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41.
The Algal Growth Potential (AGP) of water samples collected off Gamagori in Mikawa Bay was measured from May 1978 through February 1979, and the limiting nutrient was determined using regression analysis and enrichment bioassays. The surface and bottom water samples had AGP that produced increments of chemical oxygen demand (COD) of 2.1 mg l–1 and 3.1 mg l–1, respectively, on average. These values ofCOD correspond to 46% and 97% of the average COD values of the raw water samples at the surface and bottom, respectively. Seasonal changes of AGP showed a close correlation with those of dissolved inorganic nitrogen (DIN) concentration. Enrichment bioassays showed that DIN was the most deficient nutrient. The DIN:phosphate-phosphorus (PO4
3–-P) ratios and DIN: dissolved phosphorus (DP) ratios in the water samples were below the cellular N:P ratios of the natural algal populations. These results suggest that AGP was mainly limited by DIN concentration. 相似文献
42.
In order to clarify the chemical forms of minor metallic elements occurring in the ocean, a new method of separation of organic compounds of metals in sea water by using XAD-2 resin was contrived. By applying the new method of determination, it is found that, (1) More than 80 % of V, Fe, Cd and Cu dissolved in sea water are present in organic forms regardless of the depth; (2) A most part of Co and Pb are present in organic forms near the surface, but they change into inorganic forms in the deep layer up to 50 to 60%; (3) Of the total amounts of dissolved Al, Ni, Zn, Ag, Mo, and U, less than 30 % are present in organic forms in sea water anywhere in the ocean; (4) Up to 45% of Se is in organic forms. 相似文献
43.
Yukio Oonishi 《Journal of Oceanography》1978,34(4):140-159
Characteristics of the tidal residual flow, the steady current induced in the tidal current system, are studied by a numerical method. The model basin has the same topography as that studied byYanagi (1976) and byOonishi (1977) where only the horizontal motion of the residual flow is concerned. In this study, the effect of the vertical motion is investigated as it is associated with the tidal residual flow. To this end, the bottom friction omitted in the previous study (Oonishi, 1977) is included and a two-leveled model is adopted.The first two experiments exclude the earth's rotation and the buoyancy effect on the flow. The results are as follows. The horizontal flow pattern is essentially the same as that obtained in the previous Oonishi study. The bottom friction results in the reduction of the velocity of the residual flow especially in the bottom level. An important result is that vertical velocity is as strong as the horizontal velocity multiplied by the scale ratio and that it remains even in the time-average. Upwelling appears at the center of the residual circulation. This upwelling explains Yanagi's observation in the hydraulic model that the sediment is swept by the flow and accumulates horizontally in the area at the bottom below the center of the residual circulation. The distribution of a tracer, which is simultaneously calculated in these cases, indicates the important role of vertical motion in the material dispersion in the model.The last experiment includes the earth's rotation and the buoyancy effect presuming a more actual sea. It shows another effect of the vertical motion. The Coriolis term, which operates only under the condition that a horizontal divergence of the flow is present, skews the horizontal residual flow pattern. 相似文献
44.
The Coriolis effect on frontogenesis in the transitional region between the inner bay and the outer ocean is studied by running
several three-dimensional numerical experiments. The aim is to clarify what external parameters, including the transverse
scale of the basin, control the phenomena. The characteristics of the front in each case are described by defining three diagnostic
quantities, namely, the sharpness of the front, the intrusion of the front, and the buoyancy difference between the minimum
buoyancy region and the surrounding part, as the existence of the minimum buoyancy region is closely related to frontogenesis.
The three quantities are shown to depend on two nondimensional numbers,R
of (=f
−1
L
−2/3
F
b
1/3
: defined as flux Rossby number) andR
ef (=ν
v
−1
L
−2/3
F
b
1-3
H
2: defined as flux Reynolds number). 相似文献
45.
Yukio Fujinawa Yoshinobu Tsuji Isao Watabe Ken Sasaki Masao Nomoto Toshiaki Hara Yoshito Tsuji 《Journal of Oceanography》1980,36(5):253-258
The results of laboratory and field experiments on a CTD measuring unit attached to a controllable towed body is described. It was verified that the three-dimensional distribution of salinity and temperature could be observed with sufficient accuracy (to 0.03 in salinity and to 0.01°C in temperature if proper correction is adopted) while cruising at up to 4 knots. A double integrated A/D converter is used to compensate for effects of extraneous environmental changes. 相似文献
46.
The uranium content and activity ratio A234U/A238U were determined in open ocean water, marine plankton, marine algae and sea water in the environment in which plankton and
algae live. The average uranium content of 3.34±0.28×10−6 g/l and the average activity ratio of 1.13±0.04 were obtained in open ocean water. The uranium contents in plankton and algae
were respectively from 1.7 to 7.8×10−7 g/g and 0.4 to 23.5×10−7 g/g on dry basis with the respective concentration factors of 48 to 260 and 10 to 733. The activity ratio in plankton and
algae ranged from 1.07 to 1.18 which coincided well with those in the environmental sea water. 相似文献
47.
Seasonal variations of the Hawaiian Lee Countercurrent induced by the meridional migration of the trade winds 总被引:1,自引:0,他引:1
Hideharu Sasaki Shang-Ping Xie Bunmei Taguchi Masami Nonaka Yukio Masumoto 《Ocean Dynamics》2010,60(3):705-715
Seasonal variations of the Hawaiian Lee Countercurrent (HLCC) are investigated using satellite observations of sea surface
height and wind stress as well as eddy-resolving ocean model simulations. The HLCC is strong from summer to winter and weak
in spring between the dateline and the Hawaiian Islands. In response to the seasonal migration of the northeast trade winds
in the meridional direction, the wind curl dipole lee of Hawaii varies in strength, exciting westward-propagating Rossby waves.
The analyses of both observations and simulations show that the propagation of Rossby waves south of the HLCC, driven by the
southern pole of the wind curl dipole in the lee of the islands, contributes the most to the seasonal variations of the HLCC.
Unlike the wind-driven seasonal variations, our analysis suggests that other mechanisms such as mode water intrusion or air–sea
interaction may cause the interannual variations of the HLCC. 相似文献
48.
Characteristics of coastal trapped waves along the southern and eastern coasts of Australia 总被引:1,自引:0,他引:1
The spatial structures and propagation characteristics of coastal trapped waves (CTWs) along the southern and eastern coasts
of Australia are investigated using observed daily mean sea level data and results from a high-resolution ocean general circulation
model (OGCM), and by conducting sensitivity studies with idealized numerical models. The results obtained from the sea level
observations show that shortterm variations, with a typical period of 1 to 2 weeks, dominate the sea level variability in
the southern half of Australia. The signal propagates anticlockwise around Australia with a propagation speed of 4.5 m/s or
faster in the western and southern coasts and 2.1 to 3.6 m/s in the eastern coast. Strong seasonality of the wave activity,
with large amplitude during austral winter, is also observed. It turns out that the waves are mainly generated by synoptic
weather disturbances in the southwestern and southeastern regions. The numerical experiment with idealized wind forcing and
realistic topography confirms that the propagating signals have characteristics of the CTW both in the southern and eastern
coasts. Sensitivity experiments demonstrate that the difference in the phase speed between the coasts and reduction of the
amplitude of the waves in the eastern coast are attributed to the different shape of the continental shelf in each region.
The structures and the propagation characteristics of the CTWs around Australia are well reproduced in OFES (OGCM for the
Earth Simulator) with dominant contribution from the first mode, although meso-scale eddies may modify the structure of the
CTWs in the eastern coast. It is also found that generation or reinforcement of the waves by the wind forcing in the southern
part of the eastern coast is necessary to obtain realistically large amplitude of the CTWs in the eastern coast. 相似文献
49.
50.
Yoshiko Kawabata Tsuneo Tsukatani Yukio Katayama 《International Journal of Salt Lake Research》1999,8(2):99-112
Lake Balkhash is one of the many closed lakes in Central Asia. Mechanisms of demineralization in Lake Balkhash were considered from results of surveys undertaken on the lake and along the Ili River. Electrical conductivity (EC) values at the eastern coast in south-western Lake Balkhash were higher than those of the western coast. The Ili River enters at the south-western corner of the lake, so that EC values of this area are low. This water flows westwards. The distribution of Ca2+ concentrations showed that these were lower value in Lake Balkhash than along the Ili River, implying Ca2+ removal by the lake. Amongst suspended mineral matter in the lake occur calcite and dolomite. Thus, a possible mechanism of calcium removal is that it is removed as crystals of calcite or dolomite. SO
4
2–
concentration within the lake has increased for the past 37 years. This may be caused by the discharge into the lake from the city of Balkhash of waste water from a copper smelter. 相似文献