2003 Vol. 22, No. 2
Display Method:
2003, (2): 151-170.
Abstract:
A semi-implicit and Eulerian-Lagrangian finite difference method for three-dimensional shallow flow has been extended to a more complete system of equations incorporating second-moment turbulence closure model and transport equations of salinity and temperature. The simulation for flood-ing and drying of mudflats has been improved. The model is applied to Xiamen waters. Based on extensive survey data, water level elevation, temperature and salinity field along the eastern open boundary and at the Jiulong River inlets and runoffs are analyzed, specified and calibrated. The computed results show good agreement with the measured data, reproduce flooding, emergence of large and complex mudflat region.
A semi-implicit and Eulerian-Lagrangian finite difference method for three-dimensional shallow flow has been extended to a more complete system of equations incorporating second-moment turbulence closure model and transport equations of salinity and temperature. The simulation for flood-ing and drying of mudflats has been improved. The model is applied to Xiamen waters. Based on extensive survey data, water level elevation, temperature and salinity field along the eastern open boundary and at the Jiulong River inlets and runoffs are analyzed, specified and calibrated. The computed results show good agreement with the measured data, reproduce flooding, emergence of large and complex mudflat region.
2003, (2): 171-178.
Abstract:
The measurements by using ADCP (500 KH) and CTD were made during August 2000 in the south (37°55'N, 120°25'E) of the Bohai Sea, where the water depth was about 16.5m. The data of horizontal velocity with sampling interval of 2 min in 7 layers were obtained. The power spec-trum analysis of these data indicates that there are very energetic infragrvity waves with a period of about 6 min. The coherence spetrum analysis and the analysis of temporal variation of shear show that these infragravity waves are mainly the free wave model (properties of edge waves), in the meantimethey possess some characteristics of internal waves, which are likely due to the distinctive marine environment in this area. It is speculated on that the instability processes (chiefly shear instability) of sheared stratified tidal flow owing to the effect of sea-floor slope in the coastal area might be the main mechanism generating these infragravity waves.
The measurements by using ADCP (500 KH) and CTD were made during August 2000 in the south (37°55'N, 120°25'E) of the Bohai Sea, where the water depth was about 16.5m. The data of horizontal velocity with sampling interval of 2 min in 7 layers were obtained. The power spec-trum analysis of these data indicates that there are very energetic infragrvity waves with a period of about 6 min. The coherence spetrum analysis and the analysis of temporal variation of shear show that these infragravity waves are mainly the free wave model (properties of edge waves), in the meantimethey possess some characteristics of internal waves, which are likely due to the distinctive marine environment in this area. It is speculated on that the instability processes (chiefly shear instability) of sheared stratified tidal flow owing to the effect of sea-floor slope in the coastal area might be the main mechanism generating these infragravity waves.
Spatial and temporal variability of heat content above the thermocline in the tropical Pacific Ocean
2003, (2): 179-190.
Abstract:
Heat content of the upper layer above the 20℃ isotherm in the tropical Pacific Ocean is estimated by using the sea temperature data set with a resolution 2°latitude×5°longitude (1980~1993) for the water depths (every 10 m) from 0 m to 400 m, and its temporal and spatial variabilities are analyzed. (1) The temporal variability indicates that the total heat in the upper layer of the equatorial Pacific Ocean is charcterized by the interannual variability. The time series of the equatorial heat anomaly 5 months lead that of the El Nino index at the best positive lag correlation between the two, and the former 13 months lag behind the latter at their best negative lag correlation. Therefore the equatorial heat content can be used as a better predictor than the El Nino index for a warm or cold event. In addition, it is also found that less heat anomaly in the equator corresponds to the stronger warm events in the period (1980~1993) and much more heat was accumulated in the 4 years including 1992/11993 ENSO (1989~1993) than the 4 years including 1982/1983 ENSO (1980~1983); (2) The spatial variability indicates that the area with the highest lag correlation among the grids moves in an anti-clockwise circle in the northern tropical Pacific Ocean within 4 years period and in a clockwise circle in the southern tropical Pacific Ocean. This result provides scientific evidence for the quasi-cycle theory of El Nino events.
Heat content of the upper layer above the 20℃ isotherm in the tropical Pacific Ocean is estimated by using the sea temperature data set with a resolution 2°latitude×5°longitude (1980~1993) for the water depths (every 10 m) from 0 m to 400 m, and its temporal and spatial variabilities are analyzed. (1) The temporal variability indicates that the total heat in the upper layer of the equatorial Pacific Ocean is charcterized by the interannual variability. The time series of the equatorial heat anomaly 5 months lead that of the El Nino index at the best positive lag correlation between the two, and the former 13 months lag behind the latter at their best negative lag correlation. Therefore the equatorial heat content can be used as a better predictor than the El Nino index for a warm or cold event. In addition, it is also found that less heat anomaly in the equator corresponds to the stronger warm events in the period (1980~1993) and much more heat was accumulated in the 4 years including 1992/11993 ENSO (1989~1993) than the 4 years including 1982/1983 ENSO (1980~1983); (2) The spatial variability indicates that the area with the highest lag correlation among the grids moves in an anti-clockwise circle in the northern tropical Pacific Ocean within 4 years period and in a clockwise circle in the southern tropical Pacific Ocean. This result provides scientific evidence for the quasi-cycle theory of El Nino events.
2003, (2): 191-200.
Abstract:
The study area lies in the subaqueous delta, which came into being in 1964~1976. One oil-field road has been built for exploring petroleum to form a wave barrier. The hydrodynamic conditionson the north side of the road are relatively violent, on the contrary the hydrodynamic conditions on the south side of the road are nearly placid. This makes the study area a natural laboratory for studying the influence of the hydrodynamic conditions on the fractal characteristics of the tidal flat. Selecting an area is named Case Ⅰ on the side of stronger hydrodynamic activities and an area is named Case Ⅱ on the other side. Measuring the topography and sampling and analyzing the granulometrical comoposition, it is found that the hydrodynamic conditions have fatal influence on the surface fractal dimensions and the granulo-metrical fractal dimensions of the area. In Case Ⅰ, which has strong hydrodynamic conditions, the surface fractal dimensions are obviously large than those of Case Ⅱ, and the granulometrical fractal dimensions are relatively smaller than those of Case Ⅱ, the surface fractal dimensions of Case Ⅰ decrease quickly with the increase of grid size; the granulometrical fractal dimensions are disperse, while the hydrodynamic conditions of Case Ⅱ are just reverse. A sampling line and a core sampling on each side of the road are selected. It is found that on the south side of the road the granulometrical fractal dimensions vary regularly in the line and with the depth, the farther apart from the road, the smaller the fractal dimensions, and the deeper the sampling position the larger the fractal dimensions, while granulometrical fractal dimensions on the north side of the road have no such regularity pattern. The mechanism of the influence of the hydrodynamic conditions on the fractal characteristics is discussed.
The study area lies in the subaqueous delta, which came into being in 1964~1976. One oil-field road has been built for exploring petroleum to form a wave barrier. The hydrodynamic conditionson the north side of the road are relatively violent, on the contrary the hydrodynamic conditions on the south side of the road are nearly placid. This makes the study area a natural laboratory for studying the influence of the hydrodynamic conditions on the fractal characteristics of the tidal flat. Selecting an area is named Case Ⅰ on the side of stronger hydrodynamic activities and an area is named Case Ⅱ on the other side. Measuring the topography and sampling and analyzing the granulometrical comoposition, it is found that the hydrodynamic conditions have fatal influence on the surface fractal dimensions and the granulo-metrical fractal dimensions of the area. In Case Ⅰ, which has strong hydrodynamic conditions, the surface fractal dimensions are obviously large than those of Case Ⅱ, and the granulometrical fractal dimensions are relatively smaller than those of Case Ⅱ, the surface fractal dimensions of Case Ⅰ decrease quickly with the increase of grid size; the granulometrical fractal dimensions are disperse, while the hydrodynamic conditions of Case Ⅱ are just reverse. A sampling line and a core sampling on each side of the road are selected. It is found that on the south side of the road the granulometrical fractal dimensions vary regularly in the line and with the depth, the farther apart from the road, the smaller the fractal dimensions, and the deeper the sampling position the larger the fractal dimensions, while granulometrical fractal dimensions on the north side of the road have no such regularity pattern. The mechanism of the influence of the hydrodynamic conditions on the fractal characteristics is discussed.
2003, (2): 201-211.
Abstract:
In order to understand the type and extent of marine fouling in offshore areas southeast of the Zhujiang (Pearl) River delta, within the period form May 1986 to June 1987, two biological buoys were deployed at water depths of 95 m and 113 m located in 114 km and 160 km off the coast of Hong Kong, respectively. Moreover, the fouling community of a Marex hydrological buoy located in 115 m depth water 172 km off Hong Kong was also surveyed. The results show that a total of 78 species were collected and identified. The panels exposed for 3 months were mainly dominated by stalked barnacles Conchoderma hunteri and Lepas anatifera and hydroids Orthopyxis sp. As for the buoys, including the subsurface buoy, and their mooring systems exposed for 6 and 12 months, respec-tively, some hard foulers such as common oysters, pearl oysters, acorn barnacles and bryozoans were also found. The compositions of fouling communities also varied greatly with depth.
In order to understand the type and extent of marine fouling in offshore areas southeast of the Zhujiang (Pearl) River delta, within the period form May 1986 to June 1987, two biological buoys were deployed at water depths of 95 m and 113 m located in 114 km and 160 km off the coast of Hong Kong, respectively. Moreover, the fouling community of a Marex hydrological buoy located in 115 m depth water 172 km off Hong Kong was also surveyed. The results show that a total of 78 species were collected and identified. The panels exposed for 3 months were mainly dominated by stalked barnacles Conchoderma hunteri and Lepas anatifera and hydroids Orthopyxis sp. As for the buoys, including the subsurface buoy, and their mooring systems exposed for 6 and 12 months, respec-tively, some hard foulers such as common oysters, pearl oysters, acorn barnacles and bryozoans were also found. The compositions of fouling communities also varied greatly with depth.
2003, (2): 213-220.
Abstract:
The effects on hepatic EROD (7-ethoxyresorufin O-deethylase) in Mugil so-iuy exposed to benzo(a)pyrene (BaP), pyrene and their mixtures of equal concentration were investigated, at concentrations of 0.1, 1.0, 5.0, 10.0, 50.0 μg/dm3, in experimental condition. Time-effects and dose-response of the biochemical indexs were observed. The results showed that the hepatic EROD activities were induced by the exposure of BaP, pyrene and their mixtures at high concentration. Dose-response connections were that the hepatic EROD activities were elevated with increasing concentration of the pollutants. The combined effect of BaP and pyrene at 1:1 concentration ratio on hepatic EROD activity was antagonism.
The effects on hepatic EROD (7-ethoxyresorufin O-deethylase) in Mugil so-iuy exposed to benzo(a)pyrene (BaP), pyrene and their mixtures of equal concentration were investigated, at concentrations of 0.1, 1.0, 5.0, 10.0, 50.0 μg/dm3, in experimental condition. Time-effects and dose-response of the biochemical indexs were observed. The results showed that the hepatic EROD activities were induced by the exposure of BaP, pyrene and their mixtures at high concentration. Dose-response connections were that the hepatic EROD activities were elevated with increasing concentration of the pollutants. The combined effect of BaP and pyrene at 1:1 concentration ratio on hepatic EROD activity was antagonism.
2003, (2): 221-231.
Abstract:
The growth rate of the hyalid amphipod Hyale perieri was studied on the bases of Ikeda's growth model which is based on the inter moult period (IP) and moult increarment (△BL). To apply this approach, laboratory experiments were carried out at three temperatures regimes (15℃, 20℃, 25℃) to gain accurate data of IP and BL. The total number of specimens used in this study was 86 at 15℃, 24 at 20℃ and 70 at 25℃. The number of flagellar segments of both antennae of the Hyale perieri could not be used as an index of growth (instar criterion). The obtained results indicated that, the predicted IP of the specimens was inversely related to temperature and in good agreement with the observed values at the experimental temperatures. IP data obtained from laboratory-reared specimes are combined with △BL data to establish a growth model for Hyale perieri from its release from the marsupium (1.64 mm BL) to the maximum size (12.67 mm BL) as a function of temperature. The maximum numbers of consecutive moults recorded during the experiment were 13 moults (14 instar) at 15℃, 14 moults (15 instar) at 20℃ and 12 moults (13 instar) at 25℃. The predicted life span for BL=12.67 mm (moult 13) was 203.82 d at 15℃, for BL=11.75 mm (moult 14) was 138.94 d at 20℃ and forBL=8.65 mm (moult 12) was 75.40 d at 25℃ respectively, thus confirming that the life span of the species is inversely proportional to temperature. Within the experimental temperatures tested, the optimum temperature for the growth of the species was 20℃.
The growth rate of the hyalid amphipod Hyale perieri was studied on the bases of Ikeda's growth model which is based on the inter moult period (IP) and moult increarment (△BL). To apply this approach, laboratory experiments were carried out at three temperatures regimes (15℃, 20℃, 25℃) to gain accurate data of IP and BL. The total number of specimens used in this study was 86 at 15℃, 24 at 20℃ and 70 at 25℃. The number of flagellar segments of both antennae of the Hyale perieri could not be used as an index of growth (instar criterion). The obtained results indicated that, the predicted IP of the specimens was inversely related to temperature and in good agreement with the observed values at the experimental temperatures. IP data obtained from laboratory-reared specimes are combined with △BL data to establish a growth model for Hyale perieri from its release from the marsupium (1.64 mm BL) to the maximum size (12.67 mm BL) as a function of temperature. The maximum numbers of consecutive moults recorded during the experiment were 13 moults (14 instar) at 15℃, 14 moults (15 instar) at 20℃ and 12 moults (13 instar) at 25℃. The predicted life span for BL=12.67 mm (moult 13) was 203.82 d at 15℃, for BL=11.75 mm (moult 14) was 138.94 d at 20℃ and forBL=8.65 mm (moult 12) was 75.40 d at 25℃ respectively, thus confirming that the life span of the species is inversely proportional to temperature. Within the experimental temperatures tested, the optimum temperature for the growth of the species was 20℃.
2003, (2): 233-242.
Abstract:
With the onset of winter, polar marine microalgae would have faced total darkness for a period of up to 6 months. A natural autumn community of Arctic sea ice microalgae was collected for dark survival experiments from the Greenland Sea during the ARKTIS-XI/2 Expedition of RV Polarstern in October 1995. After a dark period of 161 days, species dominance in the algal assemblage have changed from initially pennate diatoms to small phytoflagellates (< 20 μm). Over the entire dark period, the mean algal growth rate was -0.01 d-1. Nearly all diatom species had negative growth rates, while phytoflagellate abundance increased. Resting spore formation during the dark period was observed in less than 4.5% of all cells and only for dinoflagellates and the diatom Chaetoceros spp. We assume that facultative heterotrophy and energy storage are the main processes enabling survival during the dark Arctic winter. After an increase in light intensity, microalgal cells reacted with fast growth within days. Phytoflagellates had the highest growth rate, followed by Nitzschia frigida. Further investigations and experiments should focus on the mechanisms of dark survival (mixotrophy and energy storage) of polar marine microalgae.
With the onset of winter, polar marine microalgae would have faced total darkness for a period of up to 6 months. A natural autumn community of Arctic sea ice microalgae was collected for dark survival experiments from the Greenland Sea during the ARKTIS-XI/2 Expedition of RV Polarstern in October 1995. After a dark period of 161 days, species dominance in the algal assemblage have changed from initially pennate diatoms to small phytoflagellates (< 20 μm). Over the entire dark period, the mean algal growth rate was -0.01 d-1. Nearly all diatom species had negative growth rates, while phytoflagellate abundance increased. Resting spore formation during the dark period was observed in less than 4.5% of all cells and only for dinoflagellates and the diatom Chaetoceros spp. We assume that facultative heterotrophy and energy storage are the main processes enabling survival during the dark Arctic winter. After an increase in light intensity, microalgal cells reacted with fast growth within days. Phytoflagellates had the highest growth rate, followed by Nitzschia frigida. Further investigations and experiments should focus on the mechanisms of dark survival (mixotrophy and energy storage) of polar marine microalgae.
2003, (2): 243-253.
Abstract:
The colony-forming Phaeocystis species are causative agents of dense bloom occurrences in coastal waters worldwide. It is difficult to separate them because of the different morphologies associated with their colonial stages. In this study we applied molecular approaches to analyze the genetic variation of Phaeocystis globosa and Phaeocystis pouchetii from several geographic regions, and to assist in tracing the dispersal of bloom-forming Phaeocystis species in coastal waters of China. The sequences of the internal transcribed spacers (ITS1 and ITS2) of rDNA and the 5.8S ribosomal RNA gene of Phaeocystis strains were determined. Sequence comparison shows that P.globosa was the most divergent to P. pouchetii, exhibiting sequence divergence higher than 0.08. However, lower genetic divergences existed between strains of P.globosa. The sequence comparison of the Phaeocystis rDNA ITS clearly shows that the species isolated from the southeast coast of China is identified as P.globosa rather than P. cf. pouchetii or other species. Furthermore, the significance of rDNA variation in distinct global populations of P.globosa suggested it might have had sufficient time to accumulate detectable mutations at the rDNA locus, supporting the hypothesis of ancient dispersal of P.globosa to many areas, meaning that P.globosa blooms in the coastal waters of China are endemic rather than a newly introduced species or a foreign source. Finally, based on the high divergent region of rDNA ITS, a pair of species-specific primers for P.globosa were designed, they could be useful to detect the presence of this species in mixed plankton assemblages or flagellate stages that are recognized with diffculties by means of conventional microscopy.
The colony-forming Phaeocystis species are causative agents of dense bloom occurrences in coastal waters worldwide. It is difficult to separate them because of the different morphologies associated with their colonial stages. In this study we applied molecular approaches to analyze the genetic variation of Phaeocystis globosa and Phaeocystis pouchetii from several geographic regions, and to assist in tracing the dispersal of bloom-forming Phaeocystis species in coastal waters of China. The sequences of the internal transcribed spacers (ITS1 and ITS2) of rDNA and the 5.8S ribosomal RNA gene of Phaeocystis strains were determined. Sequence comparison shows that P.globosa was the most divergent to P. pouchetii, exhibiting sequence divergence higher than 0.08. However, lower genetic divergences existed between strains of P.globosa. The sequence comparison of the Phaeocystis rDNA ITS clearly shows that the species isolated from the southeast coast of China is identified as P.globosa rather than P. cf. pouchetii or other species. Furthermore, the significance of rDNA variation in distinct global populations of P.globosa suggested it might have had sufficient time to accumulate detectable mutations at the rDNA locus, supporting the hypothesis of ancient dispersal of P.globosa to many areas, meaning that P.globosa blooms in the coastal waters of China are endemic rather than a newly introduced species or a foreign source. Finally, based on the high divergent region of rDNA ITS, a pair of species-specific primers for P.globosa were designed, they could be useful to detect the presence of this species in mixed plankton assemblages or flagellate stages that are recognized with diffculties by means of conventional microscopy.
2003, (2): 255-263.
Abstract:
Based on the research of juvenile (2, 3, 4 months) growth and survival of three populations of two different geographic areas in Chlamys farreri from Russian and China and their F1 hybrids derived from Chinese cultural population (CC)♀×Russian population (RW)♂, Chinese wild popu-lation (CW)♀×Russian population (RW)♂, Russian population (RW)♀×Chinese wild popula-tion (CW)♂, the study of the medium-term (6, 8, 10, 12 months) growth and development of Chlamys farreri was carried out. The four determined results indicated that there existed different extent heterosis (3%~52%) for the growth in three types of F1 hybrids, and the offspring derived from CC♀×R♂ had a stronger heterosis among the crosses at the medium-term; the uptrend among traits are wet weight > shell width > shell length > shell height, Chinese cultural population could be recognized as excellent parent, and seasonal variations influence very much on the daily increment and growth rate of each trait of Chlamys farreri and it is only able to survive and could barely grow in winter (6~8 months), but grows fast in temperate season (10~12 months).
Based on the research of juvenile (2, 3, 4 months) growth and survival of three populations of two different geographic areas in Chlamys farreri from Russian and China and their F1 hybrids derived from Chinese cultural population (CC)♀×Russian population (RW)♂, Chinese wild popu-lation (CW)♀×Russian population (RW)♂, Russian population (RW)♀×Chinese wild popula-tion (CW)♂, the study of the medium-term (6, 8, 10, 12 months) growth and development of Chlamys farreri was carried out. The four determined results indicated that there existed different extent heterosis (3%~52%) for the growth in three types of F1 hybrids, and the offspring derived from CC♀×R♂ had a stronger heterosis among the crosses at the medium-term; the uptrend among traits are wet weight > shell width > shell length > shell height, Chinese cultural population could be recognized as excellent parent, and seasonal variations influence very much on the daily increment and growth rate of each trait of Chlamys farreri and it is only able to survive and could barely grow in winter (6~8 months), but grows fast in temperate season (10~12 months).
2003, (2): 265-272.
Abstract:
The carbon and nitrogen budgets were estimated on the adult females, juveniles and postfurcilia larvae of Pseudeuphausia sinica fed on newly hatching nauplii of Artemia salina in the laboratory. It was found that the ingestion rate was linearly related to the food concentration, suggesting high feeding potential. The linear correlation could be established between the respirating rate (carbon consumption rate) and carbon ingestion rate, as well as carbon assimilation rate. The regression coefficients (i.e.specific dynamic action coefficients) were in the range from 9% to 16% (ingested C) or 10% to 17% (assimilated C) respectively, with lower in the post-furcilia larvae. There also existed a linear correlation equation between estimated total nitrogen excretion rate and the rates of nitrogen ingestion and assimilation separately, except for the juveniles. The defecation rates increased with the increase of the ingestion rate; as a result, assimilation efficiency was not related to the ingestion rate, ranging from 0.84 to 0.95. The results inducated that the nitrogen content in food particles was a key factor limiting the growth of P. sinica. The critical ingestion rate was 10 μgN·mg-1 body dry weight per day. Assimilated N was lost mostly by excretion, following allocated to somatic growth. The nitrogen loss by moult only accounted for a minor part. As for carbon budget, respiration and somatic growth also accounted for most of assimilation, but varied with ingestion rates. Moult loss was minor. Estimated reproductive growth (C&N) in the adult females accounted for somewhat higher percent of assimilation than the moult growth. The net growth efficiency (K2) increased with the increase of the ingestion rates, but decreased slightly for juvenile and post-furcilia larvae after the rates up to a certain value.
The carbon and nitrogen budgets were estimated on the adult females, juveniles and postfurcilia larvae of Pseudeuphausia sinica fed on newly hatching nauplii of Artemia salina in the laboratory. It was found that the ingestion rate was linearly related to the food concentration, suggesting high feeding potential. The linear correlation could be established between the respirating rate (carbon consumption rate) and carbon ingestion rate, as well as carbon assimilation rate. The regression coefficients (i.e.specific dynamic action coefficients) were in the range from 9% to 16% (ingested C) or 10% to 17% (assimilated C) respectively, with lower in the post-furcilia larvae. There also existed a linear correlation equation between estimated total nitrogen excretion rate and the rates of nitrogen ingestion and assimilation separately, except for the juveniles. The defecation rates increased with the increase of the ingestion rate; as a result, assimilation efficiency was not related to the ingestion rate, ranging from 0.84 to 0.95. The results inducated that the nitrogen content in food particles was a key factor limiting the growth of P. sinica. The critical ingestion rate was 10 μgN·mg-1 body dry weight per day. Assimilated N was lost mostly by excretion, following allocated to somatic growth. The nitrogen loss by moult only accounted for a minor part. As for carbon budget, respiration and somatic growth also accounted for most of assimilation, but varied with ingestion rates. Moult loss was minor. Estimated reproductive growth (C&N) in the adult females accounted for somewhat higher percent of assimilation than the moult growth. The net growth efficiency (K2) increased with the increase of the ingestion rates, but decreased slightly for juvenile and post-furcilia larvae after the rates up to a certain value.
2003, (2): 273-280.
Abstract:
A survey was carried out in the central and north part of the Huanghai Sea (34.5°~37.0°N, 120.5°~124.0°E) during June 12~27, 2000. It was found that the abundance of marine flagellate ranged from 45 to 1 278 cell/ml, 479 cell/ml in average. Flagellate was more abundant in the central part than in the north part of Huanghai Sea, and the abundance decreased with the increasing distance from the coast, showing a similar distribution pattern with isotherm. Vertically, high density of flagellate was always presented in the bottom of thermocline, and formed a dense accumulation in the central area of the Huanghai Sea Cold Water Mass. The effects of physical and biological factors on the distribution of marine flagellate in early summer were discussed. Water temperature (especially the existence of thermocline) rather than salinity showed significant effect on the distribution pattern of marine flagellate in the Huanghai Sea in early summer. When comparing the abundance of marine flagellate with that of other microorganisms, it revealed a comparatively stable relationship among these organhisms, with a ratio of heterotrophic bacteria:cyanobacteria:flagellate:dinoflagellate:ciliate being 105:103:102:101:100.
A survey was carried out in the central and north part of the Huanghai Sea (34.5°~37.0°N, 120.5°~124.0°E) during June 12~27, 2000. It was found that the abundance of marine flagellate ranged from 45 to 1 278 cell/ml, 479 cell/ml in average. Flagellate was more abundant in the central part than in the north part of Huanghai Sea, and the abundance decreased with the increasing distance from the coast, showing a similar distribution pattern with isotherm. Vertically, high density of flagellate was always presented in the bottom of thermocline, and formed a dense accumulation in the central area of the Huanghai Sea Cold Water Mass. The effects of physical and biological factors on the distribution of marine flagellate in early summer were discussed. Water temperature (especially the existence of thermocline) rather than salinity showed significant effect on the distribution pattern of marine flagellate in the Huanghai Sea in early summer. When comparing the abundance of marine flagellate with that of other microorganisms, it revealed a comparatively stable relationship among these organhisms, with a ratio of heterotrophic bacteria:cyanobacteria:flagellate:dinoflagellate:ciliate being 105:103:102:101:100.
2003, (2): 281-286.
Abstract:
The test organisms (Paralichthys olivaceus) were exposed to CB-28 with different spiked concentrations. After 72 h, EROD activities in livers of the test organisms were measured. It was found that EROD activities significantly mounted up with the increase of spiked quantity. Therefore, there existed a dose-response relationship between EROD activities and specific pollutant concentrations. In the meantime, the optimal conditions for the analysis of EROD activity were discussed. The limitation of EROD activities as a monitoring parameter was also analyzed.
The test organisms (Paralichthys olivaceus) were exposed to CB-28 with different spiked concentrations. After 72 h, EROD activities in livers of the test organisms were measured. It was found that EROD activities significantly mounted up with the increase of spiked quantity. Therefore, there existed a dose-response relationship between EROD activities and specific pollutant concentrations. In the meantime, the optimal conditions for the analysis of EROD activity were discussed. The limitation of EROD activities as a monitoring parameter was also analyzed.
2003, (2): 287-299.
Abstract:
Nonlinear water wave propagation passing a submerged shelf is studied experimentally and numerically. The applicability of the wave propagation model of higher-order Boussinesq equations derived by Zou (2000, Ocean Engineering, 27, 557~575) is investigated. Physical experiments are conducted; three different front slopes (1:10, 1:5 and 1:2) of the shelf are set-up in the experiment and their effects on the wave propagation are investigated. Comparisons of the numerical results with test data are made and the higher-order Boussinesq equations agree well with the measurements since the dispersion of the model is of high accuracy. The numerical results show that the good results can also be obtained for the steep-slope cases although the mild-slope assumption is employed in the derivation of the higher-order terms in the higher-order Boussinesq equations.
Nonlinear water wave propagation passing a submerged shelf is studied experimentally and numerically. The applicability of the wave propagation model of higher-order Boussinesq equations derived by Zou (2000, Ocean Engineering, 27, 557~575) is investigated. Physical experiments are conducted; three different front slopes (1:10, 1:5 and 1:2) of the shelf are set-up in the experiment and their effects on the wave propagation are investigated. Comparisons of the numerical results with test data are made and the higher-order Boussinesq equations agree well with the measurements since the dispersion of the model is of high accuracy. The numerical results show that the good results can also be obtained for the steep-slope cases although the mild-slope assumption is employed in the derivation of the higher-order terms in the higher-order Boussinesq equations.
2003, (2): 301-308.
Abstract:
2003, (2): 309-319.
Abstract:
Intertidal zone is a significant wetland between land and ocean. It plays an important role in maintaining local ecological balance. Both Mai Po and Futian intertidal mudflats are located in Shenzhen Bay and are important "refueling" point along the East Asian/Australian flyway of migratory birds. The environmental quality of Mai Po and Futian mudflats have aroused great concern due to rapid economic developments in Hong Kong and Shenzhen in recent decades. Macroinfauna of Mai Po and Futian mudflats was investigated in December 2000 and the faunal data were used to assess their environmental quality. Two other mudflats, namely Ma Wan Typhoon Shelter (a more disturbed area) and Luk Keng intertidal mudflat (a place with relatively less human disturbance), were also sampled for macroinfauna and used as reference mudflats. Shannon -Weaver species diversity index (Isd), biotic coefficient (Cb) and macrofaunal pollution index (Imp) of the macrofauna community on four intertidal mudflats were used to determine their environmental quality. The results showed that Luk Keng intertidal mudflat was unpolluted, Mai Po and Futian mudflats were slightly polluted, and Ma Wan was moderately polluted. The pollution in Ma Wan Typhoon Shelter mainly came from various types of rubbish and fishing boats that disturbed the sediment, while pollution sources in Mai Po and Futian mudflats were discharges of industrial water, municipal sewage and from nearby rivers.
Intertidal zone is a significant wetland between land and ocean. It plays an important role in maintaining local ecological balance. Both Mai Po and Futian intertidal mudflats are located in Shenzhen Bay and are important "refueling" point along the East Asian/Australian flyway of migratory birds. The environmental quality of Mai Po and Futian mudflats have aroused great concern due to rapid economic developments in Hong Kong and Shenzhen in recent decades. Macroinfauna of Mai Po and Futian mudflats was investigated in December 2000 and the faunal data were used to assess their environmental quality. Two other mudflats, namely Ma Wan Typhoon Shelter (a more disturbed area) and Luk Keng intertidal mudflat (a place with relatively less human disturbance), were also sampled for macroinfauna and used as reference mudflats. Shannon -Weaver species diversity index (Isd), biotic coefficient (Cb) and macrofaunal pollution index (Imp) of the macrofauna community on four intertidal mudflats were used to determine their environmental quality. The results showed that Luk Keng intertidal mudflat was unpolluted, Mai Po and Futian mudflats were slightly polluted, and Ma Wan was moderately polluted. The pollution in Ma Wan Typhoon Shelter mainly came from various types of rubbish and fishing boats that disturbed the sediment, while pollution sources in Mai Po and Futian mudflats were discharges of industrial water, municipal sewage and from nearby rivers.
