Based on the field data obtained during cruises on the shelf of the East China Sea from 1997 to 1999, seasonal variations of coastal upwelling on the inner shelf are discussed by using cross-shelf transect profiles an...Based on the field data obtained during cruises on the shelf of the East China Sea from 1997 to 1999, seasonal variations of coastal upwelling on the inner shelf are discussed by using cross-shelf transect profiles and horizontal distributions of chemical and hydrographic variables. Results show that the coastal upwelling was year-round, but the areas and intensities of the upwelling were quite different in season. The coastal upwelling occurred in all of the coastal areas of the region in spring and summer, but in autumn only in the area off Zhejiang Province, and in winter in the area off Fujian Prov- ince. It was the strongest in summer and the weakest in winter. Geographically, it was the strongest in the area off Zhejiang Province and the weakest in the southmost or northmost parts of the East China Sea. The estimated nutrient fluxes upward into euphotic zone through coastal upwelling were quite large, es- pecially for phosphate, which contributed significantly to primary production and improved the nutrient structure of the coastal ecosystem in the East China Sea.展开更多
Spatio-temporal distribution of chub mackerel Scomber japonicus is strongly susceptible to climate variability.In this study,a weighting-based habitat suitability index(HSI)model was established to assess the impacts ...Spatio-temporal distribution of chub mackerel Scomber japonicus is strongly susceptible to climate variability.In this study,a weighting-based habitat suitability index(HSI)model was established to assess the impacts of Pacific Decadal Oscillation(PDO)on habitat range and distribution of S.japonicus in the East China Sea(ECS)using vertical water temperature at depths of 2.5 m,25 m and 50 m.Results showed that the optimal HSI model selected from ten weighting scenarios can yield reliable predictions.Correlation analysis revealed a significant negative relationship between the PDO index and water temperature anomaly at different depths.The water temperatures at three different layers on the fishing ground of S.japonicus tended to be low in the warm PDO phase and high in the cold PDO phase,respectively.The range of suitable habitats and its spatial distribution exhibited large differences between the warm and cold PDO regimes.During a warm PDO phase,vertical water temperature became cool,and the monthly preferred water temperature at each depth for S.japonicus shifted southeastward.Consequently,habitat quality dramatically decreased,and suitable habitat ranges also reduced and moved southeastward.Conversely,in a cool PDO phase,with the warmer vertical water temperature and northwestward shift of the preferred water temperature,the suitable habitats enlarged and migrated in the same direction.Our findings indicate that the PDO produced significant impacts on habitat range and distribution of S.japonicus in the East China Sea.展开更多
In this study, the inverse method is used to compute the Kuroshio in the East China Sea and southeast of Kyushu and the currents east of the Ryukyu Islands, on the basis of hydrographic data obtained during September-...In this study, the inverse method is used to compute the Kuroshio in the East China Sea and southeast of Kyushu and the currents east of the Ryukyu Islands, on the basis of hydrographic data obtained during September-October, 1987 by R/V Chofu Maru. The results show that: (1)A part of the Taiwan Warm Current has a tendency to converge to the shelf break; (2) the Kuroshio flows across the section C3 (PN) with a reduced current width, and the velocity of the Kuroshio at the section C3 increases and its maximum current speed is about 158 cm/s, and its volume transport here is about 26×106m3/s; (3) the Kuroshio has two current cores at the sections C3 (PN) and B2 (at the Tokara Strait); (4) the currents east of the Ryukyu Islands are found to flow northward over the Ryukyu Trench during September-October, 1987. The velocities of the currents are not strong throughout the depths. At the section C2 east of the Ryukyu Islands, the maximum current speed is at the 699 m levei and its magnitude is 25 cm/s, and its volume transport is about 21×06 m3/s; (5) the volume transports of the Kuroshio through the sections B2 (at the Tokara Strait) and C6 (southeast of Kyushu) are 23. 33, 67. 31×106 m3/s, respectively; (6) there are two meso-scale anticyclonic warm eddies between 135° E and the area east of the Ryukyu Islands, and their characters and hydrographic structure are discussed.展开更多
Water samples were collected in the coastal area of the Changjiang Estuary on four cruises from August 2002 to May 2003. The seasonal variations of dissolved inorganic arsenic (DIAs) distributions were analyzed. The...Water samples were collected in the coastal area of the Changjiang Estuary on four cruises from August 2002 to May 2003. The seasonal variations of dissolved inorganic arsenic (DIAs) distributions were analyzed. The results showed that the distributions of DIAs were mainly influenced by Water (KSSW). The concentration of the total dissolved the terrestrial input and the intrusion of the Kuroshio Subsurface inorganic arsenic (TDIAs) decreased consecutively from winter to summer, while it increased in autumn. The distributions of TDIAs showed some relationships with salinity and suspended particulate matter (SPM). The relationships between DIAs speciation (including arsenite [ As( Ⅲ ) ] and arsenate [ As( Ⅴ ) ]), biological activity and the availabilities of the phosphate were investigated in the study area for the cruise August 2002. The ratio of As (Ⅲ)/TDIAs increased with the decrease of phosphate concentrations. In the bottom water, the As( Ⅲ )/TDIAs ratio decreased with the increasing of N/P. The concentration of TDIAs decreased 28.7% approximately after the occurrence of harmful algal blooms (HAB) because of the uptake of arsenate by algae. Further study is needed about the arsenic source/sink relationships in their vertical or horizontal profiles and the uptake mechanism during the occurrence of harmful algal blooms.展开更多
Three dimensional diagnostic,semidiagnostic and prognostic models in the σ coordinate are used to compute the current in the East China Sea with wind and hydrographic data obtained from the investigation of ocea...Three dimensional diagnostic,semidiagnostic and prognostic models in the σ coordinate are used to compute the current in the East China Sea with wind and hydrographic data obtained from the investigation of ocean fluxes in the East China Sea during the cruise of April 1994.The computed results show that:the density and velocity fields and so on have been adjusted when time t ≈ 23 d, i.e.,the solution of semidiagnostic calculation has been obtained.The quasi steady state solution also has been reached after about 60 d.Comparing the results of diagnostic calculation with those of semidiagnostic and prognostic calculations,it is found that they agree qualitatively.For example,they all show that:(1)The Kuroshio flows along the shelf break of 200~1 000 m isobaths;(2)In the southeastern part of the computational region there is a stronger counter current with an anticyclonic eddy;(3)The volume transport through Section PN is about 30×10 6m 3/s and so on.However there are some quantitative differences between them.For example,(1)For the semidiagnostic results the Kuroshio current is stronger and clearer than that for diagnostic results and the Kuroshio width is more narrow than that for diagnostic results.This shows that the semidiagnostic calculation can better reflect the topography effect;(2)In most computed region the vertical component of velocity intensifies for semidiagnostic result,especially on the shelf break.Comparing the results of semidiagnostic calculation with those of prognostic calculation,they agree qualitatively,and also agree quantitatively in the middle of computed region.展开更多
Biomarkers had been widely used to reconstruct phytoplankton productivity, and this method was applied in the East China Sea and the Huanghai Sea (Yellow Sea). In this study, Biologic Silicon (BSi) was used as pro...Biomarkers had been widely used to reconstruct phytoplankton productivity, and this method was applied in the East China Sea and the Huanghai Sea (Yellow Sea). In this study, Biologic Silicon (BSi) was used as productivity proxy to reconstruct productivity change of phytoplankton during last 200 years. The results show that the BSi contents of surficial'sediments were in the range of 0.018%-2.516%, averaging 0.726%, and had a similar variation trend with phytoplankton biomass. The vertical distribution profiles revealed that BSi contents were relatively stable, in accordance with the variations of the contemporary phytoplankton standing crop index. According to the stability analysis of BSi in sediments, BSi was not degradaded for the past two hundred years and remained in sediments steadily. Thus, BSi in sediments had the potential to invert paleoproductivity. To conduct further survey, the linear regression equation between BSi contents and phytoplankton biomass index could be used to calculate the phytoplankton productivity by BSi, so that paleoproduetivity may be reconstructed during last 200 years.展开更多
On the basis of perennial monthly mean temperature and salinity data, the classification of monthly water masses at the surface and the bottom in the Bohai Sea, the Huanghai Sea and the East China Sea, has been made b...On the basis of perennial monthly mean temperature and salinity data, the classification of monthly water masses at the surface and the bottom in the Bohai Sea, the Huanghai Sea and the East China Sea, has been made by using the method of fuzzy cluster from the modified characteristic of water masses in the shallow water area. In this paper, the basic features, growth and decline patterns of water masses in relation to fishing grounds in the whole shelves of the Bohai Sea, the Huanghai Sea and the East China Sea are discussed with emphasis.展开更多
Most fisheries in China do not have maximum sustainable yield(MSY) estimates due to limited and poor data.Therefore, finding a common method to estimate MSY or total allowable catch(TAC) for fishery management is ...Most fisheries in China do not have maximum sustainable yield(MSY) estimates due to limited and poor data.Therefore, finding a common method to estimate MSY or total allowable catch(TAC) for fishery management is necessary. MSYs of three important fisheries in the East China Sea were evaluated through a catch-based model.Estimates for intrinsic rate of increase(r) and five levels of process error were considered. Results showed hairtail Trichiurus japonicas(Temminck and Schlegel) and small yellow croaker Larimichthys polyactis(Bleeker) fisheries experienced overfishing from the mid-1990 s to the early 2000 s, and the suggested TACs were 55.8×10^4 t and9.06×10^4 t, respectively. Decades of overfishing in wintering and spawning grounds of large yellow croaker Larimichthys crocea(Richardson) caused the fishery's collapse in the 1980 s, and it has not recovered until today.The Catch–MSY model generated similar estimated MSYs with other methods and may be a useful choice for the assessment of regional stocks in China.展开更多
Based on the recent research results on dry and wet deposition of nutrient elements and sulphate, we estimate the atmospheric flux of nutrient elements and sulphate to the southern Yellow Sea and the East China Sea in...Based on the recent research results on dry and wet deposition of nutrient elements and sulphate, we estimate the atmospheric flux of nutrient elements and sulphate to the southern Yellow Sea and the East China Sea in each season. The results suggest that the concentrations of nutrient elements and sulphate in aerosol and precipitation show an apparent seasonal cycle with the maximum values in winter and the minimum values in summer. Depositions of nitrate and sulphate are dominated by wet deposition, while the deposition for phosphate is mainly dry deposition. Moreover, compared with the riverine inputs, the atmospheric deposition may be the main source of dissolved inorganic nutrients in the southern Yellow Sea and the East China Sea.展开更多
The Yithi submarine canyons, composed of four canyons less than 60 km in length, are located on the narrowest part of the East China Sea (ECS) slope. They extend from the shelf break at 160 m down to water depth of ...The Yithi submarine canyons, composed of four canyons less than 60 km in length, are located on the narrowest part of the East China Sea (ECS) slope. They extend from the shelf break at 160 m down to water depth of 1 500 m with an average gradient (along the canyon axis) of 3°(〈1 000 m) and 0.7°(〈1 000 m). The sinuosity of the canyons ranges form 1.02 to 1.14 and their pathways extend radially from the shelf break to the axis of the Okinawa Trough. Structural and evolution pattern of the Yithi canyons are mainly controlled by sediment mass-movements and turbidity current and similar with that of the canyons in Ebro continental slope. The whole canyon system consists of three parts: the canyon, the channel and the fan. Slumps and slides often develop in the upper part of canyon where the water depth is less than 1 000 m, and the turbidities usually developed on the fan. The scale of turbidites becomes smaller and their inner structures become more regular towards the ends of the canyons. Canyon-fans are often associated with small angle progradational reflection. Most canyon-fans and levees were transversely cut by active normal faults with NEE- SWW trending that are coupled to the modern extension of the Okinawa Trough. According to the age of formation of canyon-fans and sediments incised by canyons, we can infer that the Yithi canyons were formed since the middle the Medio-Pleistocene.展开更多
The available data on tidal currents spanning periods greater than six months for the continental shelf of the East China Sea (26°30.052′N, 122°35.998′E) were analyzed using several methods. Tidal Current ...The available data on tidal currents spanning periods greater than six months for the continental shelf of the East China Sea (26°30.052′N, 122°35.998′E) were analyzed using several methods. Tidal Current Harmonic Analysis results demonstrated that semi-diurnal tides dominated the current movement. The tidal currents of the principal diurnal and semidiurnal rotated clockwise with depth, with the deflection of the major semi-axes to the right in the upper layer and to the left in the lower layer. The vertical structures of two principal semi-diurnal constituents-M2 and S2-were similar, which indicates that the tidal currents are mainly barotropic in this area. The main features of the variation of the four principal tidal constituents with depth demonstrate that the currents in this region are influenced by the upper and lower boundary layers. Therefore, the tidal constituents of the shallow water are similar. Different vertical modes were calculated based on the Empirical Orthogonal Function (EOF) analysis of the Eastern and Northern components of the tidal currents, with a variance contribution for the zero-order model of at least 90%. The variance contribution of the baroclinic model is minimal, which further reveals a strong barotropic character for the tidal currents of this region.展开更多
The structure of current speed and the variability of volume transports of the Kuroshio in the Tokara-kaikyo and Osumi-kaikyo are discussed on the basis of data of KER in the period from 1977 to 1984. The average geos...The structure of current speed and the variability of volume transports of the Kuroshio in the Tokara-kaikyo and Osumi-kaikyo are discussed on the basis of data of KER in the period from 1977 to 1984. The average geostrophic transport through these two straits is estimated to be 24. 5×106 m3/s and only 1/12 of the transport is through the Osumi-kaiky5. Countercurrents on both sides of the Kuroshio trunk are observed in the Tokara-kaikyo. Calculation indicates that the average geostrophic current speed is less than the GEK current speed, systematically. On the basis of the current measurements, the northward transports through the Taiwan Strait in winter and summer are estimated to be 1. 05×106and 3. 16×106m3/s, respectively. From Chu's data (1976) the average transport of the Kuroshio flowing into the East China Sea passing through the passage east of Taiwan is about 29. 3×106m3/s. From Miita and Ogawa's data (1984) the average transport through the Tsushima-kaikyo is 3. 6×106m3/s. Thus the volume transports through the above four straits are roughly in balance, the total outflowing transport is slightly larger than the total inflowing transport. The possible reasons resulting in the difference of transports are also discussed.展开更多
Ocean current forecasting is still in explorative stage of study. In the study, we face some problems that have not been met before. The solving of these problems has become fundamental premise for realizing the ocean...Ocean current forecasting is still in explorative stage of study. In the study, we face some problems that have not been met before. The solving of these problems has become fundamental premise for realizing the ocean current forecasting. In the present paper are discussed in depth the physical essence for such basic problems as the predictability of ocean current, the predictable currents, the dynamical basis for studying respectively the tidal current and circulation, the necessity of boundary model, the models on regions with different scales and their link. The foundations and plans to solve the problems are demonstrated. Finally a set of operational numerical forecasting system for ocean current is proposed.展开更多
A new species of cymothoid Isopoda, Nerocila donghaiensis , collected from the body of a sciaenid fish, Johnius sp., is described in the present paper. The new species can be distinguished from the other species of ge...A new species of cymothoid Isopoda, Nerocila donghaiensis , collected from the body of a sciaenid fish, Johnius sp., is described in the present paper. The new species can be distinguished from the other species of genus Nerocila by its endopod of uropods with deep notch, sharply serrated on the lateral margin and strongly serrated on the medial margin; antennule with 1st article swollen; dactyli of pereopods I, II, IV, V swollen.展开更多
The Cold Eddy in the East China Sea(CEECS) is located about 150 km southwest of Cheju Island.This region experiences a complex current system under the influences of the Yellow Sea Warm Current(YSWC),the Yellow Sea Co...The Cold Eddy in the East China Sea(CEECS) is located about 150 km southwest of Cheju Island.This region experiences a complex current system under the influences of the Yellow Sea Warm Current(YSWC),the Yellow Sea Coastal Current(YSCC),and the northward Kuroshio residual.To identify the strength of the CEECS,a simple subsurface intensity index is developed.Because the CEECS can be traced by temperature minimum,the intensity index is determined by the difference in sea temperature averaged across cores within and surrounding the region.Based on SODA,the CEECS subsurface intensity index time series can be calculated,with which the inter-annual variation of the CEECS is analyzed.展开更多
-A two-dimensional.nonlinear numerical model is used to study the residual current generated by tides in the East China Sea (ECS)and the South Huanghai Sea (SHS). At first, the principal semidiurnal lunar tide (M2)and...-A two-dimensional.nonlinear numerical model is used to study the residual current generated by tides in the East China Sea (ECS)and the South Huanghai Sea (SHS). At first, the principal semidiurnal lunar tide (M2)and the tidal current are derived in these areas. The results obtained with the model are strongly supported by the observational results available. Then, the tide-induced residual flow is determined by using the currents generated by the tidal input. The main features of the residual current in ECS and SHS are presented by analyzing the calculated results. Some of the problems are discussed such as the cause of generating residual current and the contribution of the residual current to the observed current.展开更多
-The material discussed in this paper is from four cruises which were carried out in May -June, 1986 (spring), July -August, 1987(summer) .October -November, 1988(autumn)and December, 1987(winter)respectively. Identif...-The material discussed in this paper is from four cruises which were carried out in May -June, 1986 (spring), July -August, 1987(summer) .October -November, 1988(autumn)and December, 1987(winter)respectively. Identified dinoflagellates were 141 species (including varieties and forms) belonging to 18 genera.According to the distribution and ecological characteristics of dinoflagellates species, we can divide them into three groups: 1) Hyporhaline-neritic group: they are distributed only in type Ⅲ and typeⅣ water and they perform an evident function indicating continental coast water; 2) Eurythermic-euryhaline group represented by Protoperidinium depressum, Gentium fusus, etc. They are fond of perching in mixing water which character is similar to that of coast water even though they are distributed in different water systems; 3) Hyperthermic-hyperhaline group: on the basis of varying degrees to which they tolerate temperature and salinity, we can divide them into two sub-groups: euryhyperthermic-euryhyperha-line subgroup and stenohyperthermic- stenohyperhaline subgroup. The first subgroup is represented by Pyrocystis pseudoxoctiluca whose adaptability reaction occurred with the changing of hydrographic environment. The second subgroup is tropic oceanic species which can serve as a good indicator for Kuroshio in the East China Sea. Its biological boundary coincides well with the hydrographic boundary of Kuroshio water.展开更多
On the basis of the historical profile observations and the recent Kuroshio observations,the yearly formation,development and decay of the high density water found between 50 to 100 m isobath over the middle and south...On the basis of the historical profile observations and the recent Kuroshio observations,the yearly formation,development and decay of the high density water found between 50 to 100 m isobath over the middle and southern East China Sea continental shelf are anyalysed. The formation of this high density water occurs between November and March of the following year. A possible reason for it is that as the mixed water between the coastal water and the outer sea water transports northward by the Taiwan Warm Current, its density increases by surface cooling. It also mixes with the neighbouring lower density water masses. The transportation and decay of the high density water through April to July are also descussed. They can be ascribed to the seasonal surface layer warming and the fast development of Taiwan Warm Current. The high density water disappears in August.展开更多
In the course of identifying the samples of Siphonophora from the East China Sea and South China Sea, a new Siphonophora, Vogtia microsticella sp. nov. , was noted. The new species is distinguished from other five spe...In the course of identifying the samples of Siphonophora from the East China Sea and South China Sea, a new Siphonophora, Vogtia microsticella sp. nov. , was noted. The new species is distinguished from other five species in the genus in nectophore as follows: Parahorse-shoe shaped with five bluntly rounded projections, the two projections below the ostium, i. e. the basal projections, approach each other. The dorsal facet is smooth without any gelatinous prominence. Smaller are the nectosac and the ostium.展开更多
In summer and winter, 1987,and in spring and autumn, 1988, the concentrations and size distribution of marine aerosols were measured over the East China Sea and the South Japan Sea. This paper deals with the study on ...In summer and winter, 1987,and in spring and autumn, 1988, the concentrations and size distribution of marine aerosols were measured over the East China Sea and the South Japan Sea. This paper deals with the study on the seasonal variation of the marine aerosols with the meteorological parameters, the differences and the relations between the marine and continental aerosols. The results show that the marine aerosol concentrations and size distribution over the East China Sea have distinct seasonal change characteristics, which may be attributed to the East Asian atmospheric circulation. The size distribution is discussed by using a three-parameter size distribution model.展开更多
基金Supported by the National Basic Research Program of China (973 Pro-gram), No. 2001CB4097
文摘Based on the field data obtained during cruises on the shelf of the East China Sea from 1997 to 1999, seasonal variations of coastal upwelling on the inner shelf are discussed by using cross-shelf transect profiles and horizontal distributions of chemical and hydrographic variables. Results show that the coastal upwelling was year-round, but the areas and intensities of the upwelling were quite different in season. The coastal upwelling occurred in all of the coastal areas of the region in spring and summer, but in autumn only in the area off Zhejiang Province, and in winter in the area off Fujian Prov- ince. It was the strongest in summer and the weakest in winter. Geographically, it was the strongest in the area off Zhejiang Province and the weakest in the southmost or northmost parts of the East China Sea. The estimated nutrient fluxes upward into euphotic zone through coastal upwelling were quite large, es- pecially for phosphate, which contributed significantly to primary production and improved the nutrient structure of the coastal ecosystem in the East China Sea.
基金the National Key R&D Program of China(No.2018YFD0900906)the National Natural Science Foundation of China(No.41906073)+1 种基金the Natural Science Foundation of Shanghai(No.19ZR1423000)the Shanghai Universities First-Class Disciplines Project(Fisheries A).
文摘Spatio-temporal distribution of chub mackerel Scomber japonicus is strongly susceptible to climate variability.In this study,a weighting-based habitat suitability index(HSI)model was established to assess the impacts of Pacific Decadal Oscillation(PDO)on habitat range and distribution of S.japonicus in the East China Sea(ECS)using vertical water temperature at depths of 2.5 m,25 m and 50 m.Results showed that the optimal HSI model selected from ten weighting scenarios can yield reliable predictions.Correlation analysis revealed a significant negative relationship between the PDO index and water temperature anomaly at different depths.The water temperatures at three different layers on the fishing ground of S.japonicus tended to be low in the warm PDO phase and high in the cold PDO phase,respectively.The range of suitable habitats and its spatial distribution exhibited large differences between the warm and cold PDO regimes.During a warm PDO phase,vertical water temperature became cool,and the monthly preferred water temperature at each depth for S.japonicus shifted southeastward.Consequently,habitat quality dramatically decreased,and suitable habitat ranges also reduced and moved southeastward.Conversely,in a cool PDO phase,with the warmer vertical water temperature and northwestward shift of the preferred water temperature,the suitable habitats enlarged and migrated in the same direction.Our findings indicate that the PDO produced significant impacts on habitat range and distribution of S.japonicus in the East China Sea.
文摘In this study, the inverse method is used to compute the Kuroshio in the East China Sea and southeast of Kyushu and the currents east of the Ryukyu Islands, on the basis of hydrographic data obtained during September-October, 1987 by R/V Chofu Maru. The results show that: (1)A part of the Taiwan Warm Current has a tendency to converge to the shelf break; (2) the Kuroshio flows across the section C3 (PN) with a reduced current width, and the velocity of the Kuroshio at the section C3 increases and its maximum current speed is about 158 cm/s, and its volume transport here is about 26×106m3/s; (3) the Kuroshio has two current cores at the sections C3 (PN) and B2 (at the Tokara Strait); (4) the currents east of the Ryukyu Islands are found to flow northward over the Ryukyu Trench during September-October, 1987. The velocities of the currents are not strong throughout the depths. At the section C2 east of the Ryukyu Islands, the maximum current speed is at the 699 m levei and its magnitude is 25 cm/s, and its volume transport is about 21×06 m3/s; (5) the volume transports of the Kuroshio through the sections B2 (at the Tokara Strait) and C6 (southeast of Kyushu) are 23. 33, 67. 31×106 m3/s, respectively; (6) there are two meso-scale anticyclonic warm eddies between 135° E and the area east of the Ryukyu Islands, and their characters and hydrographic structure are discussed.
基金This research was supported by the National Basic Research Program of China (Nos. 2001CB409703 and G1999043705) the National Natural Science Foundation of China (Nos. 40036010 and 40206017).
文摘Water samples were collected in the coastal area of the Changjiang Estuary on four cruises from August 2002 to May 2003. The seasonal variations of dissolved inorganic arsenic (DIAs) distributions were analyzed. The results showed that the distributions of DIAs were mainly influenced by Water (KSSW). The concentration of the total dissolved the terrestrial input and the intrusion of the Kuroshio Subsurface inorganic arsenic (TDIAs) decreased consecutively from winter to summer, while it increased in autumn. The distributions of TDIAs showed some relationships with salinity and suspended particulate matter (SPM). The relationships between DIAs speciation (including arsenite [ As( Ⅲ ) ] and arsenate [ As( Ⅴ ) ]), biological activity and the availabilities of the phosphate were investigated in the study area for the cruise August 2002. The ratio of As (Ⅲ)/TDIAs increased with the decrease of phosphate concentrations. In the bottom water, the As( Ⅲ )/TDIAs ratio decreased with the increasing of N/P. The concentration of TDIAs decreased 28.7% approximately after the occurrence of harmful algal blooms (HAB) because of the uptake of arsenate by algae. Further study is needed about the arsenic source/sink relationships in their vertical or horizontal profiles and the uptake mechanism during the occurrence of harmful algal blooms.
文摘Three dimensional diagnostic,semidiagnostic and prognostic models in the σ coordinate are used to compute the current in the East China Sea with wind and hydrographic data obtained from the investigation of ocean fluxes in the East China Sea during the cruise of April 1994.The computed results show that:the density and velocity fields and so on have been adjusted when time t ≈ 23 d, i.e.,the solution of semidiagnostic calculation has been obtained.The quasi steady state solution also has been reached after about 60 d.Comparing the results of diagnostic calculation with those of semidiagnostic and prognostic calculations,it is found that they agree qualitatively.For example,they all show that:(1)The Kuroshio flows along the shelf break of 200~1 000 m isobaths;(2)In the southeastern part of the computational region there is a stronger counter current with an anticyclonic eddy;(3)The volume transport through Section PN is about 30×10 6m 3/s and so on.However there are some quantitative differences between them.For example,(1)For the semidiagnostic results the Kuroshio current is stronger and clearer than that for diagnostic results and the Kuroshio width is more narrow than that for diagnostic results.This shows that the semidiagnostic calculation can better reflect the topography effect;(2)In most computed region the vertical component of velocity intensifies for semidiagnostic result,especially on the shelf break.Comparing the results of semidiagnostic calculation with those of prognostic calculation,they agree qualitatively,and also agree quantitatively in the middle of computed region.
基金The National Key Basic Research Program of China under contract No.2006CB400007the National Natural Science Foundation of China under contract No.40876088
文摘Biomarkers had been widely used to reconstruct phytoplankton productivity, and this method was applied in the East China Sea and the Huanghai Sea (Yellow Sea). In this study, Biologic Silicon (BSi) was used as productivity proxy to reconstruct productivity change of phytoplankton during last 200 years. The results show that the BSi contents of surficial'sediments were in the range of 0.018%-2.516%, averaging 0.726%, and had a similar variation trend with phytoplankton biomass. The vertical distribution profiles revealed that BSi contents were relatively stable, in accordance with the variations of the contemporary phytoplankton standing crop index. According to the stability analysis of BSi in sediments, BSi was not degradaded for the past two hundred years and remained in sediments steadily. Thus, BSi in sediments had the potential to invert paleoproductivity. To conduct further survey, the linear regression equation between BSi contents and phytoplankton biomass index could be used to calculate the phytoplankton productivity by BSi, so that paleoproduetivity may be reconstructed during last 200 years.
基金This subject is aided financially by Chinese National Natural Science Foundation.
文摘On the basis of perennial monthly mean temperature and salinity data, the classification of monthly water masses at the surface and the bottom in the Bohai Sea, the Huanghai Sea and the East China Sea, has been made by using the method of fuzzy cluster from the modified characteristic of water masses in the shallow water area. In this paper, the basic features, growth and decline patterns of water masses in relation to fishing grounds in the whole shelves of the Bohai Sea, the Huanghai Sea and the East China Sea are discussed with emphasis.
基金The National Natural Science Foundation of China under contract No.31602157the Special Fund for Agroscientific Research in the Public Interest under contract No.201403008the Central Public-interest Scientific Institution Basal Research Fund of South China Sea Fisheries Research Institute under contract No.2016TS06
文摘Most fisheries in China do not have maximum sustainable yield(MSY) estimates due to limited and poor data.Therefore, finding a common method to estimate MSY or total allowable catch(TAC) for fishery management is necessary. MSYs of three important fisheries in the East China Sea were evaluated through a catch-based model.Estimates for intrinsic rate of increase(r) and five levels of process error were considered. Results showed hairtail Trichiurus japonicas(Temminck and Schlegel) and small yellow croaker Larimichthys polyactis(Bleeker) fisheries experienced overfishing from the mid-1990 s to the early 2000 s, and the suggested TACs were 55.8×10^4 t and9.06×10^4 t, respectively. Decades of overfishing in wintering and spawning grounds of large yellow croaker Larimichthys crocea(Richardson) caused the fishery's collapse in the 1980 s, and it has not recovered until today.The Catch–MSY model generated similar estimated MSYs with other methods and may be a useful choice for the assessment of regional stocks in China.
基金This work is supported by the State"973"basic research program under contract(G19990437)the international cooperation program under contract(2001CB711004).
文摘Based on the recent research results on dry and wet deposition of nutrient elements and sulphate, we estimate the atmospheric flux of nutrient elements and sulphate to the southern Yellow Sea and the East China Sea in each season. The results suggest that the concentrations of nutrient elements and sulphate in aerosol and precipitation show an apparent seasonal cycle with the maximum values in winter and the minimum values in summer. Depositions of nitrate and sulphate are dominated by wet deposition, while the deposition for phosphate is mainly dry deposition. Moreover, compared with the riverine inputs, the atmospheric deposition may be the main source of dissolved inorganic nutrients in the southern Yellow Sea and the East China Sea.
基金The National Natural Science Foundation of China under contract Nos 40576033 and 40406013the Marine Science Foundation of State Oceanic Administration under contract No.2006306
文摘The Yithi submarine canyons, composed of four canyons less than 60 km in length, are located on the narrowest part of the East China Sea (ECS) slope. They extend from the shelf break at 160 m down to water depth of 1 500 m with an average gradient (along the canyon axis) of 3°(〈1 000 m) and 0.7°(〈1 000 m). The sinuosity of the canyons ranges form 1.02 to 1.14 and their pathways extend radially from the shelf break to the axis of the Okinawa Trough. Structural and evolution pattern of the Yithi canyons are mainly controlled by sediment mass-movements and turbidity current and similar with that of the canyons in Ebro continental slope. The whole canyon system consists of three parts: the canyon, the channel and the fan. Slumps and slides often develop in the upper part of canyon where the water depth is less than 1 000 m, and the turbidities usually developed on the fan. The scale of turbidites becomes smaller and their inner structures become more regular towards the ends of the canyons. Canyon-fans are often associated with small angle progradational reflection. Most canyon-fans and levees were transversely cut by active normal faults with NEE- SWW trending that are coupled to the modern extension of the Okinawa Trough. According to the age of formation of canyon-fans and sediments incised by canyons, we can infer that the Yithi canyons were formed since the middle the Medio-Pleistocene.
基金supported by the National Basic Research Program of China (2007CB411807)the National Natural Science Foundation of China (40806072,41176009)
文摘The available data on tidal currents spanning periods greater than six months for the continental shelf of the East China Sea (26°30.052′N, 122°35.998′E) were analyzed using several methods. Tidal Current Harmonic Analysis results demonstrated that semi-diurnal tides dominated the current movement. The tidal currents of the principal diurnal and semidiurnal rotated clockwise with depth, with the deflection of the major semi-axes to the right in the upper layer and to the left in the lower layer. The vertical structures of two principal semi-diurnal constituents-M2 and S2-were similar, which indicates that the tidal currents are mainly barotropic in this area. The main features of the variation of the four principal tidal constituents with depth demonstrate that the currents in this region are influenced by the upper and lower boundary layers. Therefore, the tidal constituents of the shallow water are similar. Different vertical modes were calculated based on the Empirical Orthogonal Function (EOF) analysis of the Eastern and Northern components of the tidal currents, with a variance contribution for the zero-order model of at least 90%. The variance contribution of the baroclinic model is minimal, which further reveals a strong barotropic character for the tidal currents of this region.
文摘The structure of current speed and the variability of volume transports of the Kuroshio in the Tokara-kaikyo and Osumi-kaikyo are discussed on the basis of data of KER in the period from 1977 to 1984. The average geostrophic transport through these two straits is estimated to be 24. 5×106 m3/s and only 1/12 of the transport is through the Osumi-kaiky5. Countercurrents on both sides of the Kuroshio trunk are observed in the Tokara-kaikyo. Calculation indicates that the average geostrophic current speed is less than the GEK current speed, systematically. On the basis of the current measurements, the northward transports through the Taiwan Strait in winter and summer are estimated to be 1. 05×106and 3. 16×106m3/s, respectively. From Chu's data (1976) the average transport of the Kuroshio flowing into the East China Sea passing through the passage east of Taiwan is about 29. 3×106m3/s. From Miita and Ogawa's data (1984) the average transport through the Tsushima-kaikyo is 3. 6×106m3/s. Thus the volume transports through the above four straits are roughly in balance, the total outflowing transport is slightly larger than the total inflowing transport. The possible reasons resulting in the difference of transports are also discussed.
文摘Ocean current forecasting is still in explorative stage of study. In the study, we face some problems that have not been met before. The solving of these problems has become fundamental premise for realizing the ocean current forecasting. In the present paper are discussed in depth the physical essence for such basic problems as the predictability of ocean current, the predictable currents, the dynamical basis for studying respectively the tidal current and circulation, the necessity of boundary model, the models on regions with different scales and their link. The foundations and plans to solve the problems are demonstrated. Finally a set of operational numerical forecasting system for ocean current is proposed.
文摘A new species of cymothoid Isopoda, Nerocila donghaiensis , collected from the body of a sciaenid fish, Johnius sp., is described in the present paper. The new species can be distinguished from the other species of genus Nerocila by its endopod of uropods with deep notch, sharply serrated on the lateral margin and strongly serrated on the medial margin; antennule with 1st article swollen; dactyli of pereopods I, II, IV, V swollen.
基金Supported by National Basic Research Program of China (Nos. 2005CB422307, 2007CB411803)Program for New Century Excellent Talents in University (NCET-08-0510)National 908 Program of China (No. 908-02-02-02)
文摘The Cold Eddy in the East China Sea(CEECS) is located about 150 km southwest of Cheju Island.This region experiences a complex current system under the influences of the Yellow Sea Warm Current(YSWC),the Yellow Sea Coastal Current(YSCC),and the northward Kuroshio residual.To identify the strength of the CEECS,a simple subsurface intensity index is developed.Because the CEECS can be traced by temperature minimum,the intensity index is determined by the difference in sea temperature averaged across cores within and surrounding the region.Based on SODA,the CEECS subsurface intensity index time series can be calculated,with which the inter-annual variation of the CEECS is analyzed.
文摘-A two-dimensional.nonlinear numerical model is used to study the residual current generated by tides in the East China Sea (ECS)and the South Huanghai Sea (SHS). At first, the principal semidiurnal lunar tide (M2)and the tidal current are derived in these areas. The results obtained with the model are strongly supported by the observational results available. Then, the tide-induced residual flow is determined by using the currents generated by the tidal input. The main features of the residual current in ECS and SHS are presented by analyzing the calculated results. Some of the problems are discussed such as the cause of generating residual current and the contribution of the residual current to the observed current.
文摘-The material discussed in this paper is from four cruises which were carried out in May -June, 1986 (spring), July -August, 1987(summer) .October -November, 1988(autumn)and December, 1987(winter)respectively. Identified dinoflagellates were 141 species (including varieties and forms) belonging to 18 genera.According to the distribution and ecological characteristics of dinoflagellates species, we can divide them into three groups: 1) Hyporhaline-neritic group: they are distributed only in type Ⅲ and typeⅣ water and they perform an evident function indicating continental coast water; 2) Eurythermic-euryhaline group represented by Protoperidinium depressum, Gentium fusus, etc. They are fond of perching in mixing water which character is similar to that of coast water even though they are distributed in different water systems; 3) Hyperthermic-hyperhaline group: on the basis of varying degrees to which they tolerate temperature and salinity, we can divide them into two sub-groups: euryhyperthermic-euryhyperha-line subgroup and stenohyperthermic- stenohyperhaline subgroup. The first subgroup is represented by Pyrocystis pseudoxoctiluca whose adaptability reaction occurred with the changing of hydrographic environment. The second subgroup is tropic oceanic species which can serve as a good indicator for Kuroshio in the East China Sea. Its biological boundary coincides well with the hydrographic boundary of Kuroshio water.
文摘On the basis of the historical profile observations and the recent Kuroshio observations,the yearly formation,development and decay of the high density water found between 50 to 100 m isobath over the middle and southern East China Sea continental shelf are anyalysed. The formation of this high density water occurs between November and March of the following year. A possible reason for it is that as the mixed water between the coastal water and the outer sea water transports northward by the Taiwan Warm Current, its density increases by surface cooling. It also mixes with the neighbouring lower density water masses. The transportation and decay of the high density water through April to July are also descussed. They can be ascribed to the seasonal surface layer warming and the fast development of Taiwan Warm Current. The high density water disappears in August.
文摘In the course of identifying the samples of Siphonophora from the East China Sea and South China Sea, a new Siphonophora, Vogtia microsticella sp. nov. , was noted. The new species is distinguished from other five species in the genus in nectophore as follows: Parahorse-shoe shaped with five bluntly rounded projections, the two projections below the ostium, i. e. the basal projections, approach each other. The dorsal facet is smooth without any gelatinous prominence. Smaller are the nectosac and the ostium.
文摘In summer and winter, 1987,and in spring and autumn, 1988, the concentrations and size distribution of marine aerosols were measured over the East China Sea and the South Japan Sea. This paper deals with the study on the seasonal variation of the marine aerosols with the meteorological parameters, the differences and the relations between the marine and continental aerosols. The results show that the marine aerosol concentrations and size distribution over the East China Sea have distinct seasonal change characteristics, which may be attributed to the East Asian atmospheric circulation. The size distribution is discussed by using a three-parameter size distribution model.