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1.
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.
2.
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.
3.
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.
4.
Temporal and spatial variations in the spawning activity ofSergia lucens were investigated in relation to some environmental conditions of Suruga Bay. The daily egg abundance varied considerably with the coefficient of variation from 81% to 269% in July. The spawning activity was most clearly affected by temperature, but the relationship to lunar period and content of chlorophylla were not obvious. Timing of the July spawning is predictable with increase of the surface temperature to 24°C and strong vertical movements of the 18°C isotherm depth; it is also related to modal length of the shrimp in June. It is suggested that intrusion of cold water at 20–50 m affects reproduction of the shrimps and vertical distribution of eggs and larvae. The shrimp population seemed to relate principally to two spawning grounds,i.e. the head part and the western part of the bay. The timing of spawning is not always synchronous throughout the bay. The spawning is sporadic and the distribution of eggs is patchy. This may reflect a recent decrease in the population of the shrimp due to increased fishing pressure.A part of the present paper is based on the thesis submitted by G. H. B. in partial fulfilment of the requirements for her degree of Master of Science at the Tokyo University of Fisheries in 1986. 相似文献
5.
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.
6.
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.
7.
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.
8.
F. Sardà J.B. Company N. Bahamón G. Rotllant M.M. Flexas J.D. Sánchez D. Zúñiga J. Coenjaerts D. Orellana G. Jordà J. Puigdefábregas A. Sánchez-Vidal A. Calafat D. Martín M. Espino 《Progress in Oceanography》2009,82(4):227-238
We performed a multidisciplinary study characterizing the relationships between hydrodynamic conditions (currents and water masses) and the presence and abundance of the deep-water rose shrimp Aristeus antennatus in a submarine canyon (Blanes canyon in the NW Mediterranean Sea). This species is heavily commercially exploited and is the main target species of a bottom trawl fishery. Seasonal fluctuations in landings are attributed to spatio-temporal movements by this species associated with submarine canyons in the study area. Despite the economic importance of this species and the decreases in catches in the area in recent years, few studies have provided significant insight into the environmental conditions driving shrimp distribution. We therefore measured daily A. antennatus catches over the course of an entire year and analyzed this time series in terms of daily average temperature, salinity, mean kinetic energy (MKE), and eddy kinetic energy (EKE) values using generalized additive models and decision trees. A. antennatus was captured between 600 and 900 m in the Blanes canyon, depths that include Levantine Intermediate Water (LIW) and the underlying Western Mediterranean Deep Water (WMDW). The greatest catches were associated with relatively salty waters (38.5–38.6), low MKE values (6 and 9 cm2 s−2) and moderate EKE values (10 and 20 cm2 s−2). Deep-water rose shrimp occurrence appears to be driven in a non-linear manner by environmental conditions including local temperature. A. antennatus appears to prefer relatively salty (LIW) waters and low currents (MKE) with moderate variability (EKE). 相似文献
9.
《Oceanologica Acta》1999,22(1):127-131
A large proliferation of Noctiluca scintillans (Dinophyceae: Noctilucidea) was observed in neritic waters off the central Cantabrian coast during late April 1995. Eggs of Acartia clausi (Crustacea: Copepoda) were the most conspicuous prey within vacuoles of Noctiluca. Noctiluca ingested 73 % of the total stock of A. clausi eggs. This intense predation on copepod eggs could potentially affect the recruitment of nauplii. The potential impact on the stock of Acartia clausi eggs and on the daily egg production of the population is discussed. There is a negative correlation between the average number of ingested eggs by a single Noctiluca cell and the abundance of Noctiluca. This fact, coupled with the lack of significant correlation between the former variable and the abundance of Acartia clausi eggs, suggests that interference processes play a major role in regulating the predator-prey interaction between Noctiluca and Acartia eggs. 相似文献
10.
Siphonophores were sampled using stratified 1.67-m2-mouth 330-μm mesh nets during both day- and nighttime in Sagami Bay (35°0.50′N, 139°20′E), off south-eastern Japan during a 9-day period in March 2006, when the Kuroshio Current was in an offshore non-large meander phase. The samples were collected at 50-m intervals spanning from 1,000 m depth to the surface. Fifty-eight species and 11 eudoxid forms of unknown parentage were collected, of which 5 represent first-time records from Japanese waters, and Clausophyes laetmata Pugh and Pagès 1993, Eudoxia cf. galathea Moser 1925 and Lensia panikkari Daniel 1970 were recorded for the first time not only from Japan but from the entire Pacific Ocean. The highest abundance and diversity was found below the thermocline during the day, and above it at night. A second peak in abundance, around 400 m depth, associated with a decrease in diversity, could be linked to the increase in abundance of a single species—Dimophyes arctica (Chun 1897). The siphonophore communities could be related to the different water masses in the Bay, with an important influence of lateral transport of both tropical and subarctic species into the Bay by the different water masses. 相似文献
11.
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.
12.
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).
13.
N. K. Khristoforova V. Ya. Kavun Yu. Ya. Latypov Dam Dook Tien E. V. Zhuravel’ Nguen Xuan Tuyan 《Oceanology》2007,47(5):685-690
To characterize the terrigenous, anthropogenic, and technogenous impacts upon the ecosystems of coral reefs in the shallow-water Ha Long Bay, which was declared by UNESCO to be a world natural heritage site, the levels of Fe, Mn, Zn, Cd, Pb, and Ni in the soft tissues of six mass species of bivalve mollusks from island coastal waters were studied. Taking into account the abundance and distribution, as well as the capability to represent the geochemical conditions of the environment, for further biomonitoring of heavy metal contents in the coastal waters of the bay, the following species were recommended: Septifer binocularis, Barbatia amygdalumtostum, and Isognomon isognomon. 相似文献
14.
T. Juteau D. Bideau O. Dauteuil G. Manac'h D. D. Naidoo P. Nehlig H. Ondreas M. A. Tivey K. X. Whipple J. R. Delaney 《Marine Geophysical Researches》1995,17(5):399-430
During July and August 1991, the French-American Blanconaute dive program used the French submersibleNautile to investigate the West Blanco Depression (WBD), a deep, elongate trough located at the intersection of the Blanco Transform Fault Zone with the southern Juan de Fuca Ridge (JdFR). Twenty dives were carried out along the north wall of the WBD, which exposes the upper oceanic crust over a 65 km distance, from the JdFR axis (to the west) to the oblique trace of an ancient propagator (to the east, crustal age around 2 Ma). Thirteen of these dives were precisely located within a 13 × 7 km zone of the north wall, covered by a high-resolution sonar mapping operation during the Blancotrough cruise in 1987. This series of geological traverses, plus 4 dives across the south wall of the WBD (one dive) and the adjacent Parks Plateau (3 dives), collected 242 rock samples. We report here the main results of the dive program and preliminary laboratory studies:
- Transform-related tectonic activity has recently abandoned the southern margin of Parks Plateau, and is presently located inside the WBD area, mainly along its northern wall. The tectonic features observed are compatible with a right-lateral strike-slip system, with a NE-SW extensional component.
- Three main lithological units are exposed along the north wall of the WBD. From top to bottom, they are: (1) a Volcanic Unit, forming a steep upper cliff, made of massive and pillow flows and basaltic dikes, with an estimated average thickness of 800 m; (2) a less steep Transition Zone, about 150 to 400 m thick, largely masked by rubble but exposing both diabase outcrops and pillow flows; and (3) a massive Diabase Unit, exposed over 700–800 m, with a dike complex structure visible from place to place, and cut by a net of hydrothermal veins. Deep crustal rocks such as gabbros were not observed.
- Spectacular mass-wasting features are visible all along the north wall of the WBD. About 60% of the face of the wall is masked by talus cones, rubble, rock avalanche deposits and slide blocks. Three main landslides, of approximately one km3 in volume each, were tentatively identified. One of them was mapped in detail and consists of an approximately 300 m thick (0.85 km3), coherent slide block detached from a zone where intense hydrothermal alteration and faulting have obviously weakened the bedrock, that is in places entirely altered to blue clays.
- The basaltic lavas of the WBD north wall show a remarkable evolution with time, from east to west. Around the tip of the ancient propagator, they are restricted to primitive, olivine-rich picritic basalts. Proceeding westward, they exhibit a wide range of differentiation, including highly fractionated, FeTi-rich ferrobasalts at about 35–45 km from the JdFR axis. When approaching the JdFR axis, the FeTi enrichment decreases gradually, and the ferrobasalts evolve towards slightly differentiated MORB-type basalts, typical of the southern JdFR. This magmatic evolution marks the transition from the end of a propagating rift regime to a steady-state accretion regime.
- The WBD north wall also permits the study of weathering and hydrothermal alteration processes and their evolution in space and time. Vertically, the alteration products evolve from oceanic weathering and zeolite facies (Volcanic Unit) to the greenschist facies (Transition Zone and Diabase Unit). Horizontally, the evolution with time is mainly a general hydration of the crust that is, however, very irregularly distributed.
- Several vertical magnetic traverses along the north wall of the WBD, using a bottom magnetometer attached to the basket of the submersible, have shown a sharp 5000 to 7000 nT positive anomaly at about 3500 m depth. This anomaly corresponds exactly to the first appearance of extrusive pillow-lava outcrops, and confirms the dramatic decrease in magnetic anomaly amplitude below that depth, detected during the Blancotrough cruise in 1987. The vertical magnetic profiles thus appear to have imaged the base of the magnetic source layer.
15.
以没有放流幼虾的1987年的河口区仔虾相对数量和8月份幼虾数量比值(109)为系数(a),以ni=axi式(ni是i年自然补充量,x_i是i年河口区仔虾相对数量),估算胶州湾中国对虾有关年份自然补量。将各年8月份幼虾数量(Ni)扣除自然补充量后,再按捕捞系数(k)为0.75,以Ci=(Ni—ni)k/R式估算放流虾的回捕量和回捕率(C)。结果表明,1985,1986和1988—1990年回捕率分别为16.05,11.23,8.49,13.69和17.40％。对虾放流增殖效果显著。 相似文献
16.
A. K. Zalota G. A. Kolyuchkina A. V. Tiunov S. V. Biriukova V. A. Spiridonov 《Oceanology》2017,57(2):289-297
This work concerns the trophic web positioning of the alien crab Rhithropanopeus harrisii and other common marine invertebrate species and fishes in the benthic ecosystem of the shallows of Taman Bay, Sea of Azov. The base of the trophic web in this system is composed of phytoplankton, macrophytes (algae and marine grasses), and reeds that use atmospheric carbon for photosynthesis. Analysis of the isotopic composition of nitrogen and carbon has shown that although marine grasses are dominating primary producers in the shallows of the bay, primary consumers (such as Cerastoderma glaucum, Porifera gen. sp., Gammarus aequicauda, Deshayesorchestia deshayesii and Idotea balthica) only partially use this organic source; instead, they use a combination of different sources of primary production. It has been shown that the food source of the alien crab is primarily of animal origin. In Taman Bay, R. harrisii is on the same trophic level as other carnivores/scavengers: benthic fishes Syngnathus nigrolineatus, Gobius spp. and native crab Pilumnus hirtellus and shrimp Palaemon adspersus. 相似文献
17.
Gamak Bay is one of the largest aquaculture areas in the South Sea of Korea and exhibits hypoxia conditions during the summer. The harmful effects of hypoxia on aquaculture fish stock have not been elucidated. This study describes the biochemical effects of low levels of dissolved oxygen (DO) on cultivated juvenile Sebastes schlegeli in Gamak Bay. The hypoxia-inducible factor 1α (HIF1α) gene was induced significantly in S. schlegeli collected from low oxygen level areas, which suggests that fluctuations in the DO induces the expression of HIF1α. The level of antioxidant enzyme exhibited significantly higher activities in fish obtained from station F2 in which low levels of DO were shown in 2010 and 2011. The results of this study demonstrate that cultivated S. schlegeli are affected by the low levels of DO in Gamak Bay and superoxide dismutase enzymes operate dependently with HIF1α. The plasma glucose level did not exhibit significant difference in the fish among the sampling stations. We noted that HIF1α and the superoxide dismutase enzymes are useful biomarkers that might enable the detection of otherwise unnoticed hypoxic stress. 相似文献
18.
The yearly variations of mean sea levels at various locations along the coasts of Japan have been investigated, based upon the data of observation taken at 55 tide-gauge stations from 1953 to 1970, and some discussions have been made on the relationships between those variations and meteorological and oceanographical conditions, etc. The results obtained are as follows:
- In cases covering 90% of all the tide-gauge stations, the magnitude of the annual mean rate of variation of ground level is less than 10 mm/year, and the mean value of the magnitude for all the stations is ?3.17 mm/year, while that exclusive of Osaka is ?1.7 mm/year.
- The effect of atmospheric pressure variation on the height of annual mean sea level is of the order of several centimeters in view from both time and place.
- In view of the characteristic types of variations, the coasts of Japan may be divided into five regions of similar mean sea level deviations. And in the yearly variations of mean sea levels, there can be seen a kind of variation which corresponds to the variation of oceanographical conditions such as abnormal fall of seawater temperature.
- The mean sea level deviations at various locations along the coasts of Japan, referred to the standard sea level “T.P.” are different for different places. Namely, (1) on the coast of the Japan Sea, the west coast of Kyushu, the coast of Sanriku and the coast of Hokkaido, the mean sea level is higher than on the Pacific coasts from Southern Kyushu to Southern Honshu. (2) Along the coast of the Seto-Inland Sea, the mean sea level is generally higher.
19.
This study aims to constrain the base of the hydrates stability field in structurally complexsites using the case of Woolsey Mound, a fault-controlled, transient, thermogenic hydrates system, in Mississippi Canyon Block 118, northern Gulf of Mexico. We have computed the base of the hydrates stability field integrating results from a recent heat-flow survey, designed to investigate geothermal anomalies along fault zones which exhibit different fluid flux regimes. An advanced “compositional” simulator was used to model hydrate formation and dissociation at Woolsey Mound and addresses the following hypotheses:
- 1.Migrating thermogenic fluids alter thermal conditions of the Hydrate Stability Zone (HSZ), so heat-flow reflects fault activity;
- 2.Gas hydrate formation and dissociation vary temporally at active faults, temporarily sealing conduits for migration of thermogenic fluids;
- 3.High salinity and inclusion of thermogenic gases with higher molecular weight than methane produce opposite effects on the depth to the bottom of the hydrate stability zone.
20.
Current measurements in the surface layer in Sagami and Suruga Bays showed existence of significant tidal currents which are considered to be mainly due to internal tides (Inaba, 1982; Ohwaki,ea al., 1991). In addition, the prevailing period of the tidal currents is semidiurnal in Sagami Bay, but diurnal in Suruga Bay. To explain this difference in the prevailing, periods, numerical experiments were carried out using a two layer model. The internal tides are generated on the Izu Ridge outside the two bays. The semidiurnal internal tide propagates into Sagami Bay having characteristics of an internal inertia-gravity wave, while it propagates into Suruga Bay having characteristics of either an internal inertia-gravity wave or an internal Kelvin wave. The diurnal internal tide behaves only as an internal Kelvin wave, because the diurnal period is longer than the inertia period. Thus, the diurnal internal tide generated on the Izu Ridge can be propagated into Suruga Bay, while it cannot propagate into the inner region of Sagami Bay, though it is trapped around Oshima Island, which is located at the mouth of Sagami Bay. The difference in the propagation characteristics between the semidiurnal and diurnal internal tides can give a mechanism to explain the difference in the prevailing periods of the internal tides between Sagami and Suruga Bays. 相似文献