巻号一覧
47 巻 (1986)
- 4 号 p. 307-
- 3 号 p. 207-
- 2 号 p. 101-
- 1 号 p. 1-
47 巻, 4 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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河合 幸一郎, 高橋 正雄1986 年 47 巻 4 号 p. 307-314
発行日: 1986/10/30
公開日: 2009/11/13
ジャーナル フリーThe distribution of chironomid larvae in the Ohta River, Hiroshima Prefecture, was studied at 12 sampling stations covering almost its entire length. Bottom samples were collected at each station, cultured in the laboratory, and the male adults emerging from the samples were identified.
As a result, a total of 96 species were recorded, 32 of which were new findings from Japan. Some species, e. g., Brillia japonica and Polypedilum unifascium were distributed only in the mountainous streams while another some others, e. g., Cricotopus bimaculatus and Microtendipes truncatus were distributed over almost the entire river length.
The composition of the communities of chironomid larvae at rapids remarkably differed from those at pools. However, the difference tended to be unclear in the downstream area. There existed certain habitat-partitionings among closely related species. For example, Polypedilum convictum larvae were distributed only at the rapids, while Polypedilum parviacumen larvae distributed only at the pools.
These results suggest that the distribution of chironomid larvae depends not only on the chemical quality of water, such as the degree of eutrophication, but on the physical environment of the river such as the velocity and river-bed type.抄録全体を表示PDF形式でダウンロード (782K) -
菅井 隆吉, 牟田口 勝平, 松本 宗人1986 年 47 巻 4 号 p. 315-324
発行日: 1986/10/30
公開日: 2009/11/13
ジャーナル フリーVertical distribution of DO, Cl-, NH4+, and PO43- in the water layer adjacent to the bottom in lake Shinji was investigated, especially during summer-fall periods, in 1981-1983. A water column sampler for micro-stratification was made to obtain near-bottom water at 10-20 cm depth intervals from the bottom to 1.3 m. Salinity stratification in the deeper part of the lake allows the development of an anoxic condition and the accumulation of NH4+ and PO43-. This suggests that anaerobic conditions enhance the release of phosphate from sediment. DO concentration in the near-bottom water (St. 4) in July 1982 was 0.5 mg·l-1 from the bottom to 50-70 cm and the highest PO43- concentration, 0.885 mg·l-1(0-10 cm) and NH4+ concentration, 1.267mg·l-1 were found in the anoxic layer. T-P increase in the upper zone from July through August in 1982 would correspond to the internal supply. The chlorinity distribution along the long axis in Lake Shinji in 1983 proved that salt water from R. Ohashi flowed into Lake Shinji and left the high saline layer in the deeper part of lake. Gross release rates were estimated from mass changes of PO43- and NH4+ in the stratified zone. The estimated gross release rate of PO43- and NH4+ was 11.6 mg·m-2·day-1, 29.9 mg·m-2·day-1, respectively. When the chlorinity concentration in the upper zone was over 1, 500 mg·l-1, the depth of high saline layer exceeded 40 cm.抄録全体を表示PDF形式でダウンロード (1005K) -
-淡塩水境界面モデルによる数値解析-柿沼 忠男, 岸 洋介, 井内 国光1986 年 47 巻 4 号 p. 325-336
発行日: 1986/10/30
公開日: 2009/11/13
ジャーナル フリーThe motion of the coastal confined groundwater in the presence of various pumping patterns was investigated by numerical analyses, based on one and two-dimensional, unsteady fresh-salt water interface models. Approximate equations describing the temporal variation of groundwater level and fresh-salt water interface were utilized in the numerical computations together with appropriate boundary conditions. The results were as follows : 1) Groundwater level varied very quickly in response to sudden change in pumping amount, whereas the interface varied very slowly ; 2) movement of the interface was faster when the groundwater was pumped in the fresh water region as compared to that in the saline water region ; 3) movement of the interface was faster when retreating toward the sea as compared to when it was advancing inland ; 4) artificial recharge through wells in the fresh water region and the saline water region was effective to retreat the toe of the interface and to decrease the thickness of salt water layer, respectively ; 5) in the two-dimensional model, results similar to those in the one-dimensional model were obtained for movement of the interface in the presence of various pumping patterns ; 6) characteristic features of the two-dimensional model in the presence of areal distribution of pumping points were also found, e. g., the speeds of interface toe movement close to and far from pumping points were considerably different.抄録全体を表示PDF形式でダウンロード (1405K) -
村上 哲生1986 年 47 巻 4 号 p. 337-344
発行日: 1986/10/30
公開日: 2009/11/13
ジャーナル フリーA recent sediment core was collected from a heavily polluted irrigation pond, “Niinomi-ike”. Vertical distribution of species composition of diatom assemblages was examined to evaluate their succession in relation to phosphorus concentration in the sediments. It was found that the species composition of planktonic and periphytic assemblages in the lower part of the core was replaced by different species in accordance with the increase in total-phosphorus concentration in the sediment. Thus in the planktonic assemblages, Cyclotella comta, C. stelligera, Melosira ambigua and M. distans were replaced by C. meneghiniana, C. pseudostelligera and M. granulate. In the periphytic assemblages, Achnanthes minutissima was also replaced by Navicula frugalis and Nitzschia palea. Additionally, there is the decrease in frustules of acidophilous taxa. The succession process observed in the planktonic assemblages was characterised by the replacement of the related species in the same genus. Based on the succession of diatom assemblages, it was concluded that this pond has changed from a eutrophic one to a hypereutrophic one, and the saprobity in the periphytic environment has changed from a oligo or β-mesosaprobic status to an α-mesosaprobic one.抄録全体を表示PDF形式でダウンロード (1513K) -
石田 典子, 三田村 緒佐武1986 年 47 巻 4 号 p. 345-350
発行日: 1986/10/30
公開日: 2009/11/13
ジャーナル フリーThe utilization of nitrogenous compounds by freshwater phytoplankton was studied, after enrichments of nitrogen and phosphorus, on the surface waters collected from three areas with different trophic grade in Lake Biwa.
During the incubation period, in all experiments, the concentration of ammonia decreased at first, urea decreased subsequently, and finally nitrate decreased. The assimilation of nitrate appeared when the ammonia concentration was almost undetectable in water. The assimilation of urea was also suppressed due to the high concentration of ammonia. This suggests the preference of phytoplankton for ammonia as a nitrogen source.
The increasing rate of particulate nitrogen was almost equal to the decreasing rate of total nitrogenous nutrients in the water during the phytoplankton growing period.抄録全体を表示PDF形式でダウンロード (671K) -
工藤 勲, 松永 勝彦1986 年 47 巻 4 号 p. 351-354
発行日: 1986/10/30
公開日: 2009/11/13
ジャーナル フリーThe relationship between dissolved cadmium and dissolved total inorganic nitrogen was examined. The resultant equation is as follows : Cd (nM)=0.025 N(μM)-0.13. The slope (0.025) is in good agreement with that reported in seawater (0.024). This indicates that the removal of cadmium and the dissolved nitrogen from surface waters to deeper waters by biological assimilation and their regeneration in deeper waters would occur with the same ratio as in seawater.抄録全体を表示PDF形式でダウンロード (355K) -
II. Sedimentation Rate and its Sedimentary Processes Introduced from the 1977 Usu Volcanic Ash Layer of Sediment Core.知北 和久1986 年 47 巻 4 号 p. 355-368
発行日: 1986/10/30
公開日: 2009/11/13
ジャーナル フリーIn Lake Okotanpe, Hokkaido, sediment cores were obtained at 15 points from the lake bottom. A fresh volcanic ash layer was seen at the bottom part of twelve cores among them. Its thickness of about 1 mm suggests that the volcanic ash layer originates in the ash-fall from the 1977 eruption of Usu Volcano, Hokkaido. Hence, in order to clarify quantitatively the origins of core sediments, the Usu volcanic ash (1977-Us-II), and a surf icial soil and a riverbed material in the lake drainage area were mineralogically compared with the core sediments according to the following items.
(i) mineral composition of sand (250>d>37μ) and clay (d<2μ)
(ii) geometry of each sand mineral
(iii) chemical composition of fresh volcanic glass
The clay mineral composition and the chemical composition of volcanic glass were obtained with X-ray diffractometer and electron probe microanalyser, respectively. From the results involving vertical distributions of grain size and ignition loss of sediment core, the following conclusions can be drawn:
(1) The volcanic ash layer of sediment core was formed from the 1977 volcanic ash-fall of Usu Volcano.
(2) A “volcanic ash-mixed” layer on the pure ash one consists of the Usu volcanic ash and original lake sediments. The sediments of the two origins were both supplied from the surrounding drainage area through torrential rains.
(3) The lake-infilling is in considerable progress because of relatively heavy rains after the 1977 ash fall. The annual sediment accumulation of 1981 and 1982 is 15.2 and 10.1 cm yr-1, respectively, averaged for three representative cores.
(4) A spatial distribution of average sedimentation rate (cm yr-1 ) for 1977-1983 was obtained from the twelve cores. This distribution pattern in the lake can be consistently explained by sedimentary processes of river-induced turbidity currents and sediment dispersion during the river sediment discharge, as presented by CHIKITA (1986).抄録全体を表示PDF形式でダウンロード (1578K) -
松山 通郎1986 年 47 巻 4 号 p. 369-375
発行日: 1986/10/30
公開日: 2010/11/22
ジャーナル フリーN2 fixation rate of a large Phototrophic bacterium, which prevails at the bacterial plate of Lake Kaiike (Kamikoshiki Island), and has been isolated using the medium of PFENNIG (1965), was measured by the C2H2 reduction method. The N2 fixation rate was closely associated with the bacterial growth and required light and H2S. In situ measurement revealed a very low N2 fixation rate at the bacterial plate on 22 May 1986. But when the bacterial plate sample was exposed at a high light intensity, and particularly when it was supplied with H2S at the same light intensity, it showed a significantly elevated rate of N2 fixation. At the bacterial plate the bacterium was suggested to grow at an extremely low rate due to limitation by both factors.抄録全体を表示PDF形式でダウンロード (852K)
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