawa River was studied during different seasons and in different colored Periphyton. Shannon's diversity index of bacterial generic composition was highly correlated to the amount of chlorophyll in the periphyton. In the bacterial generic composition of brownish periphyton mainly composed of Bacillariophyta, yellowish brown Cytophaga sp. (represented as Cytophaga (yb)) was the predominant bacterial group in summer, and red Flavobacterium sp. (Flavobacterium (r)) in winter and spring. Greenish periphyton contained Ulothrix zonata in addition to Bacillariophyta, small yellow Flavobacterium sp. (Flavobacterium (sy)) was predominant. Cytophaga (yb) was accompanied by the exponential growth phase of Cymbella sp., and Flavobacterium (r) predominated only under low nutritional conditions when other bacterial groups could not grow. Flavobacterium (sy) was observed with Ulothrix zonata and Navicula spp., but the appearance of this group was paralleled by an increase in the total bacterial number. As a result, it predominated when a larger number of bacteria were present. Bacterial generic groups at the river region studied were divided into three categories: (i) those groups existing primarily in running water, (ii) those mainly inhabiting the periphyton, and (iii) those consistently isolated from both periphyton and running water.抄録全体を表示PDF形式でダウンロード (1665K) -
森川 和子1987 年 48 巻 1 号 p. 67-70
発行日: 1987/01/30
公開日: 2009/11/13
ジャーナル フリーThree predominant bacterial strains obtained from periphyton at Unazawa in the Tamagawa River were examined further to clarify their taxonomical status, because their tentative identification at generic level was not valid. Reddish Flavobacterium sp. and small yellowish Flavobacterium sp. had 55.1 and 57.6 mol % of G+C content, respectively, which were different from the value described to date. Thus, they should be classified as members of a new genus.抄録全体を表示PDF形式でダウンロード (568K)
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