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Volume 36, Issue 4
Displaying 1-8 of 8 articles from this issue
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Tadashiro KOYAMA, Mitsugu NISHIMURA, Hiromi MATSUDA1975 Volume 36 Issue 4 Pages 111-116
Published: October 30, 1975
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSIn order to determine the exchange rate of CO2 between air and lake surface, a floating box experiment was conducted on an eutrophic lake. The air in the floating box was collected at proper intervals and the CO2-concentration in the air was determined by using infrared gas analyser. From the relationship between the CO2-concentration and floating time, the exchange rate of CO2 was determined. The average flux of CO2 across the air-lake interface through a day was estimated from the diurnal exchange rate of CO2.View full abstractDownload PDF (663K) -
Mikio NAGASAWA, Toshio HONDA, Isao MINAMI, Teruaki TERAGUCHI1975 Volume 36 Issue 4 Pages 117-121
Published: October 30, 1975
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThe second series of experiments was carried out at the confined aquifers in the eastern part of Osaka. The city water of 179, 000m3 (supplied from the Yodo River) was artificially recharged into two wells for a period of Nov. 1973 to Jun. 1974. Then, 88, 000m3 of water were pumped up from a well for the succeeding period of July to Oct. 1974. Its change of quality was investigated. The original groundwater in the well had been high in alkalinity, low in the chloride concentration, and contained 9-10me/l of the total ions. Owing to the first recharge and pumping-up, the total ion content was reduced to less than 6me/l, whereas that of the recharge water was around 2.4me/l. With pumping-up, the followings were always increased : the specific conductance, alkalinity and the contents of ammonia, calcium, magnesium, sodium, potassium and silica. The iron content was reduced at first and increased later. The DO and sulfate contents decreased, and the latter increased at first and decreased later. The chloride content remained unchanged consistently. These results suggests the existence of the interactions which were induced not only by mixing with the original groundwater, but also by oxidation-reduction reactions as well as the geological environment.View full abstractDownload PDF (643K) -
(1) The Sasu and the Se Rivers of Tsushima in WinterYoshihiko MACHIDA, Syuzo ISHIZAKI1975 Volume 36 Issue 4 Pages 122-130
Published: October 30, 1975
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThe Benthic communities of two river systems at the town of Izuhara-cho in the Tsushima Islands were investigated in February 1975, with a view to evaluate biologically the change of environmental conditions. The River Sasu receives discharge of an abandoned zinc mine since more than a year, while there is seen only a little such influences in the River Se.
The sampling stations were twelve in the River Sasu and seven in the River Se. Two samples were collected at each station by a surver net. The dominant species at the unpolluted stations in the Sasu was Simulium japonicum for St. 1 and Ephemerella sp. (ED) for St. 2, respectively ; the subdominant species were Chironomidae and Antocha sp. At St. 9 only seven species were recognized and the values of three different diversity indexes were significantly low. For the River Se, more than twenty species were recognized at all the stations, neither Chironomidae nor Antocha sp. being dominant. The values of diversity indexes at the stations where Epeorus latifolium dominated were comparatively lower than at the other stations where did not be so. This may be caused by a large number of E. latifolium.
These results show that the heavy metals such as Cu, Zn, Pb or Cd contained in the effluent of the Zinc Mine affect the Benthic communities of the river, especially for the abundance of their components.View full abstractDownload PDF (995K) -
Yasuhiko TEZUKA, Hidetake HAYASHI1975 Volume 36 Issue 4 Pages 131-138
Published: October 30, 1975
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSSurface water of Lake Yunoko, a small eutrophic lake in central Japan, was bottled, enriched with glucose and/or mineral nutrients, and incubated for five days in the surface layer of that lake.
Bacteria reacted promptly to the addition of glucose. When, however, an ample amount of glucose was added to the lake water, certain mineral nutrients, possibly nitrogen, became secondarily limiting to the growth of bacteria. Although mineral nutrients alone stimulated the growth of algae, the stimulatory effect was far greater when both glucose and mineral nutrients were enriched.View full abstractDownload PDF (981K) -
Ikuko YASUDA, Masami ARAI, Yoko IYAMA1975 Volume 36 Issue 4 Pages 139-146
Published: October 30, 1975
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThis article deals with the community structure of plankton in the Nishina Three Lakes on 68 August 1974. Cyclotella comta and Asterionella gracillima are found dominantly in all the three lakes. In addition to those two species, Fragilaria crotonensis is found abundantly in Lake Nakatsuna, and together with the above three species Attheya zachariasi, Asterionella formosa and Pediastrum duplex var. gracillimum occur in Lake Kizaki. Holopedium gibberum is the dominant species of zooplankton in Lake Aoki, while Polyarthra trigla and Bosminopsis deitersi abound in Lake Nakatsuna and Lake Kizaki. Kellicottia longispina is found abundantly in the deeper layer of Lake Nakatsuna. There are some difference in the plankton fauna between the present report and the result obtained in the summer 1925 in Lake Nakatsuna. Concerning the plankton fauna in Lake Aoki and Lake Kizaki, the present results show the decrease of the number of species and the change of dominant species as compared with those in the summer 1927. In regard to the feature of plankton fauna and flora as well as the vertical distribution of dissolved oxygen content, it may be inferable that Lake Aoki is oligotrophic, Lake Nakatsuna eutrophic, and Lake Kizaki is mesotrophic.View full abstractDownload PDF (926K) -
Nobutada NAKAMOTO, Masahiro OCHI-AI, Tatsuo MIZUTANI, Hidetake HAYASHI1975 Volume 36 Issue 4 Pages 147-156
Published: October 30, 1975
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThe study on the freezing-out phenomena of lake water is carried out in two mountain lakes, Lake Suwa and Lake Haruna in the central part of Japan. The reduction rates were measured concerning the following components : dissolved oxygen, carbon dioxide, ions (Cl, Na, Mg, and Ca), dissolved organic carbon, particulate organic carbon and nitrogen, and bacterial number. Substances in solution in the waters freeze out to 80%. The freezing-out of dissolved oxygen and carbon dioxide was also observed. This may account for the significant accumulation of dissolved gases immediately under the ice at the distinct inverse stratification in Lake Suwa. This accumulation was not observed at a volcanic lake of Haruna. In Lake Suwa a trend of the decrease of concentration was observed in the ice from its upper layer to the bottom. In Lake Haruna the opposite tendency was observed. The viable number of bacteria reduces by factor 103 or more in freezing.View full abstractDownload PDF (1098K) -
Toshinobu Tokui1975 Volume 36 Issue 4 Pages 157-159
Published: October 30, 1975
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSDownload PDF (419K) -
Ritsuo OTA1975 Volume 36 Issue 4 Pages 160-163
Published: October 30, 1975
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSDuring the period from May to October 1973, the author carried out three times the chemical analyses of the water of 11 main rivers inflowing the Bay of Ise. The results of analyses of the river waters in terms of PO4-P, NH4-N, NO2-N, NO3-N and organic-N are given in Table 2.
The rivers like Tenpaku, Shidomo and Seta flowing through the city have the water containing organic substances in higher concentrations derived mostly from urban sewage, while those like Inobe, Asake, Miya flowing in the garden city seem to keep relatively natural conditions.View full abstractDownload PDF (369K)
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