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Volume 43, Issue 3
Displaying 1-9 of 9 articles from this issue
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G. H. DURY, Nobuo KOHCHI1982 Volume 43 Issue 3 Pages 147-156
Published: July 30, 1982
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSAnalysis designed to test for step functions in time series provides an alternative to cyclic and secular analysis; it also amplifies probability analysis as this is usually practised. For the Ishikari River, step-functional testing identifies blocks of years, with average length 5 years, when annual floods ran generally above, generally below, or generally close to the series mean. Parallel testing for the Wabash River identifies runs of either high or low values, with average length between 4 and 5 years. Separate Gumbel graphs can be drawn for the high-flow and low-flow regimes, and also (if it exists) for the regime close to the mean. While long-term forecasting is not affected by our results, these do suggest great fluctuations in the flood hazard, in the short term.View full abstractDownload PDF (1340K) -
Distribution of Total and Acid-soluble CuFumi TADA, Shizuo SUZUKI1982 Volume 43 Issue 3 Pages 157-163
Published: July 30, 1982
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe total and 0.5N-HCl soluble Cu contents in the bottom mud of major rivers in Japan were determined. The base-line levels of total and acid-soluble Cu were 23 ppm and 7 ppm, respectively. Rivers are divided into three types based on the distributions of total and acid-soluble Cu contents in mud as follows : 1) Non-polluted rivers : Total and acid-soluble Cu contents show the value near the base-line level from upper to lower streams. Total Cu contents are affected by the parent materials of the sampling station, however, and the amount of acid-soluble Cu is less than 30 per cent of total Cu. 2) Urban rivers : Total and acid-soluble Cu contents increase remarkably downstream, and the amount of acid-soluble Cu is more than 60 per cent of total Cu. 3) Mining rivers : Total and acid-soluble Cu contents are remarkably high upstream where the waste water from mines is received, and decrease during transport.View full abstractDownload PDF (821K) -
Katsuji MATSUNAGA1982 Volume 43 Issue 3 Pages 164-172
Published: July 30, 1982
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe oxygen uptake by biological reaction in the hypolimnetic water and the oxygen flux into the sediment were studied quantitatively in order to make clear the development of the oxygen depletion in the hypolimnion observed in Lake Kizaki by applying of a one-dimensional diffusion model.
The biological 42 consumption rate constant (k) and eddy diffusion coefficient (D) were found to be 5 × 10-8 s-1 and 5 × 10-2cm2·s-1 respectively, by applying the fixed initial and boundary conditions to the one-dimensional diffusion model.
The total depletion of oxygen in the hypolimnion and oxygen flux into the sediment tended to increase with time to become maximum on June 25, 1975, and these values decreased rapidly there-after, while the oxygen uptake by biological reaction decreased gradually with time throughout the whole period of observation.
The oxygen uptake in the hypolimnetic water and oxygen flux into the sediment in May, June and July of 1975, were found to be 25, 20 and 13 mmol m-2 d-1 and 11, 22 and 18 mmol m-2 d-1 respectively.View full abstractDownload PDF (1168K) -
David M FARMER, Masayuki TAKAHASHI1982 Volume 43 Issue 3 Pages 173-181
Published: July 30, 1982
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThis article raises the question of interaction between fluid motions of relatively short time scale (1-3 hours) and time lags of similar length in algal adaptation. Convective circulation in early spring in a lake is used as an illustrative example, and it is shown that on the basis of time scales deduced from the physical mechanism, photo-inhibition is probably suppressed. An analytical model is used to evaluate the significance of this suppression, and the results are discussed in terms of the effect on interpretation of experiments based on the 14C method.View full abstractDownload PDF (1232K) -
Katsuhiko MATSUNAGA, Kohji IGARASHI, Sigeru FUKASE1982 Volume 43 Issue 3 Pages 182-188
Published: July 30, 1982
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSWater samples were taken from Lake Ohnuma and a river which flows into it. Concentrations of organically-bound iron and nitrate in both the lake and the river were measured throughout one year. The iron complex in the river water is a dissolved small molecular size species and diffuses into the lake without physical deposition. The iron complex in the lake shows a lower concentration during the period from spring to autumn than in the river because of utilization by phytoplankton. In winter the iron complex concentration became equal to that in the river. Throughout one year the iron complex showed the same behavior as nitrate. The iron complex increased the growth rate of phytoplankton in a culture experiment and passed through a semipermeable membrane with a pore size of 24 A. The iron complex was assumed to be fulvic acid-Fe.View full abstractDownload PDF (888K) -
Yuki YUSA1982 Volume 43 Issue 3 Pages 189-198
Published: July 30, 1982
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSWhen the water layer with a salinity gradient positive downwards undergoes the surface cooling, the development of thermosolutal convection can be investigated by a simple model, in which diffusivities are given by the effective thermosolutal Rayleigh number. Results showed; (1) the appearance of a series of convecting layers separated by non-convecting thin sheets : step-like structures of temperature and salinity profiles are formed; (2) the uppermost convecting layer extends downwards and the approximate uniformity of temperature and salinity is attained in a relatively short time; (3) the density difference between adjacent convecting layers increases with time; (4) even if the initial stratification is very stable because of the temperature gradient positive upwards, the convection develops rather rapidly due to the surface cooling; (5) magnitudes of apparent diffusivities are in the range of 10-2 to 1 cm2 s-1.View full abstractDownload PDF (1738K) -
Kiyoshi HOSOYA, Norio OGURA1982 Volume 43 Issue 3 Pages 199-207
Published: July 30, 1982
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSInfluences of human excrement (night-soil) on water quality in Minami-Asakawa River were studied during July 26-27, 1979, using coprostanol as an index of fecal pollution.
Concentrations of coprostanol were 0.0-2.7μg·l-1 (mean 1.6μg·l-1) at MA-3 (midstream) and 0.03-12.2μg·l-1 (mean 4.0 μg·l-1) at MA-5 (downstream). Higher concentrations were observed in sewage water flowing into the river between MA-3 and MA-5 : 4.3-61.21μg·l-1 (mean 22.9 μg·l-1) at Sw-1 and 2.2-43.4 μg·l-1 (mean 11.8 μg·l-1) at Sw-2. Coprostanol seemed to be derived from waste water mainly from septic tanks.
It was found by budgets between MA-3 and MA-5 that coprostanol tends to change from particulate to dissolved form during river flow. However, apparent decrease of the total amount was not observed, and therefore coprostanol is considered to be fairly resistant to bacterial attack and behaves as a conservative substance in the river.
It was suggested that organic loadings of night-soil origin were only 2% of the daily loadings of total organic carbon at MA-5, and great parts of remaining loadings were due to untreated domestic waste water.View full abstractDownload PDF (1220K) -
Akira TERASHIMA, Masami NAKANISHI1982 Volume 43 Issue 3 Pages 208-214
Published: July 30, 1982
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSAmounts of chlorophyll a, particulate organic carbon and nitrogen of sessile algal communities in Nepalese mountain rivers were estimated. Samplings were performed at 34 points in the three main river systems of the east, middle and west Nepal from December 1978 to June 1979.
Chlorophyll a amounts ranged from 1.3-189.6 mg·m-2 (average, 18.6). The ratio of particulate organic carbon (POC) to particulate organic nitrogen (PON) ranged from 5.8 to 22.1. High POC/PON ratios above 10 were obtained mainly from the samples of turbid rivers with water sources in the Inner Himalaya region.View full abstractDownload PDF (665K) -
Yasuhiko TEZUKA1982 Volume 43 Issue 3 Pages 215-220
Published: July 30, 1982
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe dominant Phytoplankton, chlorophyll a, phosphorus (total and dissolved inorganic) and nitrate plus nitrite nitrogen were surveyed at 7- to 10-day intervals from spring of 1980 to summer of 1981 in nearshore waters of the south basin of Lake Biwa.
From June to November, green algae dominated approximately with the following succession : Closterium, Pediastrum, and Staurastrum. The most dominant phytoplankters from December to May were Fragilaria, Asterionella and Cryptomonas. Moreover, Melosira and Cryptomonas were abundant almost throughout the year. Besides the above-mentioned genera, Anabaena, Uroglena or Mougeotia dominated for short periods of time. Peaks of chlorophyll a concentration appeared in spring with the predominance of Cryptomonas, Uroglena or Closterium and in autumn with the predominance of Staurastrum, Melosira or Fragilaria. Total phosphorus showed a large fluctuation ranging from 20 to 85μg·l-1 with the annual mean of 4μg·l-1. Dissolved inorganic phosphorus was rather high (3-40 μg·l-1) from May to October and low (0-5 μg·l-1) from November to April. No clear correlation was found between the concentrations of chlorophyll a and total phosphorus or dissolved inorganic phosphorus. Nitrate plus nitrite nitrogen disappeared frequently in summer, suggesting the nitrogen limitation to Phytoplankton growth in this season. In other seasons except for a short period of autumn, these forms of nitrogen were high (100-300 μg·l-1).View full abstractDownload PDF (704K)
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