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1.
Deep currents measured by moored current meters over the shelf-slope off Cape Shiono-misaki, Kii Peninsula during the period from 28 April, 1981 to 4 May, 1982 are analyzed to determine characteristics of the deep current before and after the large meander of the Kuroshio formed. The observed deep currents show some different characteristics between the periods before and after the formation of the large meander of the Kuroshio,i.e.:
- The mean current direction over the shelf slope changed to westward after the meander was formed, though it was eastward at two offshore stations before the meander was formed.
- The eddy kinetic energy, \(ke((\overline {u'^2 } + \overline {\upsilon '^2 } )/2)\) became large at all stations after the meander formed.
- It appears that there were current variations in the period band shorter than 10 days which propagated offshore before the meander formed but inshore after the meander formed.
- After the meander formed, the current variations with a period of O(25 days) were amplified at two of the three stations. The current variations in this period band showed high coherence among the three stations.
2.
The oil pollution in the Izu Islands waters are observed as follows:
- Globules and lumps of oil were collected 2.56 g on the average in wet weight by each taw(174 m3) of a larval net at 389 stations, up to the maximum collection of more than 500 g.
- On the investigation of the Oshima—Torishima line (J1–J10), globules and lumps of oil were collected more at the south of the Kuroshio Current than at the north.
- In the coastal region (T1–T19) of Japan, many globules and lumps of oil were collected when a cold water mass was located at the west side of the Izu Islands, from south to east side of where the Kuroshio Current took a roundabout and closed near to the Bōsō peninsula (Aug. 1971, Jun. 1972, Aug. 1972), or when the Kuroshio Current took a roundabout the cold water mass which extended as far as Oshima from the coast of the Bōsō peninsula (Sept. 1971).
3.
Tomotoshi Okaichi 《Journal of Oceanography》1983,39(5):267-278
The cause of red tides appearing in neritic waters in Japan have been discussed by several workers in relation to the development of eutrophication. The author has been engaged in marine environmental studies on outbreaks of red tides, mainly, in the Seto Inland Sea since 1964 using a combination of the following approaches:
- surveys of the red tides that have occurred,
- elucidation of the oceanographical and biological characters of the water areas where red tides occur,
- isolation of the red tide organisms for physiological studies of their growth,
- chemical and biological assays of the growth promoting factors, and
- estimation of the effects of pollutants on the growth of the red tide organisms.
4.
Mean sea level variations in the eastern Asia region during 1950 to 1991 are investigated with the use of observed sea level data at 16 stations. It is suggested from the data analysis, that the main cause of long-term sea level variation in this region may be the plate tectonic processes. The mean sea levels along the eastern coasts of Japan and the Philippines, and that along the southern coast of Indonesia have risen due to the subsidence of Pacific, Philippine and Australian plates under the Eurasian plate, respectively. On the other hand, the mean sea levels along the western coasts of Japan and the Philippines, and that along the northern coast of Indonesia have fallen. The distribution map of mean sea level rise at the year 2030 from 1985 in this region is presented on the basis of the results of this work and IPCC (1990). 相似文献
5.
A study is made on the surface distribution ofTrichodesmium thiebautii Gomont in the East China Sea during the years 1961–1967.
- This alga is very scarce or absent in the period from January to March, and begins to increase in May and June, reaching the maximum population density from July to September, and again decreases in October and November.
- In summerT. thiebautii is predominantly distributed in the area along the Kuroshio current with high densities of 102–103 filaments/l, occasionally exceeding 103 filaments/l. This alga is estimated to occupy the major part or almost all the parts of chlorophylla in situ contained in the surface water of this season.
- The occurrence ofT. thiebautii off the southern coasts of Central Japan seems to be caused rather by the multiplication in its own habitat than by the transportation by the Kuroshio current from the East China Sea.
6.
Abyssal currents along the northern periphery of the Shikoku Basin south of Japan were measured by current meters moored off Cape Daio-zaki, Cape Shiono-misaki and Cape Ashizuri-misaki and on the eastern foot of the northernmost part of the Kyushu-Palau Ridge. Total length of observation off Cape Shiono-misaki was about five years including the periods of the Kuroshio large meander and no meander. Analyses of current data show:
- Mean currents with a magnitude of 5–10 cm sec?1 were observed during the whole observation period at all of current meters which were set 400 m above the sea bottom that was deeper than 4,500 m. The mean current for each current meter was parallel to the local bottom contour arond each station and was toward a direction looking the Nankai Trough (a trough located along the northern end of the Shikoku Basin) to the left.
- At each station located above the shelf toe off Cape Daio-zaki and off Cape Shiono-misaki and on the foot of the Kyushu-Palau Ridge, the mean current increases with depth (a bottomward intensification of the mean current), and the vertical extent of the mean current is estimated to be about 2,000 m above the sea bottom.
- At a station located at 2,600 m depth on the continental slope off Cape Shiono-misaki, no bottom-ward intensification of currents was observed.
7.
P. Melchior B. Ducarme M. Van Ruymbeke C. Poitevin M. De Becker 《Marine Geophysical Researches》1984,7(1-2):77-91
The problem of interactions between earth tides and oceanic tides is rather complex as it involves effects of newtonian attraction, loading and associated change of earth potential, tangential pressure and friction on the moving ocean floor which are not always easy to evaluate, principally for coastal or island stations. This paper takes advantage of two facts:
- By the end of 1983 the International Center of Earth Tides has collected and evaluated a considerable amount of data from 223 stations including those of the Trans World Profiles developed by the same group of authors (102 stations). This ensures, for the first time, a World wide distribution including the tropical areas and the southern hemisphere.
- In 1978–80, new oceanic cotidal maps of high quality, established by E.W. Schwiderski, became available.
8.
Shinsuke Tanabe 《Journal of Oceanography》1985,41(5):358-370
I am extremely grateful and honored for being awarded the Okada Prize (1985) for my study. The present article reviews my research on the distribution, behavior and fate of PCBs in the marine environment. The outline of this study is summarized as follows:
- Polychlorinated biphenyls (PCBs) were detectable in the wide range of environmental media and biota of the Seto-Inland Sea, Japan, in which much high concentrations were found in sediment and biological samples due to their hydrophobic, lipophilic and less biodegradable properties as well as their extensive production and use in estuarine and coastal regions.
- PCBs extend the boundaries of their distribution all over the global environment, being evidenced by their occurrence in open ocean atmosphere, hydrosphere and biosphere, even in Antarctica. The global contamination of PCBs is much more prominent in northern hemisphere than in southern hemisphere.
- The sinking rate of PCBs from surface to deeper layers in open ocean water column is relatively slower in tropical waters than in high latitude ones. This implies the possible prolonged contamination of persistent synthetic organic chemicals in the tropical marine environment.
- The bioaccumulation processes in marine ecosystems can be explained by the physicochemical and biochemical properties of PCBs and the metabolic capacity of organisms. In higher animals, additional factors such as parturition and lactation are also related to this process.
- Total PCB load in global environment was estimated to be about 370 thousand tons. Of this, most amounts were in coastal sediment and open ocean water. Presently, about 780 thousand tons of PCBs are still in use mainly in electrical equipments. In order to reduce the PCB levels in marine environment, pertinent measures to prevent the further discharge and safe disposal of PCBs are required.
9.
High quality CTD data were collected in the north of the Shikoku Basin where an abyssal boundary current has been observed through direct current measurements. Analyses of hydrographic data showed:
- Colder and saltier water (heavier water) compared to surrounding waters is found above the continental shelf-toe and the eastern flank of the Kyushu-Palau Ridge where the existence of the abyssal boundary current has been expected. The heavier water has a horizontal extent of about 50 km.
- The heavier water has the vertical scale of 2000 m from the sea bottom, and is associated with a thermal wind shear which enhances a component of the flow toward a direction looking the Nankai Trough (a trough located along the northern end of the Shikoku Basin) to the left in the abyss. The assumed “level of no motion” at about 2500 m depth gives the geostrophically estimated current in a good agreement with the directly measured current.
10.
Hideo Watanabe 《Journal of Oceanography》1972,28(6):229-241
The tide-gauge records of large tsunamis are classified into three types, A, B and C. The “A” type record is made up of one or a few large waves near the wave front. The “B” type record consists of one or a few wave groups. The “C” type is the combination of the “A” and “B” types. The data used are; the Kamchatka Tsunami of Nov. 4, 1952, the Aleutian Tsunami of March 9, 1957, the Chilean Tsunami of May 22, 1960 and the Alaska Tsunami of March 28, 1964. The A type occurs mostly at isolated islands in the Pacific Ocean and occasionally at continental coasts. The B type is mostly distributed on the continental coast and along the island-arc. The distribution of the C type differs from tsunami to tsunami. The relation between the delay time of the maximum wave and the the travel time of the wave front is as follows:
- For the wave of the A type and the head wave of C type, the delay time (t D ) is constant for all travel times.
- For the first wave group of B and C types, the delay time (T 1) is constant or slow decreases with travel time. For the second and third wave groups of B and C types, the definite decrease of delay times (T 2 andT 3) with travel time is observed.
11.
The distribution of pelagic blue-green algae, especially ofTrichodesmium thiebautii, was investigated on the basis of the collection of theHakuhō Maru Cruise KH-69-4 along 155°W (50°N-15°S) in the North Pacific Ocean from September to November 1969.
- Five species were identified:Trichodesmium thiebautii (most predominant),T. erythraeum, Oscillatoria sp.,Katagnymene spiralis andRichelia intracellularis.
- T. thiebautii was most abundant in the western North Pacific central water and abundant next to it in the equatorial water, but it did not occur in the subarctic water.
- T. thiebautii was ubiquitously distributed in the lower layer of 100–200 m in the equatorial water, though not in a large quantity.
- T. thiebautii inhabited only the water warmer than 20°C. In its main habitat, nitrate and nitrite were almost zero, but ammonia and phosphate were present. There was not found any correlation between its occurrence and the salinity.
- Blue-green algae were generally thinly populated in the water rich in diatoms.
12.
Response of the low-frequency fluctuations of sea level to atmospheric forcing along the coasts of the Huanghai Sea and the East China Sea 总被引：1，自引：0，他引：1
In this paper, the low-frequency fluctuations of sea level and their relationship to atmospheric forcing along the coasts of the Huanghai Sea and the East China Sea are studied. Spectrum analyses are made for the time series of daily mean sea level, atmospheric pressure and wind stress at seven coastal stations. It is found that at all the stations, the main part of the energy of the sea level fluctuations, within the (2-60)-day period, is concentrated on the (12-60)-day period band and that an obvious spectral peak appears at the 3-day period. Along the coast of the Huanghai Sea, variations in the sea level are greater in winter than in summer. In winter, along the coasts of the Huanghai Sea and the East China Sea there is a kind of sea level fluctuations propagating southwards. Among the many factors causing sea level variation, the most obvious one is atmospheric pressure, followed next by the alongshore wind stress. 相似文献
13.
Masaki Kawabe 《Journal of Oceanography》1980,36(2):97-104
Sea level variations from 1974 through 1976 at 9 stations on the south coast of Japan (from west to east, Aburatsu, Tosa-shimizu, Muroto-misaki, Kushimoto, Uragami, Owase, Toba, Maisaka and Omaezaki) were analysed in relation to the large meander in the Kuroshio. From May to July in 1975, a small maximum in sea level variation was observed at every station west of Cape Shionomisaki from Aburatsu to Kushimoto. It propagated eastward along with the eastward propagation of a small meander in the Kuroshio until it reached Kushimoto, when the sea levels at Uragami and Owase started to rise sharply. This remarkable rise appeared at all stations in August when a large meander in the Kuroshio was established. The mean sea level at the stations east of Cape Shionomisaki from Uragami to Omaezaki rose by about 10 cm. The difference in sea level variations between the regions east and west of Cape Shionomisaki, which had been present before the rise, disappeared. A similar characteristic of sea level variation was also found in the generation stage of the large meander in 1959. The sea level variations along the south coast of Japan indicate that, prior to the generation of the large meander, the small meander in the Kuroshio was generated southeast of Kyushu and propagated eastward and that, just when this meander reached off Cape Shionomisaki, a large scale oceanic event covering over the whole region of the south coast of Japan occurred. This large scale event seems to be one of the necessary conditions for the generation of the large meander in the Kuroshio off Enshû-nada. 相似文献
14.
Akira Kurata 《Journal of Oceanography》1970,26(2):81-86
Transudation of vitamin B12 from the surface layer of bottom muds in Maizuru Bay and in the Sea of Hiuchi was investigated in this report. The total counts of heterotrophs and bacteria producing vitamin B12 in the bottom muds in these coastal regions were also examined. Results obtained were as follows:
- In the marine bottom in these coastal regions, vitamin B12 is continuously transuded from the surface layer of bottom muds to sea water. Accordingly, it is reasonably supposed that the surface layer of bottom muds, in which vitamin B12 is produced and accumulated, is a source of provision of the vitamin in the coastal regions.
- On an average, the quantity of transudation of vitamin B12 from the surface layer of bottom muds to sea water is 2.6 μμg/cm2/hr and 5.2μμg/cm2/hr in Maizuru Bay and in the Sea of Hiuchi respectively.
- In the surface layer of bottom muds in these coastal regions, the quantity of transudation of vitamin B12 is correlated with the content of the vitamin and the counts of bacteria producing the vitamin.
15.
The distribution of inorganic nitrogen compounds and the metabolic rates of these compounds by microorganisms as a whole were investigated in the Seas of Hiuchi and Bingo. The results obtained are as follows:
- Of inorganic nitrogen compounds, the contents in sea water, those in bottom muds, the uptake or liberation rates of microorganisms as a whole in sea water, and the liberation rates from bottom muds to sea water are 0.2～4.0 μg at. N/l, 3～60 μg at.N/100 g, 0.01～0.5 μg at.N//lhr, and 0.3～1.9 μg at.N/100 cm2/hr, respectively, and these contents or rates of ammonia usually are the largest of these inorganic nitrogen compounds.
- From the above-mentioned results and the others, it is suggested that the nitrogen in the seas circulates mainly in sea water itself and the course of nitrogen cycle, which passes through bottom muds, is not so important, and further that, of the cycle of inorganic nitrogen compounds, the main course is the course which ammonia is liberated from organic nitrogen compounds and it is immediately uptaked by microorganisms, and the course which it is oxidized to nitrate and the others are not so important.
16.
《Oceanologica Acta》1998,21(1):21-31
During the PROGEMA I cruise which took place on the south-western Pacific coast of Mexico (between 14° and 16° N, 92° and 96° W), 3.5 kHz echosounding profiles, surface samples and cores as well as hydrological and oxygen minimum measurements down to 2250 m water depth were made in the Gulf of Tehuantepec. Chemical, sedimentological, mineralogical, X-ray and BEM analyses of waters, core and surface samples provided new data which permit a better knowledge of the Gulf of Tehuantepec margin, where tectonic activity is due to an active subduction.On the shelf of the gulf, the distribution pattern of quaternary deposits is affected by a double tectonic forcing and by eustatic oscillations of the sea level. The first tectonic control is linked to the existence of north-south tectonic troughs in the Tehuantepec Isthmus, in which the atmospheric circulation between the Gulfs of Mexico and Tehuantepec is accelerated by the Venturi effect. The resulting winds, called “Tehuanos”, play an important role in the forcing of surface circulation in the Gulf of Tehuantepec, inducing a deviation of the general circulation and thus forcing the distribution pattern of terrigenous sediment supply according to two physiographically and mineralogically distinct provinces, inherited from the past tectonic evolution, which are separated by the Tehuantepec axis.
- •-|A southeastern province related to the Caribbean Plate and fed by: (1) the rivers draining the Chiapas Massif; and (2) the Costa-Rica Current driving tropical and subtropical waters from Central America.
- •-|A northwestern province part of the North American Plate and fed by: (1) the Rio Tehuantepec which drains the Sierra de Oaxaca; and (2) the Californian Current.
- •-|shallow banks where the products of a present-day phosphatogenesis are concentrated because they are swept by upwellings. The latter are reinforced because the banks are situated south of the wind corridor;
- •-|tectonic depressions acting as sediment traps;
- •-|numerous canyons cutting the slope along brittle accidents, driving weak turbidity currents but which play an important role in the forcing of upwelling currents. Antarctic diatoms are found which are conveyed by the deep circulation from the South-Eastern Pacific and provide evidence that Antarctic Cold Water masses (AABW) rise towards the shelf.
17.
《Marine and Petroleum Geology》1987,4(3):226-242
Geohistory analyses have been applied to the generally well-dated Triassic-Jurassic successions of three areas in the Hebrides Basin, north-west Scotland, and the importance of making corrections for decompaction, palaeobathymetry and eustatic changes of sea level are assessed. The thermo-tectonic subsidence patterns in the Skye areas (north) suggest a three-phase history of crustal stretching, though only the first phase is well developed in the Mull area (south).Episodes of relatively rapid subsidence are:
- 1.(1) Late Triassic (c210 Ma) until earliest Toarcian (186 Ma);
- 2.(2) Latest Toarcian (180 Ma) until late Bathonian (c161 Ma);
- 3.(3) Early Oxfordian (154) Ma) until at least early Kimmeridgian (incomplete.).
18.
This paper considers wave impacts on baffles, on baffles or decks adjacent to a vertical wall, and on porous seawalls and/or sea beds. For seawalls and vertical baffles, impacts can occur in steep waves, whilst a deck can be struck from below by a rising wave crest either in open sea or in a tank with standing waves (sloshing). A simple analytical model for the pressure impulse, P, due to a wave of idealized geometry and dynamics is developed and applied to the following geometries with impermeable surfaces:
- •horizontal wave impact onto a vertical wall with a deck at the waterline,
- •vertical wave impact under a deck in the same configuration (equivalent to vertical water impact of a horizontal plate),
- •horizontal wave impact onto a surface-piercing vertical baffle in open sea,
- •as for 3. but with the baffle in front of a wall,
- •as for 4. but with a deck extending from the vertical wall to the baffle,
- •bottom-mounted baffle in front of a wall with impact occurring on the wall.
19.
The commercially important sergestid shrimp,Sergia lucens (Hansen), has long been considered an endemic species of Japan because it had been found only in Suruga Bay and neighbouring waters. Recently, however, a considerable amount of a similar shrimp was caught by trawl nets off Tung-kang, southwestern Taiwan. This shrimp is distributed at depths of 100–300 m on the continental slope, around a deep submarine canyon adjacent to the mouth of the Kao-ping River. A morphological comparison with specimens from Suruga Bay reveals that the shrimp is identical toS. lucens. However, a slight difference in the patterns of water-soluble proteins was observed in a thin layer isoelectrophoretic examination. A difference was also observed in the spawning season of the two populations, indicating sexual and geographic isolation. Considering the distribution and phylogeny of the family Sergestidae, based on a possible evolutionary development from a benthic neritic organism to a pelagic oceanic one along the generaSicyonella-Sergestes-Sergia, it is assumed thatS. lucens entered a lower epipelagic habitat in the coastal waters from the warm oceanic mesopelagic habitat of the original stock. A hypothesis is proposed that speciation ofS. lucens from the original stock occurred when it was trapped in a semi-enclosed inlet (the paleo-East China Sea Gulf) that existed at the present Okinawa Trough during the late Pliocene to early Pleistocene. The inlet was deep, but had a neritic environment due to drainage from ancient large river systems, including the paleo-Yangtze River. The species expanded its distribution to the neighbouring waters during the warm interglacial period. However, a rapid rise in sea level after 14,000 years significantly changed the environmental conditions in the distributional area and the species could not expand into a neritic environment, which was too shallow for survival. Accordingly,S. lucens populations remained only in Suruga Bay and Tung-kang waters, where the environment has remained stable for the last 17,000 years or more. The two areas have the following common characteristics:
- A large amount of fresh water is discharged into the deep submarine canyon adjacent to the river mouth.
- The northeastern part is surrounded by land so that a direct inflow of boreal water into the environment is blocked.
- Warm Kuroshio extension water intrudes and mixes with water from the rivers, and for Suruga Bay there is a current system that keeps distribution of the eggs and larvae restricted to the local habitats.
20.
On the basis of the analyses of significant periods for the sea level observation data taken from recent several decades at 12 tide stations, the monthly mean sea level observations are fitted by a model of linear trend of sea level change superimposed with several variations of different fixed periods. The trends of sea level relative changes and their errors are estimated by the LS method. The results are reduced to the isostatic datum proposed and established in the paper (Huang et al. , 1991, Seismology and Geology , 1, 1-15). The trends of sea level changes in the near future along the coast of China are studied. It is pointed out that the general trend of the sea level change along the coast of China is going up slowly and the rate of the change is not the same in different segments of the coasts. In a few segments, the sea level is even relatively going down. The numerical results given in this paper provide a basis for the predictions of the future sea level changes and their effects. 相似文献