巻号一覧
43 巻 (1982)
- 4 号 p. 225-
- 3 号 p. 147-
- 2 号 p. 67-
- 1 号 p. 1-
43 巻, 2 号
選択された号の論文の6件中1～6を表示しています
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中島 進1982 年 43 巻 2 号 p. 67-80
発行日: 1982/04/30
公開日: 2009/11/13
ジャーナル フリーIn order to investigate the mechanism of metal accumulation in the bottom sediment of Lake Biwa, two 22 cm long sediment cores from the center (about 90 meters in water depth) of the northern part of the lake were sliced into 2 cm sections and analyzed for Mn, Fe, As, Cd, Pb, Cu, Zn, Co and Ni.
Partitioning of these heavy metals into mineral and organic fractions was determined with selective chemical leaching techniques for core samples.
The total contents of heavy metals in the sediment core samples were classified into two groups on the basis of vertical distribution : (1) Manganese, As, and to a lesser degree Cd, Pb, Cu and Zn were concentrated in the upper 2 cm of the core. (2) Iron, Co and Ni showed no vertical gradient.
Manganese and Cd were enriched in both the exchangeable and hydrous Fe/Mn oxide fractions in the upper 2 cm layer of the core samples. Arsenic, Pb, Cu and Zn were concentrated in the hydrous Fe/Mn oxide fraction in the surface sediment layer. The heavy metal contents of sulfide, organic and silicate fractions were relatively constant regardless of depth.
The remarkable enrichment of Mn and As in the oxidized upper layer of the sediment is assumed to be mainly due to upward migration of dissolved Mn and As from the deeper, reduced sediment layers and to reprecipitation in the thin oxidized surface layer. High concentrations of Cd, Pb, Cu and Zn in the upper 2 cm are presumably due mainly to upward migration in addition to human activities.
These results suggest that hydrous Fe/Mn oxides play an important role in the sedimentation and surface enrichment of heavy metals in the sediment of Lake Biwa.抄録全体を表示PDF形式でダウンロード (2352K) -
寺島 彰, 上田 孝明1982 年 43 巻 2 号 p. 81-87
発行日: 1982/04/30
公開日: 2009/11/13
ジャーナル フリーThe bottom area (ca. 4 m deep) of 25 ha in the south basin of Lake Biwa was intensively dredged.
As a result of dredging, water depth became deep to ca. 15 m. Physico-chemical factors (light attenuation, water temperature, dissolved oxygen, pH, NH4-N, NO2-N, NO3-N, PO4-P and particulate organic carbon, particulate organic nitrogen and ignition loss of bottom sediment) and the number of Benthic animals were surveyed almost biweekly from March 1980 to April 1981, both in the dredged area (Sta. 1) and an adjacent one (Sta. 2, ca. 4 m deep).
Annual average compensation depth at Sta. 1 was about 5.5 m, and the aphotic layer was found throughout the year. Stratification of water temperature continued from April to the middle of September. Dissolved oxygen was not detected in the bottom layer during June-August, but NH4-N and PO4-P were observed in noticeably high concentrations. These nutrients must be produced under anoxic conditions.
There were no differences in the ignition loss and the organic carbon and nitrogen contents between surface sediments of the bottom at Stas. 1 and 2. This finding suggests that the organic matter content of the bottom sediment at Sta. 1 was not reduced by dredging.
Chironomidae were very few at Sta. 1 for the four months from the middle of June to the middle of October. This phenomenon might be related to the anaerobic condition of the bottom sediment during summer.抄録全体を表示PDF形式でダウンロード (1232K) -
前田 秋一1982 年 43 巻 2 号 p. 88-95
発行日: 1982/04/30
公開日: 2009/11/13
ジャーナル フリーCommunity respiration and bacterial respiration together with some environmental factors were measured in Lake Sagami, Kanagawa Prefecture. The annual mean of community respiration (3.77 g O2 m-2·day-1) was 9.7% of that of BOD in the water column of Lake Sagami. Also community respirations of 0 and 1 meter in depth (1.06 and 1.07 g O2 m-3 day-1) were 29.4 and 27.20 of the annual means of BOD, respectively. Therefore, the high activity of planktonic organisms was suggested to affect the quality of the lake water in the epilimnion. Since the annual mean of bacterial respiration (1.63 g O2· m-2·day-1) was 43, % of community respiration, bacteria were considered to play an important role in the decomposition of organic matter. But bacteria in the hypolimnion were much more inactive than those in the epilimnion. Bacterial respiration had a strong correlation with turbidity, BOD, NO3, chlorophyll α and total number of bacteria. Among other factors bacterial respiration was assumed to depend on BOD.抄録全体を表示PDF形式でダウンロード (1102K) -
瀬戸 昌之, 西田 澄子, 山本 雅子1982 年 43 巻 2 号 p. 96-101
発行日: 1982/04/30
公開日: 2009/11/13
ジャーナル フリーThe rate of oxygen (O2) consumption Y (mg O2/l·hr), as well as the amount of dissolved organic carbon (DOC) X (mg C/l), in a sample water showed almost no variation in the middle period of aerobic incubation at 25°C. The rates Y in this period were highly correlated with the amount X (Y=3.29x10-3 X1.50; correlation coefficient γ, 0.970) among the forty-six sample waters from various sources including rivers, ponds, ground waters, activated sludges and others.
Assuming that DOC is the respiratory substrate for the aquatic microbes, the turnover rate of DOC per hour was calculated to be the highest of 0.0194 (retention time t, 51.6 hrs) in the activated sludge which had been decomposing coke-oven liquors, and the lowest of 0.00093 (t, 1, 075 hrs) in the hot spring of Izu Peninsula. Considering the large differences in the turnover rate among the forty-six sample waters, the possible ecological significance and problem of DOC were discussed for the comprehension of the microbial metabolism in the waters.抄録全体を表示PDF形式でダウンロード (841K) -
鈴木 啓助1982 年 43 巻 2 号 p. 102-112
発行日: 1982/04/30
公開日: 2009/11/13
ジャーナル フリーChemical changes of snow cover were studied. The concentration of chemical constituents, pH and water equivalent of snow cover were observed together with other related factors in Sapporo during the winter of 1979-80.
During the melting periods, the concentration of chemical constituents of the total snow cover decreased and pH increased. During the temporary snowmelts and the early phase of the snowmelt season, only the surface snow layer melted, and showed a decreased concentration of chemical constituents. In these phases the meltwater flowed downwards in the form of a water channel flow. When the meltwater began flowing downwards in the form of a water-film flow as the snowmelt progressed, the snow particles changed into large granular snow and the concentration of the chemical constituents of the inner layers began to decrease.
The earlier meltwater was considered to contain extremely large amounts of chemical constituents and had a low pH. The mechanism of the decrease in the concentration of chemical constituents in the snow cover and that of the increased concentration in the meltwater were discussed.抄録全体を表示PDF形式でダウンロード (1395K) -
松永 捷司1982 年 43 巻 2 号 p. 113-120
発行日: 1982/04/30
公開日: 2009/11/13
ジャーナル フリーSediment traps were deployed at the depths of 10, 20 and 25 m in the profund area of Lake Kizaki from April to June in 1969 to collect freshly deposited materials (fresh sediment), which were then analyzed for organic carbon and nitrogen, and Ti.
Organic carbon of the fresh sediments was separated into autochthonous and allochthonous types on the basis of Ti, assuming that allochthonous organic matter was refractory.
The values of 217, 173 and 88 mgC·m-2·day-1 at the depths of 10, 20 and 25 m, respectively, were obtained for the fluxes of autochthonous organic carbon corrected by microbial attack of autochthonous organic matter during the sediment trap mooring. These results suggest that 129 mgC of autochthonous organic carbon would be degraded in the water column with 1 m2 of the cross section and depth from 10 to 25 m, for one day, which corresponded to about 60 % of the flux of autochthonous organic carbon sinking through the 10 m depth.
The fluxes of allochthonous organic carbon increased from 137 to 198 mgC·m-2·day-1 at 10 and 25 m respectively, due to the supply of allochthonous materials from the River Naka-Nogu.抄録全体を表示PDF形式でダウンロード (1124K)
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