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Volume 26, Issue 3
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Mikio NAGASAWA1965 Volume 26 Issue 3 Pages 65-75
Published: November 30, 1965
Released on J-STAGE: December 11, 2009
JOURNAL FREE ACCESSThe relationships between the ground water level and dissolved substances in the shallow ground water containing a large quantity nitrate nitrogen were discussed. There are two types of relationships between the ground water level and the concentration of dissolved substances, one is the reverse correlation (type (1), well A), the other is the converse correlation (type (2), Well C).
In the case of the type (1), nitrates are reduced in the equations shown below:
NO3-+2H+H2CO3→HNO2+HCO3-+H2O
NO3-+6H+H2CO3→NH2OH+HCO3-+3H2O
NO3-+8H+H2CO3→NH3+HCO3-+3H2O
The content of calcium in the ground water is large and calcium carbonates are accumulated in the equation also shown below as the ground water evaporates:
Ca2++2HCO3 CaCO3+H2O+CO2
Then salts such as sulfates are also taken into the accumulated precipitate in the form of co-precipitation. So there is formed, as it were, light saline soil, to decrease the salts concentration in the ground water. Then in case of rainfall, the accumulated precipitate is dissolved easily in the ground water by permeant water, to increase its concentration.
In the case of type (2), there also occur oxidation-reduction reactions, but because of the high ground water level (the ground water table is at 30 cm below ground at the highest), dilution and concentration of salts due to the change of the ground water level predominate over accumulation and eluviation of salts.
The type (2) is observed in the ordinary shallow ground water, but the type (1) is somewhat peculiar, and is observed in the ground water in this area, where much amount of nitrate exist.View full abstractDownload PDF (373K) -
Volcano RishiriTorahiko Moritani1965 Volume 26 Issue 3 Pages 76-85
Published: November 30, 1965
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESS(1) Rishiri island is covered with volcano Rishiri which has erupted on the base of a low hill composed of Pliocene sediments and igneous rocks.
(2) The tectonic line crosses through the center of the island from NNW to SSE. At the east side of this line, there are many surface waters, spring waters and crater lakes, but no water source exsits except below the sea level at the west side.
(3) In the result of our investigation, it proved that there existed free unde-ground water in lava flow behind Kutsugata-machi which is the most important city of Rishiri island.
(4) This under-ground water is elocated below the sea level and the percentage of Cl' is relatively high, it is not suitable to expect adopting a great deal of water.View full abstractDownload PDF (387K) -
Kyuemon GOSE1965 Volume 26 Issue 3 Pages 86-98
Published: November 30, 1965
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSBy the investigation in February, June and August of 1964, shell zone and shell cuticula zone were found in Lake Biwa.
The shell zone and the shell cuticula zone are situated at the depth, where the influence of wave does hardly reach.
The "plant debris zone" is formed a little deeper than the shell zone and shell cuticula zone.
The shell zone in east shore of the lake is situated deeper than that in west snore, because the dominant wind in this destrict is the north-west wind.View full abstractDownload PDF (2641K) -
Toshiharu WATANABE1965 Volume 26 Issue 3 Pages 99-105
Published: November 30, 1965
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSThe plankton taken on September 28th and 30th 1965 at Okutadami Reservoir and Tagokura Reservoir which belong to the Tadami River and lie near the boundary of Niigata Prefecture and Fukushima Prefecture.
Okutadami Reservoir has 458, 000, 000m3 of available pondage and is about 150m deep, Tagokura Reservoir has 9, 952km2 of area and is about 145m deep.
From the view point of plankton study, these lakes belong to the "Dinobr-yonseen" proposed by C. APSTEIN, and it is considered that Tagokura Reservoir is more eutrophic than Okutadami Reservoir.
The plankton collected in these lakes were shown in table 2.View full abstractDownload PDF (1179K) -
Masaharu KAWAKATSU1965 Volume 26 Issue 3 Pages 106-112
Published: November 30, 1965
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSLake Tahoe (altitude, 2, 097m ; deepest point, 548m) in the Sierra Nevada Mountains in California and Nevada in North America and Lake Biwa-ko (altitude, 85m; deepest point, 102m) in Kinki Region in Middle Japan are located at approximately the same latitude. Two species of true lake-dwelling planarians, Phagocata nivea tahoena KAWAKATSU and Dendrocoelopsis hymanae KAWAKATSU, are distributed in Lake Tahoe. The former subspecies seems very common in the lake. In Lake Biwa-ko, Bdellocephala annandalei IJIMA et KABURAKI and another undescribed dendrocoelid species (Dendrocoelopsis? sp.) are distributed. The former species, which known as one of the largest freshwater planarians of the world, is rather common in the muddy bottom of middle and northern parts of the lake. The food supply seems one of the chief factor controlling the density of lake-dwelling planarians.View full abstractDownload PDF (1348K)
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