2010 Vol. 29, No. 1
Display Method:
2010, (1): 1-11.
doi: 10.1007/s13131-010-0001-7
Abstract:
An optimal interpolation assimilation model for satellite altimetry data is developed based on Princeton Ocean Model (POM), which is applied in a quasi-global domain, by the method of isotropic correlation between sea level anomaly (SLA) and sea temperature anomaly. The performance of this assimilation model is validated by the modeled results of SLA and the current patterns. Comparisons between modeling and satellite data show that both the magnitudes and distribution patterns of the simulated SLA are improved by assimilation. The most significant improvement is that meso-scale systems, e.g., eddies, are well reconstructed. The evolution of an eddy located in the northwest Pacific Ocean is traced by using the assimilation model. Model results show that during three months the eddy migrated southwestward for about 6 degrees before merging into the Kuroshio. The three dimensional structure of this eddy on 12 August 2001 is further analyzed. The strength of this warm, cyclonic eddy decreases with the increase of depth. The eddy shows different horizontal patterns at different layers, and the SLA and temperature fields agree with each other well. This study suggests that this kind of data assimilation is economic and reliable for eddy reconstruction, and can be used as a promising technique in further studies of ocean eddies as well as other fine circulation structures.
An optimal interpolation assimilation model for satellite altimetry data is developed based on Princeton Ocean Model (POM), which is applied in a quasi-global domain, by the method of isotropic correlation between sea level anomaly (SLA) and sea temperature anomaly. The performance of this assimilation model is validated by the modeled results of SLA and the current patterns. Comparisons between modeling and satellite data show that both the magnitudes and distribution patterns of the simulated SLA are improved by assimilation. The most significant improvement is that meso-scale systems, e.g., eddies, are well reconstructed. The evolution of an eddy located in the northwest Pacific Ocean is traced by using the assimilation model. Model results show that during three months the eddy migrated southwestward for about 6 degrees before merging into the Kuroshio. The three dimensional structure of this eddy on 12 August 2001 is further analyzed. The strength of this warm, cyclonic eddy decreases with the increase of depth. The eddy shows different horizontal patterns at different layers, and the SLA and temperature fields agree with each other well. This study suggests that this kind of data assimilation is economic and reliable for eddy reconstruction, and can be used as a promising technique in further studies of ocean eddies as well as other fine circulation structures.
2010, (1): 12-16.
doi: 10.1007/s13131-010-0002-6
Abstract:
Many ship target detection methods have been developed since it was verified that ship could be imaged with the space-based SAR systems. Most developed detection methods mostly emphasized ship detection rate but not computation time. By making use of the advantages of the K-distribution CFAR method and two-parameter CFAR method, a new CFAR ship target detection algorithm was proposed. In that new method, we use the K-distribution CFAR method to calculate a global threshold with a certain false-alarm rate. Then the threshold is applied to the whole SAR imagery to determine the possible ship target pixels, and a binary image is given as the preliminary result. Mathematical morphological filter are used to filter the binary image. After that step, we use the two-parameter CFAR method to detect the ship targets. In the step, the local sliding window only works in the possible ship target pixels of the SAR imagery. That step avoids the statistical calculation of the background pixels, so the method proposed can much improve the processing speed. In order to test the new method, two SAR imagery with different background were used, and the detection result shows that that method can work well in different background circumstances with high detection rate. Moreover, a synchronous ship detection experiment was carried out in Qingdao port in October 28, 2005 to verify the new method and one ENVISAT ASAR imagery was acquired to detect ship targets. It can be concluded from the experiment that the new method not only has high detection rate, but also is time-consuming, and is suitable for the operational ship detection system.
Many ship target detection methods have been developed since it was verified that ship could be imaged with the space-based SAR systems. Most developed detection methods mostly emphasized ship detection rate but not computation time. By making use of the advantages of the K-distribution CFAR method and two-parameter CFAR method, a new CFAR ship target detection algorithm was proposed. In that new method, we use the K-distribution CFAR method to calculate a global threshold with a certain false-alarm rate. Then the threshold is applied to the whole SAR imagery to determine the possible ship target pixels, and a binary image is given as the preliminary result. Mathematical morphological filter are used to filter the binary image. After that step, we use the two-parameter CFAR method to detect the ship targets. In the step, the local sliding window only works in the possible ship target pixels of the SAR imagery. That step avoids the statistical calculation of the background pixels, so the method proposed can much improve the processing speed. In order to test the new method, two SAR imagery with different background were used, and the detection result shows that that method can work well in different background circumstances with high detection rate. Moreover, a synchronous ship detection experiment was carried out in Qingdao port in October 28, 2005 to verify the new method and one ENVISAT ASAR imagery was acquired to detect ship targets. It can be concluded from the experiment that the new method not only has high detection rate, but also is time-consuming, and is suitable for the operational ship detection system.
2010, (1): 17-25.
doi: 10.1007/s13131-010-0003-5
Abstract:
The variation of colloidal phosphorus with salinity in estuary was studied in this paper, which was compared with those of particle and truly dissolved phosphorus with the purpose of finding out the similarities and differences between their behaviors in the estuary. Distribution patterns of phosphorus in particle, colloidal and truly dissolved phase at different salinities and their relationships with suspended particulate matter were also studied to understand the transformation and transportation of colloidal phosphorus in estuarine area. The result showed that the concentrations of total colloidal phosphorus, organic colloidal phosphorus and inorganic colloidall phosphate all descended from river-end to sea-end, illustrating their terrigenous source. Ratios of organic to total colloidal phosphorus decreased with salinity's increment, indicating that organic phosphorus was influenced by scavenging process of colloid more significantly as compared with inorganic phosphate. Both of the phosphorus variation tendencies and the proportion between organic and inorganic phosphorus in colloidal phase was similar with that in truly dissolved phase while different from that in particle phase.
The variation of colloidal phosphorus with salinity in estuary was studied in this paper, which was compared with those of particle and truly dissolved phosphorus with the purpose of finding out the similarities and differences between their behaviors in the estuary. Distribution patterns of phosphorus in particle, colloidal and truly dissolved phase at different salinities and their relationships with suspended particulate matter were also studied to understand the transformation and transportation of colloidal phosphorus in estuarine area. The result showed that the concentrations of total colloidal phosphorus, organic colloidal phosphorus and inorganic colloidall phosphate all descended from river-end to sea-end, illustrating their terrigenous source. Ratios of organic to total colloidal phosphorus decreased with salinity's increment, indicating that organic phosphorus was influenced by scavenging process of colloid more significantly as compared with inorganic phosphate. Both of the phosphorus variation tendencies and the proportion between organic and inorganic phosphorus in colloidal phase was similar with that in truly dissolved phase while different from that in particle phase.
2010, (1): 26-32.
doi: 10.1007/s13131-010-0004-4
Abstract:
A two-month study was conducted to test the effects of macroalgae on the growth and survivorship of juvenile lined seahorse (Hippocampus erectus) in aquaria. Twenty-day old seahorses were cultured in the tanks with green alga Chaetomorpha linum, red alga Gracilaria tikvahiae, green plastic artificial plant (stargrass), and black plastic net, respectively. Increases in wet mass and standard length for the seahorses were significantly higher in the tanks with macroalgae than those without macroalgae. The seahorse survivorships in the two macroalgal treatments were also significantly higher than those of the two treatments without macroalgae. In the treatments with macroalgae, the DO and pH were higher than those without marcoalgae. During the experiment, the color of seahorses was changed to certain extent. In the green background (the treatments with C. linum and stargrass), 24.1%-28.4% of black seahorses decreased over time; whereas in the black (plastic net) or brown (G. tikvahiae) background treatments, 14.1%-16.3% of yellow seahorses decreased over time, for matching that of the background. Furthermore, the survival rate of seahorse was correlation with DO and pH, and strong correlation with standard length, wet mass and CF. Polyculture with macroalgae, survival rates of seahorse were higher than without macroaglae.
A two-month study was conducted to test the effects of macroalgae on the growth and survivorship of juvenile lined seahorse (Hippocampus erectus) in aquaria. Twenty-day old seahorses were cultured in the tanks with green alga Chaetomorpha linum, red alga Gracilaria tikvahiae, green plastic artificial plant (stargrass), and black plastic net, respectively. Increases in wet mass and standard length for the seahorses were significantly higher in the tanks with macroalgae than those without macroalgae. The seahorse survivorships in the two macroalgal treatments were also significantly higher than those of the two treatments without macroalgae. In the treatments with macroalgae, the DO and pH were higher than those without marcoalgae. During the experiment, the color of seahorses was changed to certain extent. In the green background (the treatments with C. linum and stargrass), 24.1%-28.4% of black seahorses decreased over time; whereas in the black (plastic net) or brown (G. tikvahiae) background treatments, 14.1%-16.3% of yellow seahorses decreased over time, for matching that of the background. Furthermore, the survival rate of seahorse was correlation with DO and pH, and strong correlation with standard length, wet mass and CF. Polyculture with macroalgae, survival rates of seahorse were higher than without macroaglae.
2010, (1): 33-41.
doi: 10.1007/s13131-010-0005-3
Abstract:
The formation mechanism of the large hydrothermal sulfide deposit is a complex geological process involving many controlling factors. Mixing between hydrothermal fluid and seawater plays a key role in this process. The results of the Ocean Drilling Program (ODP) indicate that mixing of the evolved seawater and hydrothermal fluid, which is wildly developed within the Trans-Atlantic GeoTraverse (TAG) hydrothermal deposit, governs the internal structure and chemical compositions of the deposit to great extent. Taking the TAG field for example, the mixing processes of hydrothermal fluid with the seawater heated to different extent are calculated, so as to discuss the impact of hydrothermal fluid/seawater mixing on the formation process of the sulfide deposit. The results indicate that:(1) mixing between the heated seawater and hydrothermal fluid derived from the deep deposit is largely responsible for the wild precipitation of anhydrite within the TAG hydrothermal deposit; (2) 330-310℃ is a special temperature range in the mixing process; (3) the mixing and hydrothermal processes in different zones of the TAG hydrothermal deposit (TAG-1, TAG-2 and TAG-5, etc.) have been discussed based on the simulated results.
The formation mechanism of the large hydrothermal sulfide deposit is a complex geological process involving many controlling factors. Mixing between hydrothermal fluid and seawater plays a key role in this process. The results of the Ocean Drilling Program (ODP) indicate that mixing of the evolved seawater and hydrothermal fluid, which is wildly developed within the Trans-Atlantic GeoTraverse (TAG) hydrothermal deposit, governs the internal structure and chemical compositions of the deposit to great extent. Taking the TAG field for example, the mixing processes of hydrothermal fluid with the seawater heated to different extent are calculated, so as to discuss the impact of hydrothermal fluid/seawater mixing on the formation process of the sulfide deposit. The results indicate that:(1) mixing between the heated seawater and hydrothermal fluid derived from the deep deposit is largely responsible for the wild precipitation of anhydrite within the TAG hydrothermal deposit; (2) 330-310℃ is a special temperature range in the mixing process; (3) the mixing and hydrothermal processes in different zones of the TAG hydrothermal deposit (TAG-1, TAG-2 and TAG-5, etc.) have been discussed based on the simulated results.
2010, (1): 42-51.
doi: 10.1007/s13131-010-0006-2
Abstract:
Phosphorus (P) is an essential nutrient utilized by all organisms for energy transport and growth. Both the conventional molybdenum-blue method and the magnesium-induced coprecipitation (MAGIC) procedures were applied for the measurement of dissolved inorganic phosphorus (DIP) and total dissolved phosphorus (TDP) in more than 840 water samples collected between 2003 and 2005, including seawater (the Huanghai Sea, the East China Sea, and the northern South China Sea), water from rivers and estuaries (the Changjiang, the Huanghe, and the major rivers emptying into the Jiaozhou Bay), groundwater (in the drainage basin surrounding the Jiaozhou Bay), rainwater, and aquaculture water samples. The MAGIC method allows the investigation of phosphorus distributions and cycling for systems in which DIP is below the detection limits of conventional methods. Comparison between the two methods demonstrated that the concentrations obtained with both methods were significantly correlated. The differences of DIP and TDP concentrations measured with the two methods were higher when the concentrations of DIP and TDP were lower, implying the lower reproducibility at low concentrations. The concentration differences increase with the increase in the proportion of DOP in TDP, which indicates that the discrepancy of DIP concentrations measured with the two methods increases when the DOP concentration is high. The discrepancies indicated that the composition of P compounds differs depending on sample sources and water type; it would be useful to infer the presence of different phosphorus compound pools from differences between the two methods. This study indicates the potential presence of a pool of alkaline-labile compounds for samples from rainwater and rivers and estuaries surrounding the Jiaozhou Bay; the potential presence of acid-labile compounds that were adsorbed by Mg(OH)2 for samples from the Changjiang Estuary, Huanghai Sea, East China Sea, and groundwater; the potential presence of a substantial pool of acid-labile compounds that were not adsorbed by Mg(OH)2 for samples from the Huanghe Estuary, aquaculture water, the East China Sea algal bloom water, and the northern South China Sea.
Phosphorus (P) is an essential nutrient utilized by all organisms for energy transport and growth. Both the conventional molybdenum-blue method and the magnesium-induced coprecipitation (MAGIC) procedures were applied for the measurement of dissolved inorganic phosphorus (DIP) and total dissolved phosphorus (TDP) in more than 840 water samples collected between 2003 and 2005, including seawater (the Huanghai Sea, the East China Sea, and the northern South China Sea), water from rivers and estuaries (the Changjiang, the Huanghe, and the major rivers emptying into the Jiaozhou Bay), groundwater (in the drainage basin surrounding the Jiaozhou Bay), rainwater, and aquaculture water samples. The MAGIC method allows the investigation of phosphorus distributions and cycling for systems in which DIP is below the detection limits of conventional methods. Comparison between the two methods demonstrated that the concentrations obtained with both methods were significantly correlated. The differences of DIP and TDP concentrations measured with the two methods were higher when the concentrations of DIP and TDP were lower, implying the lower reproducibility at low concentrations. The concentration differences increase with the increase in the proportion of DOP in TDP, which indicates that the discrepancy of DIP concentrations measured with the two methods increases when the DOP concentration is high. The discrepancies indicated that the composition of P compounds differs depending on sample sources and water type; it would be useful to infer the presence of different phosphorus compound pools from differences between the two methods. This study indicates the potential presence of a pool of alkaline-labile compounds for samples from rainwater and rivers and estuaries surrounding the Jiaozhou Bay; the potential presence of acid-labile compounds that were adsorbed by Mg(OH)2 for samples from the Changjiang Estuary, Huanghai Sea, East China Sea, and groundwater; the potential presence of a substantial pool of acid-labile compounds that were not adsorbed by Mg(OH)2 for samples from the Huanghe Estuary, aquaculture water, the East China Sea algal bloom water, and the northern South China Sea.
2010, (1): 52-57.
doi: 10.1007/s13131-010-0007-1
Abstract:
This report based on the results of investigations conducted in June 2007 and July 2008, respectively, on the benthic community structure and characteristic diversity of the Huanghai Sea (Yellow Sea) Cold Water Mass, as well as that in July 1959 during the national oceanic survey. The Naticidae specimens collected from Cold Water Mass in middle and northern Huanghai Sea were studied through morphological classification and the internal anatomy on radula. Three new species of Naticidae, i.e., Cryptonatica purpurfunda sp. nov., Cryptonatica sphaera sp. nov., and Cryptonatica striatica sp. nov. were identified. The morphological characteristics of the new species are described, and the similarties and differences between the new species and similar species are compared and discussed.
This report based on the results of investigations conducted in June 2007 and July 2008, respectively, on the benthic community structure and characteristic diversity of the Huanghai Sea (Yellow Sea) Cold Water Mass, as well as that in July 1959 during the national oceanic survey. The Naticidae specimens collected from Cold Water Mass in middle and northern Huanghai Sea were studied through morphological classification and the internal anatomy on radula. Three new species of Naticidae, i.e., Cryptonatica purpurfunda sp. nov., Cryptonatica sphaera sp. nov., and Cryptonatica striatica sp. nov. were identified. The morphological characteristics of the new species are described, and the similarties and differences between the new species and similar species are compared and discussed.
2010, (1): 58-68.
doi: 10.1007/s13131-010-0008-0
Abstract:
During spring and autumn of 2006, the investigations on abundance, carbon biomass and distribution of picoplankton were carried out in the southern Huanghai Sea (Yellow Sea, sHS). Three groups of picoplankton-Synechococcus (Syn), Picoeukaryotes (PEuk) and heterotrophic bacteria (BAC) were identified, but Prochlorococcus (Pro) was undetected. The average abundance of Syn and PEuk was lower in spring (5.0 and 1.3×103 cells/cm3, respectively) than in autumn (92.4 and 2.7×103 cells/cm3, respectively), but it was opposite for BAC (1.3 and 0.7×106 cells/cm3 in spring and autumn, respectively). And the total carbon biomass of picoplankton was higher in spring (37.23±11.67) mg/m3 than in autumn (21.29±13.75) mg/m3. The ratios of the three cell abundance were 5:1:1 341 and 30:1:124 in spring and autumn, respectively. And the ratios of carbon biomass of them were 5:7:362 and 9:4:4 in spring and autumn, respectively. Seasonal distribution characteristics of Syn, PEuk, BAC were quite different from each other. In spring, Syn abundance decreased in turn in the central waters (where phytoplankton bloom in spring occurred), the southern waters and inshore waters of the Shandong Peninsula (where even Syn was undetected); the high values of PEuk abundance appeared in the central and southern waters and the inshore of the Shandong Peninsula; the abundance of BAC was nearly three order of magnitude higher than that of photosynthetic picoplankton, and high values appeared in the central waters. In autumn, Syn abundance in central waters was higher than that in surrounding waters, while for PEuk abundance, it decreased in turn in the inshore waters of the Shandong Peninsula, the southern waters and the central waters; BAC presented a complicated blocky type distribution. Sub-surface maximum of each group of picopalnkton appeared in both spring and autumn. Compared with the available literatures concerning the studied area, the range of Syn abundance was larger, and the abundance of BAC was higher. In addition, the conversion factors for calculating picoplanktonic carbon biomass were discussed, with the conversion factors which are different from previous studies in the same surveyed waters. The result of regression analysis showed that there was distinct positive correlation between BAC and photosynthetic picoplankton in spring (r=0.61, P <0.001), but no correlation was found in autumn.
During spring and autumn of 2006, the investigations on abundance, carbon biomass and distribution of picoplankton were carried out in the southern Huanghai Sea (Yellow Sea, sHS). Three groups of picoplankton-Synechococcus (Syn), Picoeukaryotes (PEuk) and heterotrophic bacteria (BAC) were identified, but Prochlorococcus (Pro) was undetected. The average abundance of Syn and PEuk was lower in spring (5.0 and 1.3×103 cells/cm3, respectively) than in autumn (92.4 and 2.7×103 cells/cm3, respectively), but it was opposite for BAC (1.3 and 0.7×106 cells/cm3 in spring and autumn, respectively). And the total carbon biomass of picoplankton was higher in spring (37.23±11.67) mg/m3 than in autumn (21.29±13.75) mg/m3. The ratios of the three cell abundance were 5:1:1 341 and 30:1:124 in spring and autumn, respectively. And the ratios of carbon biomass of them were 5:7:362 and 9:4:4 in spring and autumn, respectively. Seasonal distribution characteristics of Syn, PEuk, BAC were quite different from each other. In spring, Syn abundance decreased in turn in the central waters (where phytoplankton bloom in spring occurred), the southern waters and inshore waters of the Shandong Peninsula (where even Syn was undetected); the high values of PEuk abundance appeared in the central and southern waters and the inshore of the Shandong Peninsula; the abundance of BAC was nearly three order of magnitude higher than that of photosynthetic picoplankton, and high values appeared in the central waters. In autumn, Syn abundance in central waters was higher than that in surrounding waters, while for PEuk abundance, it decreased in turn in the inshore waters of the Shandong Peninsula, the southern waters and the central waters; BAC presented a complicated blocky type distribution. Sub-surface maximum of each group of picopalnkton appeared in both spring and autumn. Compared with the available literatures concerning the studied area, the range of Syn abundance was larger, and the abundance of BAC was higher. In addition, the conversion factors for calculating picoplanktonic carbon biomass were discussed, with the conversion factors which are different from previous studies in the same surveyed waters. The result of regression analysis showed that there was distinct positive correlation between BAC and photosynthetic picoplankton in spring (r=0.61, P <0.001), but no correlation was found in autumn.
2010, (1): 69-78.
doi: 10.1007/s13131-010-0009-z
Abstract:
The effect of the bacterial strain CI4 on the germination of spores from the green alga Ulva pertusa was assayed and it was found that the bacterial biofilm and cell-free supernatant strongly inhibited spore germination. In attempts to define the chemical nature of the antifouling substance in the supernatant of CI4, the culture supernatants were tested for activity after heat treatment, enzymatic treatments, size fractionation, and separation into aqueous and organic fractions. Results suggest that this bacterium produces an extracellular component with specific activity toward algal spores that was heat-sensitive and between 3 and 10 kDa in molecular size. The exposure of the organic phase fraction to spores showed inhibitive effect on spore germination. Pronase and carboxypeptidase y did not significantly affect the activity of inhibitory component, suggesting that the component was not a protein or a peptide. The bacterium CI4 was identified as Pseudoalteromonas haloplanktis based on the phenotypic characters and 16S rRNA gene analysis.
The effect of the bacterial strain CI4 on the germination of spores from the green alga Ulva pertusa was assayed and it was found that the bacterial biofilm and cell-free supernatant strongly inhibited spore germination. In attempts to define the chemical nature of the antifouling substance in the supernatant of CI4, the culture supernatants were tested for activity after heat treatment, enzymatic treatments, size fractionation, and separation into aqueous and organic fractions. Results suggest that this bacterium produces an extracellular component with specific activity toward algal spores that was heat-sensitive and between 3 and 10 kDa in molecular size. The exposure of the organic phase fraction to spores showed inhibitive effect on spore germination. Pronase and carboxypeptidase y did not significantly affect the activity of inhibitory component, suggesting that the component was not a protein or a peptide. The bacterium CI4 was identified as Pseudoalteromonas haloplanktis based on the phenotypic characters and 16S rRNA gene analysis.
2010, (1): 79-87.
doi: 10.1007/s13131-010-0010-6
Abstract:
The exposed area of intertidal zone varies with tidal water level changes. If intercomparisons of satellite images are adopted as a method to determine geomorphological changes of the intertidal zone in response to accretion or erosion processes, then the effect of water level variations must be evaluated. In this study, two Landsat TM images overpassing the central Jiangsu coastal waters on 2 January and 7 March 2002, respectively, were treated by the changing detection analysis using Image Differencing and Post-classification Comparison. The simultaneous tide level data from four tide gauge stations along the coast were used for displaying the spatial variations of water levels and determining the elevations of waterlines. The results show that the spatial variations of water levels are highly significant in the central Jiangsu coastal waters. The huge differences of tidal land exposure patterns between the two imaging times are related mainly to the spatial variations of tidal water levels, which are controlled by the differences in tidal phases for different imaging times and the spatial variations of water level over the study area at each imaging time. Under complex tidal conditions, e.g., those of the central Jiangsu coastal waters, the tide-surge model should be used to eliminate effectively the effects of water level variations on remote sensing interpretation of geomorphological changes in the intertidal zone.
The exposed area of intertidal zone varies with tidal water level changes. If intercomparisons of satellite images are adopted as a method to determine geomorphological changes of the intertidal zone in response to accretion or erosion processes, then the effect of water level variations must be evaluated. In this study, two Landsat TM images overpassing the central Jiangsu coastal waters on 2 January and 7 March 2002, respectively, were treated by the changing detection analysis using Image Differencing and Post-classification Comparison. The simultaneous tide level data from four tide gauge stations along the coast were used for displaying the spatial variations of water levels and determining the elevations of waterlines. The results show that the spatial variations of water levels are highly significant in the central Jiangsu coastal waters. The huge differences of tidal land exposure patterns between the two imaging times are related mainly to the spatial variations of tidal water levels, which are controlled by the differences in tidal phases for different imaging times and the spatial variations of water level over the study area at each imaging time. Under complex tidal conditions, e.g., those of the central Jiangsu coastal waters, the tide-surge model should be used to eliminate effectively the effects of water level variations on remote sensing interpretation of geomorphological changes in the intertidal zone.
2010, (1): 88-99.
doi: 10.1007/s13131-010-0011-5
Abstract:
In this study, characteristics of flow field and wave propagation near submerged breakwater on a sloping bed are investigated with numerical model. The governing equations of the vertical twodimensional model are Reynolds Averaged Navier Stokes equations. The Reynolds stress terms are closed by a nonlinear k-ε turbulence transportation model. The free surface is traced through the PILC-VOF method. The proposed numerical model is verified with experimental results. The numerical result shows that the wave profile may become more asymmetrical when wave propagates over breakwater. When wave crest propagates over breakwater, the anticlockwise vortex may generate. On the contrary, when wave hollow propagates over breakwater, the clockwise vortex may generate. Meanwhile, the influenced zone of vortex created by wave crest is larger than that created by wave hollow. All the maximum values of the turbulent kinetic energy, turbulent dissipation and eddy viscosity occur on the top of breakwater. Both the turbulent dissipation and eddy viscosity increase as the turbulent kinetic energy increases. Wave energy may rapidly decrease near the breakwater because turbulent dissipation increases and energy in lower harmonics is transferred into higher harmonics.
In this study, characteristics of flow field and wave propagation near submerged breakwater on a sloping bed are investigated with numerical model. The governing equations of the vertical twodimensional model are Reynolds Averaged Navier Stokes equations. The Reynolds stress terms are closed by a nonlinear k-ε turbulence transportation model. The free surface is traced through the PILC-VOF method. The proposed numerical model is verified with experimental results. The numerical result shows that the wave profile may become more asymmetrical when wave propagates over breakwater. When wave crest propagates over breakwater, the anticlockwise vortex may generate. On the contrary, when wave hollow propagates over breakwater, the clockwise vortex may generate. Meanwhile, the influenced zone of vortex created by wave crest is larger than that created by wave hollow. All the maximum values of the turbulent kinetic energy, turbulent dissipation and eddy viscosity occur on the top of breakwater. Both the turbulent dissipation and eddy viscosity increase as the turbulent kinetic energy increases. Wave energy may rapidly decrease near the breakwater because turbulent dissipation increases and energy in lower harmonics is transferred into higher harmonics.
2010, (1): 100-107.
doi: 10.1007/s13131-010-0012-4
Abstract:
The unstable state of nitrite results in its very low concentration in seawater, which is below the limit of detection (LOD) of conventional techniques of analysis. Some sensitivity-enhanced methods have been proposed for the determination of nitrite at nanomolar level to illustrate the role of nitrite in the marine nitrogen cycle. However, most of previous reports are not widely accepted, because of their complexity and cost equipment or intensive labor requirement. In this study, a simple automatic system for the determination of nanomolar level nitrite using on-line preconcentration with spectrophotometric detection was described. An Oasis HLB cartridge was adopted to quantitatively enrich the pink-colored azo compound, formed from nitrite via Griess reaction. The cartridge was rinsed with water and ethanol (volume fraction is 55%, the same below), in turn, then eluted by an eluent containing 50% ethanol and 0.25 M(mol/dm3) H2SO4, and determined at 543 nm with a 2 cm path-length flow cell. Under the optimized experimental conditions, the calibration curve showed a good linearity in the range of 1.4-85.7 nM, and the LOD (3σ) was estimated to be 0.5 nM. The relative standard deviations of 7 measurements were 4.0% and 1.0% for the samples spiked at 7.1 and 28.6 nM, respectively. The recoveries for the different natural water samples were between 92.2%-108.4%. Each HLB cartridge could be reused for at least 50 times. As compared with other SPE methods, the advantages of this method included the free of interference from salinity variation and less sample consuming. The results of the application of the proposed method to natural water showed good agreement with liquid waveguide capillary cell detection method.
The unstable state of nitrite results in its very low concentration in seawater, which is below the limit of detection (LOD) of conventional techniques of analysis. Some sensitivity-enhanced methods have been proposed for the determination of nitrite at nanomolar level to illustrate the role of nitrite in the marine nitrogen cycle. However, most of previous reports are not widely accepted, because of their complexity and cost equipment or intensive labor requirement. In this study, a simple automatic system for the determination of nanomolar level nitrite using on-line preconcentration with spectrophotometric detection was described. An Oasis HLB cartridge was adopted to quantitatively enrich the pink-colored azo compound, formed from nitrite via Griess reaction. The cartridge was rinsed with water and ethanol (volume fraction is 55%, the same below), in turn, then eluted by an eluent containing 50% ethanol and 0.25 M(mol/dm3) H2SO4, and determined at 543 nm with a 2 cm path-length flow cell. Under the optimized experimental conditions, the calibration curve showed a good linearity in the range of 1.4-85.7 nM, and the LOD (3σ) was estimated to be 0.5 nM. The relative standard deviations of 7 measurements were 4.0% and 1.0% for the samples spiked at 7.1 and 28.6 nM, respectively. The recoveries for the different natural water samples were between 92.2%-108.4%. Each HLB cartridge could be reused for at least 50 times. As compared with other SPE methods, the advantages of this method included the free of interference from salinity variation and less sample consuming. The results of the application of the proposed method to natural water showed good agreement with liquid waveguide capillary cell detection method.
2010, (1): 108-115.
doi: 10.1007/s13131-010-0013-3
Abstract:
Spatial and temporal distributions of nutrients (N and P) and heavy metals (Cu, Zn, Pb and Cd) in the intertidal sediments at Dongtan wetland of the Changjiang River (Yangtze River) Estuary were examined by laying one transect running seaward to landward during January, April, June, August and October of 2005. Total nitrogen (TN) and heavy metal concentrations in the intertidal sediment showed an increasing trend from open bare flat to the high marsh, with the maximum concentrations in the high marsh and the minimum values in open bare flat. In contrast, sediment total phosphorus (TP) concentrations changed little among sampling sites. One-way ANOVA found that there were significantly temporal variations of nutrients and heavy metals concentrations in the intertidal sediment (P <0.05). The concentrations of heavy metals generally showed an increasing trend from January to October. As compared with other large estuaries, heavy metal contamination in the intertidal sediment of the Changjiang River Estuary was relatively low.
Spatial and temporal distributions of nutrients (N and P) and heavy metals (Cu, Zn, Pb and Cd) in the intertidal sediments at Dongtan wetland of the Changjiang River (Yangtze River) Estuary were examined by laying one transect running seaward to landward during January, April, June, August and October of 2005. Total nitrogen (TN) and heavy metal concentrations in the intertidal sediment showed an increasing trend from open bare flat to the high marsh, with the maximum concentrations in the high marsh and the minimum values in open bare flat. In contrast, sediment total phosphorus (TP) concentrations changed little among sampling sites. One-way ANOVA found that there were significantly temporal variations of nutrients and heavy metals concentrations in the intertidal sediment (P <0.05). The concentrations of heavy metals generally showed an increasing trend from January to October. As compared with other large estuaries, heavy metal contamination in the intertidal sediment of the Changjiang River Estuary was relatively low.
2010, (1): 116-119.
doi: 10.1007/s13131-010-0014-2
Abstract:
In order to provide pertinent evidence of ion channel with immune response in the fish, whole cell patch-clamp technique was employed for potassium ion channel study in turbot (Scophthalmus maximus). Lymphocytes were isolated by Percoll density gradient centrifugation from peripheral blood samples, and electrophysiological characters of the channel were analyzed. In the recorded cells, activated voltage of the channels was -42.5±3.7 mV and the average peak current was 313.12±28.2 pA. The channel was identified as voltage dependent, the current was outward and it could be inhibited by 10 mmol/dm3 TEA or 5 mmol/dm3 4-AP, a specific potassium channel inhibitor, identifying the existence of potassium channel in peripheral lymphocytes of the turbot.
In order to provide pertinent evidence of ion channel with immune response in the fish, whole cell patch-clamp technique was employed for potassium ion channel study in turbot (Scophthalmus maximus). Lymphocytes were isolated by Percoll density gradient centrifugation from peripheral blood samples, and electrophysiological characters of the channel were analyzed. In the recorded cells, activated voltage of the channels was -42.5±3.7 mV and the average peak current was 313.12±28.2 pA. The channel was identified as voltage dependent, the current was outward and it could be inhibited by 10 mmol/dm3 TEA or 5 mmol/dm3 4-AP, a specific potassium channel inhibitor, identifying the existence of potassium channel in peripheral lymphocytes of the turbot.
2010, (1): 120-126.
doi: 10.1007/s13131-010-0015-1
Abstract:
Dissected tissues of three shellfish species, the Chinese scallop, Chlamys farreri, Manila clam, Ruditapes philippinarum, and Razor shell, Solen strictu were evaluated for in vitro transformation of paralytic shellfish poisoning (PSP) toxins. Tissue homogenates were incubated with extraction from toxic algae Alexandrium minutum to determine toxin conversion. The effects of heating and addition of a natural reductant (glutathione) on toxin conversion were also assessed. The toxin profile was investigated through high performance liquid chromatography with fluorescence detection (HPLC-FLD). The evident variations in the toxin content were observed only in Chinese scallop viscera homogenates. The concentration of GTX4 was reduced by 45% (approximately 0.8 μmol/dm3) and 25% (approximately 1 μmol/dm3) for GTX1, while GTX2 and GTX3 increased by six times (approximately 1 μmol/dm3) and 3 times (approximately 0.3 μmol/dm3) respectively. Simultaneously, the total toxicity decreased by 38% during the 48 h incubation period, the final toxicity was 20.4 nmol STXeq/g. Furthermore, heated Chinese scallop viscera homogenates samples were compared with non-heated samples. The concentration of the GTX4 and GTX1 was clearly 28% (approximately 0.53 μmol/dm3) and 17% (approximately 0.69 μmol/dm3) higher in heated samples, GTX2 and GTX3 were four times (0.66 μmol/dm3) and two times (0.187 μmol/dm3) lower respectively. GSH (+) Chinese scallop viscera homogenates samples were compared with GSH (-) samples, the concentration in the GTX4 and GTX1 was 9% (approximately 0.12 μmol/dm3) and 11% (approximately 0.36 μmol/dm3) lower respectively, GTX2 and GTX3 was 17% (approximately 0.14 μmol/dm3) and 19% (approximately 0.006 μmol/dm3) higher respectively. In contrast,there was a little change in the concentration of PSP toxins of Manila clam and Razor shell tissue homogenates. These observations on three shellfish tissues confirmed that there were species-specific differences in PSP toxins transformation. PSP toxins transformation was more pronounced in viscera tissue than in muscle tissue. PSP toxins was possibly interfered by some carbamoylase enzyme, and the activity in Chinese scallop viscera tissue is more remarkable than in the other two species.
Dissected tissues of three shellfish species, the Chinese scallop, Chlamys farreri, Manila clam, Ruditapes philippinarum, and Razor shell, Solen strictu were evaluated for in vitro transformation of paralytic shellfish poisoning (PSP) toxins. Tissue homogenates were incubated with extraction from toxic algae Alexandrium minutum to determine toxin conversion. The effects of heating and addition of a natural reductant (glutathione) on toxin conversion were also assessed. The toxin profile was investigated through high performance liquid chromatography with fluorescence detection (HPLC-FLD). The evident variations in the toxin content were observed only in Chinese scallop viscera homogenates. The concentration of GTX4 was reduced by 45% (approximately 0.8 μmol/dm3) and 25% (approximately 1 μmol/dm3) for GTX1, while GTX2 and GTX3 increased by six times (approximately 1 μmol/dm3) and 3 times (approximately 0.3 μmol/dm3) respectively. Simultaneously, the total toxicity decreased by 38% during the 48 h incubation period, the final toxicity was 20.4 nmol STXeq/g. Furthermore, heated Chinese scallop viscera homogenates samples were compared with non-heated samples. The concentration of the GTX4 and GTX1 was clearly 28% (approximately 0.53 μmol/dm3) and 17% (approximately 0.69 μmol/dm3) higher in heated samples, GTX2 and GTX3 were four times (0.66 μmol/dm3) and two times (0.187 μmol/dm3) lower respectively. GSH (+) Chinese scallop viscera homogenates samples were compared with GSH (-) samples, the concentration in the GTX4 and GTX1 was 9% (approximately 0.12 μmol/dm3) and 11% (approximately 0.36 μmol/dm3) lower respectively, GTX2 and GTX3 was 17% (approximately 0.14 μmol/dm3) and 19% (approximately 0.006 μmol/dm3) higher respectively. In contrast,there was a little change in the concentration of PSP toxins of Manila clam and Razor shell tissue homogenates. These observations on three shellfish tissues confirmed that there were species-specific differences in PSP toxins transformation. PSP toxins transformation was more pronounced in viscera tissue than in muscle tissue. PSP toxins was possibly interfered by some carbamoylase enzyme, and the activity in Chinese scallop viscera tissue is more remarkable than in the other two species.
