2006 Vol. 28, No. 5
Display Method:
2006, 28(5): 1-14.
Abstract:
On the basis of the wind data from NCEP and the hydrographic data obtained on 22 April~24 May 1998, the circulation in the South China Sea(SCS) are computed by the three dimensional diagnostic model.The combination of SSH Aderived from T/Paltimeter and numerical results provides a consistent circulation pattern for the SCS, and the main circulation features can be summarized as follows: (1) The Kuro shio intrusion weakens and the pathway of the most of Kuroshio by passes.However, a part of Kuro-shiointrudes west ward above 300 m levels.This west ward intruded flow is located narrowly confined in the continental slope south of China above 300 m levels and does not appear to follow the western boundary throug hout,which agrees with the viewpoint of Qu et al.(2) The basinOscalecy clonicgy redominates in the northern SCS and consists of two cyclonic eddies C2 and C3 above 300 m levels.However, it is separated into two parts by ananti Ocycloniceddy W4 below 300 m levels.The scope of the basinOscale cyclonicgyre is wider in winter than that in the cruise 1.(3) The basinOscale antiOcy clonic gyredominates in the central SCS and consists of the three antiOcyclonic eddies W1, W2 and W3 above 300 m levels.However,below 300 m levels it consists of the anti-Ocy clonic eddies W1, W2 and W4 and extends northward to near 20°N.The cold eddy C1 exists southeast of the antiOcy clonic eddy W1.(4) A northward coastal jetis present at the western boundary near the coast of Vietnamat depths above the 300 m level, and develops northward more far about the distance 3b15c N than that in the cruise 2.(5) Most important dynamical mechanism is because of the joint effect of the baroclinity and relief (JEBAR).The second dynamical mechanism is because of the interaction between the wind stress and relief (IBWSR) under the southeasterly wind.The Sverdrup' relation can not been satisfied in the SCS.
On the basis of the wind data from NCEP and the hydrographic data obtained on 22 April~24 May 1998, the circulation in the South China Sea(SCS) are computed by the three dimensional diagnostic model.The combination of SSH Aderived from T/Paltimeter and numerical results provides a consistent circulation pattern for the SCS, and the main circulation features can be summarized as follows: (1) The Kuro shio intrusion weakens and the pathway of the most of Kuroshio by passes.However, a part of Kuro-shiointrudes west ward above 300 m levels.This west ward intruded flow is located narrowly confined in the continental slope south of China above 300 m levels and does not appear to follow the western boundary throug hout,which agrees with the viewpoint of Qu et al.(2) The basinOscalecy clonicgy redominates in the northern SCS and consists of two cyclonic eddies C2 and C3 above 300 m levels.However, it is separated into two parts by ananti Ocycloniceddy W4 below 300 m levels.The scope of the basinOscale cyclonicgyre is wider in winter than that in the cruise 1.(3) The basinOscale antiOcy clonic gyredominates in the central SCS and consists of the three antiOcyclonic eddies W1, W2 and W3 above 300 m levels.However,below 300 m levels it consists of the anti-Ocy clonic eddies W1, W2 and W4 and extends northward to near 20°N.The cold eddy C1 exists southeast of the antiOcy clonic eddy W1.(4) A northward coastal jetis present at the western boundary near the coast of Vietnamat depths above the 300 m level, and develops northward more far about the distance 3b15c N than that in the cruise 2.(5) Most important dynamical mechanism is because of the joint effect of the baroclinity and relief (JEBAR).The second dynamical mechanism is because of the interaction between the wind stress and relief (IBWSR) under the southeasterly wind.The Sverdrup' relation can not been satisfied in the SCS.
2006, 28(5): 15-25.
Abstract:
On the basis of hydrog raphic data obtained from 12 June to 6 July,1998, the three dimensional structure of circulation in the South China Sea (SCS) is computed by using three dimensional diagnostic model.The combination of sea surface height anomaly from altimeter data and numerical results provides a consistent circulation pattern for the SCS, and the main circulation features can be summ arized as follows: (1) In the northern SCS, there are a cycloniceddy C1 near Dongsha Islands and an anti-cycloniceddy W1 in the area west of Luzon Island.(2) In the central SCS, a strong eranti-cyclonic eddy W3 and a cyclonic eddy C3 compose a quasi-dipole in the area southeast of Vietnam.(3) A coastal northwardjet is present at the western boundary near the coast of Vietnam.This northward coastjet flows northward and turns eastward at the about 14°N, and then it flows southeast ward into the area between eddies W3 and C3.(4) In the sout hern SCS the current is weaker.(5) Most important dynamical mechanism is because of the joint effect of the baro clinity and relief.The second dynamical mechanism is because of the interaction between the wind stress and relief.(6) The distribution of the vertical component of current velocity is discussed.(7) Comparing of the circulation in 1998 with 2000, their change is not large.
On the basis of hydrog raphic data obtained from 12 June to 6 July,1998, the three dimensional structure of circulation in the South China Sea (SCS) is computed by using three dimensional diagnostic model.The combination of sea surface height anomaly from altimeter data and numerical results provides a consistent circulation pattern for the SCS, and the main circulation features can be summ arized as follows: (1) In the northern SCS, there are a cycloniceddy C1 near Dongsha Islands and an anti-cycloniceddy W1 in the area west of Luzon Island.(2) In the central SCS, a strong eranti-cyclonic eddy W3 and a cyclonic eddy C3 compose a quasi-dipole in the area southeast of Vietnam.(3) A coastal northwardjet is present at the western boundary near the coast of Vietnam.This northward coastjet flows northward and turns eastward at the about 14°N, and then it flows southeast ward into the area between eddies W3 and C3.(4) In the sout hern SCS the current is weaker.(5) Most important dynamical mechanism is because of the joint effect of the baro clinity and relief.The second dynamical mechanism is because of the interaction between the wind stress and relief.(6) The distribution of the vertical component of current velocity is discussed.(7) Comparing of the circulation in 1998 with 2000, their change is not large.
2006, 28(5): 26-34.
Abstract:
Huanghai Sea Cold Water Mass (HSCWM) is a unique hydrographic phenomenon in the Huanghai Sea.Compared with the previous studies, the new contributions of this study are as follows.The formation and evolution of the HSCWM are analyzed on the basis of the GDEM data of water temperature with a high resolution of 10'×10' from Americal Navy, together with observations of several massive surveys in recent years.Meanw hile, some new views on the distribution and evolution of the cold centers of the HSCWM are suggested.Besides, the evolution mechanism of the HSCWM is delineated further by analyzing the relationship between the formation and evolution of the HSCWM and the development of the thermocline in the Huanghai Sea.Atlast,the relationship between the HSCWM and its adjacent water masses during evolution is approached further.Analyses indicate that in a period of great prosperity of the development of the HSCWM,the Qing dao Cold Water Mass, Ren-Can Off-Shore Cold Water Mass, and the bottom cold water in the northern East Chine Sea are embodied in the HSCWM.
Huanghai Sea Cold Water Mass (HSCWM) is a unique hydrographic phenomenon in the Huanghai Sea.Compared with the previous studies, the new contributions of this study are as follows.The formation and evolution of the HSCWM are analyzed on the basis of the GDEM data of water temperature with a high resolution of 10'×10' from Americal Navy, together with observations of several massive surveys in recent years.Meanw hile, some new views on the distribution and evolution of the cold centers of the HSCWM are suggested.Besides, the evolution mechanism of the HSCWM is delineated further by analyzing the relationship between the formation and evolution of the HSCWM and the development of the thermocline in the Huanghai Sea.Atlast,the relationship between the HSCWM and its adjacent water masses during evolution is approached further.Analyses indicate that in a period of great prosperity of the development of the HSCWM,the Qing dao Cold Water Mass, Ren-Can Off-Shore Cold Water Mass, and the bottom cold water in the northern East Chine Sea are embodied in the HSCWM.
2006, 28(5): 35-43.
Abstract:
Robust evidencoes of the existence of the barrier layer (BL) in the central South China Sea (10°~19°N, 108°~122°E) are provided, which occurs most frequently in summer (52.8%),and then autumn (41.0%) and spring (10.5%).BL occurrence zone in spring (Apr.) Jun.1998) and autumn (Dec.1998) is largely confined in the adjacent ocean west of the Luzon Island, with mean thickness as 6.8 and 11.2 m, respectively.By contrast,BL occurs not only in the adjacent ocean west of the Luzon Island, but also extends to the southeast of Vietnam (12°~14°N, 110°~114°E).Its mean thickness is 14.2 m.Besides, the annual occurrence frequency of BL surpasses 20% west of Luzon Island (12°~16°N, 116°~120°E) and near the Paracel Islands (16°~18°N, 110°~116°E).Rain-formed mechanism and stratification-formed mechanism are responsible mainly for the occurrence of BL in spring-summer and autumn in central South China Sea, respectively.Among which, rain-formed mechanism and the south eastward Ekman advection explains well the occurrence of BL west of the Luzon Island in spring and summer.The strong rainfall plays the vital role in inducing the BL sout heast of Vietnam in summer, moreover, the anticyclone eddy (warm) is favorable for the occurrence of BL.
Robust evidencoes of the existence of the barrier layer (BL) in the central South China Sea (10°~19°N, 108°~122°E) are provided, which occurs most frequently in summer (52.8%),and then autumn (41.0%) and spring (10.5%).BL occurrence zone in spring (Apr.) Jun.1998) and autumn (Dec.1998) is largely confined in the adjacent ocean west of the Luzon Island, with mean thickness as 6.8 and 11.2 m, respectively.By contrast,BL occurs not only in the adjacent ocean west of the Luzon Island, but also extends to the southeast of Vietnam (12°~14°N, 110°~114°E).Its mean thickness is 14.2 m.Besides, the annual occurrence frequency of BL surpasses 20% west of Luzon Island (12°~16°N, 116°~120°E) and near the Paracel Islands (16°~18°N, 110°~116°E).Rain-formed mechanism and stratification-formed mechanism are responsible mainly for the occurrence of BL in spring-summer and autumn in central South China Sea, respectively.Among which, rain-formed mechanism and the south eastward Ekman advection explains well the occurrence of BL west of the Luzon Island in spring and summer.The strong rainfall plays the vital role in inducing the BL sout heast of Vietnam in summer, moreover, the anticyclone eddy (warm) is favorable for the occurrence of BL.
2006, 28(5): 44-48.
Abstract:
A new algorithm about the sea surface wind field retrieval is presented based on neural network using NSCAT scatterometer data.The net work for retrieving wind speed is a multi-layer perceptron.The wind direction is derived using a mixture density net work which is composed of multi-layer perceptron and mixture density model with Gaussian kernel functions.The effectiveness of this kind of neural net work is demonst rated by comparing the result with ECMWF model wind and JMA buoy data.
A new algorithm about the sea surface wind field retrieval is presented based on neural network using NSCAT scatterometer data.The net work for retrieving wind speed is a multi-layer perceptron.The wind direction is derived using a mixture density net work which is composed of multi-layer perceptron and mixture density model with Gaussian kernel functions.The effectiveness of this kind of neural net work is demonst rated by comparing the result with ECMWF model wind and JMA buoy data.
2006, 28(5): 49-55.
Abstract:
Time-series Mark Ⅶ sediment trap was deployed at 62°28' 63"S,72°58' 55"E(north of the Prydz Bay, Antarctica) during the cruise of CHINARE-15 cooperated with the Marine Univ ersity of America.Biogenic components were investigated in order to reveal the composition characteristics and biogeochemistry of sinking particles in the deep ocean.The results show that the total mass flux of sinking particles at 1 000 m depth ranges from 13.00 to 334.59 mg/(m2·d) and is high seasonal, the main part of particles is biogenic matter, accounting for more than 80% of the biogenic matter.The observation of high ratio of biogenic silicon content to organic carbon one and ratio of inorganic carbon content to organic carbon one suggest sthatorganic carbon and biogenic siliconcy cles are non-coupled in the study area, CO2 is removed from surface water by biological activity.
Time-series Mark Ⅶ sediment trap was deployed at 62°28' 63"S,72°58' 55"E(north of the Prydz Bay, Antarctica) during the cruise of CHINARE-15 cooperated with the Marine Univ ersity of America.Biogenic components were investigated in order to reveal the composition characteristics and biogeochemistry of sinking particles in the deep ocean.The results show that the total mass flux of sinking particles at 1 000 m depth ranges from 13.00 to 334.59 mg/(m2·d) and is high seasonal, the main part of particles is biogenic matter, accounting for more than 80% of the biogenic matter.The observation of high ratio of biogenic silicon content to organic carbon one and ratio of inorganic carbon content to organic carbon one suggest sthatorganic carbon and biogenic siliconcy cles are non-coupled in the study area, CO2 is removed from surface water by biological activity.
2006, 28(5): 56-63.
Abstract:
Turbidity,horizontal and vertical current speeds,echointensity,water depth,salinity and temperature were observed using OBS-3A and ADP-XR during a spring-neap period,on 17~24 August 2004.Meanwhile,suspended and bed sediments were sampled for grain size analysis.On the basis of calibration of turbidity with in situ sediment samples and regression between the turbidity and the echointensity,the turbidity and the echointensity were converted to a suspended sediment concentration (SSC).The SSC is found to be generally low.For most of the tidal duration,the near bottom(30 cm abovebed)SSC is less than 30 m g/dm3.Because mud grains are abundant in the bed sediments,the low SSC is mainly at tributed to low water energy especially weak currents.The near bottom current speed is generally less than 15 cm/s due to the narrow ness of the intertidal zone(500 m in width).However,the high SSC ranging f rom 100 mg/dm3 to greater than 1 000 mg/dm3 occurs during the shallow and short stages mainly due to the action of waves.As a result,the time series of near-bottom SSC is "U"-shaped during each tidal cycle.The vertical stratification of SSC tends to occurduring deep stages and calm weathers.The SSC does not show spring-neap cyclicity,which is at tributed to the int erference of waves.It is concluded that resuspension/settling over the study intertidal flat is governed by waves.
Turbidity,horizontal and vertical current speeds,echointensity,water depth,salinity and temperature were observed using OBS-3A and ADP-XR during a spring-neap period,on 17~24 August 2004.Meanwhile,suspended and bed sediments were sampled for grain size analysis.On the basis of calibration of turbidity with in situ sediment samples and regression between the turbidity and the echointensity,the turbidity and the echointensity were converted to a suspended sediment concentration (SSC).The SSC is found to be generally low.For most of the tidal duration,the near bottom(30 cm abovebed)SSC is less than 30 m g/dm3.Because mud grains are abundant in the bed sediments,the low SSC is mainly at tributed to low water energy especially weak currents.The near bottom current speed is generally less than 15 cm/s due to the narrow ness of the intertidal zone(500 m in width).However,the high SSC ranging f rom 100 mg/dm3 to greater than 1 000 mg/dm3 occurs during the shallow and short stages mainly due to the action of waves.As a result,the time series of near-bottom SSC is "U"-shaped during each tidal cycle.The vertical stratification of SSC tends to occurduring deep stages and calm weathers.The SSC does not show spring-neap cyclicity,which is at tributed to the int erference of waves.It is concluded that resuspension/settling over the study intertidal flat is governed by waves.
2006, 28(5): 64-68.
Abstract:
Both piezoelectric ceramic bender element and resonant columntest technologies were used to measure effectively the shear wave velocity of seabed sediments from the East China Sea and the South China Sea in laboratory.Shear wave velocity data measured by these two methods appeared to be good consistency and no obvious frequency dispersion was found from a few hertzs to tens of kilohertzs.The shear wave velocity changed greatly in different physiographic areas and different sediment types.According to measurement data, the shear wave velocity of inshore silts is about 100 m/s and finer sediments show less than 100 m/s velocity.Coarse sediments on continental shelves are characterized by maximum shear wave velocity values, all more than 100 m/s, and fine deep-sea sediments have minimum shear wave velocity values, generally less than 50 m/s.The shear wave velocity shares a good correlation with physical properties of sediment,such as water content, density, porosity,plastic limit and liquidlimit of sediment,which reflects a strong relationship between them.The shear wave velocity also shows a positive correlation with the compressional wave velocity, but the ratio of shear wave velocity to compressional wave velocity changes obviously with the compressional wave velocity valuerange.
Both piezoelectric ceramic bender element and resonant columntest technologies were used to measure effectively the shear wave velocity of seabed sediments from the East China Sea and the South China Sea in laboratory.Shear wave velocity data measured by these two methods appeared to be good consistency and no obvious frequency dispersion was found from a few hertzs to tens of kilohertzs.The shear wave velocity changed greatly in different physiographic areas and different sediment types.According to measurement data, the shear wave velocity of inshore silts is about 100 m/s and finer sediments show less than 100 m/s velocity.Coarse sediments on continental shelves are characterized by maximum shear wave velocity values, all more than 100 m/s, and fine deep-sea sediments have minimum shear wave velocity values, generally less than 50 m/s.The shear wave velocity shares a good correlation with physical properties of sediment,such as water content, density, porosity,plastic limit and liquidlimit of sediment,which reflects a strong relationship between them.The shear wave velocity also shows a positive correlation with the compressional wave velocity, but the ratio of shear wave velocity to compressional wave velocity changes obviously with the compressional wave velocity valuerange.
2006, 28(5): 69-75.
Abstract:
Total platinum-group elements concentrations (ΣPGE) from Mariana Trough basalts ranged from 0.418 to 1.022 ng/g, and primitive mantle-normalized PGE concentration patterns are of positive slope with a clear Ptnegative anomaly (Pt/Pt* = 0.01~0.15),showing the relative enrichment of PPGE and Au relative to IPGE.Compared with other mantleoriginated rocks, Mariana Trough basalts have lower PGE contents and wider ranges of (Pd/Ir) N, (Pd/Pt) N, (Pd/Ru) N.On the other hand, Mariana Trough basalts exhibited a relative Pt and Ir depletion.Characteristics of PGE patterns indicated that the studied Mariana Trough basalts were originated from low partial melting, and the MORB mantle beneath the spreading center had been contaminated byarcisland mantle.In the aspect of trace elements, Mariana Trough basalts showed the enrichment of LILE, Pb and LREE, indicating that they had been influenced by subduction compositions.All these demonstrated that Mariana Trough basalts are products of partial melting from amixed mantle (the contamination of MORB mantle by are-island mantle).
Total platinum-group elements concentrations (ΣPGE) from Mariana Trough basalts ranged from 0.418 to 1.022 ng/g, and primitive mantle-normalized PGE concentration patterns are of positive slope with a clear Ptnegative anomaly (Pt/Pt* = 0.01~0.15),showing the relative enrichment of PPGE and Au relative to IPGE.Compared with other mantleoriginated rocks, Mariana Trough basalts have lower PGE contents and wider ranges of (Pd/Ir) N, (Pd/Pt) N, (Pd/Ru) N.On the other hand, Mariana Trough basalts exhibited a relative Pt and Ir depletion.Characteristics of PGE patterns indicated that the studied Mariana Trough basalts were originated from low partial melting, and the MORB mantle beneath the spreading center had been contaminated byarcisland mantle.In the aspect of trace elements, Mariana Trough basalts showed the enrichment of LILE, Pb and LREE, indicating that they had been influenced by subduction compositions.All these demonstrated that Mariana Trough basalts are products of partial melting from amixed mantle (the contamination of MORB mantle by are-island mantle).
2006, 28(5): 76-82.
Abstract:
Radioo nuclides in the surface sediments in special biological population dropping amended soil collecing from Antarctica have been measured with spectrometer.The average contents of 40K,137Cs,210Pb,226Ra,228Ra,228Th and 238U are 143, 7.56, 24.1, 3.65, 5.36, 4.15 and 6.5 Bq/kg.The specific activity of 210Pb for the core samples in sea birds dropping amended soil,respectively from Ardley Island, have been measured.A ccording to the profiles of 210Pb specific activity, we used CRS model to date the core samples.Which spans about 74 a(1928~2002).Base on the dating, we estimateth evelocity of deposition.Effece of the naturalr adionuclides treca on dating,relations between storage method of radionuclides and regional climate anomaly variation, and of under the construction of Antarctica have been distributed.
Radioo nuclides in the surface sediments in special biological population dropping amended soil collecing from Antarctica have been measured with spectrometer.The average contents of 40K,137Cs,210Pb,226Ra,228Ra,228Th and 238U are 143, 7.56, 24.1, 3.65, 5.36, 4.15 and 6.5 Bq/kg.The specific activity of 210Pb for the core samples in sea birds dropping amended soil,respectively from Ardley Island, have been measured.A ccording to the profiles of 210Pb specific activity, we used CRS model to date the core samples.Which spans about 74 a(1928~2002).Base on the dating, we estimateth evelocity of deposition.Effece of the naturalr adionuclides treca on dating,relations between storage method of radionuclides and regional climate anomaly variation, and of under the construction of Antarctica have been distributed.
2006, 28(5): 83-89.
Abstract:
Mytilopsis sallei belongs to Dreissenidae, Veneroida, Bivalvia, Mollusca.Mytilopsis sallei was introduced to the Maluan Bay for the food of fish and shrimp in the early 1990s and it became the dominant species of fouling organism and it seriously affacted malacological culture.A new paneltest was designed to study the quant it ative relat ionship between Mytilopsis sallei and other macrozoo benthos out side a shrimp pond in the Maluan Bay in the summer of 2004.Results of regression analysis showed that there was negative correlation between Mytilopsis sallei and Balanus reticulatus.A high mortality of Balanus reticulatus was noted when Mytilopsis sallei was at high density (more than 105 ind./m2).Mytilopsis sallei tended to attach to the shell of Balanus reticulatus and out-competed Balanus reticulatus for food.There were positive correlations among Mytilopsis sallei,Capitella capitata and Polydoraciliata both in the sediment and on panel, because clusters of Mytilopsis sallei were propitious to construction of soft muddy tubes by Capitella capitata and Polydora ciliata.
Mytilopsis sallei belongs to Dreissenidae, Veneroida, Bivalvia, Mollusca.Mytilopsis sallei was introduced to the Maluan Bay for the food of fish and shrimp in the early 1990s and it became the dominant species of fouling organism and it seriously affacted malacological culture.A new paneltest was designed to study the quant it ative relat ionship between Mytilopsis sallei and other macrozoo benthos out side a shrimp pond in the Maluan Bay in the summer of 2004.Results of regression analysis showed that there was negative correlation between Mytilopsis sallei and Balanus reticulatus.A high mortality of Balanus reticulatus was noted when Mytilopsis sallei was at high density (more than 105 ind./m2).Mytilopsis sallei tended to attach to the shell of Balanus reticulatus and out-competed Balanus reticulatus for food.There were positive correlations among Mytilopsis sallei,Capitella capitata and Polydoraciliata both in the sediment and on panel, because clusters of Mytilopsis sallei were propitious to construction of soft muddy tubes by Capitella capitata and Polydora ciliata.
2006, 28(5): 90-100.
Abstract:
A systemic epizootiological study on mass mortalities of the cultured scallop Chlamys farreri was carried out during the period of 2001~2003.The results showed that the accumulated mortality rate of the cultivated scallop Chlamys farreri was very high, more than 90% from April to October, and the dead peak occurred on 24 August,being about 71%.The results on investigation of environmental factors revealed that the higher water temperature, more than 23℃,might be a serious stress factor to the cultured Chlamys farreri.Several suspect pathogens infecting the scallop were found such as rickett sia-like organism (RLO),mycoplasma-like organism (MLO) and virus-like particle (VLP).The results of histological observation showed that rickett sia-like organism inclusions were common, histological widespread infectiveagent.The averaged prevalence was from 20% to 90% among cultured scallop populations with averaged sizes of 2.5~6.1 cm.The highest infection intensity of RLO in host tissues was aver aged 31 inclusions persection.The result of experiment sinfected by purified RLOs showed that RLO was a serious pathogen to the scallop.It is inference that RLO infection was positively correlated with mortality rates of the cultured populations and might be the main pathogen responsible formass mortalities of the cultured population of scallop on the basis of the observation of intensity of natural infection, histological pathology and artificial infection experiment.
A systemic epizootiological study on mass mortalities of the cultured scallop Chlamys farreri was carried out during the period of 2001~2003.The results showed that the accumulated mortality rate of the cultivated scallop Chlamys farreri was very high, more than 90% from April to October, and the dead peak occurred on 24 August,being about 71%.The results on investigation of environmental factors revealed that the higher water temperature, more than 23℃,might be a serious stress factor to the cultured Chlamys farreri.Several suspect pathogens infecting the scallop were found such as rickett sia-like organism (RLO),mycoplasma-like organism (MLO) and virus-like particle (VLP).The results of histological observation showed that rickett sia-like organism inclusions were common, histological widespread infectiveagent.The averaged prevalence was from 20% to 90% among cultured scallop populations with averaged sizes of 2.5~6.1 cm.The highest infection intensity of RLO in host tissues was aver aged 31 inclusions persection.The result of experiment sinfected by purified RLOs showed that RLO was a serious pathogen to the scallop.It is inference that RLO infection was positively correlated with mortality rates of the cultured populations and might be the main pathogen responsible formass mortalities of the cultured population of scallop on the basis of the observation of intensity of natural infection, histological pathology and artificial infection experiment.
2006, 28(5): 101-106.
Abstract:
Six treatments (fed throughout experiment;alternate starvation and refeeding at equal duration of 1 d, 2 d, 3 d and 4 d, respectively;star vation throughout experiment) were carried out to test effects of periodical starvation on the characteristic parameters of population of Brachionus plicatilis,and each treat ment was performed in 12 replicates of individual cultures.The results showed that the group fed throug hout experiment had a to preproductive value (indicated best potential population growth),and the longer starved, the lower the reproductive value.Statistical analyses also showed that individual lifespan and its reproductive period shared significantly positive correlation (r= 0.747) at different treat ments.Under starvation, the rotifer's lifespan was slihtly elongated, but mean lifespan (10.8~13.1 d) and reproductive period (6.3~8.3 d) had no difference among six treat ments (P > 0.05).While starvation increased, total larvae and total eggs were sharply decreased (P< 0.05),but the time for the first and lastegg, for the first and last larva was significantly post poned (P< 0.05).At the same time, rotifer's generation time (T) also gradually increased, but intrinsic rate of increase (rm),finite rate of increase (K) and net reproductive rate (R0) obviously decreased.
Six treatments (fed throughout experiment;alternate starvation and refeeding at equal duration of 1 d, 2 d, 3 d and 4 d, respectively;star vation throughout experiment) were carried out to test effects of periodical starvation on the characteristic parameters of population of Brachionus plicatilis,and each treat ment was performed in 12 replicates of individual cultures.The results showed that the group fed throug hout experiment had a to preproductive value (indicated best potential population growth),and the longer starved, the lower the reproductive value.Statistical analyses also showed that individual lifespan and its reproductive period shared significantly positive correlation (r= 0.747) at different treat ments.Under starvation, the rotifer's lifespan was slihtly elongated, but mean lifespan (10.8~13.1 d) and reproductive period (6.3~8.3 d) had no difference among six treat ments (P > 0.05).While starvation increased, total larvae and total eggs were sharply decreased (P< 0.05),but the time for the first and lastegg, for the first and last larva was significantly post poned (P< 0.05).At the same time, rotifer's generation time (T) also gradually increased, but intrinsic rate of increase (rm),finite rate of increase (K) and net reproductive rate (R0) obviously decreased.
2006, 28(5): 107-116.
Abstract:
To investigate the role of microzo oplankton on algal bloom in coastaleco system,phytoplankton growth rate and mortality rate resulted from micro zooplankton grazing and its effects on processes of algal bloom were measured using the dilution method in the Taiwan Strait during 1 to 6 August 2004.Mean while, pig ment-specific growth of phy toplankton and grazing rate of microzo oplankton were also studied using high-perform anceliquid chromatog raphy (HPLC) on 3 August 2004.Results showed that processes of algal bloom was in decline during the survey, phy toplankton biomass (chl a) and abundance were 2.04 µg/L and 2.99×105ind./dm3, at beginning of the survey, respectively, with dominance of Pseudo-nitzschia pungens, Asterionellopsis glacialis, Skeletonema costatum, on 1 August;however, phytoplankton biomass (chl a) and abundance were only 0.37 and 1.54×104ind/dm3 on 6 August, respectively.For community structure of phytoplankton, abundance and percentage of cyanobacteria and dinoflagellate increased during the survey, from 0.04% and 0.85% on 1 August to 9.59% and 41.97% on 6 Augst, respectively.Microzo opankton was mainly composed of aloricate ciliates, loricate ciliates, Mesodinium rubrum and heterotrophic dinoflagellates, the highest abundance was up to 3 640 ind./dm3 on 2 August, the lowest only 436 ind./dm3 on 6 August.During the observation, althoug haloricate ciliates and heterotrophic dinoflagellates were always the main components of microzo oplanton, the community structure of microzoo planon showed some changes.The percentage of heterotrophic dinoflagellates and aloricate ciliate with smaller than 30 m declined during the survey,however, Mesodinium rubrum, loricate ciliates and aloricate ciliates biger than 50 m increased.Growth and mortality rates of phytoplankton were 0.40~0.91 d-1 and 0.26~1.34 d-1 during the survey, respectively.Both growth and mortality rates of phytoplankton declined during the survey.The results also showed that there was a sig nificantly positive linear correlation between microzooplamkton grazing rates and chloro phyll a (R2 = 0.89).Pig ment-based data showed significant gazing pressure on biomass and productivity of different groups (37.97% ~82.24% and 70.71% ~281.33% respectively).Abover esults suggested that microzooplankton gazing was important fact or for controlling algal bloom.Avoiding grazing of microzoo plankton on cyanobacteria and dinoflagellate may be one of the reasons for phytoplankton community succession, from diatom-dominated to diatom and dinoflagellate-dominated community during the survey in the Taiwan Strait.
To investigate the role of microzo oplankton on algal bloom in coastaleco system,phytoplankton growth rate and mortality rate resulted from micro zooplankton grazing and its effects on processes of algal bloom were measured using the dilution method in the Taiwan Strait during 1 to 6 August 2004.Mean while, pig ment-specific growth of phy toplankton and grazing rate of microzo oplankton were also studied using high-perform anceliquid chromatog raphy (HPLC) on 3 August 2004.Results showed that processes of algal bloom was in decline during the survey, phy toplankton biomass (chl a) and abundance were 2.04 µg/L and 2.99×105ind./dm3, at beginning of the survey, respectively, with dominance of Pseudo-nitzschia pungens, Asterionellopsis glacialis, Skeletonema costatum, on 1 August;however, phytoplankton biomass (chl a) and abundance were only 0.37 and 1.54×104ind/dm3 on 6 August, respectively.For community structure of phytoplankton, abundance and percentage of cyanobacteria and dinoflagellate increased during the survey, from 0.04% and 0.85% on 1 August to 9.59% and 41.97% on 6 Augst, respectively.Microzo opankton was mainly composed of aloricate ciliates, loricate ciliates, Mesodinium rubrum and heterotrophic dinoflagellates, the highest abundance was up to 3 640 ind./dm3 on 2 August, the lowest only 436 ind./dm3 on 6 August.During the observation, althoug haloricate ciliates and heterotrophic dinoflagellates were always the main components of microzo oplanton, the community structure of microzoo planon showed some changes.The percentage of heterotrophic dinoflagellates and aloricate ciliate with smaller than 30 m declined during the survey,however, Mesodinium rubrum, loricate ciliates and aloricate ciliates biger than 50 m increased.Growth and mortality rates of phytoplankton were 0.40~0.91 d-1 and 0.26~1.34 d-1 during the survey, respectively.Both growth and mortality rates of phytoplankton declined during the survey.The results also showed that there was a sig nificantly positive linear correlation between microzooplamkton grazing rates and chloro phyll a (R2 = 0.89).Pig ment-based data showed significant gazing pressure on biomass and productivity of different groups (37.97% ~82.24% and 70.71% ~281.33% respectively).Abover esults suggested that microzooplankton gazing was important fact or for controlling algal bloom.Avoiding grazing of microzoo plankton on cyanobacteria and dinoflagellate may be one of the reasons for phytoplankton community succession, from diatom-dominated to diatom and dinoflagellate-dominated community during the survey in the Taiwan Strait.
2006, 28(5): 117-122.
Abstract:
The growth and species competition of two red tide species Thalassiosira pseudonana and Gymnodinium sp.were studied under different N/P ratio, and the algal batch culture experiments was conducted.The physiological and biochemical indexes were measured periodically,including µmax,K,G(d) and Chl-a.The results showed that when the N/P ratio was 16:1, the µmax,K and Chl-a of Thalassiosira pseudonana were all the highest,and G (d) was the shortest.This implied that the optimal N/P ratio of Thalassiosira pseudonana is 16:1.When the N/P ratio was 6:1, the max,K and Chl-a of Gymnodinium sp.were the highest, and G(d) were the shortest,so the optimal N/P ratio of Gymnodinium sp.is 6:1.From the growth curves as indicated both in cell density and Chl-a, it is suggested that the effect of N/P ratio on Chl-a and cell density are almost the same.Different N/P ratios had weak influence on succession of community of algae and the competition between the two algae.Gymnodinium sp.may use the phosphorus in vivo for growth, so it is important to payattention to the concealment of pho-sphorus, in order to avoid the out break of redtide.Based on the import ance of nitrogen and phosphorus and its ratio, the possible outbreak mechanism of red tide was also discussed in this paper.
The growth and species competition of two red tide species Thalassiosira pseudonana and Gymnodinium sp.were studied under different N/P ratio, and the algal batch culture experiments was conducted.The physiological and biochemical indexes were measured periodically,including µmax,K,G(d) and Chl-a.The results showed that when the N/P ratio was 16:1, the µmax,K and Chl-a of Thalassiosira pseudonana were all the highest,and G (d) was the shortest.This implied that the optimal N/P ratio of Thalassiosira pseudonana is 16:1.When the N/P ratio was 6:1, the max,K and Chl-a of Gymnodinium sp.were the highest, and G(d) were the shortest,so the optimal N/P ratio of Gymnodinium sp.is 6:1.From the growth curves as indicated both in cell density and Chl-a, it is suggested that the effect of N/P ratio on Chl-a and cell density are almost the same.Different N/P ratios had weak influence on succession of community of algae and the competition between the two algae.Gymnodinium sp.may use the phosphorus in vivo for growth, so it is important to payattention to the concealment of pho-sphorus, in order to avoid the out break of redtide.Based on the import ance of nitrogen and phosphorus and its ratio, the possible outbreak mechanism of red tide was also discussed in this paper.
2006, 28(5): 123-129.
Abstract:
Influences of salinity and pH value on reproduction, protein content and extracellular polymeric substances (EPS) of benthic diatom Cylindrotheca closterium (Ehr.) Reimannet Lewin were studied.Salinity and pH value fit to C.closterium were 15 and 8, respectively, showing brackish water species.Abundant EPS were secreted by C.closterium characterized by brackish water species under high salinity (> 15) and low pH (< 8) stress, showing functions in abnormal conditions.The fraction of EPS that was closely bound to the cells (at tached EPS) and the soluble fraction (colloidal EPS) were produced in differentam ounts at the different salinity and pH value.This suggested that the production of the 2 operationally defined fractions of EPS might serve different functions.No significant differences were found on intracel lular carbohydrate production of C.closterium under different salinity and pH value.
Influences of salinity and pH value on reproduction, protein content and extracellular polymeric substances (EPS) of benthic diatom Cylindrotheca closterium (Ehr.) Reimannet Lewin were studied.Salinity and pH value fit to C.closterium were 15 and 8, respectively, showing brackish water species.Abundant EPS were secreted by C.closterium characterized by brackish water species under high salinity (> 15) and low pH (< 8) stress, showing functions in abnormal conditions.The fraction of EPS that was closely bound to the cells (at tached EPS) and the soluble fraction (colloidal EPS) were produced in differentam ounts at the different salinity and pH value.This suggested that the production of the 2 operationally defined fractions of EPS might serve different functions.No significant differences were found on intracel lular carbohydrate production of C.closterium under different salinity and pH value.
2006, 28(5): 130-137.
Abstract:
31 cultures of the 110 microbial strains, which were isolated from deep-sea samples taken in tropical Pacific Ocean in Summer and Autumn, 2001, were selected for this research.The characters of their morphologies and of their adapting to the physical and chemical factors were studied, and the identification of these strains and their carbon-utilizing patterns were performed by Biolog Microstation System.The results demonstrated that the tested strains consisted of 2 yeasts, 21 Gram-positive bacteria and 8 Gram-negative bacteria, of which the Grampositive bacteria were dominant in the sediment samples while the Gram-negative bacteria were in the majority in the samples of sea waters and blue-greenalgaes.The adaptability of these st rains for different environmental factors (temperature, salinity and pH) was studied and it was found that less than 1/3 of the tested strains showed stenotropic adaption to the environmental factors, while a large proportion of the cultures was eurytropic microo rganisms with wideecological amplitude.On the other hand, among these microo rganisms, psycho trophs, moderate halophiles and alkalit olerant bacteria were in very high percentages.Furthermore most of the strains from blue-greenalgae samples could not,but those from over-laid water and sediment samples were able to, grow at 4.All these results incarnated the response of microorg anisms to their living environments.12 strains of the to taltested microo rganisms could be given the taxonomic results by the database of Biolog Microstation System.According to the carbon-utilizing spectra of the 15 strains of Grampositive bacteria vs 95 types of organic carbons in Boilog GP 2 Microplates, the numbers of the utilizable carbon sources showed a greatrange from 3 to 46 single organic carbons for each strain, embodying the great diversity of nutrition types in deep sea microorg anisms.Among the utilizable carbons, 8 types could be used by more than half of the tested Gram-positive bact eria.These organic carbon so urces are the important intermediatemet abolite in all kinds of metabolic pathway for microorg anisms.
31 cultures of the 110 microbial strains, which were isolated from deep-sea samples taken in tropical Pacific Ocean in Summer and Autumn, 2001, were selected for this research.The characters of their morphologies and of their adapting to the physical and chemical factors were studied, and the identification of these strains and their carbon-utilizing patterns were performed by Biolog Microstation System.The results demonstrated that the tested strains consisted of 2 yeasts, 21 Gram-positive bacteria and 8 Gram-negative bacteria, of which the Grampositive bacteria were dominant in the sediment samples while the Gram-negative bacteria were in the majority in the samples of sea waters and blue-greenalgaes.The adaptability of these st rains for different environmental factors (temperature, salinity and pH) was studied and it was found that less than 1/3 of the tested strains showed stenotropic adaption to the environmental factors, while a large proportion of the cultures was eurytropic microo rganisms with wideecological amplitude.On the other hand, among these microo rganisms, psycho trophs, moderate halophiles and alkalit olerant bacteria were in very high percentages.Furthermore most of the strains from blue-greenalgae samples could not,but those from over-laid water and sediment samples were able to, grow at 4.All these results incarnated the response of microorg anisms to their living environments.12 strains of the to taltested microo rganisms could be given the taxonomic results by the database of Biolog Microstation System.According to the carbon-utilizing spectra of the 15 strains of Grampositive bacteria vs 95 types of organic carbons in Boilog GP 2 Microplates, the numbers of the utilizable carbon sources showed a greatrange from 3 to 46 single organic carbons for each strain, embodying the great diversity of nutrition types in deep sea microorg anisms.Among the utilizable carbons, 8 types could be used by more than half of the tested Gram-positive bact eria.These organic carbon so urces are the important intermediatemet abolite in all kinds of metabolic pathway for microorg anisms.
2006, 28(5): 138-144.
Abstract:
An analytic method is used to analyze the transmission and reflection coefficients of a submerged rectangularbr eakwater (SRB) in oblique waves.The diffraction potential functions and expressions for reflection and transmission coefficients are obtained by using the eigenfunction expansion method.A boundary element method is used to verify the correctness of the present analytic method.The reflection and transmission properties of SRBs are studied for some specific cases.The results show that the geometrical parameters of SRBs and the angle of incident waves have appreciable influences on the transmission and reflection coefficients.The SRB can be an effective wave barrier for certain waves if properly designed in intermediate water.The results are useful for the design of SRBs.
An analytic method is used to analyze the transmission and reflection coefficients of a submerged rectangularbr eakwater (SRB) in oblique waves.The diffraction potential functions and expressions for reflection and transmission coefficients are obtained by using the eigenfunction expansion method.A boundary element method is used to verify the correctness of the present analytic method.The reflection and transmission properties of SRBs are studied for some specific cases.The results show that the geometrical parameters of SRBs and the angle of incident waves have appreciable influences on the transmission and reflection coefficients.The SRB can be an effective wave barrier for certain waves if properly designed in intermediate water.The results are useful for the design of SRBs.
2006, 28(5): 145-151.
Abstract:
On the basis of the hydrodynamic experimental results, the effects of Reynolds number, flow direction to the net,and net setting status on the drag coefficients of no deless plane fishing net were studied.According to the experimental results, empirical formulas of the drag coefficient were achieved and their validity was verified through a specific experiment of net-weight system.The results are useful to the hydrodynamic calculation of fishing gears such as deep water sea cage, and so on.
On the basis of the hydrodynamic experimental results, the effects of Reynolds number, flow direction to the net,and net setting status on the drag coefficients of no deless plane fishing net were studied.According to the experimental results, empirical formulas of the drag coefficient were achieved and their validity was verified through a specific experiment of net-weight system.The results are useful to the hydrodynamic calculation of fishing gears such as deep water sea cage, and so on.
2006, 28(5): 152-156.
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2006, 28(5): 157-161.
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2006, 28(5): 162-166.
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2006, 28(5): 167-172.
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2006, 28(5): 173-178.
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