巻号一覧
38 巻 (1977)
- 4 号 p. 109-
- 3 号 p. 75-
- 2 号 p. 41-
- 1 号 p. 1-
38 巻, 2 号
選択された号の論文の4件中1～4を表示しています
- |<
- <
- 1
- >
- >|
-
田中 信彦, 植田 芳樹, 鬼沢 雅幸, 門田 元1977 年 38 巻 2 号 p. 41-47
発行日: 1977/04/30
公開日: 2009/10/21
ジャーナル フリーPhysiological and taxonomical characteristics of the bacteria in water bodies containing organic matter in different concentrations were compared. It was found that (1) the population density of heterotrophic bacteria increased up to a certain limit in parallel with the concentration of organic matter in water, (2) the higher the concentration of organic matter in the water body, the higher the Cm value (the concentration of peptone in the counting medium which gives the maximum colony number); (3) the dominant group of bacteria was Flavobacterium in all the water bodies examined, and (4) there was a certain correlation between physiological characteristics of the dominant group of bacteria and the concentration of organic matter in the water body.抄録全体を表示PDF形式でダウンロード (799K) -
知北 和久1977 年 38 巻 2 号 p. 48-61
発行日: 1977/04/30
公開日: 2009/10/21
ジャーナル フリーObservations were made on sedimentation in Katsurazawa Reservoir in Oct., 1974, and in May and Aug., 1975. The results are represented as follows :
(1) Sediment deposits in the reservoir consist of more than 90 per cent of silt and clay in weight.
(2) The sediments, as a whole, have a tendency to gradually decrease in grain size from upstream to downstream, but deposited materials obtained at the two of all the dredging points, on the contrary, are more coarse-textured than ones on the upstream bed.
(3) Density currents passing through the reservoir were observed in May and Aug., 1975, which correspond to the periods of spring thaw and torrential floods, respectively.
In order to explain the above result (2), the writer modeled Turbidity Currents which may be a major contribution to reservoir sedimentation, and applied it to Katsurazawa Reservoir. The results analyzed with the Turbidity Currents are shown as grain-size-distributions of the sediments in the reservoir. The conclusions reached can be summarized as follows :
(4) Sediments from one dredging point are on the whole coarse-grained compared with ones on the upstream bed. The reason is principally because the flow section of Turbidity Currents increases with the beds widening from upstream towards the dredging point.
(5) A great volume of sediment is deposited at the upstream reach of the reservoir through the Turbidity Currents, which can occur for the period of spring thaw; but afterwards the sediments are transported and settle far downstream with river induced resedimentation which results from the subsequent decline of water level and the torrential runoffs at the period of lower water level.抄録全体を表示PDF形式でダウンロード (1923K) -
I. Generation of Ammonium Nitrogen in the Bottom Sediments in Lake Biwa神山 孝吉, 奥田 節夫, 河合 章1977 年 38 巻 2 号 p. 62-69
発行日: 1977/04/30
公開日: 2009/10/21
ジャーナル フリーIn the bottom sediments of aquatic regions, the decomposition of organic nitrogenous matter and the generation of ammonium nitrogen result in the vertical distributions of their concentrations. On the assumption that the sedimentation rate has been almost constant through the last several ten years, the elapsed time of the sediments in near surface layer from their deposition on the lake floor as well as the decomposition rate of the organic matter can be estimated. The rate constant in the decomposition process in the sediments was estimated to be 10-4/day in the center of Lake Biwa, and the similar value was obtained in each 0.5 cm layer through a depth of several centimeters. Ammonium salts produced by the decomposition of organic nitrogenous matter enter into the interstitial water, then diffuse through the porous media of the sediments into the overlying water. The diffusion coefficient of ammonium nitrogen in the interstitial water was estimated to be 1 × 10-6cm2/sec and the rate of its release into the overlying water was found to be 4.2μg atoms/cm2/year in the center of Lake Biwa.抄録全体を表示PDF形式でダウンロード (1004K) -
福永 栄, 手塚 泰彦1977 年 38 巻 2 号 p. 70-72
発行日: 1977/04/30
公開日: 2009/10/21
ジャーナル フリーPDF形式でダウンロード (432K)
- |<
- <
- 1
- >
- >|