2010 Vol. 32, No. 2
Display Method:
2010, 32(2): 1-11.
Abstract:
The simulation of an eddy-permitting global oceanic general circulation model (OGCM) on the South China Sea throughflow (SCSTF) and upper layer heat content of the South China Sea (SCS) is evaluated by using island rule, Simple Ocean Data Assimilation (SODA) and Expendable Bathythermograph (XBT) data. The impact of the SCSTF on upper layer heat content of the SCS is also investigated. Analysis of vertical structure of North Equatorial Current (NEC) bifurcation, seasonal variability of the SCS circulation pattern and interannual variability of Luzon Strait transport (LST) indicate that LICOM can obtain a reasonable modeling result of the SCSTF and circulation in the Indo-Pacific region. Annual mean and seasonal variability of upper layer heat content of the SCS in the model are consistent with those calculated from SODA and XBT, particularly in the inner area of the SCS. In addition, correlation analysis show that there is significant negative correlation between the LST and the SCS upper layer heat content, which further confirms the observational truth that the SCSTF acts as a cold advection in adjusting the upper layer heat content of the SCS.
The simulation of an eddy-permitting global oceanic general circulation model (OGCM) on the South China Sea throughflow (SCSTF) and upper layer heat content of the South China Sea (SCS) is evaluated by using island rule, Simple Ocean Data Assimilation (SODA) and Expendable Bathythermograph (XBT) data. The impact of the SCSTF on upper layer heat content of the SCS is also investigated. Analysis of vertical structure of North Equatorial Current (NEC) bifurcation, seasonal variability of the SCS circulation pattern and interannual variability of Luzon Strait transport (LST) indicate that LICOM can obtain a reasonable modeling result of the SCSTF and circulation in the Indo-Pacific region. Annual mean and seasonal variability of upper layer heat content of the SCS in the model are consistent with those calculated from SODA and XBT, particularly in the inner area of the SCS. In addition, correlation analysis show that there is significant negative correlation between the LST and the SCS upper layer heat content, which further confirms the observational truth that the SCSTF acts as a cold advection in adjusting the upper layer heat content of the SCS.
2010, 32(2): 12-19.
Abstract:
In this paper, a time-domain numerical model is established to consider the motion responses of a Spar platform induced by internal solitary wave which satisfies the K-dv equation. The horizontal force on the Spar is computed by Morison equation and the vertical force is computed by integration of the fluid pressure on the Spar bottom based on Bernoulli equation. The catenary theory is used to analyze the mooring force. The motion equation is solved by using fourth-order Runge-Kutta method. The numerical results show that when the internal solitary approaches to the Spar platform, the platform produces a much greater displacement comparing with the displacement induced by the surface waves. It is approved that internal solitary wave is one of the important effecting factors for the stability of offshore platform. Therefore the influence of internal solitary wave on the deep-sea platforms can not be neglected in design and estimation.
In this paper, a time-domain numerical model is established to consider the motion responses of a Spar platform induced by internal solitary wave which satisfies the K-dv equation. The horizontal force on the Spar is computed by Morison equation and the vertical force is computed by integration of the fluid pressure on the Spar bottom based on Bernoulli equation. The catenary theory is used to analyze the mooring force. The motion equation is solved by using fourth-order Runge-Kutta method. The numerical results show that when the internal solitary approaches to the Spar platform, the platform produces a much greater displacement comparing with the displacement induced by the surface waves. It is approved that internal solitary wave is one of the important effecting factors for the stability of offshore platform. Therefore the influence of internal solitary wave on the deep-sea platforms can not be neglected in design and estimation.
2010, 32(2): 20-30.
Abstract:
A barotropic tidal model covering Jiaozhou Bay (JZB) and Qingdao coastal waters is developed based on Princeton Ocean Model (POM). This numerical model, combined with the field survey currents data obtained from a vessel-mounted Acoustic Doppler Current Profiler (ADCP), is used to investigate the characteristics of the tidal currents near the mouth of JZB. Furthermore, a water quality sub-model is coupled into the tidal model to simulate the water exchange processes in JZB. The tidal model includes six main tidal constituents (M2, S2, K1, O1, M4, and MS4), and reasonably reproduces tidal current field which is consistent with ADCP observation. The tidal current in the bay mouth channel is very strong. The observed peak current speed during spring tide period was 2.01 m/s. A couple of tidal residual eddies are found at both sides of the headland of Tuandao. The residual eddies converge near Tuandao, forming an offshore jet current of 57 cm/s. The modeled mean water residence time (WRT) in JZB is 71 days, and the mean half-life time (HLT) is 25 days. The horizontal distributions of WRT and HLT are quite uneven in space: they increase from the mouth to the top of JZB. The lowest water exchange rates are found in two regions, the west-southwest part and the northeastmost part of JZB, where the WRT is above 80 days with a maximum of 120 days, and HLT mostly exceeds 40 days. Such spatial distribution differences are controlled by the structure of tidal (residual) currents as well as the distance from the bay mouth.
A barotropic tidal model covering Jiaozhou Bay (JZB) and Qingdao coastal waters is developed based on Princeton Ocean Model (POM). This numerical model, combined with the field survey currents data obtained from a vessel-mounted Acoustic Doppler Current Profiler (ADCP), is used to investigate the characteristics of the tidal currents near the mouth of JZB. Furthermore, a water quality sub-model is coupled into the tidal model to simulate the water exchange processes in JZB. The tidal model includes six main tidal constituents (M2, S2, K1, O1, M4, and MS4), and reasonably reproduces tidal current field which is consistent with ADCP observation. The tidal current in the bay mouth channel is very strong. The observed peak current speed during spring tide period was 2.01 m/s. A couple of tidal residual eddies are found at both sides of the headland of Tuandao. The residual eddies converge near Tuandao, forming an offshore jet current of 57 cm/s. The modeled mean water residence time (WRT) in JZB is 71 days, and the mean half-life time (HLT) is 25 days. The horizontal distributions of WRT and HLT are quite uneven in space: they increase from the mouth to the top of JZB. The lowest water exchange rates are found in two regions, the west-southwest part and the northeastmost part of JZB, where the WRT is above 80 days with a maximum of 120 days, and HLT mostly exceeds 40 days. Such spatial distribution differences are controlled by the structure of tidal (residual) currents as well as the distance from the bay mouth.
2010, 32(2): 31-39.
Abstract:
In order to perfectly fit complex coastlines and project structures in coastal and estuarine areas, an unstructured mesh two-dimensional coastal and estuarine hydrodynamic numerical model is established. Finite-volume method is used in spatial discretization to guarantee conservation and predictor-corrector method is used in temporal to improve accuracy. Elevation is solved at the centre of the triangular cell by continuity equation, while horizontal x-direction and y-direction velocities are solved at the middle of grid sides by momentum equations.In calculating velocity advection, TVD scheme is adopted. TVD flux of velocity advection is a combination of the first-order upwind flux and a second-order scheme flux.The proportion of each flux contributing to TVD flux is decided by the local velocity distribution. TVD scheme is low-diffusive and non-dispersive, which improves the stability of the model. Observed data are used to validate the model. Results show that elevation, flow velocity and flow direction are all well matched between calculated values and observed ones.
In order to perfectly fit complex coastlines and project structures in coastal and estuarine areas, an unstructured mesh two-dimensional coastal and estuarine hydrodynamic numerical model is established. Finite-volume method is used in spatial discretization to guarantee conservation and predictor-corrector method is used in temporal to improve accuracy. Elevation is solved at the centre of the triangular cell by continuity equation, while horizontal x-direction and y-direction velocities are solved at the middle of grid sides by momentum equations.In calculating velocity advection, TVD scheme is adopted. TVD flux of velocity advection is a combination of the first-order upwind flux and a second-order scheme flux.The proportion of each flux contributing to TVD flux is decided by the local velocity distribution. TVD scheme is low-diffusive and non-dispersive, which improves the stability of the model. Observed data are used to validate the model. Results show that elevation, flow velocity and flow direction are all well matched between calculated values and observed ones.
2010, 32(2): 40-53.
Abstract:
By using the Fog Monitor (FM-100, DMT Inc. USA) droplet collector, the droplet size distribution and droplet number concentration of sea fog from 16 to 19 March 2008 were investigated in the Science Experiment Base for Marine Meteorology at Bohe, Guangdong Province. The microphysical structure and evolution of this sea fog event, especially the LWC (liquid water content) of sea fog, are analysed. According the observational data during the same period, the synoptic factors accounting for the low atmospheric visibility assocaited with this sea fog event were also analysed.It is shown that liquid water content of sea fog had a wave-variation during the sea fog development period.The main factor for the increasement of LWC was due to the increasement of larger droplets greater than 10 μm.Accompanied with the increasement of LWC, the droplet size distribution of sea fog became wider towards larger size, and the peak value kept increasing either. In the same range of LWC, different visibility samples exhibited various droplet size distributions. In the same large drolet number concentrations range, the main reason for lower atmospheric visibility was due to the increasement of the LWC. The low atmospheric visibility caused by sea fog were affected by many synoptic factors, such as wider homogeneous pressure field, weaker low-level wind speed, slightly unstable low-level atmosphere, higher humidity at the surface level and so on.
By using the Fog Monitor (FM-100, DMT Inc. USA) droplet collector, the droplet size distribution and droplet number concentration of sea fog from 16 to 19 March 2008 were investigated in the Science Experiment Base for Marine Meteorology at Bohe, Guangdong Province. The microphysical structure and evolution of this sea fog event, especially the LWC (liquid water content) of sea fog, are analysed. According the observational data during the same period, the synoptic factors accounting for the low atmospheric visibility assocaited with this sea fog event were also analysed.It is shown that liquid water content of sea fog had a wave-variation during the sea fog development period.The main factor for the increasement of LWC was due to the increasement of larger droplets greater than 10 μm.Accompanied with the increasement of LWC, the droplet size distribution of sea fog became wider towards larger size, and the peak value kept increasing either. In the same range of LWC, different visibility samples exhibited various droplet size distributions. In the same large drolet number concentrations range, the main reason for lower atmospheric visibility was due to the increasement of the LWC. The low atmospheric visibility caused by sea fog were affected by many synoptic factors, such as wider homogeneous pressure field, weaker low-level wind speed, slightly unstable low-level atmosphere, higher humidity at the surface level and so on.
2010, 32(2): 54-65.
Abstract:
Based on the correlation analysis and the analysis of vertical structure of temperature and geopotential field in Icelandic low and Azores high, we found that the Volcanic Explosive Index (VEI) anomaly for volcano eruption above category 5 shows negative correlation with sea level pressure (SLP) in Icelandic low, and positive correlation with SLP in Azores high. From the analysis of the vertical atmospheric structure, it is found that in summer, the Azores high is a deep warm core system and the Icelandic low is a shallow system. Therefore, the VEI shows negative correlation with the SLP in Azores high and positive correlation with SLP in Icelandic low. While in winter, the Azores high is a shallow system and the Icelandic low is a deep cold core system. Hence, the VEI shows positive correlation with the SLP in Azores high and negative correlation with SLP in Icelandic low. Considering the phase shift of the temperature and geopotential height field between summer and winter in Icelandic low and Azores high, the anomaly VEI causes opposite responses in the two circulation system, forms opposite phase SLP oscillation in middle and high latitude, and hence stimulated the famous North Atlantic Oscillation.
Based on the correlation analysis and the analysis of vertical structure of temperature and geopotential field in Icelandic low and Azores high, we found that the Volcanic Explosive Index (VEI) anomaly for volcano eruption above category 5 shows negative correlation with sea level pressure (SLP) in Icelandic low, and positive correlation with SLP in Azores high. From the analysis of the vertical atmospheric structure, it is found that in summer, the Azores high is a deep warm core system and the Icelandic low is a shallow system. Therefore, the VEI shows negative correlation with the SLP in Azores high and positive correlation with SLP in Icelandic low. While in winter, the Azores high is a shallow system and the Icelandic low is a deep cold core system. Hence, the VEI shows positive correlation with the SLP in Azores high and negative correlation with SLP in Icelandic low. Considering the phase shift of the temperature and geopotential height field between summer and winter in Icelandic low and Azores high, the anomaly VEI causes opposite responses in the two circulation system, forms opposite phase SLP oscillation in middle and high latitude, and hence stimulated the famous North Atlantic Oscillation.
2010, 32(2): 66-72.
Abstract:
The effects of content and photobleaching degrees of choromophoric dissolved organic matter were examined based on the photoproduction rates of carbon monoxide for three water samples collected at three different locations in the Jiaozhou Bay in Qingdao. The absorption coefficient of organic compounds and dissolved organic carbon all decreased with increasing time of photobleaching, suggesting that the content of dissolved organic matter significantly decreased through photobleaching. In all eight wave bands, the photoproduction rates of carbon monoxide were significantly correlated with the absorption coefficient at 350 nm and dissolved organic carbon content. Both absorption coefficient at 350 nm and dissolved organic carbon content can represent the contents of chromophoric dissolved organic matter to some extent.
The effects of content and photobleaching degrees of choromophoric dissolved organic matter were examined based on the photoproduction rates of carbon monoxide for three water samples collected at three different locations in the Jiaozhou Bay in Qingdao. The absorption coefficient of organic compounds and dissolved organic carbon all decreased with increasing time of photobleaching, suggesting that the content of dissolved organic matter significantly decreased through photobleaching. In all eight wave bands, the photoproduction rates of carbon monoxide were significantly correlated with the absorption coefficient at 350 nm and dissolved organic carbon content. Both absorption coefficient at 350 nm and dissolved organic carbon content can represent the contents of chromophoric dissolved organic matter to some extent.
2010, 32(2): 73-79.
Abstract:
pH is a fundamental parameter in understanding the chemical processes in deep-sea hydrothermal and diffuse flow areas. pH is also considered to be one of the important characteristics that influences the animal distribution within hydrothermal vent sites while pH is also affected by the metabolic processes of the organism. Hence, a accurate access for deep-sea in-situ pH is a common concern of both marine chemists and marine biologists. In the former application of sea trials, two phenomena have been found: one is that the electrode can respond to the chemical abnormality, the other is due to the drifting problem of the electrode. Data acquired by the electrode can only be used as a qualitative evidence for deep-sea research.Two novel approaches to the preparation of iridium oxide electrode are proposed based on the mechanics of molten alkali metal carbonate. Experiments and SEM surface analysis were carried out to characterize the different types of IrO<em>x electrodes. Including the electrodes prepared by the traditional approach, the results show that all three of them exhibit Nernst response. Comparing both the sensing characteristics and the SEM surface analysis of the three types of IrO<em>x electrodes, however, the IrO<em>x electrodes of advanced carbonate-melted methods exhibited better pH sensitivity and stability, and more solid surface. Therefore, it can be speculated that the oxygen contents during the preparation procedure is a key factor that affects the IrO<em>x film characteristics. Among the three types of IrO<em>x electrodes, the one prepared by molten mixed carbonate lithium and sodium peroxide showed the best sensing characteristics. It exhibited good reproducibility and sensitivity, small OCP (open circuit potential) drift (＜5 mV) of 7 d continuous pH measurements, long lifetime and remarkable agreement with respect to potential/pH slopes and apparent standard electrode potentials of individual electrodes prepared from the same batch. Although the aging effects caused the apparent standard electrode potential drop about 50 mV after 3 months, the problem could be eliminated by calibration. Therefore, the good performance of the IrO<em>x electrode prepared by molten mixed carbonate lithium and sodium peroxide may allow this type of IrO<em>x electrode be suitable for being applied to in-situ deep-sea measurement.
pH is a fundamental parameter in understanding the chemical processes in deep-sea hydrothermal and diffuse flow areas. pH is also considered to be one of the important characteristics that influences the animal distribution within hydrothermal vent sites while pH is also affected by the metabolic processes of the organism. Hence, a accurate access for deep-sea in-situ pH is a common concern of both marine chemists and marine biologists. In the former application of sea trials, two phenomena have been found: one is that the electrode can respond to the chemical abnormality, the other is due to the drifting problem of the electrode. Data acquired by the electrode can only be used as a qualitative evidence for deep-sea research.Two novel approaches to the preparation of iridium oxide electrode are proposed based on the mechanics of molten alkali metal carbonate. Experiments and SEM surface analysis were carried out to characterize the different types of IrO<em>x electrodes. Including the electrodes prepared by the traditional approach, the results show that all three of them exhibit Nernst response. Comparing both the sensing characteristics and the SEM surface analysis of the three types of IrO<em>x electrodes, however, the IrO<em>x electrodes of advanced carbonate-melted methods exhibited better pH sensitivity and stability, and more solid surface. Therefore, it can be speculated that the oxygen contents during the preparation procedure is a key factor that affects the IrO<em>x film characteristics. Among the three types of IrO<em>x electrodes, the one prepared by molten mixed carbonate lithium and sodium peroxide showed the best sensing characteristics. It exhibited good reproducibility and sensitivity, small OCP (open circuit potential) drift (＜5 mV) of 7 d continuous pH measurements, long lifetime and remarkable agreement with respect to potential/pH slopes and apparent standard electrode potentials of individual electrodes prepared from the same batch. Although the aging effects caused the apparent standard electrode potential drop about 50 mV after 3 months, the problem could be eliminated by calibration. Therefore, the good performance of the IrO<em>x electrode prepared by molten mixed carbonate lithium and sodium peroxide may allow this type of IrO<em>x electrode be suitable for being applied to in-situ deep-sea measurement.
2010, 32(2): 80-86.
Abstract:
There are two methods-graphic method and moment method for grain-size parameters calculation. To estimate the result differences between these two methods, a new borehole LZ908 collected in the south coast of the Laizhou Bay in Shandong Province,China, was used for comparison. Based on the grain-size analysis, statistical methods were employed here, including correlation analysis, regression analysis, and cluster analysis, to detect possible influence through comparing the difference in the mathematical process and grain-size distribution. The conclusions are drawn as follow: the mean and sorting of grain size estimated from the two methods can be almost substituted by each other; the skewness and kurtosis of the two methods cannot or can partially be substituted; and these differences came from estimation functions, reflect some characteristics of the grain-size distributions, and are correlated with the hydrodynamic conditions significantly.
There are two methods-graphic method and moment method for grain-size parameters calculation. To estimate the result differences between these two methods, a new borehole LZ908 collected in the south coast of the Laizhou Bay in Shandong Province,China, was used for comparison. Based on the grain-size analysis, statistical methods were employed here, including correlation analysis, regression analysis, and cluster analysis, to detect possible influence through comparing the difference in the mathematical process and grain-size distribution. The conclusions are drawn as follow: the mean and sorting of grain size estimated from the two methods can be almost substituted by each other; the skewness and kurtosis of the two methods cannot or can partially be substituted; and these differences came from estimation functions, reflect some characteristics of the grain-size distributions, and are correlated with the hydrodynamic conditions significantly.
2010, 32(2): 87-95.
Abstract:
Based on the typical bore holes of the Zhujiang Delta and the long-term morphodynamic model PRD-LTMM, rapid deposition body (RDB) is examined. The RDB is defined, and the formations of typical RDBs in the Zhujiang Delta are analyzed initially. The RDBs hold the specific sedimentary environment and particular sedimentary dynamics with the annual deposition rate of centimeters; so, the research on the RDBs can help disclose the mechanism of the basic sedimentary units in the Zhujiang Delta, providing a basis for the study of mechanism of the Zhujiang Delta evolution. The initially discovered RDBs include depositions at the paleo-tide convergent flow and the paleo-flood tidal jet, fringing deposition around the palco-terrance. A study result shows that the formation of RDBs, with being highly variable in time and space, is related to the small- to medium-scale dynamic structures under particular morphologic boundaries. Understanding the morphologic boundary,its evolution process and medium- to small-scale dynamic structures under corresponding morphologic boundaries in the Zhujiang Delta is key to the research of the RDBs.
Based on the typical bore holes of the Zhujiang Delta and the long-term morphodynamic model PRD-LTMM, rapid deposition body (RDB) is examined. The RDB is defined, and the formations of typical RDBs in the Zhujiang Delta are analyzed initially. The RDBs hold the specific sedimentary environment and particular sedimentary dynamics with the annual deposition rate of centimeters; so, the research on the RDBs can help disclose the mechanism of the basic sedimentary units in the Zhujiang Delta, providing a basis for the study of mechanism of the Zhujiang Delta evolution. The initially discovered RDBs include depositions at the paleo-tide convergent flow and the paleo-flood tidal jet, fringing deposition around the palco-terrance. A study result shows that the formation of RDBs, with being highly variable in time and space, is related to the small- to medium-scale dynamic structures under particular morphologic boundaries. Understanding the morphologic boundary,its evolution process and medium- to small-scale dynamic structures under corresponding morphologic boundaries in the Zhujiang Delta is key to the research of the RDBs.
2010, 32(2): 96-105.
Abstract:
Deep-sea sediment waves are regular bed undulations on a relatively large scale on the ocean bottom of the northeast South China Sea. With high-resolution multi-beam data, seismic profiles and gravity piston columns, the geomorphology, the matter source and the forming mechanism of these sediment waves are discussed. The southern Taiwan Bank canyon divides the study area into two parts in different crestline orientation; the plan view morphology of the north part indicates that the crestline orientation is roughly parallel to the regional bathymetric contours. The dominant orientation is NE. In the south part the crestline is nearly N-S oriented and is orthogonal to the channel trend. The close relation between the sediment waves and the channel-levee system shows that the former is turbidity origin, which is also identified by the material composition and internal characteristics established by the gravity piston column and seismic-stratigraphic analysis. The development of the sediment waves are controlled by the Neogene tectonic activities. The collision between the Luzon arc and the Eurasian Plate since 6.5 Ma BP had triggered the Taiwan orogeny. The uplift and erosion of Taiwan Island offered sufficient terrigenous sediments. Furthermore, the well-developed channel-canyon system on the continental slope favors the turbidity flow’s transportation to the deep sea, while the continuous uplift and erosion of the Dongsha uplift west of the study area also provides some materials. With the decrease of the gradient of the continental slope, these turbidity sediments begin to accumulate and form NE-oriented sediment waves at the end of the channel-levee system. The NS-oriented sediment waves in the south of the south Taiwan Bank canyon are mostly resulted from flow’s spillover caused by the sharply turn of canyon’s course.
Deep-sea sediment waves are regular bed undulations on a relatively large scale on the ocean bottom of the northeast South China Sea. With high-resolution multi-beam data, seismic profiles and gravity piston columns, the geomorphology, the matter source and the forming mechanism of these sediment waves are discussed. The southern Taiwan Bank canyon divides the study area into two parts in different crestline orientation; the plan view morphology of the north part indicates that the crestline orientation is roughly parallel to the regional bathymetric contours. The dominant orientation is NE. In the south part the crestline is nearly N-S oriented and is orthogonal to the channel trend. The close relation between the sediment waves and the channel-levee system shows that the former is turbidity origin, which is also identified by the material composition and internal characteristics established by the gravity piston column and seismic-stratigraphic analysis. The development of the sediment waves are controlled by the Neogene tectonic activities. The collision between the Luzon arc and the Eurasian Plate since 6.5 Ma BP had triggered the Taiwan orogeny. The uplift and erosion of Taiwan Island offered sufficient terrigenous sediments. Furthermore, the well-developed channel-canyon system on the continental slope favors the turbidity flow’s transportation to the deep sea, while the continuous uplift and erosion of the Dongsha uplift west of the study area also provides some materials. With the decrease of the gradient of the continental slope, these turbidity sediments begin to accumulate and form NE-oriented sediment waves at the end of the channel-levee system. The NS-oriented sediment waves in the south of the south Taiwan Bank canyon are mostly resulted from flow’s spillover caused by the sharply turn of canyon’s course.
2010, 32(2): 106-117.
Abstract:
Multi-biomarkers have been applied for the reconstruction of phytoplankton productivity and community structure. This study reports phytoplankton biomarker ratios in surface sediments sampled during the second China arctic expedition from the western Chukchi Sea in the summer of 2003 and evaluates their potential as community structure proxies. The total biomarkers(sum of brassicasterol, dinosterol, alkenones) in the surveyed area were 20~3 149 ng/g, the average value was 1 010 ng/g.The distributions of biomarkers also indicate the primary productivity in the Chukchi shelf was higher than the Chukchi plateau. The brassicasterol to dinosterol ratios for different stations have an obvious diversification, but all stations show the brassicasterol is in the ascendant. At the station of the Chukchi shelf, diatom is the mainly phytoplankton, the brassicasterol accounts for 42% to 74% of the total biomarkers, and the proportion of dinosterol is 17% to 37% in the total biomarkers. On the plateau, the dominant phytoplankton is also diatom, but the ratio of dinosterol and coccolithophore has a significantly.In the Canada Basin, dinosterol and coccolithophore are the dominant phytoplankton,diatom is not the predminant population and this result is in accord with phytoplankton distribution patterns obtained by other methods such as microscope.An important modern basis that these biomarkers can be used as proxies for community structure is prcvided, and it also suggests that this method can be used for community structure reconstruction for the sediment cores.
Multi-biomarkers have been applied for the reconstruction of phytoplankton productivity and community structure. This study reports phytoplankton biomarker ratios in surface sediments sampled during the second China arctic expedition from the western Chukchi Sea in the summer of 2003 and evaluates their potential as community structure proxies. The total biomarkers(sum of brassicasterol, dinosterol, alkenones) in the surveyed area were 20~3 149 ng/g, the average value was 1 010 ng/g.The distributions of biomarkers also indicate the primary productivity in the Chukchi shelf was higher than the Chukchi plateau. The brassicasterol to dinosterol ratios for different stations have an obvious diversification, but all stations show the brassicasterol is in the ascendant. At the station of the Chukchi shelf, diatom is the mainly phytoplankton, the brassicasterol accounts for 42% to 74% of the total biomarkers, and the proportion of dinosterol is 17% to 37% in the total biomarkers. On the plateau, the dominant phytoplankton is also diatom, but the ratio of dinosterol and coccolithophore has a significantly.In the Canada Basin, dinosterol and coccolithophore are the dominant phytoplankton,diatom is not the predminant population and this result is in accord with phytoplankton distribution patterns obtained by other methods such as microscope.An important modern basis that these biomarkers can be used as proxies for community structure is prcvided, and it also suggests that this method can be used for community structure reconstruction for the sediment cores.
2010, 32(2): 118-127.
Abstract:
16S rDNA clone library combining with denaturing gradient gel electrophoresis (DGGE) technique was used to reveal the bacterial community diversity and the spatial distribution characteristics from the three stations of the sediment of the northwest Huanghai Sea. The bacterial 16S rDNA libraries of the surface sediments showed that at all three stations composed high diversity of bacterial communities, γ-and δ-proteobacteria were the donminant groups, respectively, accounting for 20% and 32% of the total sequences. DGGE profiles showed that the bacterial community structure presented a high degree of similarity at the same stations at different depths, but demonstrated far distance from different stations. The present study shows that the bacteria from the coastal sediments have a high community diversity and possess dominant groups in bacterial community, but on a smaller scale, the vertical changes of community structure are not obvious.
16S rDNA clone library combining with denaturing gradient gel electrophoresis (DGGE) technique was used to reveal the bacterial community diversity and the spatial distribution characteristics from the three stations of the sediment of the northwest Huanghai Sea. The bacterial 16S rDNA libraries of the surface sediments showed that at all three stations composed high diversity of bacterial communities, γ-and δ-proteobacteria were the donminant groups, respectively, accounting for 20% and 32% of the total sequences. DGGE profiles showed that the bacterial community structure presented a high degree of similarity at the same stations at different depths, but demonstrated far distance from different stations. The present study shows that the bacteria from the coastal sediments have a high community diversity and possess dominant groups in bacterial community, but on a smaller scale, the vertical changes of community structure are not obvious.
A multivariate assessment of eutrophication in the coastal waters of the southern Shandong Peninsula
2010, 32(2): 128-138.
Abstract:
The spatial-temporal distribution and variations of nutrients and chlorophyll a (Chl a) in the coastal waters(35.5°~36.7°N, 119.8°~121.3°E) of the southern Shandong Peninsula were studied based on four cruises during 2006-2007. Both principal component analysis (PCA) and potential eutrophication assessment were carried out to assess the eutrophication status of the investigated area, and the potential eutrophication driving factors were evaluated. Results showed that (1) seasonal variations of total nitrogen (TN) and active phosphate were similar to those of dissolved inorganic nitrogen (DIN) and active silicate with concentrations higher in autumn and winter, while concentrations of total phosphate (TP) and dissolved phosphate (DOP) were higher in winter and lower in summer and autumn. The concentration of Chl a was higher in spring and summer and lower in winter. Horizontal distributions of nutrients and Chl a centered at the Jiaozhou Bay and the Dingzi Bay with concentrations higher in shore than offshore; (2) PCA were applied to estimate the eutrophication status and four PCs were extracted from ten variables, which explained 82.00% of the total information in the original data set. The distribution of integrated score, which was considered to be an indicator for eutrophication, indicated that eutrophication was more serious in the Jiaozhou Bay and the Dingzi Bay, and the northern area showed more serious situation than southern area. Further result demonstrated that DIN was the strongest driving factor for eutrophication in the region; (3) potential eutrophication assessment was also applied to evaluating the eutrophication status of the area and the result showed that in autumn, the investigated area can be classified as moderate-level nutrient area, and the Jiaozhou Bay and the Dingzi Bay can be characterized by phosphate-limiting moderate-level nutrient in spring. PCA, which can be considered as a more sensitive method for eutrophication estimation compared with potential eutrophication assessment, it not only quantitatively reflects eutrophication state, but also determines the driving factors for eutrophication in the region.
The spatial-temporal distribution and variations of nutrients and chlorophyll a (Chl a) in the coastal waters(35.5°~36.7°N, 119.8°~121.3°E) of the southern Shandong Peninsula were studied based on four cruises during 2006-2007. Both principal component analysis (PCA) and potential eutrophication assessment were carried out to assess the eutrophication status of the investigated area, and the potential eutrophication driving factors were evaluated. Results showed that (1) seasonal variations of total nitrogen (TN) and active phosphate were similar to those of dissolved inorganic nitrogen (DIN) and active silicate with concentrations higher in autumn and winter, while concentrations of total phosphate (TP) and dissolved phosphate (DOP) were higher in winter and lower in summer and autumn. The concentration of Chl a was higher in spring and summer and lower in winter. Horizontal distributions of nutrients and Chl a centered at the Jiaozhou Bay and the Dingzi Bay with concentrations higher in shore than offshore; (2) PCA were applied to estimate the eutrophication status and four PCs were extracted from ten variables, which explained 82.00% of the total information in the original data set. The distribution of integrated score, which was considered to be an indicator for eutrophication, indicated that eutrophication was more serious in the Jiaozhou Bay and the Dingzi Bay, and the northern area showed more serious situation than southern area. Further result demonstrated that DIN was the strongest driving factor for eutrophication in the region; (3) potential eutrophication assessment was also applied to evaluating the eutrophication status of the area and the result showed that in autumn, the investigated area can be classified as moderate-level nutrient area, and the Jiaozhou Bay and the Dingzi Bay can be characterized by phosphate-limiting moderate-level nutrient in spring. PCA, which can be considered as a more sensitive method for eutrophication estimation compared with potential eutrophication assessment, it not only quantitatively reflects eutrophication state, but also determines the driving factors for eutrophication in the region.
2010, 32(2): 139-147.
Abstract:
In order to provide basic information for the taxonomy and species identification of starry flounder (Platichthys stellatus), the external morphological characteristics and internal tissue and organ system of cultured starry flounder were described and measured using the traditional methods of morphology and anatomy. Regression analysis of starry floundes measurable morphological parameters was done by bio-statistics, which shows a significant linear correlationship. The equation of total length (lt) and body length (lb) was lt=1.386 4lb-0.303 5; the relation of body length and body weight(m)presents power function correlation and their general correlation equation was m=0.033 9lb3.060 6.These results indicate that distinct morphological differences exist between different geographic populations. The skull of Platichthys stellatus has the common characteristic of Pleuronectiformes, especially ethmoidal region and orbital region shifting to the side of eyes, urohyal bone is bow shape. The front half part of hypopharyngeal is grown together, pharyngeal tooth is small; there are a pair of thin otolith with 5~6 processus mammillaris. Platichthys stellatus has a stomach with "I" shape, 2~4 pyloric caecums. The liver lies on the side of eyes in the left-eyed Platichthys stellatus. On the contrary, the liver lies on the blind side in the right-eyed ones.
In order to provide basic information for the taxonomy and species identification of starry flounder (Platichthys stellatus), the external morphological characteristics and internal tissue and organ system of cultured starry flounder were described and measured using the traditional methods of morphology and anatomy. Regression analysis of starry floundes measurable morphological parameters was done by bio-statistics, which shows a significant linear correlationship. The equation of total length (lt) and body length (lb) was lt=1.386 4lb-0.303 5; the relation of body length and body weight(m)presents power function correlation and their general correlation equation was m=0.033 9lb3.060 6.These results indicate that distinct morphological differences exist between different geographic populations. The skull of Platichthys stellatus has the common characteristic of Pleuronectiformes, especially ethmoidal region and orbital region shifting to the side of eyes, urohyal bone is bow shape. The front half part of hypopharyngeal is grown together, pharyngeal tooth is small; there are a pair of thin otolith with 5~6 processus mammillaris. Platichthys stellatus has a stomach with "I" shape, 2~4 pyloric caecums. The liver lies on the side of eyes in the left-eyed Platichthys stellatus. On the contrary, the liver lies on the blind side in the right-eyed ones.
2010, 32(2): 148-154.
Abstract:
Two new factors based on the wave energy process deduced by wavelet transform are proposed to describe the groupiness degree of waves. Through numerical wave results and field data, their effectiveness is confirmed by the comparaison with the commonly used wave groupiness parameters, therefore the ability of wavelet transform to analyze wave groupiness in the time-frequency domain is demonstrated. And the infulence of the wave record length on the variation of the groupiness factors is discussed in detail. The analyzed results indicate that the wave record length has great influence on the wave groupiness parameters, and it is suggested that, for the simulation and analysis of waves regard to wave groupiness, at least 400 to 500 waves should be simulated.
Two new factors based on the wave energy process deduced by wavelet transform are proposed to describe the groupiness degree of waves. Through numerical wave results and field data, their effectiveness is confirmed by the comparaison with the commonly used wave groupiness parameters, therefore the ability of wavelet transform to analyze wave groupiness in the time-frequency domain is demonstrated. And the infulence of the wave record length on the variation of the groupiness factors is discussed in detail. The analyzed results indicate that the wave record length has great influence on the wave groupiness parameters, and it is suggested that, for the simulation and analysis of waves regard to wave groupiness, at least 400 to 500 waves should be simulated.
2010, 32(2): 161-167.
Abstract:
2010, 32(2): 168-173.
Abstract:
2010, 32(2): 174-178.
Abstract:
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