2013 Vol. 35, No. 1
Display Method:
2013, 35(1): 1-8.
doi: 10.3969/j.issn.0253-4193.2013.01.001
Abstract:
The traveling route of tidal wave in the north part of the South China Sea is sketched from the numerical modeling result of the tidal energy flux,which shows several branches. Analysis indicates that the continental shelf area in the north part of the South China Sea including the Beibu Gulf,gets only a small part of tidal energy coming from the Pacific Ocean and passing through the Luzon Strait,and hence the tide and tidal current in that area is weak. The complex topography results in those branches of the traveling route of tidal wave pointing to different directions. In this paper by using the observational data and tidal traveling route analysis the abnormal phenomena of tidal wave in the Jiazi,east Guangdong coast are discussed. These phenomena include specially large tidal characteristic coefficient F appearing in that area,and quite different tidal characteristics for tide and tidal current. Analysis shows that the tidal energy divergence between the two tidal wave branches traveling to the south entrance of the Taiwan Strait and to the Zhujiang River Estuary as well as Guangzhou Bay might be one of the important reasons to cause these phenomena.
The traveling route of tidal wave in the north part of the South China Sea is sketched from the numerical modeling result of the tidal energy flux,which shows several branches. Analysis indicates that the continental shelf area in the north part of the South China Sea including the Beibu Gulf,gets only a small part of tidal energy coming from the Pacific Ocean and passing through the Luzon Strait,and hence the tide and tidal current in that area is weak. The complex topography results in those branches of the traveling route of tidal wave pointing to different directions. In this paper by using the observational data and tidal traveling route analysis the abnormal phenomena of tidal wave in the Jiazi,east Guangdong coast are discussed. These phenomena include specially large tidal characteristic coefficient F appearing in that area,and quite different tidal characteristics for tide and tidal current. Analysis shows that the tidal energy divergence between the two tidal wave branches traveling to the south entrance of the Taiwan Strait and to the Zhujiang River Estuary as well as Guangzhou Bay might be one of the important reasons to cause these phenomena.
2013, 35(1): 9-14.
doi: 10.3969/j.issn.0253-4193.2013.01.002
Abstract:
The volume transports of the North Equatorial Current (NEC),the Kuroshio (KC),and the Mindanao Current (MC) along the Pacific western boundary were investigated through traditional dynamical method by using long-time and high-resolution data set. The results show that the volume transports of the NEC and KC exhibited similar distinct inter-annual and inter-decadal variations. Both of them experienced a climate jump in 1976 and bear obvious intensifying trends after 1976. In contrast,the transport fluxes of the MC transport is different from that of the NEC and KC. It seems that the increased volume of the NEC mostly flows into the KC rather than the MC after 1976. The correlation analysis suggests that inter-annual variations of the NEC transport may be also greatly influenced by Rossby Wave and Mindanao cyclonic eddy.
The volume transports of the North Equatorial Current (NEC),the Kuroshio (KC),and the Mindanao Current (MC) along the Pacific western boundary were investigated through traditional dynamical method by using long-time and high-resolution data set. The results show that the volume transports of the NEC and KC exhibited similar distinct inter-annual and inter-decadal variations. Both of them experienced a climate jump in 1976 and bear obvious intensifying trends after 1976. In contrast,the transport fluxes of the MC transport is different from that of the NEC and KC. It seems that the increased volume of the NEC mostly flows into the KC rather than the MC after 1976. The correlation analysis suggests that inter-annual variations of the NEC transport may be also greatly influenced by Rossby Wave and Mindanao cyclonic eddy.
2013, 35(1): 15-24.
doi: 10.3969/j.issn.0253-4193.2013.01.003
Abstract:
Based on a finite-volume coastal ocean model (FVCOM), adopting an unstructured triangle grid, a three-dimensional tide and tidal current numerical modeling with high resolution (26 m) is applied to Quanzhou Bay. The simulated results agree well with the observed data from two tide-gauges and three continuing current stations, and reproduce the distribution features of the tide and tidal currents in the Quanzhou Bay famously. The distributions of co-tidal charts and tidal ellipses on the surface layer for four major constituents (M2,S2,K1,O1) are obtained. What's more, the distributions of the maximum probable tidal range and tidal currents velocity and tidal residual currents on the surface and bottom layers are obtained, too. By analyzing, the maximum tidal amplitude and phase-lag range for the four constituents are 219 cm and 19°,85 cm and 25°,26 cm and 12°,26 cm and 9°, respectively. The tidal wave is anti-clockwise standing wave in the east area of Shihu Port, but it is advancing wave in the west area of Shihu Port. The maximum probable tidal range increases from 8.0 m at the mouth of the bay to 8.8 m inside of the bay. The type of tidal currents is regular semi-diurnal currents inside of the bay, and the maximum velocity of ebbing is larger than flooding. The velocity in the channel of Beiwujiao is stronger than any other area, and the maximum probable tidal-current velocity is 2.4 m/s on the surface layer. The flow is rotating with anti-clockwise mainly at the mouth of the bay, while rectilinear flow is mainly inside of the bay, such as estuaries and channels. And the directions of major axes are along with channels direction mainly, or paralleling with isobaths and coastlines. The maximum tidal current velocities for the four major constituents are 1.4 m/s,0.58 m/s,0.12 m/s,0.10 m/s on the surface layer, respectively. Tidal residual currents velocity is closely related to tidal currents, the maximum velocities on the surface layer, the middle layer and the bottom layer are 26 cm/s, 20 cm/s, 16 cm/s, respectively. All of them are coming into the bay from north and going out of the bay from south.
Based on a finite-volume coastal ocean model (FVCOM), adopting an unstructured triangle grid, a three-dimensional tide and tidal current numerical modeling with high resolution (26 m) is applied to Quanzhou Bay. The simulated results agree well with the observed data from two tide-gauges and three continuing current stations, and reproduce the distribution features of the tide and tidal currents in the Quanzhou Bay famously. The distributions of co-tidal charts and tidal ellipses on the surface layer for four major constituents (M2,S2,K1,O1) are obtained. What's more, the distributions of the maximum probable tidal range and tidal currents velocity and tidal residual currents on the surface and bottom layers are obtained, too. By analyzing, the maximum tidal amplitude and phase-lag range for the four constituents are 219 cm and 19°,85 cm and 25°,26 cm and 12°,26 cm and 9°, respectively. The tidal wave is anti-clockwise standing wave in the east area of Shihu Port, but it is advancing wave in the west area of Shihu Port. The maximum probable tidal range increases from 8.0 m at the mouth of the bay to 8.8 m inside of the bay. The type of tidal currents is regular semi-diurnal currents inside of the bay, and the maximum velocity of ebbing is larger than flooding. The velocity in the channel of Beiwujiao is stronger than any other area, and the maximum probable tidal-current velocity is 2.4 m/s on the surface layer. The flow is rotating with anti-clockwise mainly at the mouth of the bay, while rectilinear flow is mainly inside of the bay, such as estuaries and channels. And the directions of major axes are along with channels direction mainly, or paralleling with isobaths and coastlines. The maximum tidal current velocities for the four major constituents are 1.4 m/s,0.58 m/s,0.12 m/s,0.10 m/s on the surface layer, respectively. Tidal residual currents velocity is closely related to tidal currents, the maximum velocities on the surface layer, the middle layer and the bottom layer are 26 cm/s, 20 cm/s, 16 cm/s, respectively. All of them are coming into the bay from north and going out of the bay from south.
2013, 35(1): 25-37.
doi: 10.3969/j.issn.0253-4193.2013.01.004
Abstract:
A three-dimensional hydrodynamic model for Yangtze Estuary and the adjacent sea was developed within the framework of Environmental Fluid Dynamics Code (EFDC). This model was used to study the relationship between winds and Changjiang (Yangtze) River diluted water (CRDW) in summer. Simulated elevations,currents,temperatures and salinities are fairly consistent with observed data. Numerical experiments show that wind plays an important role in the expansion of CRDW. Wind induced Ekman transport would push CRDW to the right of wind direction. At a speed of 5 m/s,easterly,southeasterly,southerly and southwesterly wind push CRDW seaward significantly,while westerly,northwesterly,northerly and northeasterly wind confine CRDW to the coastal area. The Ekman transport is intensified with intensified wind,resulting that more CRDW will be transported to the right of wind direction. Due to stratified water,the turbulence is relatively weak in the axis of the low-salinity tongue. Weak turbulence consumes less wind energy. So the water in the axis of the tongue is accelerated more than water in other areas. Then,more diluted water is transported through the axis area of the low-salinity tongue. Eventually,the width of the tongue becomes smaller with stronger winds. Statistical analysis of observed data also verifies the numerical conclusions.
A three-dimensional hydrodynamic model for Yangtze Estuary and the adjacent sea was developed within the framework of Environmental Fluid Dynamics Code (EFDC). This model was used to study the relationship between winds and Changjiang (Yangtze) River diluted water (CRDW) in summer. Simulated elevations,currents,temperatures and salinities are fairly consistent with observed data. Numerical experiments show that wind plays an important role in the expansion of CRDW. Wind induced Ekman transport would push CRDW to the right of wind direction. At a speed of 5 m/s,easterly,southeasterly,southerly and southwesterly wind push CRDW seaward significantly,while westerly,northwesterly,northerly and northeasterly wind confine CRDW to the coastal area. The Ekman transport is intensified with intensified wind,resulting that more CRDW will be transported to the right of wind direction. Due to stratified water,the turbulence is relatively weak in the axis of the low-salinity tongue. Weak turbulence consumes less wind energy. So the water in the axis of the tongue is accelerated more than water in other areas. Then,more diluted water is transported through the axis area of the low-salinity tongue. Eventually,the width of the tongue becomes smaller with stronger winds. Statistical analysis of observed data also verifies the numerical conclusions.
2013, 35(1): 38-43.
doi: 10.3969/j.issn.0253-4193.2013.01.005
Abstract:
A numerical model of typhoon-generated wave based on SWAN model, including the coupled propagation of astronomical tide and storm surge, is built. Typhoon No. 5612, the most intense to land in China since 1949, is taken as the typical super typhoon for the middle and north typhoon routes. The typhoon-generated wave process along the coast is calculated by the model under the conditions of typical typhoons coinciding with the high tidal level when they lands. The results show that the wave height is greater downstream than upperstream, and along north shore than along south shore. The maximal significant wave height is 5.5 m along both shores in front of sea wall at the representative section. The typhoon-generated wave height is a process with single peak in the middle route, and with double peaks along the north shore in the north route. The high storm surge and wave peak do not always occur simultaneously, with a maximal interval about 4 hours. According to the analysis of the frequency curve, the return periods of the super-typhoon-generated wave at Zhapu Station are 135 years and 350 years in the middle route and north route, respectively. The typhoon-generated wave heights of the middle tide and neap tide are 0.1-0.2 m lower than those of the spring tide and middle tide, respectively. The results have practical significance for design of coastal engineering and minimization of damage during super typhoons.
A numerical model of typhoon-generated wave based on SWAN model, including the coupled propagation of astronomical tide and storm surge, is built. Typhoon No. 5612, the most intense to land in China since 1949, is taken as the typical super typhoon for the middle and north typhoon routes. The typhoon-generated wave process along the coast is calculated by the model under the conditions of typical typhoons coinciding with the high tidal level when they lands. The results show that the wave height is greater downstream than upperstream, and along north shore than along south shore. The maximal significant wave height is 5.5 m along both shores in front of sea wall at the representative section. The typhoon-generated wave height is a process with single peak in the middle route, and with double peaks along the north shore in the north route. The high storm surge and wave peak do not always occur simultaneously, with a maximal interval about 4 hours. According to the analysis of the frequency curve, the return periods of the super-typhoon-generated wave at Zhapu Station are 135 years and 350 years in the middle route and north route, respectively. The typhoon-generated wave heights of the middle tide and neap tide are 0.1-0.2 m lower than those of the spring tide and middle tide, respectively. The results have practical significance for design of coastal engineering and minimization of damage during super typhoons.
2013, 35(1): 44-54.
doi: 10.3969/j.issn.0253-4193.2013.01.006
Abstract:
The sea surface temperature (SST) of China Ocean Reanalysis (CORA) from 1986 to 2008 is validated using Simple Ocean Data Assimilation (SODA),Levitus and Advanced Very High Resolution Radiometer (AVHRR) dataset. Comparing with AVHRR,the bias and root mean square error(RMSE) of CORA are less than that of SODA. Comparing with Levitus,the RMSE of COAR is also less than that of SODA. The results of Empirical Orthogonal Function (EOF) analysis show that the first three modes of CORA have similar temporal and spatial variations with those of SODA dataset,and the main differences are that CORA can represent more subtle features than SODA. The seasonal and interannual variability of SST in the coastal China seas can be well presented by CORA data. The second mode of EOF reveals the SST response to wind-induced latent heat. The third mode presents the northeast-southwestern distribution of SST front,which is coincident to the transitionally seasonal characters between summer and winter. The interannual variability of SST is closely related to ENSO.The regional average of SSTA of CORA in the South China Sea has more coincident correlation to Nino indexes than that of SODA.
The sea surface temperature (SST) of China Ocean Reanalysis (CORA) from 1986 to 2008 is validated using Simple Ocean Data Assimilation (SODA),Levitus and Advanced Very High Resolution Radiometer (AVHRR) dataset. Comparing with AVHRR,the bias and root mean square error(RMSE) of CORA are less than that of SODA. Comparing with Levitus,the RMSE of COAR is also less than that of SODA. The results of Empirical Orthogonal Function (EOF) analysis show that the first three modes of CORA have similar temporal and spatial variations with those of SODA dataset,and the main differences are that CORA can represent more subtle features than SODA. The seasonal and interannual variability of SST in the coastal China seas can be well presented by CORA data. The second mode of EOF reveals the SST response to wind-induced latent heat. The third mode presents the northeast-southwestern distribution of SST front,which is coincident to the transitionally seasonal characters between summer and winter. The interannual variability of SST is closely related to ENSO.The regional average of SSTA of CORA in the South China Sea has more coincident correlation to Nino indexes than that of SODA.
2013, 35(1): 55-62.
doi: 10.3969/j.issn.0253-4193.2013.01.007
Abstract:
A storm surge inundation numerical simulation model with high resolution based on unstructured triangle grid has been established for Binhai New Area including the resolution of 50-80 meters in land area,the numerical simulation is carried on to two storm surge processes and the calculated results agree well with the observations. 19 year statistical high astronomical tide is assigned and four levels weather system is developed by the analysis of historical weather process also. Four ranks of extratropical storm surge biggest inundation extent are simulated at Binhai New Area. Comprehensive consideration of storm surge hazard and vulnerability,the GIS-based storm surge disaster risk spatial distribution map is produced. most parts of Binhai New Area has storm surge disaster risk and the coastal areas risk are bigger than the inland areas,and Tianjin Port,Near port industrial district,north shore Haihe River and the south area of Dagang appeared the biggest risk.
A storm surge inundation numerical simulation model with high resolution based on unstructured triangle grid has been established for Binhai New Area including the resolution of 50-80 meters in land area,the numerical simulation is carried on to two storm surge processes and the calculated results agree well with the observations. 19 year statistical high astronomical tide is assigned and four levels weather system is developed by the analysis of historical weather process also. Four ranks of extratropical storm surge biggest inundation extent are simulated at Binhai New Area. Comprehensive consideration of storm surge hazard and vulnerability,the GIS-based storm surge disaster risk spatial distribution map is produced. most parts of Binhai New Area has storm surge disaster risk and the coastal areas risk are bigger than the inland areas,and Tianjin Port,Near port industrial district,north shore Haihe River and the south area of Dagang appeared the biggest risk.
2013, 35(1): 63-75.
doi: 10.3969/j.issn.0253-4193.2013.01.008
Abstract:
Based on the simple ocean data assimilation(SODA)1958-2007 monthly mean datasets and the thermal equation,the charateristics of interannual and interdecadal variability of the North Pacific sea surface temperature anomalies(SSTA)and their local factors are analyzed. The results show that,after Aleutian low deepened and moved southeastward around 1976/1977,the North Pacific SST cooled down in two regions: one is in the subtropical interior around 30°N,controlled by the wind stress anomalies;the other is located in the boundary region between the subpolar and the subtropical gyres around 40°N,controlled by the displacement of the zero wind stress curl line.In the subtropical interior region,the SST cooling reached its extreme during 1978-1982. Two main contributors are the surface heat flux and the meridional advection anomalies,which account for about 50%-60% of the SST anomalies. The residual term in the thermal equation accounts for about 20%-50% in this region. The SSTA shifted to negatives around 1975 almost simultaneously in the interior and western boundary region between the subpolar and the subtropical gyres. But the shift of vertical mixing term in the interior region occurred about 5 years earlier than in the western boundary region. Both the heatflux and the meridional advection terms are responsible for SST anomalies in this region,but the meridional advection terms dominant the SST variations during 1983-1988. The vertical mixing terms of these two regions are both small,but show strong decadal variations. The meridional advection is two times larger than the zonal advection.
Based on the simple ocean data assimilation(SODA)1958-2007 monthly mean datasets and the thermal equation,the charateristics of interannual and interdecadal variability of the North Pacific sea surface temperature anomalies(SSTA)and their local factors are analyzed. The results show that,after Aleutian low deepened and moved southeastward around 1976/1977,the North Pacific SST cooled down in two regions: one is in the subtropical interior around 30°N,controlled by the wind stress anomalies;the other is located in the boundary region between the subpolar and the subtropical gyres around 40°N,controlled by the displacement of the zero wind stress curl line.In the subtropical interior region,the SST cooling reached its extreme during 1978-1982. Two main contributors are the surface heat flux and the meridional advection anomalies,which account for about 50%-60% of the SST anomalies. The residual term in the thermal equation accounts for about 20%-50% in this region. The SSTA shifted to negatives around 1975 almost simultaneously in the interior and western boundary region between the subpolar and the subtropical gyres. But the shift of vertical mixing term in the interior region occurred about 5 years earlier than in the western boundary region. Both the heatflux and the meridional advection terms are responsible for SST anomalies in this region,but the meridional advection terms dominant the SST variations during 1983-1988. The vertical mixing terms of these two regions are both small,but show strong decadal variations. The meridional advection is two times larger than the zonal advection.
2013, 35(1): 76-84.
doi: 10.3969/j.issn.0253-4193.2013.01.009
Abstract:
Study of air-sea momentum exchange and wave character is becoming even more important for an accurate forecasting of cyclone evolution and atrocious ocean. Followed previous method, typhoon was divided into three sectors: (1) swell along wind, (2) swell against wind and (3) swell cross wind. Combining buoy data and hurricane paths data, the azimuth and distance of buoys relative to hurricane were obtained. By analyses theses data, the laws of wave height and phase velocity with wind speed increase were derived. And then, friction velocity(u*), the drag coefficient(CDN) and aerodynamic roughness length(z0)was calculated by using the GWW parameterization scheme. Compared with anterior representative studies, we found the estimated results were consistent well with their observation and conclusions. This study proves the GWW parameterization scheme is applicable well under high wind speed regime.
Study of air-sea momentum exchange and wave character is becoming even more important for an accurate forecasting of cyclone evolution and atrocious ocean. Followed previous method, typhoon was divided into three sectors: (1) swell along wind, (2) swell against wind and (3) swell cross wind. Combining buoy data and hurricane paths data, the azimuth and distance of buoys relative to hurricane were obtained. By analyses theses data, the laws of wave height and phase velocity with wind speed increase were derived. And then, friction velocity(u*), the drag coefficient(CDN) and aerodynamic roughness length(z0)was calculated by using the GWW parameterization scheme. Compared with anterior representative studies, we found the estimated results were consistent well with their observation and conclusions. This study proves the GWW parameterization scheme is applicable well under high wind speed regime.
2013, 35(1): 85-93.
doi: 10.3969/j.issn.0253-4193.2013.01.010
Abstract:
In terms of the methodology of oil spill identifying in SAR images, it is usually arbitrary to select qualitative or/and quantitative features for classifying dark objects as oil spill or look-alikes. The features selected in different classification models are not the same. The feature extraction and the criticality analysis are made in SAR images. Its aim is to apply the minimum distance method to discriminating oil spills from look-alikes. First, through correlation analysis, the redundancy is removed. Next,a criticality coefficient is introduced to quantitatively study the criticality of features. Then, distinguishing features are extracted. Sequentially, the dimension of feature vector is reduced to fit for the application research of the minimum distance method.
In terms of the methodology of oil spill identifying in SAR images, it is usually arbitrary to select qualitative or/and quantitative features for classifying dark objects as oil spill or look-alikes. The features selected in different classification models are not the same. The feature extraction and the criticality analysis are made in SAR images. Its aim is to apply the minimum distance method to discriminating oil spills from look-alikes. First, through correlation analysis, the redundancy is removed. Next,a criticality coefficient is introduced to quantitatively study the criticality of features. Then, distinguishing features are extracted. Sequentially, the dimension of feature vector is reduced to fit for the application research of the minimum distance method.
2013, 35(1): 94-103.
doi: 10.3969/j.issn.0253-4193.2013.01.011
Abstract:
Oil spill in ocean has been one of the primary factors which lead to deteriorations of marine ecological balance. The analysis of marine oil spill detection has become an important subject of the marine environmental protection. However, traditional methods to extract oil spill merely base on the spectral information of optical image or backscattering coefficient of SAR image respectively, which may lead to misclassification of different objects with same spectrum or similar roughness. Hence, texture information is combineal with the traditional image information to improve the extraction accuracy of oil spill. In the process of texture analysis, there are many parameters which will directly affect the extraction accuracy. So it is important to select appropriate parameters. In this paper, we choose three SAR images in the same orbit which covered the Bohai Sea area in 2006 as data resource, and use method based on gray level co-occurrence matrix (GLCM) to analyze texture feature. Because GLCM-based texture analysis method can perceive the surface of image well and describe the texture feature in detail by gray correlation of pixels, it is more suitable for marine oil spill detection in SAR images. Then we discuss, experiment, select and verify the parameters of texture analysis. Finally, this paper selected four parameters include local stationary, non-similarity, contrast and change as the texture feature statistics, determined the value of these parameters, used neural network classification considered both texture feature and backscattering coefficient of SAR. With the classification accuracy up to 80.65%, the method combined the traditional information with the texture information to extract oil spill turn out to be feasible and effective and also laid a good foundation for the future study on marine oil spill detection.
Oil spill in ocean has been one of the primary factors which lead to deteriorations of marine ecological balance. The analysis of marine oil spill detection has become an important subject of the marine environmental protection. However, traditional methods to extract oil spill merely base on the spectral information of optical image or backscattering coefficient of SAR image respectively, which may lead to misclassification of different objects with same spectrum or similar roughness. Hence, texture information is combineal with the traditional image information to improve the extraction accuracy of oil spill. In the process of texture analysis, there are many parameters which will directly affect the extraction accuracy. So it is important to select appropriate parameters. In this paper, we choose three SAR images in the same orbit which covered the Bohai Sea area in 2006 as data resource, and use method based on gray level co-occurrence matrix (GLCM) to analyze texture feature. Because GLCM-based texture analysis method can perceive the surface of image well and describe the texture feature in detail by gray correlation of pixels, it is more suitable for marine oil spill detection in SAR images. Then we discuss, experiment, select and verify the parameters of texture analysis. Finally, this paper selected four parameters include local stationary, non-similarity, contrast and change as the texture feature statistics, determined the value of these parameters, used neural network classification considered both texture feature and backscattering coefficient of SAR. With the classification accuracy up to 80.65%, the method combined the traditional information with the texture information to extract oil spill turn out to be feasible and effective and also laid a good foundation for the future study on marine oil spill detection.
2013, 35(1): 104-110.
doi: 10.3969/j.issn.0253-4193.2013.01.012
Abstract:
On the basis of the data obtained in the field survey of the northern South China Sea in January 2010, it was discovered that DO, at the depth of 150-1 000 m, decreased from northeast to southwest. Meanwhile, the vertical distribution of DO reduced from surface to bottom. The concentration of DO contour line more than 8 mg/dm3 occupied the 50 m shallow water influenced by strongly water exchange. It was showed that the spatial distribution in the middle and the bottom layer of DO changed greatly by mesoscale vortex, which lead to the concentrations of DO nearby the center of warm vortex at the depth from 150 m to 500 m being remarkably higher than in other areas. Furthermore, DO shows great correlation with nutrients, temperature, salinity and pH in different layers, which indicated that the distribution of DO was influenced by physical and biochemistry process.
On the basis of the data obtained in the field survey of the northern South China Sea in January 2010, it was discovered that DO, at the depth of 150-1 000 m, decreased from northeast to southwest. Meanwhile, the vertical distribution of DO reduced from surface to bottom. The concentration of DO contour line more than 8 mg/dm3 occupied the 50 m shallow water influenced by strongly water exchange. It was showed that the spatial distribution in the middle and the bottom layer of DO changed greatly by mesoscale vortex, which lead to the concentrations of DO nearby the center of warm vortex at the depth from 150 m to 500 m being remarkably higher than in other areas. Furthermore, DO shows great correlation with nutrients, temperature, salinity and pH in different layers, which indicated that the distribution of DO was influenced by physical and biochemistry process.
2013, 35(1): 111-120.
doi: 10.3969/j.issn.0253-4193.2013.01.013
Abstract:
Nitrogen in marine sediment of Huanghai Sea and East China Sea continental shelf area was defined as transferable part and non-transferable part,with a sequential extraction separation method. Four forms of transferable part in marine sediment were ion-exchange form(IEF-N),carbonate form(CF-N), iron-manganese oxides form(IMOF-N),and organic matter-sulfide form (OSF-N),respectively.The horizontal,vertical distribution,and the age of the deposition profiles of the four forms were given.The correlation among different forms of nitrogen and biogenic silica (BSi)-the alternative indicators of paleoproductivity were further explored,revealing the geochemistry of the forms of nitrogen and relations with the total phytoplankton.The results showed that transferable nitrogen accounted for 16.81% of total nitrogen (TN) and the average content of four different transferable forms nitrogen in the surface area were IMOF-N(66.65 μg/g)>IEF-N(22.96 μg/g)>OSF-N(17.40 μg/g)>CF-N(11.26 μg/g),respectively. IMOF-N was the advantage form of transferable nitrogen in the surface area; various forms of nitrogen in each station were different,and there's a wide variation in different nitrogen forms of the Changjiang Estuary,compared with the central southern Huanghai Sea; BSi, IEF-N and IMOF-N in the southern Huanghai Sea surface sediments and columnar were correlated significantly,and the relevance of BSi and various forms of nitrogen were not obvious in the Changjiang Estuary and along the coast of Fujian and Zhejiang Province. IEF-N and IMOF-N had a greater contribution to the total phytoplankton.
Nitrogen in marine sediment of Huanghai Sea and East China Sea continental shelf area was defined as transferable part and non-transferable part,with a sequential extraction separation method. Four forms of transferable part in marine sediment were ion-exchange form(IEF-N),carbonate form(CF-N), iron-manganese oxides form(IMOF-N),and organic matter-sulfide form (OSF-N),respectively.The horizontal,vertical distribution,and the age of the deposition profiles of the four forms were given.The correlation among different forms of nitrogen and biogenic silica (BSi)-the alternative indicators of paleoproductivity were further explored,revealing the geochemistry of the forms of nitrogen and relations with the total phytoplankton.The results showed that transferable nitrogen accounted for 16.81% of total nitrogen (TN) and the average content of four different transferable forms nitrogen in the surface area were IMOF-N(66.65 μg/g)>IEF-N(22.96 μg/g)>OSF-N(17.40 μg/g)>CF-N(11.26 μg/g),respectively. IMOF-N was the advantage form of transferable nitrogen in the surface area; various forms of nitrogen in each station were different,and there's a wide variation in different nitrogen forms of the Changjiang Estuary,compared with the central southern Huanghai Sea; BSi, IEF-N and IMOF-N in the southern Huanghai Sea surface sediments and columnar were correlated significantly,and the relevance of BSi and various forms of nitrogen were not obvious in the Changjiang Estuary and along the coast of Fujian and Zhejiang Province. IEF-N and IMOF-N had a greater contribution to the total phytoplankton.
2013, 35(1): 121-130.
doi: 10.3969/j.issn.0253-4193.2013.01.014
Abstract:
On the basis of the examination of the distribution, sources and molecular composition of the aliphatic hydrocarbons in surface sediments of the Bohai Sea, the sedimentary biomarkers of those hydrocarbons and their indication for the petroleum contamination was elucidated. The occurrence of unresolved complex mixtures and the distribution and compositional patterns of the n-alkanes in the sediments indicated the presence of a widespread petroleum contamination, especially for the coastal Bohai Bay. The n-alkane average chain length (ACL) in the samples from the offshore Bohai Bay and Huanghe River estuary was significant lower than those from the other regions, coupling with the lower ratios of Pr/Ph (<1.0), which suggesting the potential impact of the offshore oil exploration, shipping activity and fluvial input for the petroleum residue input. The conventional diagnostic ratios of the petroleum biomarkers, such as Ts/Tm, homohopanes S/(S+R) and αααC29 sterane S/(S+R) ratios indicated a presence of mature constituents in the sediments, implying the contribution of crude oil or its products. By comparing the molecular composition to the samples from the surrounding environmental setting, the steranes and terpanes in the sediment samples was mainly derived from the crude oil and/or its products. After normalization of the aliphatic hydrocarbon parameters, the petroleum hydrocarbon index (PHI) was achieved. The PHI has figured out four divided regions as the relatively intense contaminated regions with a total area of 1.22×106 km2, accounting for 24% of the study area.
On the basis of the examination of the distribution, sources and molecular composition of the aliphatic hydrocarbons in surface sediments of the Bohai Sea, the sedimentary biomarkers of those hydrocarbons and their indication for the petroleum contamination was elucidated. The occurrence of unresolved complex mixtures and the distribution and compositional patterns of the n-alkanes in the sediments indicated the presence of a widespread petroleum contamination, especially for the coastal Bohai Bay. The n-alkane average chain length (ACL) in the samples from the offshore Bohai Bay and Huanghe River estuary was significant lower than those from the other regions, coupling with the lower ratios of Pr/Ph (<1.0), which suggesting the potential impact of the offshore oil exploration, shipping activity and fluvial input for the petroleum residue input. The conventional diagnostic ratios of the petroleum biomarkers, such as Ts/Tm, homohopanes S/(S+R) and αααC29 sterane S/(S+R) ratios indicated a presence of mature constituents in the sediments, implying the contribution of crude oil or its products. By comparing the molecular composition to the samples from the surrounding environmental setting, the steranes and terpanes in the sediment samples was mainly derived from the crude oil and/or its products. After normalization of the aliphatic hydrocarbon parameters, the petroleum hydrocarbon index (PHI) was achieved. The PHI has figured out four divided regions as the relatively intense contaminated regions with a total area of 1.22×106 km2, accounting for 24% of the study area.
2013, 35(1): 131-143.
doi: 10.3969/j.issn.0253-4193.2013.01.015
Abstract:
The chemical composition of amphibole in the surface sediments of the Huanghe River is studied by means of the electron microprobe analysis.The cation coefficients of the 69 amphibole are calculated on the basis of oxygen measurement. Limited by the stoichiometry,the average coefficients of Fe3+, Fe2+ and other relevant cation are estimated. According to the cation coefficients, the possible molecular formulas of the crystal structure and corresponding crystal-chemical characteristics are obtained. The results show that although the amphiboles of the Huanghe River have a large variation in the chemical composition, they are all characterized by high content’s silicon, calcium, magnesium and low alkalinity. According to crystallochemical classification, the 69 amphiboles whose spices are relatively simple all belong to the calcic-amphibole. It contains ten kinds of hornblende; the projected spots are concentrating in the graphics of classification of the calatic amphiboles, including more than 50% of magnesiohornblende and small amount of edenite. The characteristics of crystallochemistry of these can provide identification basis for distinguishing the Huanghe River sediments form other sedimentary body. The crystallochemistry-genesis illustration demonstrates that the 69 hornblendes are mainly derived from the intermediate-acidic magmatites, and then are metamorphic origin rocks. And the magmatic origin type of amphiboles is originated from a crust-mantle mixed source (mainly) and a mantle source (secondly), while the metamorphic genesis origin type comes in metamorphic environments below middle pressures and middle temperatures. Amphibole in the Huanghe River whose species and features are most common indicate that their original sources are universal and stable, and can be used as standardized material in the upper crustal terrigenous sediments in northern China.
The chemical composition of amphibole in the surface sediments of the Huanghe River is studied by means of the electron microprobe analysis.The cation coefficients of the 69 amphibole are calculated on the basis of oxygen measurement. Limited by the stoichiometry,the average coefficients of Fe3+, Fe2+ and other relevant cation are estimated. According to the cation coefficients, the possible molecular formulas of the crystal structure and corresponding crystal-chemical characteristics are obtained. The results show that although the amphiboles of the Huanghe River have a large variation in the chemical composition, they are all characterized by high content’s silicon, calcium, magnesium and low alkalinity. According to crystallochemical classification, the 69 amphiboles whose spices are relatively simple all belong to the calcic-amphibole. It contains ten kinds of hornblende; the projected spots are concentrating in the graphics of classification of the calatic amphiboles, including more than 50% of magnesiohornblende and small amount of edenite. The characteristics of crystallochemistry of these can provide identification basis for distinguishing the Huanghe River sediments form other sedimentary body. The crystallochemistry-genesis illustration demonstrates that the 69 hornblendes are mainly derived from the intermediate-acidic magmatites, and then are metamorphic origin rocks. And the magmatic origin type of amphiboles is originated from a crust-mantle mixed source (mainly) and a mantle source (secondly), while the metamorphic genesis origin type comes in metamorphic environments below middle pressures and middle temperatures. Amphibole in the Huanghe River whose species and features are most common indicate that their original sources are universal and stable, and can be used as standardized material in the upper crustal terrigenous sediments in northern China.
2013, 35(1): 144-148.
doi: 10.3969/j.issn.0253-4193.2013.01.016
Abstract:
Deep sea environment is usually characterized by extremely high salinity, high pressure, high/low temperature and darkness. The physicochemical features ensured that may exist in microorganisms unique metabolic and physiological activities, molecular and cellular structure to adapt to these extreme conditions. Therefore, the exploration of biological and function diversity of microorganisms in deep sea are expected to yield novel metabolites. To access to the microbial genetic resources of deep-sea sediment with a culture-independent approach, The sediment DNA was extracted from deep-sea sediments of the South China Sea and cloned into fosmid vector generating a library of 39 600 clones with inserts of 24-45 kb and an average insert size of 33 kb. The metagenomic library represented about 1 320 Mbp of genomic DNA in deep-sea sediments. The library was screened for amylase activity and three recombinant clones showed amylolytic activity. The clone, amy7, with lower optimal temperature was further analyzed. Subsequent library of insert DNA of amy7 was constructed and a positive subclone, designated as amy7-4, was screened. Sequencing of the clone revealed that it contains a 3 291 bp fragment. An open reading frame of 1 920 bp was identified from the fragment and showed high identity with genes of glycosidase from various organisms.
Deep sea environment is usually characterized by extremely high salinity, high pressure, high/low temperature and darkness. The physicochemical features ensured that may exist in microorganisms unique metabolic and physiological activities, molecular and cellular structure to adapt to these extreme conditions. Therefore, the exploration of biological and function diversity of microorganisms in deep sea are expected to yield novel metabolites. To access to the microbial genetic resources of deep-sea sediment with a culture-independent approach, The sediment DNA was extracted from deep-sea sediments of the South China Sea and cloned into fosmid vector generating a library of 39 600 clones with inserts of 24-45 kb and an average insert size of 33 kb. The metagenomic library represented about 1 320 Mbp of genomic DNA in deep-sea sediments. The library was screened for amylase activity and three recombinant clones showed amylolytic activity. The clone, amy7, with lower optimal temperature was further analyzed. Subsequent library of insert DNA of amy7 was constructed and a positive subclone, designated as amy7-4, was screened. Sequencing of the clone revealed that it contains a 3 291 bp fragment. An open reading frame of 1 920 bp was identified from the fragment and showed high identity with genes of glycosidase from various organisms.
2013, 35(1): 149-157.
doi: 10.3969/j.issn.0253-4193.2013.01.017
Abstract:
It was analyzed that δ13C and δ15N of plants, animals and faeces, then built up a simplified salt marsh food web model in Yancheng coastal salt marshes, Jiangsu Province. The main results showed: (1) The δ13C value of primary producers are between-28.856×10-3 and-10.952×10-3, and the δ15N are between 1.219×10-3 and 6.496×10-3,with significant differences. The δ13C value of consumers are between -27.564×10-3 and -11.641×10-3, and the δ15N are between 4.462×10-3 and 10.339×10-3; (2) The ecosystem of Yancheng coastal marshes can be divided into intertidal sub-ecosystem and supratidal sub-ecosystem, and the main food source of supratidal belt is Phragmites australis, while in the intertidal belt are Spartina alterniflora and micro-algae, Saudea salva contributes to both the two sub-ecosystems but with low contribution; (3) Most of the large herbivorous mammals and benthic organisms in Yancheng coastal marshes occupy the second trophic level; (4) The animals living in Yancheng coastal marshes can be divided into 8 major ecological groups as herbivorous mammals, herbivorous insects, birds, fresh-water swimming animals, salt-water fishes, endofauna, epifauna and zooplankton. Therefore, the diversity of animal food composition of the intertidal belt was slightly higher than that of the supratidal belt. The food competition between intertidal animals was very intense, and the dominant species which overlapped on the bare belt have a slightadj food niche differentiation.
It was analyzed that δ13C and δ15N of plants, animals and faeces, then built up a simplified salt marsh food web model in Yancheng coastal salt marshes, Jiangsu Province. The main results showed: (1) The δ13C value of primary producers are between-28.856×10-3 and-10.952×10-3, and the δ15N are between 1.219×10-3 and 6.496×10-3,with significant differences. The δ13C value of consumers are between -27.564×10-3 and -11.641×10-3, and the δ15N are between 4.462×10-3 and 10.339×10-3; (2) The ecosystem of Yancheng coastal marshes can be divided into intertidal sub-ecosystem and supratidal sub-ecosystem, and the main food source of supratidal belt is Phragmites australis, while in the intertidal belt are Spartina alterniflora and micro-algae, Saudea salva contributes to both the two sub-ecosystems but with low contribution; (3) Most of the large herbivorous mammals and benthic organisms in Yancheng coastal marshes occupy the second trophic level; (4) The animals living in Yancheng coastal marshes can be divided into 8 major ecological groups as herbivorous mammals, herbivorous insects, birds, fresh-water swimming animals, salt-water fishes, endofauna, epifauna and zooplankton. Therefore, the diversity of animal food composition of the intertidal belt was slightly higher than that of the supratidal belt. The food competition between intertidal animals was very intense, and the dominant species which overlapped on the bare belt have a slightadj food niche differentiation.
2013, 35(1): 158-164.
doi: 10.3969/j.issn.0253-4193.2013.01.018
Abstract:
To improve the forecasting accuracy of pelagic fishing ground and meet the needs of the practical fishery production, a method of albacore fishing ground forecast model in the Indian Ocean based on random forest was proposed.The Indian Ocean fishery environmental and spatio-temporal data by 5°×5° grid of every month from 2002 to 2009 were taken as predictor variables and the CPUE(catch per unit effort,unit∶inds per 1 000 hooks)of albacore,classified into high CPUE, moderate CPUE and low CPUE by tertile, was selected as the response variable in the random forest training. The training result indicated that the OOB(out-of-bag)misclassification rate tends to be steady when the number of decision trees reached 100. The random forest obtained through the training was applied to the albacore fishing ground monthly forecast in 2010.The isosurface chart on forecasted probabilities was overlapped on the practical fishery production and a comparison was made between them.The result demonstrated that the high CPUE fishing ground probability distribution and the CPUE of actual fishery ground tally well. Through the ROC analysis, AUCs (Area Under ROC Curve)of high CPUE, moderate CPUE and low CPUE were 0.847,0.743 and 0.803 respectively, indicating that the forecast precision was high. Finally the reason of the relatively low precision of medium CPUE probability in the forecast was analyzed.
To improve the forecasting accuracy of pelagic fishing ground and meet the needs of the practical fishery production, a method of albacore fishing ground forecast model in the Indian Ocean based on random forest was proposed.The Indian Ocean fishery environmental and spatio-temporal data by 5°×5° grid of every month from 2002 to 2009 were taken as predictor variables and the CPUE(catch per unit effort,unit∶inds per 1 000 hooks)of albacore,classified into high CPUE, moderate CPUE and low CPUE by tertile, was selected as the response variable in the random forest training. The training result indicated that the OOB(out-of-bag)misclassification rate tends to be steady when the number of decision trees reached 100. The random forest obtained through the training was applied to the albacore fishing ground monthly forecast in 2010.The isosurface chart on forecasted probabilities was overlapped on the practical fishery production and a comparison was made between them.The result demonstrated that the high CPUE fishing ground probability distribution and the CPUE of actual fishery ground tally well. Through the ROC analysis, AUCs (Area Under ROC Curve)of high CPUE, moderate CPUE and low CPUE were 0.847,0.743 and 0.803 respectively, indicating that the forecast precision was high. Finally the reason of the relatively low precision of medium CPUE probability in the forecast was analyzed.
2013, 35(1): 165-171.
doi: 10.3969/j.issn.0253-4193.2013.01.019
Abstract:
Molecular phylogenetic relationships of 21 species including 11 Pomadasys and 10 other Haemulinae species collected from the water regions of China,America and Africa were analyzed using partial sequences of the 1st intron of S7 ribosomal protein gene. The phylogenetic trees were constructed using a methed of maximum parsimony and Bayesian inference. The result revealed that Pomadasys groups were non-monophyletic. Apart from a small group formed by six Pomadasys species,other Pomadasys were grouped in different positions of the phylogenetic trees. Pomadasys corvinaeformis was clustered with Conodon nobilis and Pomadasys macracanthus was clustered with Anisotremus species,Pomadasys stridens and Pomadasys striatum were closely related with Haemulon. Pomadasys peroteti was first separated and rooted on the basis of the Haemulinae clade. Such phylogenetic relationships were found to be correlated with their geographic distributions.
Molecular phylogenetic relationships of 21 species including 11 Pomadasys and 10 other Haemulinae species collected from the water regions of China,America and Africa were analyzed using partial sequences of the 1st intron of S7 ribosomal protein gene. The phylogenetic trees were constructed using a methed of maximum parsimony and Bayesian inference. The result revealed that Pomadasys groups were non-monophyletic. Apart from a small group formed by six Pomadasys species,other Pomadasys were grouped in different positions of the phylogenetic trees. Pomadasys corvinaeformis was clustered with Conodon nobilis and Pomadasys macracanthus was clustered with Anisotremus species,Pomadasys stridens and Pomadasys striatum were closely related with Haemulon. Pomadasys peroteti was first separated and rooted on the basis of the Haemulinae clade. Such phylogenetic relationships were found to be correlated with their geographic distributions.
2013, 35(1): 172-176.
doi: 10.3969/j.issn.0253-4193.2013.01.020
Abstract:
A reversed phase high performance liquid chromatographic method was developed to determine dissolved acrylic acid in seawater. Using the Agilent SB-Aq-C18 column (100 mm×4.6 mm i.d., 5 μm) and 0.35% H3PO4-water (pH=2) as the mobile phase, the column eluate was monitored by ultraviolet detector. The wavelength of UV detector was 210 nm, and an external standard method was adopted. The detection limit of the method was 4 nmol/dm3(S/N=3). The peak area is linear with acrylic acid concentration in the range of 0.01~10 μmol/dm3, with a correlation coefficient of 0.999 6. The average recovery was 95.4%~98.1% and RSD was 1.3%~1.6%. Samples for acrylic acid could be stored in the dark at 4℃ after gravity filter through 0.2 μmWhatman membrane. The highly sensitive and accurate analytical method has been successfully applied to the determination of acrylic acid in natural seawater and algal culture.
A reversed phase high performance liquid chromatographic method was developed to determine dissolved acrylic acid in seawater. Using the Agilent SB-Aq-C18 column (100 mm×4.6 mm i.d., 5 μm) and 0.35% H3PO4-water (pH=2) as the mobile phase, the column eluate was monitored by ultraviolet detector. The wavelength of UV detector was 210 nm, and an external standard method was adopted. The detection limit of the method was 4 nmol/dm3(S/N=3). The peak area is linear with acrylic acid concentration in the range of 0.01~10 μmol/dm3, with a correlation coefficient of 0.999 6. The average recovery was 95.4%~98.1% and RSD was 1.3%~1.6%. Samples for acrylic acid could be stored in the dark at 4℃ after gravity filter through 0.2 μmWhatman membrane. The highly sensitive and accurate analytical method has been successfully applied to the determination of acrylic acid in natural seawater and algal culture.
Email alert
RSS