2010 Vol. 32, No. 1
Display Method:
2010, 32(1): 1-9.
Abstract:
According to the obtained CTD data of Zhujiang River estuary and the surrounding waters during the winter cruise in 2006, it found that under the convection effect of the cooling surface water and the strong dynamical condition of northeast monsoon, wave and current act., the shelf water mixed uniform vertically, however, eastern Guangdong coastal waters has remarkable thermocline and inverse halocline, which caused by the transporting of high temperature and salinity surface water from shelf to coast under the Ekman effect of northeast monsoon, the offshore transporting of low temperature and salinity coastal bottom water under the Ekman effect of bottom boundary layer due to the southwest coastal current drived by northeast monsoon, these led to the secondary circulation in the shelf direction and downwelling in the coastal area which embodys in the phenomena of inverse halocline and thermocline in the costal area. In the area with remarkable downwelling, the dissolved oxygen concentration is uniform vertically and higher than other area. This should ascribe to downwelling effect which can bring the surface water with higher concentration dissolved oxygen to the deep layer.
According to the obtained CTD data of Zhujiang River estuary and the surrounding waters during the winter cruise in 2006, it found that under the convection effect of the cooling surface water and the strong dynamical condition of northeast monsoon, wave and current act., the shelf water mixed uniform vertically, however, eastern Guangdong coastal waters has remarkable thermocline and inverse halocline, which caused by the transporting of high temperature and salinity surface water from shelf to coast under the Ekman effect of northeast monsoon, the offshore transporting of low temperature and salinity coastal bottom water under the Ekman effect of bottom boundary layer due to the southwest coastal current drived by northeast monsoon, these led to the secondary circulation in the shelf direction and downwelling in the coastal area which embodys in the phenomena of inverse halocline and thermocline in the costal area. In the area with remarkable downwelling, the dissolved oxygen concentration is uniform vertically and higher than other area. This should ascribe to downwelling effect which can bring the surface water with higher concentration dissolved oxygen to the deep layer.
2010, 32(1): 10-22.
Abstract:
By using two tropical cyclone datasets for northwest Pacific (NWP) of China Meteorological Administration (CMA) and Joint Typhoon Warning Center (JTWC), the differences with respect to TC location and intensity between them were analyzed. Results showed that for TC location, large discrepancies existed in two periods: 1951-early 1960s and 1988-1990s, and geographically always appeared in regions where TC landed or highlatitude areas. For TC intensity, the CMA dataset was apparently overestimated in 1950s and from the late 1960s to the early 1970s, while the JTWC dataset overestimated in 1993-2003. TC Intensity discrepancies showed scattered large values in different regions before 1980s, after which with the increase of intensity for JTWC dataset, it was significantly greater than that of CMA dataset in most of NWP, while the latter was greater in the coast regions of East Asia. Further analysis reveals that the discrepancies are obviously related to the TC observational techniques. Before the era of application of meteorological satellite in operational typhoon Centers (1951-early 1960s), and after the termination of aircraft reconnaissance (1988-), large discrepancies existed in not only TC intensity but also TC location. The smaller discrepancies period (1973-1987) for TC intensity also coincided with timeframe when aircraft reconnaissance data and the Dvorak technique were both available in TC operational centers. For the two TC datasets, although obvious discrepancies existed between them, each had its own characteristics. Currently, it is still difficult to judge which one is better, but for TC activities affecting China, the CMA dataset has obvious advantages.
By using two tropical cyclone datasets for northwest Pacific (NWP) of China Meteorological Administration (CMA) and Joint Typhoon Warning Center (JTWC), the differences with respect to TC location and intensity between them were analyzed. Results showed that for TC location, large discrepancies existed in two periods: 1951-early 1960s and 1988-1990s, and geographically always appeared in regions where TC landed or highlatitude areas. For TC intensity, the CMA dataset was apparently overestimated in 1950s and from the late 1960s to the early 1970s, while the JTWC dataset overestimated in 1993-2003. TC Intensity discrepancies showed scattered large values in different regions before 1980s, after which with the increase of intensity for JTWC dataset, it was significantly greater than that of CMA dataset in most of NWP, while the latter was greater in the coast regions of East Asia. Further analysis reveals that the discrepancies are obviously related to the TC observational techniques. Before the era of application of meteorological satellite in operational typhoon Centers (1951-early 1960s), and after the termination of aircraft reconnaissance (1988-), large discrepancies existed in not only TC intensity but also TC location. The smaller discrepancies period (1973-1987) for TC intensity also coincided with timeframe when aircraft reconnaissance data and the Dvorak technique were both available in TC operational centers. For the two TC datasets, although obvious discrepancies existed between them, each had its own characteristics. Currently, it is still difficult to judge which one is better, but for TC activities affecting China, the CMA dataset has obvious advantages.
2010, 32(1): 23-33.
Abstract:
Based on 233 stations daily precipitation datasets in the East China from 1955 to 2004, NCEP/NCAR reanalysis height fields, vertical velocity, specific humidity, surface pressure and NOAA reconstruct sea surface temperature, and with singular value decomposition, compose analysis methods, relation between Pacific sea surface temperature and extreme precipitation events of East China is researched. It is found that winter Pacific sea surface temperature have remarkable relations with anaphase summer extreme precipitation events of East China, and Equator middle and East Pacific is key area which affect to summer extreme precipitation events of East China, when sea surface temperature occur anomaly phenomenon in the Equator middle and East Pacific in winter, by PNA (AntiPNA) and WP (AntiWP) teleconnection on atmospheric circulation take place adjustment from winter to summer, thus West Pacfic SubTropic High Pressure also take palce anomaly, at last summer extreme precipitation events of North China occur anomaly phenomenon. It is also found that tropic West Pacific is key area which affect to summer extreme precipitation events of northeast China and south of Changjiang River, when sea surface temperature occur anomaly phenomenon in the tropic West Pacific in winter, the average latitudinal vertical circulation of 105°~135°E take place anomaly phenomenon, and vertical motion occur anomaly in the northeast China and south of Changjiang River, at last the extreme precipitation events of the areas also occur anomaly.
Based on 233 stations daily precipitation datasets in the East China from 1955 to 2004, NCEP/NCAR reanalysis height fields, vertical velocity, specific humidity, surface pressure and NOAA reconstruct sea surface temperature, and with singular value decomposition, compose analysis methods, relation between Pacific sea surface temperature and extreme precipitation events of East China is researched. It is found that winter Pacific sea surface temperature have remarkable relations with anaphase summer extreme precipitation events of East China, and Equator middle and East Pacific is key area which affect to summer extreme precipitation events of East China, when sea surface temperature occur anomaly phenomenon in the Equator middle and East Pacific in winter, by PNA (AntiPNA) and WP (AntiWP) teleconnection on atmospheric circulation take place adjustment from winter to summer, thus West Pacfic SubTropic High Pressure also take palce anomaly, at last summer extreme precipitation events of North China occur anomaly phenomenon. It is also found that tropic West Pacific is key area which affect to summer extreme precipitation events of northeast China and south of Changjiang River, when sea surface temperature occur anomaly phenomenon in the tropic West Pacific in winter, the average latitudinal vertical circulation of 105°~135°E take place anomaly phenomenon, and vertical motion occur anomaly in the northeast China and south of Changjiang River, at last the extreme precipitation events of the areas also occur anomaly.
2010, 32(1): 34-46.
Abstract:
A three dimensional water quality model was developed to investigate DO vertical transport in the Zhujiang (Pearl) River Estuary (PRE) in summer. Results show that the tidal, wind, topography and upwelling breakdown pycnocline in the PRE intermittently, leading to the fluctuation of DO vertical advective and dispersive fluxes associate with tidal cycle. Outside the west outlets, DO vertical advective and dispersive fluxes are low due to the stable stratification. In the deep channel, interaction between fresh water discharge and tidal force is intensified, leading to intermittent breakdown of stratification. DO vertical advective fluxes are greater than dispersive fluxes. In the western shoal of the Lingdingyang Estuary, stratification is more stable than in deep channel area, and the DO vertical advective fluxes is lower than dispersive fluxes. These results indicate that impacts of advection and dispersion on DO vertical transport show spatial differences in the PRE, and influence the DO concentration in the water column.
A three dimensional water quality model was developed to investigate DO vertical transport in the Zhujiang (Pearl) River Estuary (PRE) in summer. Results show that the tidal, wind, topography and upwelling breakdown pycnocline in the PRE intermittently, leading to the fluctuation of DO vertical advective and dispersive fluxes associate with tidal cycle. Outside the west outlets, DO vertical advective and dispersive fluxes are low due to the stable stratification. In the deep channel, interaction between fresh water discharge and tidal force is intensified, leading to intermittent breakdown of stratification. DO vertical advective fluxes are greater than dispersive fluxes. In the western shoal of the Lingdingyang Estuary, stratification is more stable than in deep channel area, and the DO vertical advective fluxes is lower than dispersive fluxes. These results indicate that impacts of advection and dispersion on DO vertical transport show spatial differences in the PRE, and influence the DO concentration in the water column.
2010, 32(1): 47-55.
Abstract:
The concentrations of four kinds of volatile halocarbons (VHCs) in the seawater of the northern Huanghai Sea (NHS) were systematically measured. The results show that the concentrations of CHCl3, C2 HCl3, CHBr2 Cl and CHBr3 in the surface seawater in the NHS are 9.9~63.4 (14.1±8.1), 7.1~29.4 (15.4±6.2), 0.1~30.3 (8.8±10.0) and 4.2~56.4 (21.6±12.2)pmol/dm3, respectively. The concentrations of the 4 VHC in the surface seawater showed a certain degree of spatial variation, which may be subject to different effects of riverine input, human activities and biological produce. The depth and intensity of maxima of the four kinds of VHC coneentration in the vertical distributions are different among stations, due to different geographical locations and different effects of hydrological conditions. Therefore, no obvious consistency of the vertical profiles of VHC was observed. The concentrations of four kinds of VHC exhibited a clear diurnal variation in the surface seawater, with the highest concentrations appearing between 13:00 and 16:00, presumably due to co-effect of illumination, tide and other factors at this time. On the basis of gas exchange calculations, the mean sea-to-air fluxes of CHCl3, C2HCl3 and CHBr3 were estimated to be, respectively, 14.8 (0.2~104.4), 23.2(1.8~93.0)and 15.6 (0.7~55.1) nmol/(m-2·d), indicating that the study area appears to be a source of atmospheric CHCl3, C2HCl3 and CHBr3 during the investigated time.
2010, 32(1): 56-66.
Abstract:
The content values and distribution of the PGE from surficial sediments in the South China Sea are reported .The contents (in dried weight) of rathenium, palladium,iridium, platium, rhodium, gold in 52 surficial sediments are 0.40×10-9~3.20×10-9(average 1.20×10-9), 0.01×10-9~13.30×10-9(average 4.31×10-9), 0.59×10-9~4.49×10-9(average 1.21×10-9), 1.27×10-9~16.21×10-9(average 5.26×10-9), 0.05×10-9~0.20×10-9(average 0.12×10-9) and 0.43×10-9~27.38×10-9(average 6.92×10-9) ,respectively.The relationship between contents and grain sizes is not clear,but the contents of palatinum group elements show a decreasing trend with the increase of grain size generally. The calculated background values of platinum, palladium,ruthenium,rhodium,iridium and gold are 1.168×10-9±0.190×10-9,3.228×10-9±0.403×10-9,1.085×10-9±0.189×10-9,4.432×10-9±0.258×10-9,0.123×10-9±0.023×10-9 and 4.720×10-9±0.413×10-9 ,respectively, which are much higher than those of the continental crust of eastern China,but keep the same order with the sediments of deep ocean or slightly higher than them, and showing the connatural characterstics of the marine sediments rich in platinum group elements.The platinum group elements enrich not only in shallow continental shelf area of main river mouths,but also in central deep sea basin area due to the contribution of volcanics input in deep ocean basin area.
The content values and distribution of the PGE from surficial sediments in the South China Sea are reported .The contents (in dried weight) of rathenium, palladium,iridium, platium, rhodium, gold in 52 surficial sediments are 0.40×10-9~3.20×10-9(average 1.20×10-9), 0.01×10-9~13.30×10-9(average 4.31×10-9), 0.59×10-9~4.49×10-9(average 1.21×10-9), 1.27×10-9~16.21×10-9(average 5.26×10-9), 0.05×10-9~0.20×10-9(average 0.12×10-9) and 0.43×10-9~27.38×10-9(average 6.92×10-9) ,respectively.The relationship between contents and grain sizes is not clear,but the contents of palatinum group elements show a decreasing trend with the increase of grain size generally. The calculated background values of platinum, palladium,ruthenium,rhodium,iridium and gold are 1.168×10-9±0.190×10-9,3.228×10-9±0.403×10-9,1.085×10-9±0.189×10-9,4.432×10-9±0.258×10-9,0.123×10-9±0.023×10-9 and 4.720×10-9±0.413×10-9 ,respectively, which are much higher than those of the continental crust of eastern China,but keep the same order with the sediments of deep ocean or slightly higher than them, and showing the connatural characterstics of the marine sediments rich in platinum group elements.The platinum group elements enrich not only in shallow continental shelf area of main river mouths,but also in central deep sea basin area due to the contribution of volcanics input in deep ocean basin area.
2010, 32(1): 67-82.
Abstract:
Total of 146 sediment samples were collected from the shelf of the East China Sea and five rivers, including the Huanghe River, the Changjiang River, the Qiantang River, the Oujiang River and the Minjiang River. The sediment grain-size and the content of rare earth element (REE) were measured with a laser particle size analyzer and an ICP-MS respectively. Results show that the REE absolute content and the ratio of LREE (light REE) to HREE (heavy REE) content are different in the sediments between rivers. There are higher REE contents in being less than 2 μm and 2~31 μm fractions in Changjiang Estuary surface sediments, and the bulk sediment REE contents are dominated by the corresponding values of those prevalent size-fractions. In the study area, the REE absolute contents of sediments are higher near the estuaries, and they trend downward in seaward direction on the inner shelf of the East China Sea. The ratio of LREE to HREE content has a tendency of increase southward from 28° N, whilst hydrodynamic conditions are dominated by the spacial distributions of the surficial sediment’s REE parameters. In some cases, the current flows tend to remove the coarser light grains from initial populations, whilst deposit the finer heavy mineral grains. In most situations, the currents will change the ratio of sediment constituents, for example, between silts and clays. As a result, the various values of the REE absolute content or ratio of LREE to HREE content in different bulk sediments result from the change of size-fractions, rather than represent their different sources. Under the long-term stable hydrodynamic environment, i.e., on the East China Sea shelf, a new sediment transport model based on the size and density gradation concept may help to understand the spatial distribution patterns of REE parameters.
Total of 146 sediment samples were collected from the shelf of the East China Sea and five rivers, including the Huanghe River, the Changjiang River, the Qiantang River, the Oujiang River and the Minjiang River. The sediment grain-size and the content of rare earth element (REE) were measured with a laser particle size analyzer and an ICP-MS respectively. Results show that the REE absolute content and the ratio of LREE (light REE) to HREE (heavy REE) content are different in the sediments between rivers. There are higher REE contents in being less than 2 μm and 2~31 μm fractions in Changjiang Estuary surface sediments, and the bulk sediment REE contents are dominated by the corresponding values of those prevalent size-fractions. In the study area, the REE absolute contents of sediments are higher near the estuaries, and they trend downward in seaward direction on the inner shelf of the East China Sea. The ratio of LREE to HREE content has a tendency of increase southward from 28° N, whilst hydrodynamic conditions are dominated by the spacial distributions of the surficial sediment’s REE parameters. In some cases, the current flows tend to remove the coarser light grains from initial populations, whilst deposit the finer heavy mineral grains. In most situations, the currents will change the ratio of sediment constituents, for example, between silts and clays. As a result, the various values of the REE absolute content or ratio of LREE to HREE content in different bulk sediments result from the change of size-fractions, rather than represent their different sources. Under the long-term stable hydrodynamic environment, i.e., on the East China Sea shelf, a new sediment transport model based on the size and density gradation concept may help to understand the spatial distribution patterns of REE parameters.
2010, 32(1): 83-93.
Abstract:
Column-like cores were collected in the Jiaozhou Bay in June 2006 and the lead-210 specific activity was measured in the sediments of these cores. The results show that there are four types of vertical distribution patterns of lead-210 specific activity, i.e., the two-section, three-section, multisection and reversed-section patterns. Based on the CIC (constant initial concentration) model, the deposition rates and the depositonal fluxes are estunated as 1.49~24.96 mm/a and 0.17~2.62 g/(cm2 a), respectively. The magnitude of the accumulation rate is 100 in the study area. A slight sedimentation or even partial erosion occur in the deep channels in the bay. It indicates that the sedimentary environment is relatively stable in the Jiaozhou Bay during the past century.
Column-like cores were collected in the Jiaozhou Bay in June 2006 and the lead-210 specific activity was measured in the sediments of these cores. The results show that there are four types of vertical distribution patterns of lead-210 specific activity, i.e., the two-section, three-section, multisection and reversed-section patterns. Based on the CIC (constant initial concentration) model, the deposition rates and the depositonal fluxes are estunated as 1.49~24.96 mm/a and 0.17~2.62 g/(cm2 a), respectively. The magnitude of the accumulation rate is 100 in the study area. A slight sedimentation or even partial erosion occur in the deep channels in the bay. It indicates that the sedimentary environment is relatively stable in the Jiaozhou Bay during the past century.
2010, 32(1): 94-106.
Abstract:
Sedimentological data are acquired from a piston core KCES1 off the southern Ulleung Basin margin in the East Sea (the Sea of Japan). These data include sediment color, X-ray radiographs, grain-size distribution and AMS carbon-14 dating. Four kinds of sediments (homogeneous, laminated, crudely laminated and hybrid sediments) are identified according to the characteristics of the sedimentary structures that are considered to reflect changes in bottom-water oxygenation. The alternations of dark laminated /crudely laminated sediments and light homogeneous sediments represent millennial-scale variations which are possibly associated with the high-resolution changes in East Asian monsoon (EAM). The relative contributions of the East China Sea coastal water (ECSCW) and the Tsushima Warm Current (TWC) have been likely main reasons for the repetition of the anoxic and oxic depositional conditions in the East Sea since the last 48 ka BP. During the interstadial, the strengthened summer EAM was attributed to the development of expansion of the ECSCW because of more humid climate in central Asia, and more strongly low-salinity, nutrient-enriched water was introduced into the East Sea. The ventilation of deep water was restricted and the dark laminated layer deposited therefore under the anoxic bottom water condition. During the lowest stand of sea level in last glacial maximum, the isolated East Sea dominated by stratified water masses and the euxinic depositional environment formed. The homogenous sediments predominated since 17.5 ka BP indicate that the TWC has intruded into the East Sea gradually with the stepwise rise of sea level and the bottom water oxygen level is high. During the late Younger Dryas (YD) period, the last dark laminated layer deposited because the ventilation of bottom water was restricted by stronger summer EAM. The TWC has strengthened and the bottom water has become oxic again since 10.5 ka BP.
Sedimentological data are acquired from a piston core KCES1 off the southern Ulleung Basin margin in the East Sea (the Sea of Japan). These data include sediment color, X-ray radiographs, grain-size distribution and AMS carbon-14 dating. Four kinds of sediments (homogeneous, laminated, crudely laminated and hybrid sediments) are identified according to the characteristics of the sedimentary structures that are considered to reflect changes in bottom-water oxygenation. The alternations of dark laminated /crudely laminated sediments and light homogeneous sediments represent millennial-scale variations which are possibly associated with the high-resolution changes in East Asian monsoon (EAM). The relative contributions of the East China Sea coastal water (ECSCW) and the Tsushima Warm Current (TWC) have been likely main reasons for the repetition of the anoxic and oxic depositional conditions in the East Sea since the last 48 ka BP. During the interstadial, the strengthened summer EAM was attributed to the development of expansion of the ECSCW because of more humid climate in central Asia, and more strongly low-salinity, nutrient-enriched water was introduced into the East Sea. The ventilation of deep water was restricted and the dark laminated layer deposited therefore under the anoxic bottom water condition. During the lowest stand of sea level in last glacial maximum, the isolated East Sea dominated by stratified water masses and the euxinic depositional environment formed. The homogenous sediments predominated since 17.5 ka BP indicate that the TWC has intruded into the East Sea gradually with the stepwise rise of sea level and the bottom water oxygen level is high. During the late Younger Dryas (YD) period, the last dark laminated layer deposited because the ventilation of bottom water was restricted by stronger summer EAM. The TWC has strengthened and the bottom water has become oxic again since 10.5 ka BP.
2010, 32(1): 107-113.
Abstract:
A comprehensively physicomechanica1 property study for the sea bottom sediments was made through the analysis of the sediment samples taken from the Fujian-Zhejiang coastal area. It is revealed that the sediment here is composed of fine sand,silt,mud,muddy clay,clay,and silty clay, of which mud and muddy clay are the main types. The sediments are characterized by high water content,high void ratio, high compressibility, high plasticity and low shear strength . Furthermore, the reasons caused the poorly geotechnical properties of the bottom sediments were analyzed from the points of microstructure, matter source and composition, hydrodynamic environment. They are the dominating factors to induce the poorly geotechnical properties of the sediment in this area.
A comprehensively physicomechanica1 property study for the sea bottom sediments was made through the analysis of the sediment samples taken from the Fujian-Zhejiang coastal area. It is revealed that the sediment here is composed of fine sand,silt,mud,muddy clay,clay,and silty clay, of which mud and muddy clay are the main types. The sediments are characterized by high water content,high void ratio, high compressibility, high plasticity and low shear strength . Furthermore, the reasons caused the poorly geotechnical properties of the bottom sediments were analyzed from the points of microstructure, matter source and composition, hydrodynamic environment. They are the dominating factors to induce the poorly geotechnical properties of the sediment in this area.
2010, 32(1): 114-119.
Abstract:
To understand the difference of suspended particulates adhering to tidal marsh plants, the mass of particulates adhering to three species of marsh plants was measured in the Changjiang Delta. The results are as follows:(1) The mass of suspended particulates adhering to plants growing on unit land area decreases at a rate of 1%~3%/m with distance from outer marsh edge or tidal creak where a suspended sediment content is higher; (2) the mass of suspended particulates adhering to plants decreases from the lowest stem section upward to the end of plants, and the mass of suspended particulates adhering to the lowest 5~10 cm stem of distance from marsh surface is more than one third of the total; (3)the mass of suspended particulates adhering to Spartina alterniflora is greater than the mass of suspended particulates adhering to Phragmites australis and Scirpus mariqueter , because the biomass of S.alterniflora is greater than the biomass of P. australis and S.mariqueter, however, the mass of suspended particulates adhering plants for unit plant biomass is the highest for S. mariqueter and the lowest for P. australis , and between the above-mentioned two for S. alterniflora ; (4) the seasonal change in mass of suspended particulates adhering to marsh plants can be significant. The mass of suspended particulates adhering to S. mariqueter in September was six times more than that in May. In winter, this pioneer plant withered and was washed away by tidal water, and thereby lost its ability to trap suspended particulates. It was concluded that the mass of suspended particulates adhering to marsh plants is determined by the plant biomass,the suspended particulate content and submerged conditions (the relative importance of elevation and tidal range).
To understand the difference of suspended particulates adhering to tidal marsh plants, the mass of particulates adhering to three species of marsh plants was measured in the Changjiang Delta. The results are as follows:(1) The mass of suspended particulates adhering to plants growing on unit land area decreases at a rate of 1%~3%/m with distance from outer marsh edge or tidal creak where a suspended sediment content is higher; (2) the mass of suspended particulates adhering to plants decreases from the lowest stem section upward to the end of plants, and the mass of suspended particulates adhering to the lowest 5~10 cm stem of distance from marsh surface is more than one third of the total; (3)the mass of suspended particulates adhering to Spartina alterniflora is greater than the mass of suspended particulates adhering to Phragmites australis and Scirpus mariqueter , because the biomass of S.alterniflora is greater than the biomass of P. australis and S.mariqueter, however, the mass of suspended particulates adhering plants for unit plant biomass is the highest for S. mariqueter and the lowest for P. australis , and between the above-mentioned two for S. alterniflora ; (4) the seasonal change in mass of suspended particulates adhering to marsh plants can be significant. The mass of suspended particulates adhering to S. mariqueter in September was six times more than that in May. In winter, this pioneer plant withered and was washed away by tidal water, and thereby lost its ability to trap suspended particulates. It was concluded that the mass of suspended particulates adhering to marsh plants is determined by the plant biomass,the suspended particulate content and submerged conditions (the relative importance of elevation and tidal range).
2010, 32(1): 120-129.
Abstract:
The spatiotemoral distributions and seasonal variations of phytoplankton chlorophyll biomass and its size structure in the Huanghai(Yellow) Sea Cold Water Mass were studied based on the four cruises during 2006—2007. The results show that the average chlorophyll concentration in the upper 30 m layer is in the order of spring (1.01 mg/m3) greater than summer (0.81 mg/m3) greater than autumn (0.72 mg/m3)greater than winter (0.68 mg/m3). The phytoplankton size structures are significantly different between the area where Chl a concentration is greater than 1 mg/m3and less than 1 mg/m3. In the whole region, smallersized nanophytoplankton and picophytoplankton dominated the biomass (>65%), while the contribution of microphytoplankton was relatively higher in winter and spring cruises. The average size index of phytoplankton is in the order of spring (15.47 μm) greater than winter (11.08 μm) greater than autumn (8.61 μm) greater than summer (6.52 μm). The relationships between the total biomass and the contributions of different size fractions show consistent trend in the four cruises in spite of the contrasting physical and chemical environments. The analysis of the relationships between the environmental factors and the chlorophyll concentrations shows that the growth of phytoplankton is limited by the nutrients availability in summer and by the weak light conditions caused by vertical mixing in winter. Phosphorus limitation and vertical mixing might be collectively responsible for the low chlorophyll level in autumn. The distribution patterns of phytoplankton size structures were mainly determined by their relatively competition advantages in different environments.
The spatiotemoral distributions and seasonal variations of phytoplankton chlorophyll biomass and its size structure in the Huanghai(Yellow) Sea Cold Water Mass were studied based on the four cruises during 2006—2007. The results show that the average chlorophyll concentration in the upper 30 m layer is in the order of spring (1.01 mg/m3) greater than summer (0.81 mg/m3) greater than autumn (0.72 mg/m3)greater than winter (0.68 mg/m3). The phytoplankton size structures are significantly different between the area where Chl a concentration is greater than 1 mg/m3and less than 1 mg/m3. In the whole region, smallersized nanophytoplankton and picophytoplankton dominated the biomass (>65%), while the contribution of microphytoplankton was relatively higher in winter and spring cruises. The average size index of phytoplankton is in the order of spring (15.47 μm) greater than winter (11.08 μm) greater than autumn (8.61 μm) greater than summer (6.52 μm). The relationships between the total biomass and the contributions of different size fractions show consistent trend in the four cruises in spite of the contrasting physical and chemical environments. The analysis of the relationships between the environmental factors and the chlorophyll concentrations shows that the growth of phytoplankton is limited by the nutrients availability in summer and by the weak light conditions caused by vertical mixing in winter. Phosphorus limitation and vertical mixing might be collectively responsible for the low chlorophyll level in autumn. The distribution patterns of phytoplankton size structures were mainly determined by their relatively competition advantages in different environments.
2010, 32(1): 130-138.
Abstract:
Studies on genetic variation in marine organisms are an important component of successful and sustainable management of marine fishery resources.Genetic variation of six Octopus ocellatus populations in Chinas coastal waters were investigated using the mitochondrial gene(COI) sequencing method. Results show that ,compared with other cephalopod species, O.ocellatus shows higher genetic diversity in populations. 42 polymorphic sites were detected in 654 bp aligned sequence, which reprented for 6.42% of the total length of sequenced COI gene. 23 hapotypes were detected out of 60 individuals from six populations. The hapotype diversity, mean nucleotide diversity and average number of nucleotide differences reached 0.200~0.867, 0.000 3~0.009 7, 0.200~6.311, respectively. Molecular variance analysis revealed strong genetc sturcture in six O.ocellatus populations(P＜0.05). A pattern of genetic-isolation-by-distance, comforming to a stepping stone model, was detected when plotting gene flow against geographic distance.UPGMA tree constructed shows that six O.ocellatus populations studied can be divided into two lineages. One is consisited of Dalian, Qingdao,Lianyungang plulations. The other is consisted of other three populations. Between them, 20 fixed nucleotide sites and two fixed amino acid sites subtitute were detected along the gene sequence and coded protein, respectively. The Fst between them reached 0.8602 (P＜0.01) and the gene flow between them turned out to be much lower than 1. AMOVA test, which showing 12.72% of the genetic variation lies within populations and 87.28% lies between populations, further suggested the genetic differentiation between these two lineages. These findings in the aspect of genetic variation of O.ocellatus will contribute to better exploitment and refined management of this precious cephalopod resources along the coast of China in future.
Studies on genetic variation in marine organisms are an important component of successful and sustainable management of marine fishery resources.Genetic variation of six Octopus ocellatus populations in Chinas coastal waters were investigated using the mitochondrial gene(COI) sequencing method. Results show that ,compared with other cephalopod species, O.ocellatus shows higher genetic diversity in populations. 42 polymorphic sites were detected in 654 bp aligned sequence, which reprented for 6.42% of the total length of sequenced COI gene. 23 hapotypes were detected out of 60 individuals from six populations. The hapotype diversity, mean nucleotide diversity and average number of nucleotide differences reached 0.200~0.867, 0.000 3~0.009 7, 0.200~6.311, respectively. Molecular variance analysis revealed strong genetc sturcture in six O.ocellatus populations(P＜0.05). A pattern of genetic-isolation-by-distance, comforming to a stepping stone model, was detected when plotting gene flow against geographic distance.UPGMA tree constructed shows that six O.ocellatus populations studied can be divided into two lineages. One is consisited of Dalian, Qingdao,Lianyungang plulations. The other is consisted of other three populations. Between them, 20 fixed nucleotide sites and two fixed amino acid sites subtitute were detected along the gene sequence and coded protein, respectively. The Fst between them reached 0.8602 (P＜0.01) and the gene flow between them turned out to be much lower than 1. AMOVA test, which showing 12.72% of the genetic variation lies within populations and 87.28% lies between populations, further suggested the genetic differentiation between these two lineages. These findings in the aspect of genetic variation of O.ocellatus will contribute to better exploitment and refined management of this precious cephalopod resources along the coast of China in future.
2010, 32(1): 139-145.
Abstract:
Complete sequences of the mitochondrial DNA control region from 11 species of snapper species were amplified by polymerase chain reaction (PCR) and directly sequenced. The structure of the control region was analyzed with six other species of snapper from GenBank. According to the alignment, three domains, the termination associated sequence domain (TAS), the central conserved domain (CD) and the conserved sequence block domain (CSB), were identified in the mtDNA control region of snapper species. The extended termination associated sequence (ETAS), three conserved blocks (CSB-F, CSB-D,CSB-D) in the central conserved sequence block domain and three conserved sequence blocks (CSB1,CSB2,CSB3) in the conserved sequence block domain were successfully identified. With Emmelichthys struhsakeri as outgroup, the phylogenetic trees were constructed using the neighbor-joining (NJ) method and the minimum evolution (ME) method. It can be concluded that the control region can be used for the phylogenetic analysis, and the phylogenetic relationships from mtDNA data are consistent with Allen’s morphology-based system.
Complete sequences of the mitochondrial DNA control region from 11 species of snapper species were amplified by polymerase chain reaction (PCR) and directly sequenced. The structure of the control region was analyzed with six other species of snapper from GenBank. According to the alignment, three domains, the termination associated sequence domain (TAS), the central conserved domain (CD) and the conserved sequence block domain (CSB), were identified in the mtDNA control region of snapper species. The extended termination associated sequence (ETAS), three conserved blocks (CSB-F, CSB-D,CSB-D) in the central conserved sequence block domain and three conserved sequence blocks (CSB1,CSB2,CSB3) in the conserved sequence block domain were successfully identified. With Emmelichthys struhsakeri as outgroup, the phylogenetic trees were constructed using the neighbor-joining (NJ) method and the minimum evolution (ME) method. It can be concluded that the control region can be used for the phylogenetic analysis, and the phylogenetic relationships from mtDNA data are consistent with Allen’s morphology-based system.
2010, 32(1): 146-152.
Abstract:
2010, 32(1): 153-160.
Abstract:
2010, 32(1): 161-169.
Abstract:
2010, 32(1): 170-175.
Abstract:
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