巻号一覧
47 巻 (1986)
- 4 号 p. 307-
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47 巻, 2 号
選択された号の論文の10件中1～10を表示しています
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-A Preliminary Study-太井子 宏和, 山本 淳之, 金成 誠一1986 年 47 巻 2 号 p. 101-108
発行日: 1986/04/30
公開日: 2009/11/13
ジャーナル フリーAge-scaling is attempted using the vertical profile of bulk density of the uppermost clayey layer (240-250 m in thickness) in a new deep core sample from Lake Biwa. At first, the empirical porosity-depth relation is physically examined on the basis of a consolidation theory. The vertical profile of bulk density in the upper 180 m of the clayey layer is approximately described by the empirical bulk density-depth relation, which is derived from the porosity-depth relation. By applying the age by fission-track dating to the age-depth relation analytically derived from the bulk density-depth relation, an average sedimentation rate in the upper clayey layer is estimated to be 0.033 g m-2 yr-1 and then the age-depth curve is obtained for the upper clayey layer. The age-depth curve in the lower clayey layer from 180 to 240 m in depth is obtained under the assumption that the sedimentation rate is constant through the whole clayey layer. The result shows that the age of the base of the clayey layer at about 240 m in depth is estimated to be 0.63 Ma.抄録全体を表示PDF形式でダウンロード (1233K) -
M. S. AMMAR, S. H. ELWAN, A. A. RAZAK, E. H. GHANEM.1986 年 47 巻 2 号 p. 109-114
発行日: 1986/04/30
公開日: 2009/11/13
ジャーナル フリーSeasonal estimations of viable bacterial counts (VBC) were performed for Nile River water at two water purification stations during the year 1981-1982 using 5 different enumeration media at 30 or 55°C. In general, the counts varied with the depth, season, locality, enumeration medium and temperature of incubation. Identification of 146 bacterial strains isolated from the different enumeration plates revealed the presence of 14 genera covering 21 species. Suggestions were made to protect the Nile River water from the pollution caused by human waste and sewage.抄録全体を表示PDF形式でダウンロード (893K) -
II.セジメントトラップ試料, 浮遊懸濁物および堆積物中の炭水化物とアミノ酸落合 正宏, 山本 修一, 林 秀剛, 福島 和夫, 小椋 和子, 石渡 良志1986 年 47 巻 2 号 p. 115-120
発行日: 1986/04/30
公開日: 2009/11/13
ジャーナル フリーThe very early diagenesis of particulate organic matter, particularly that of carbohydrates and amino acids, was studied in the course of the transportation of particulate organic matter through the water column with sediment traps in Lake Haruna. There was a great difference in neutral sugar and amino acid composition ratio between suspended particles and sinking particles. However, there was a similarity in the composition ratio between sinking particles and surface sediment. The results on neutral sugar and amino acid composition ratio suggest that carbohydrates and amino acids in sinking particles were the residual fractions of particulate organic matter which had been degraded. Particulate carbohydrates and amino acids are considered to be rapidly subject to degradation process in the water column and sediment traps. The remaining refractory fractions may be slowly degraded in the sediment.抄録全体を表示PDF形式でダウンロード (845K) -
-植物プランクトンによる無機態窒素の取り込み-清家 泰, 近藤 邦男, 伊達 善夫, 石田 祐三郎1986 年 47 巻 2 号 p. 121-132
発行日: 1986/04/30
公開日: 2009/11/13
ジャーナル フリーThe uptake rates of ammonium and nitrate by the natural phytoplankton community in the shallow brackish lake Nakanoumi were measured thirteen times from August 1983 to July 1984 using the 15N tracer technique.
Ammonium was uptaked in preference to nitrate, and nitrate use began when ammonium was depleted to about 3 μg N·liter-1.
The result of the multiple regression analysis implied that the uptake rate of ammonium was modified primarily by water temperature, phytoplankton standing stock (POC concentration) and ambient concentration of ammonium.
Nitrogen appears to be the most important limiting element for the phytoplankton growth in the euphotic layer at the central part of Lake Nakanoumi from May to December, because the halocline acts as an effective barrier for the vertical transport of enriched nitrogen nutrient in the overlying water.
The seasonal pattern of nitrate concentration in the euphotic layer at the central part of Lake Nakanoumi is also discussed relative to nitrate uptake rate by the phytoplankton standing stocks.抄録全体を表示PDF形式でダウンロード (1827K) -
-夏期における底泥表層部での脱窒特性-清家 泰, 近藤 邦男, 伊達 善夫, 石田 祐三郎1986 年 47 巻 2 号 p. 133-141
発行日: 1986/04/30
公開日: 2009/11/13
ジャーナル フリーFactors controlling denitrification were investigated by the acetylene inhibition technique using epilimnetic sediment sample collected from the brackish lake Nakanoumi. Temperature and substrate concentrations (nitrite and nitrate) were important factors for controlling denitrification in sediments.
Denitrification rate estimated from temperature and substrate concentration was about 12.0mg N·m-2 d-1 (August 1981). The decrease of total inorganic nitrogen concentration in hypolimnion from July to August 1981 was principally caused by nitrification denitrification.
The capacity for the reductions of NO3- to N2 (N2O), NH4+, and organic nitrogen was also measured in 15NO3--amended epilimnetic sediment by the acetylene inhibition technique and the 15N-label tracer method. 15NH4+ and org.15N accounted for about 30% of the three products. The result suggested that the pathway of nitrate reduction to NH4+ and PON was important as well as denitrification in sediments of the brackish lake Nakanoumi.抄録全体を表示PDF形式でダウンロード (1525K) -
後藤 敏一, 根来 健一郎1986 年 47 巻 2 号 p. 143-153
発行日: 1986/04/30
公開日: 2009/11/13
ジャーナル フリーThe diatom community in the Totsu-kawa, Kumano-gawa River System was investigated as to the community characteristics and the relationship between the community and the topographical classification of streams which was proposed by KANI (1944, 1981). The diatom community was organized by 1527 forms at each station. The communities varied in species diversity (SHANNON-WIENI.R. DI (bit)) from 0.480 to 2.637. The communities of lower species diversity were predominated by the blue-green alga Homoeothrix janthina. It is assumed that the lower diversity is not due to the organic pollution but to the growth of H. janthina. According to the cluster analysis based on the similarity indices among diatom communities, three types of community were found : Gomphonema clevei var. javanica predominates in station type Aa; Nitzschia frustulum predominates in stations types Aa-Bb and Bb; and Achnanthes convergens predominates in station types Aa, Bb and Bc. The relationship between the diatom community and the topographical classification of streams was not clear in this study. It is considered that where A. convergens or N. frustulum predominates, the communites are the result of a succession oriented by the newly produced microenvironment by the growing of H. janthina. The values 51.8 to 99.5 of diatom assemblage index of water pollution (DAIpo; WATANABE and ASAI. 1985) were rather lower in N. frustulum predominant communities and higher in A. convergens predominant communities than the water quality.抄録全体を表示PDF形式でダウンロード (2351K) -
中西 正己, 成田 哲也, 三田村 緒佐武, 鈴木 紀雄, 岡本 州弘1986 年 47 巻 2 号 p. 155-164
発行日: 1986/04/30
公開日: 2009/11/13
ジャーナル フリーThe horizontal distribution of chlorophyll a concentration was surveyed in the south basin of Lake Biwa during April 1978 to March 1979. Three types of distribution patterns were observed; (1) nearly uniform distribution, and (2) uneven distribution with higher chlorophyll a concentration along the east side and (3) higher concentrations along both the east and west sides. Pattern (2) with the east (high) -west (low) gradient was observed frequently and seemed to be typical in the south basin. Change in the patterns was mainly due to a great variation of chlorophyll a on the east side during the investigation period. As a whole, the horizontal distribution patterns depended mainly on nannoplankton contribution to total phytoplankton except in August -October, when netplankton were relatively abundant.
Seasonal changes in chlorophyll a and dissolved inorganic nitrogen (DIN) concentrations were compared among stations along the west-offshore-east sides or among offshore stations from the north to the south. Chlorophyll aconcentration tended to change seasonally with three peaks, in which dominant algal species differed among stations. Chlorophyll a and DIN concentrations were extraordinarily higher and fluctuated much more at the east stations than at the west and offshore stations.抄録全体を表示PDF形式でダウンロード (1515K) -
本山 秀明, 小林 大二, 小島 賢治1986 年 47 巻 2 号 p. 165-176
発行日: 1986/04/30
公開日: 2009/11/13
ジャーナル フリーThe specific runoff in a snowy region is, in general, larger than that in a snow-free region. In a region with deep snow, the bottom layer of the snowcover melts by the conductive heat from the ground during the winter. We investigated the quantitative influence of the bottom-melt to the stream flow.
We measured the bottom-melt and the river runoff in an experimental watershed under deep snow and severe coldness conditions during two winter seasons. The bottom-melt was measured by two different methods at our field station in the watershed. In one method the meltwater was measured directly by a lysimeter. And in the other, the heat flux in the ground and in the snowcover were measured to estimate the melting heat energy.
The amount of bottom-melt was estimated by numerically calculating the heat flux in the snowcover from the air temperature and snow depth. Simulation of runoff amount was achieved successfully by using the tank model. We also calculated the runoff water in the case of no bottom melt. This calculated runoff amount was half of the observed one in March. The bottom-melt supplied about a half of the runoff water to the watershed. These results indicate that the bottom-melt of snow plays an important role in the water balance during the winter.抄録全体を表示PDF形式でダウンロード (1503K) -
The Holocene Development of Lake Kamo-ko II佐藤 裕司, 熊野 茂1986 年 47 巻 2 号 p. 177-183
発行日: 1986/04/30
公開日: 2009/11/13
ジャーナル フリーBased on the ecological spectra of the diatoms grouped into marine, brackish and freshwater, sediments from Loc. 2 were classified into four diatom zones : (1) Transitional Zone 3 (Tr-3), characterized by the alternation of marine and freshwater species as dominant. (2) Marine Diatom Zone 2 (MD-2) reflecting the small transgression at c.a. 3, 000 yBP is dominated by marine species. (3) Transitional Zone 4 (Tr-4) including remarkable changes in sedimentary environment is subdivided into Tr-4a and Tr-4b. (4) Freshwater Diatom Zone 3 FD 3) is dominated by freshwater species and may reflect the lowering stage of sea level during the Yayoi Age.
Each zone is considered to be closely related with the development of Lake Kamo-ko caused by Holocene sea-level changes.抄録全体を表示PDF形式でダウンロード (1466K) -
1986 年 47 巻 2 号 p. 187-200
発行日: 1986/04/30
公開日: 2009/11/13
ジャーナル フリーPDF形式でダウンロード (2241K)
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