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Volume 32 (1976)
- Issue 6 Pages 249-
- Issue 5 Pages 195-
- Issue 4 Pages 155-
- Issue 3 Pages 99-
- Issue 2 Pages 53-
- Issue 1 Pages 1-
Volume 32, Issue 5
Displaying 1-7 of 7 articles from this issue
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Hideo SEKIGUCHI, Takashi KATO1976 Volume 32 Issue 5 Pages 195-198
Published: October 31, 1976
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSThe influence of Noctiluca's predation on the Acartia population in Ise Bay wasexamined by taking samples at 27 stations once a month from May to December, 1974.
The copepod eggs were found in Noctiluca mainly in May and June. Considering fromvarious spawning types of copepods, the eggs were presumed to be Acartia, the most numerousspecies of all copepods in the bay. Noctiluca was dominant plankton in May and June when Acartia was abundantly distributed. Acartia eggs were found in 33.2-39.3% of individualsof Noctiluca in May and June. Noctiluca was more frequently observed to contain one eggof Acartia per individual. It was suggested that 55.0 eggs per Acartia female per day wereeaten by the Noctiluca population in May wherease 3.5 eggs in June. It was deduced that 74% of the eggs produced by Acartia was preyed on by Noctiluca (about 5% in June). Thepredation by Noctiluca as well as that by the sand-eel must influence greatly to the productionof Acartia in the bayView full abstractDownload PDF (866K) -
Tetsuo YANAGI1976 Volume 32 Issue 5 Pages 199-208
Published: October 31, 1976
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSThe tidal residual circulation in a bay was experimentally investigated with useof a hydraulic model. The model basin is a square bay of 5 m sides with a one-sided mouthof 1 m wide. The depth of the basin is 0.1 m. The tide of a six-minute period was providedby a tide generator of plunger type through the mouth. Tidal currents in the bay alwaysflow in one direction though its strengths change according to the tidal phase, that is, astrong tidal residual circulation occurs in the bay. A similar flow pattern was observed tooccur in a field with a horizontal boundary geometrically similar to the present model. Thevorticity transfer from tidal current to residual flow is balanced with the vorticity advectionof residual flow and the dissipation due to the viscosity.View full abstractDownload PDF (3264K) -
Sachiko NAGASAWA, Ryuzo MARUMO1976 Volume 32 Issue 5 Pages 209-218
Published: October 31, 1976
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSThe feeding of Sagitta nagae was analyzed in connection with food chains inthe pelagic and near-bottom communities of Suruga Bay. The following results are obtained:(1) S. nagae feeds on dominant copepod species both in the free water (upper water layers) andthe near-bottom habitats;(2) S. nagae did not show any food-size selection in the range of0.2 to 1.2 mm in cephalothorax width and height of copepods;(3) Feeding activity of S. nagae in the free water is highest at night, while in the near-bottom habitat the species feeds moreactively during the day than at night; and (4) S. nagae migrates between the bottom andfree water and plays an important role in shallow water by connecting the near-bottomcommunity with the pelagic community.View full abstractDownload PDF (1532K) -
Byong-Kwon PARK, Sang-Joon HAN, Jong-Wha LEE1976 Volume 32 Issue 5 Pages 219-227
Published: October 31, 1976
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSThe bottom sediments of Jinhae Bay area contain, on average, 45% illite, 23%kaolinite, 17% intergrade clay, 10 % chlorite, and 5% smectite. The geographicaldistributionof the clay minerals shows, in general, an ir crease in illite, a decreasein kaolinite, and a slight decrease in chlorite seawards. The distributional trends of smectite and intergradeclay are irregular. The clay fractions of the sediments of Jinhae Bay are suppliedfromstream-borne sediments and are mixed with sediments transported landwards from the East China Sea. Local erosion and redeposition of the clay fractions of the bottom sediments iscaused by rapid tidal currents.View full abstractDownload PDF (1434K) -
Yutaka NAGAYA, Kiyoshi NAKAMURA1976 Volume 32 Issue 5 Pages 228-234
Published: October 31, 1976
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSThe concentrations of 90Sr and 137Cs, derived from the radioactive fallout, in thesurface layers of the adjacent seas of Japan and the North Pacific were determinedradiochemicallyduring 1969 to 1973. The 90Sr and 137Cs concentrations in sea water decreasedmarkedly with increase of the depth and below the depth of 1, 000m, the concentrations wereapproximately uniform. The distribution of 90Sr in the surface water of the North Pacific inspring of 1970 was approximately uniform, except two regions; rather large low-concentrationregion between 160°E and 170°W and relatively higher contamination area around32°N and 146°W.View full abstractDownload PDF (836K) -
Yukio SUGIMURA, Yoshimi SUZUKI, Yasuo MIYAKE1976 Volume 32 Issue 5 Pages 235-241
Published: October 31, 1976
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSBy using the new fluorometric method of determination of the total selenium (Σ Se), Se (IV) and Se (VI), the content of selenium in sea weter was determined in thewestern North Pacific. Results showed that the content of Σ Se in surface water rangedfrom 0.06 to 0.12 μg 1-1, while in deeper layers, the content increased to 0.20 μg 1-1. It wasfound that Se (IV) showed rather uniform distribution with depth, while Se (VI) increasedwith depth to about three times that in the surface. The ratio of Se (IV) to the Σ Se rangedfrom 0.5 to 0.8 in the surface and 0.4 to 0.6 in the deep. The coexistence of the hexa- andtetravalent ions of selenium was confirmed both in surface and deep layers. Some resultsof observations on the content of selenium in the coastal areas of Japan were also reported.View full abstractDownload PDF (1008K) -
Akihiko MURAKAMI, Tokio MATSUDA, Nobuhiro WATANABE, Shinichi NAGASAWA1976 Volume 32 Issue 5 Pages 242-248
Published: October 31, 1976
Released on J-STAGE: June 17, 2011
JOURNAL FREE ACCESSThe ability to degrade n-paraffin mixture of two bacterial strains, Caulobacter sp.and Flavobacterium sp., isolated from sea water of Tokyo Bay was studied experimentallyin the enriched seawater (ESW) medium. These bacteria degraded actively the mixture of n-tridecane, n-tetradecane, n-pentadecane and n-hexadecane.
The maximum rate of degradation was observed after a lag period of 2 to 8 day andthese bacteria were found to degrade the n-paraffin mixture at rates calculated to be in arange from 3.3×10-12 to 3.4×10-11 mg-oil cell-1 h-1 at 20°C.The maximum degradation rate, rm mg-oil 1-1 was correlated with the amount of theinitial total n-paraffin, S mg-oill-1, as expressed by the following equation:
rm=(rm) max (S/S+Km)
where (rm) max denotes the largest value of rm when n-paraffin exists in large excess and Kmis a constant and represents the amount of n-paraffin at which the degradation rate, rm, reaches 1/2 of its largest value, (rm) max.
The values of (rm) max and Km were calculated to be as follows: In the case of Caulobacter sp.(strain KM-1), (nit) max=6.0 mg-oil 1-1 h-1 and Km=191 mg-oil 1Esw-1; in the caseof Flavobacterium sp., (rm) max=5.47 mg-oil 1-1 h-1 and Km=152 mg-oil 1Esw-1.View full abstractDownload PDF (1007K)
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