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Volume 31, Issue 3
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Mikio NAGASAWA1970 Volume 31 Issue 3 Pages 69-81
Published: November 30, 1970
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESSIt has been found that the water quality of confined ground water in the eastern Osaka district variations with passage of time. This was initially thought to be due to drying up of stagnant ground water of high salt content by excessive pumping up of water to cause purification of the water. However, it has been discovered by continuing observations that the dissolved salt of the observation wells which have been swabbed indicated a large increase without exception. That is, the stagnant ground water of high salt content has not dried up but rather, it is due to the phenomena of aging and recovery of the pumping function of the well. This has been proved by drilling test wells of 50 m, 100m and 200m and analysis the water quality. More accurately, the water intake pipe of the test wells were located between 4550m, 9297m and 170191m. Analysis of the water quality of the test wells indicated that each aquifer had a characteristic water quality. The chloride content of the 100m well was 6mg/ 1, 200mg/l in case of the 200m well, and the total of all anions and cations was 15me/l in case of the 50m well, 10me/l for the 100m well and 20me/l for the 200m well.View full abstractDownload PDF (1147K) -
Taizo MIURA, Kenji NAKA1970 Volume 31 Issue 3 Pages 83-95
Published: November 30, 1970
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESS(1) A statistical analysis was made in the estimation processes of density of various freshwater plankters netted with a common shaped plankton net, specially in the process of subsampling.
(2) The results obtained by the analysis made in three dominated zooplankton species reveal that 10 subsamples which were approximately 1/100 fraction of the sample withdrawn with a large-bore pippet (2mm dia.) allow to have a fairly accurate information of the mean, and that the subsamples have a Poisson or uniform distribution which indicates that the subsampling process was under a satisfied condition. The samples collected from a water mass are significantly different from one to another.
(3) The subsampling method for phytoplankton applied here have two processes; the one is the same as used in zooplankton, and in the rest the withdrawn fraction is introduced into a standard counting cell, and then a microscopic field is taken as the secondary fraction, (approximately 1/32, 000 of a sample in this study). The results obtained by the analysis made in four dominated green algae species reveal that the first process was under a fairly good condition, while in the second some of the treatments were unsatisfied because the fractions (microscopic fields) had a contagious distribution with a great deviation. The samples collected from a water mass are significantly different from one to another.
(4) Causes responsible for introduction of error in the processes of numerical estimation of plankton was discussed.View full abstractDownload PDF (1435K) -
Kyuemon GOSE1970 Volume 31 Issue 3 Pages 96-106
Published: November 30, 1970
Released on J-STAGE: October 16, 2009
JOURNAL FREE ACCESS1. The life history of Stenopsyche griseipennis was studied on the basis of the samples taken from the River Yoshino at the stations Ano and Ikadaba, Nara Prefecture and the samples taken from the River Abashiri at the station Abashiri, Hokkaido.
2. Stenopsyche griseipennis has five instars.
3. The accumulated temperature of water temperature required by one generation of Stenopsyche griseipennis is 55 month degrees.
4. The minimum effective temperature is assumed to be 4°C. At about 4°C this larva stops to eat.
5. By the instar analysis it was determined that this species has two generations in a year at the station Ano, three generations in two years at Ikadaba. and only one generation in a year at Abashiri.
6. From the other stand point, that is on the basis of the accumulated temperature the number of generations were estimated.View full abstractDownload PDF (1342K)
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