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Volume 19, Issue 3-4
Displaying 1-5 of 5 articles from this issue
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Ken-ichirô NEGORO1958 Volume 19 Issue 3-4 Pages 77-84
Published: March 25, 1958
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSProfessors K. SUGAWARA and T. KOYAMA of Nagoya University succeeded in obtaining a core of the bottom deposit in the pro fundal region 90 m. in depth of Lake Biwa-ko off Hikone City. It measures 112 cm. in length below the mud surface. This paper deals with my stratigraphical analysis of diatom shells in that core sample.
The results obtained are as follows
As already reported by me (1954, in Japanese) on a core taken up from the pro fundal region of this lake off Omatsuzaki, the constancy of the diatom association in every zone of a core of the deposits is also ascertained in this case.View full abstractDownload PDF (870K) -
Toshiharu WATANABE1958 Volume 19 Issue 3-4 Pages 85-93
Published: March 25, 1958
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESS1. Ecological studies were made on Euglena scum which occurred in the gold-fish culturing ponds at Koriyama, Nara Prefecture, based on a series of samples collected in June of 1957 and on the observations made thereafter.
2. The scum may be divided into three groups according to their colors and the ratio of numbers of Euglena sanguinea as to whether it has haematochrome or not (Table 2 and 3). The three groups in color are Light olive, Old gold and Bristle. The ratio mentioned above becomes small in order of the color groups. The colors of the Euglena scum seem, therefore, to be chiefly decided by this ratio.
3. When scum is made, Euglena sanguinea produces floating gelatinous discs, on which its cells connect with one another (Fig. 1). This phenomenon may be a type of the temporary cyst of Euglena sanguinea, as is stated by JAHN.
4. Figure 2 shows the curves of transmittance of Euglena scum to each of monochromatic lights which were obtained by using eight interference filters of HITACHI Corporation. These curves can be classified under three groups, being the same as those which were obtained by colors of scum.
5. The pH of pond water beneath the surface with and. without Euglena scum showed no difference between them in the pond, which have the highest transmittance and Old gold scum. However, in the other pond which has Light olive or Bristle scum, there is a 0.3 difference in the pH in each.
6. From these facts, it seems to be a control to photosynthesis of phytoplankton in the pond water only when Light olive or Bristle scum occurs.View full abstractDownload PDF (1000K) -
Hikomi IGARASHI1958 Volume 19 Issue 3-4 Pages 94-101
Published: March 25, 1958
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSDownload PDF (1085K) -
VI. Seasonal variations in the amount of deposition (1)Hideo KURASAWA1958 Volume 19 Issue 3-4 Pages 102-117
Published: March 25, 1958
Released on J-STAGE: January 27, 2010
JOURNAL FREE ACCESS1) The seasonal variations in the amount and the chemical nature of the deposits were clarified by the observations which were carried out from Aug. 1951 to Dec. 1953 at three fire pools in Tokyo.
2) PETRI dishes 10 cm in diameter set in the flower pots were suspended in water at the depths of 1 and 2. 5 m. respectively. At intervals of about one and two months, they were hauled up and their contents were examined.
3) The amounts of deposition increase both in spring and in autumn every year, and decrease in early summer (May and June). Heavy deposition sometimes seen in autumn may indicate that substances suspended in water during the summer stagnation were precipitated at a stretch in the circulation in autumn.
4) The mean values (dry weight) of deposition per day were 6-30g/m2, richest in Pool B, and scanty in Pool A. Loss on ignition fluctuated between 40-60 %, and organic nitrogen varied between 20-25 mg/g. The value of the former changed in direct proportion to the amount of deposition, the latter vice versa.
5) The percentage of loss on ignition and the amount of organic nitrogen in the bottom muds varied from 30 % to 35 % and from 12 mg/g to 14 mg/g respectively. These values are similar to those of certain dystrophic lakes. Loss on ignition of bottom mud was 2/3 of that of deposits and 1/2of that of seston, while the amount of organic nitrogen of bottom mud was only 37 of seston and1/7 of plankton. These facts indicate that organic nitrogen in these matters must return back to the water with a high speed.
6) The rate of deposition of matters in the pools varied from 2 to 6 mm thick year by year, increasing with age. The amount of accumulation was found to be 1. 26-5. 56 kg/m2/year, which are similar to those of certain eutrophic lakes.
7) The maxima of deposit occurred either at the same time or immediately after the maxima of seston and of net production. The mean amount of organic matters in deposits is 1-3 times more than that of net production calculated on the basis of chlorophyll content, and is 3-7 times more than net production measured by using the oxygen bottle (WINKLER'S method).View full abstractDownload PDF (2106K) -
Aritsune SAEKI1958 Volume 19 Issue 3-4 Pages 118-129
Published: March 25, 1958
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSThe nitrogen cycle in the balanced aquarium was studied in regard to the secretion of nitrogen compounds by fish, nitrification, denitrification, and assimilation by plants and bacteria. And then cultivable capacity of fish was estimated. When the initial content of ammonia in the water is A, secreted nitrogen compounds from fish F, nitrogen nitrified by bacteria x1, nitrogen assimilated by bacteria x2, by aquatic plants x3, denitrified nitrogen x4, and the ammonia content at a given time t is M :
M=A+F+X1+X2+X3+X4
When fish is cultured in the healthy and normal condition, df/dt=dx1/dt+dx2/dt+dx2/dt+dx3/dt+dx4/dt
100 grams fish secrets 50 mg of nitrogen compounds per day. When the bottom of the aquarium is covered with either calcite or weathered granite sand 25mm in size, the velocity of nitrification by bacteria growing on it is 240 γ per 100 cm2 per day. And, nitrogen assimilated by bacteria is 170 γ per day, if the bottom of aquarium is made clean occasionally. When 1 litre of water contains 1 shoot of Cabornba and Hydrophila 10 cm long respectively, which grows three times in length during a month, nitrogen assimilated by them is 250 γ per day. Denitrification is determined by measuring the ratio of argon to nitrogen gas. Its velocity per litre is 16 γ per day.
From these data, the velocities of nitrification, assimilation and denitrification in the aquarium are 76?674 γ/day, as shown in Table 5, and cultivable fish in that is given in Fig 4.View full abstractDownload PDF (1198K)
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