2006 Vol. 28, No. 4
Display Method:
2006, 28(4): 1-8.
Abstract:
Based on monthly data of the second version of Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite data (HOAPS) from 1988 to 2002, the temporal and spatial variability of potential heat, sensible heat and sea surface temperature (SST) of South China Sea (SCS) has been analyzed by the EOF (Empirical Orthogonal Function) method.The results show:in summer, the potential heat in northern SCS is larger than the southern SCS, and the sensible heat in middle SCS is smaller than the other regimes.The ocean almost transport the potential heat and sensible heat into the atmosphere while the atmosphere transport the sensible heat to the ocean sometimes; In winter, both the potential and sensible heat is high in the northern SCS.There exists a high potential and sensible heat core in northeastern SCS which is mainly caused by the wind field; The SST has a half annual variability because there is a cold water in summer, and the SST lags behind the potential heat by about one month in winter; Except the summer and the winter mode, the transition mode from winter to summer is also significant; Compare the HOAPS data to the National Center of Environment Prediction (NCEP) Data, the temporal and spatial variability of potential heat, sensible heat and sea surface temperature bear much resemblance, and HOAPS data can describe higher resolution spatial characters of these air sea flux than NCEP data.
Based on monthly data of the second version of Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite data (HOAPS) from 1988 to 2002, the temporal and spatial variability of potential heat, sensible heat and sea surface temperature (SST) of South China Sea (SCS) has been analyzed by the EOF (Empirical Orthogonal Function) method.The results show:in summer, the potential heat in northern SCS is larger than the southern SCS, and the sensible heat in middle SCS is smaller than the other regimes.The ocean almost transport the potential heat and sensible heat into the atmosphere while the atmosphere transport the sensible heat to the ocean sometimes; In winter, both the potential and sensible heat is high in the northern SCS.There exists a high potential and sensible heat core in northeastern SCS which is mainly caused by the wind field; The SST has a half annual variability because there is a cold water in summer, and the SST lags behind the potential heat by about one month in winter; Except the summer and the winter mode, the transition mode from winter to summer is also significant; Compare the HOAPS data to the National Center of Environment Prediction (NCEP) Data, the temporal and spatial variability of potential heat, sensible heat and sea surface temperature bear much resemblance, and HOAPS data can describe higher resolution spatial characters of these air sea flux than NCEP data.
2006, 28(4): 9-16.
Abstract:
The major modes and variations of Indian Ocean (IO) sea surface temperature (SST) and relationship with Indian Summer Monsoon Rainfalls (ISMR) are analyzed.The results show that the most significant mode of IOSST in recent 50 a is the warming trend at most of the ocean basin and there is abrupt warming in 1976, 1986 and 1996 respectively.The warming trend of IOSST has weak relationship with the decreasing trend of ISMR.During the different backg rounds after the leaps of IOSST, the relationship of ISMR between SST had changed in many regions but rather stable in extrat ropical IO.The stable correlation distribution is similar to the second mode of Indian Ocean SST EOF analysis and named as South Indian Ocean Dipole (SIOD).ISMR generally increase during positive SIOD (PSIOD) years and decrease during negative SIOD (NSIOD) years.The general circulation analysis shows, during PSIOD (NSIOD) phase, the SST anomalies of extratropcical IO will enhance (weaken) the Mascarene high by interacting with regional atmosphere, then enhance (weaken) the cross equatorial flow off Somali, produce convergence (divergence) at low level and divergence (convergence) at high level over India, and finally lead the ISMR increasing (decreasing).
The major modes and variations of Indian Ocean (IO) sea surface temperature (SST) and relationship with Indian Summer Monsoon Rainfalls (ISMR) are analyzed.The results show that the most significant mode of IOSST in recent 50 a is the warming trend at most of the ocean basin and there is abrupt warming in 1976, 1986 and 1996 respectively.The warming trend of IOSST has weak relationship with the decreasing trend of ISMR.During the different backg rounds after the leaps of IOSST, the relationship of ISMR between SST had changed in many regions but rather stable in extrat ropical IO.The stable correlation distribution is similar to the second mode of Indian Ocean SST EOF analysis and named as South Indian Ocean Dipole (SIOD).ISMR generally increase during positive SIOD (PSIOD) years and decrease during negative SIOD (NSIOD) years.The general circulation analysis shows, during PSIOD (NSIOD) phase, the SST anomalies of extratropcical IO will enhance (weaken) the Mascarene high by interacting with regional atmosphere, then enhance (weaken) the cross equatorial flow off Somali, produce convergence (divergence) at low level and divergence (convergence) at high level over India, and finally lead the ISMR increasing (decreasing).
2006, 28(4): 17-25.
Abstract:
The radiative fluxes are of primary importance in the energy and mass balance of the sea ice cover.The various parameterizations of radiative fluxes in the thermo dynamic sea ice model are studied in this paper.Model outputs of the surface radiative and heat fluxes and mass balance are compared with observations.The contribution of short wave radiation is limited in large part of the winter.Therefore, simple schemes are often sufficient.Errors in estimations of the short wave radiation are mainly due to cloud effects and occasionally due to multi reflection between surface and ice crystals in the air.The long wave radiation plays an important role in heat and mass balance of ice surface during large part of winter.The effect of clouds on the accuracy of simple radiative schemes is critical, which needs further attention.In general, accuracy of the ice model results is in consistent with the accuracy of estimation of the radiative fluxes.
The radiative fluxes are of primary importance in the energy and mass balance of the sea ice cover.The various parameterizations of radiative fluxes in the thermo dynamic sea ice model are studied in this paper.Model outputs of the surface radiative and heat fluxes and mass balance are compared with observations.The contribution of short wave radiation is limited in large part of the winter.Therefore, simple schemes are often sufficient.Errors in estimations of the short wave radiation are mainly due to cloud effects and occasionally due to multi reflection between surface and ice crystals in the air.The long wave radiation plays an important role in heat and mass balance of ice surface during large part of winter.The effect of clouds on the accuracy of simple radiative schemes is critical, which needs further attention.In general, accuracy of the ice model results is in consistent with the accuracy of estimation of the radiative fluxes.
2006, 28(4): 26-35.
Abstract:
The heat exchange interfaced ocean and atmosphere acts an important role in the climatic variation, but it has influenced on further research of the air-sea interaction because the observations over ocean are sparse.In this paper the satellite data from SSM/I and AVHRR are applied to estimate the sensible flux and latent flux on the air-sea interface over China coastal sea (CCS) with the advanced method (COARE3.0).Comparison with the in-situ observations in Xisha and Wenchang stations, the estimated results are reasonable well.the root mean square (RMS) of sensible flux and latent flux are 2.9 and 29.9 W/m2, respectively, contrasted with the observation data from Xisha Station in May 2002.The RMS of sensible flux are 4.42 W/m2 (October 2000) and 4.19 W/m2 (November 2000), the RMS of latent flux are 43.05 W/m2 (October 2000) and 40.8 W/m2 (November 2000) contrasted with Wenchang Station.The temporal and spatial distributions from this method are generally consistent with that of GSSTF2.Based on the analysis with the satellite data in CCS, the RMS is 11.7 W/m2 for sensible flux and 43.2 W/m2 for latent flux.It means that the sat ellite data could be taken as an efficient alternative for sparse observations over ocean and it has important role in the study of the air-sea interaction in CCS, as well it has been used as important basis on the climate forecast and research in China.
The heat exchange interfaced ocean and atmosphere acts an important role in the climatic variation, but it has influenced on further research of the air-sea interaction because the observations over ocean are sparse.In this paper the satellite data from SSM/I and AVHRR are applied to estimate the sensible flux and latent flux on the air-sea interface over China coastal sea (CCS) with the advanced method (COARE3.0).Comparison with the in-situ observations in Xisha and Wenchang stations, the estimated results are reasonable well.the root mean square (RMS) of sensible flux and latent flux are 2.9 and 29.9 W/m2, respectively, contrasted with the observation data from Xisha Station in May 2002.The RMS of sensible flux are 4.42 W/m2 (October 2000) and 4.19 W/m2 (November 2000), the RMS of latent flux are 43.05 W/m2 (October 2000) and 40.8 W/m2 (November 2000) contrasted with Wenchang Station.The temporal and spatial distributions from this method are generally consistent with that of GSSTF2.Based on the analysis with the satellite data in CCS, the RMS is 11.7 W/m2 for sensible flux and 43.2 W/m2 for latent flux.It means that the sat ellite data could be taken as an efficient alternative for sparse observations over ocean and it has important role in the study of the air-sea interaction in CCS, as well it has been used as important basis on the climate forecast and research in China.
2006, 28(4): 36-42.
Abstract:
The primary features of tropical cyclone activity within 300 nautical miles of the China coast line are investigated using the 54 a (1949~2004) tropical cyclone data in this study.The differences of the tropical cyclone activities north and south of 25°N and the associated differences in the sea surface temperature (SST) and 500 hPa geopotential height, especially on the interannual and interdecadal time scales, are examined.The tropical cyclone activities north and south of 25°N are different.Increasing (decreasing) tropical cyclones affected the region north (south) of 25°N since the 1980s.The compositing large scale environmental fields for the above (below) average years indicate significant differences for these two categories.In addition, the correlation analysis of the large scale fields leads to some useful predictors for longterm tropical cyclone prediction.
The primary features of tropical cyclone activity within 300 nautical miles of the China coast line are investigated using the 54 a (1949~2004) tropical cyclone data in this study.The differences of the tropical cyclone activities north and south of 25°N and the associated differences in the sea surface temperature (SST) and 500 hPa geopotential height, especially on the interannual and interdecadal time scales, are examined.The tropical cyclone activities north and south of 25°N are different.Increasing (decreasing) tropical cyclones affected the region north (south) of 25°N since the 1980s.The compositing large scale environmental fields for the above (below) average years indicate significant differences for these two categories.In addition, the correlation analysis of the large scale fields leads to some useful predictors for longterm tropical cyclone prediction.
2006, 28(4): 43-48.
Abstract:
Side-scan sonar image (SSI) must be segmented into regions of shadow, sea-bottom-reverberation, and object-highlight before underwater object can automatically be detected and recognized.Because strong background noises exist, traditional algorithms of image segmenting are useless.The algorithm based on Markov random field model is introduced.The segmentation can be constrained by the aprior information, according to the characteristics of object on the SSI.Furthermore, it is highlight intensity in an object area and low light intensity in a shadow area, so the ratio of shadow intensity to object intensity is very small.The SSI can be initially segmented by the three apriorinformation.After the initial segmentation has been completed, a false objects can be detected through the characteristic that the difference between the widths of object and shadow is close to one.And then, an MRF model parameter can be solved with the least square, and an noise parameter can be calculated with the maximum likelihood approach.Finally, the segmentation can be accomplished with the ICE method.The MRF model provides a reliable method for obtaining this underlying label field through incorporating pixel dependencies into the segmentation model.This is rational and robust.It has few influences when strong speckle noise exists.This fine result is obtained through the real SSI.
Side-scan sonar image (SSI) must be segmented into regions of shadow, sea-bottom-reverberation, and object-highlight before underwater object can automatically be detected and recognized.Because strong background noises exist, traditional algorithms of image segmenting are useless.The algorithm based on Markov random field model is introduced.The segmentation can be constrained by the aprior information, according to the characteristics of object on the SSI.Furthermore, it is highlight intensity in an object area and low light intensity in a shadow area, so the ratio of shadow intensity to object intensity is very small.The SSI can be initially segmented by the three apriorinformation.After the initial segmentation has been completed, a false objects can be detected through the characteristic that the difference between the widths of object and shadow is close to one.And then, an MRF model parameter can be solved with the least square, and an noise parameter can be calculated with the maximum likelihood approach.Finally, the segmentation can be accomplished with the ICE method.The MRF model provides a reliable method for obtaining this underlying label field through incorporating pixel dependencies into the segmentation model.This is rational and robust.It has few influences when strong speckle noise exists.This fine result is obtained through the real SSI.
2006, 28(4): 49-55.
Abstract:
Thermal infrared images from the NOAA AVHRR taken over 13 a between 1989 and 2001 have been used to study the sea surface thermal front in the Taiwan Strait and its adjacent seas.Information about the location, length, width and strength of the front has been retrieved from the thermal infrared images.Satellite observations have revealed that the front exists all year round and has a length of 470 km.The frontal location coincides approximately with 50 m off shore depth contour.The frontal width and strength vary with time, with average values of about 15.15 km and 0.147℃/km respectively.The front is instable and charact erized by the presence along its edges of eddies which have a time scale of 1~7 d and a length of 25~70 km.
Thermal infrared images from the NOAA AVHRR taken over 13 a between 1989 and 2001 have been used to study the sea surface thermal front in the Taiwan Strait and its adjacent seas.Information about the location, length, width and strength of the front has been retrieved from the thermal infrared images.Satellite observations have revealed that the front exists all year round and has a length of 470 km.The frontal location coincides approximately with 50 m off shore depth contour.The frontal width and strength vary with time, with average values of about 15.15 km and 0.147℃/km respectively.The front is instable and charact erized by the presence along its edges of eddies which have a time scale of 1~7 d and a length of 25~70 km.
2006, 28(4): 56-63.
Abstract:
semi-analy tical models are hot topics on ocean color remote sensing, and the backscattering coefficient is one of the important parameters in semi-analy tical algorithms.On the basis of the analysis about inherent optical properties data in the Huanghai Sea and the East China Sea, some characteristics of scattering have been found.The variation of backscat tering coefficients by sediments with wavelengths in highly turbid waters is very different compared with that in low turbid waters.Moreover, the primary relationship between the backscat tering coefficient and the total suspended matter concentration is obtained which can help in the establishment of semi-analy tical models as well as radiative transfer calculation in waters.
semi-analy tical models are hot topics on ocean color remote sensing, and the backscattering coefficient is one of the important parameters in semi-analy tical algorithms.On the basis of the analysis about inherent optical properties data in the Huanghai Sea and the East China Sea, some characteristics of scattering have been found.The variation of backscat tering coefficients by sediments with wavelengths in highly turbid waters is very different compared with that in low turbid waters.Moreover, the primary relationship between the backscat tering coefficient and the total suspended matter concentration is obtained which can help in the establishment of semi-analy tical models as well as radiative transfer calculation in waters.
2006, 28(4): 64-80.
Abstract:
The Zhujiang River Delta is one of the most complicated large-scale estuarine systems in China.It consists of a reticulated network system and several estuary bays.A long-term morphdynamic model (PRD-LTMM) is developed to simulate the evolution of the Zhujiang River Delta and its estuarine system.Long-term simulation method and concept of model verification are discussed.The underwater topography of the estuarine bay in the last transgr ession maximum about 6 000 a BP is reconstructed and serves as an initial condition of this model.The driving forces and control factors considered in the long-term delta evolution model include presentative tides, river discharge, and sediment supply from the Zhujiang River system, sea-level variation, sediment compaction and neotectonic movement.Deposition rates and total deposition volume are investigated and determined and then used to calibrate the model.More than 34 bore hole data with 14C dating are carefully analyzed to verify the model-simulated deposition.The local archaeological evidence is compared with the model out put as circumst antial verification.New findings of the Holocene delta evolution indicate that the chronological and spatial progress of the delta is different from previous studies in many aspects.More details are provided to the delta and network development originated from the effects of the morphodynamic sturctures "gate" and associated bi-directional jets.The model confirms that the mor phological constraint, e.g., the rocky islands in the shallowest uarine baysis one of the most important control factors affecting the long-term delta evolution of the Zhujiang River Delta.
The Zhujiang River Delta is one of the most complicated large-scale estuarine systems in China.It consists of a reticulated network system and several estuary bays.A long-term morphdynamic model (PRD-LTMM) is developed to simulate the evolution of the Zhujiang River Delta and its estuarine system.Long-term simulation method and concept of model verification are discussed.The underwater topography of the estuarine bay in the last transgr ession maximum about 6 000 a BP is reconstructed and serves as an initial condition of this model.The driving forces and control factors considered in the long-term delta evolution model include presentative tides, river discharge, and sediment supply from the Zhujiang River system, sea-level variation, sediment compaction and neotectonic movement.Deposition rates and total deposition volume are investigated and determined and then used to calibrate the model.More than 34 bore hole data with 14C dating are carefully analyzed to verify the model-simulated deposition.The local archaeological evidence is compared with the model out put as circumst antial verification.New findings of the Holocene delta evolution indicate that the chronological and spatial progress of the delta is different from previous studies in many aspects.More details are provided to the delta and network development originated from the effects of the morphodynamic sturctures "gate" and associated bi-directional jets.The model confirms that the mor phological constraint, e.g., the rocky islands in the shallowest uarine baysis one of the most important control factors affecting the long-term delta evolution of the Zhujiang River Delta.
2006, 28(4): 81-86.
Abstract:
Since the Cenozoic, crust tectonic movement in the northern continental shelf and slope and its surrounding of the South China Sea has occurred with an uniform regional tectonic stress field, which generally appeared as a regional rifting and sinking background.The tectonic movement was charact erized by a kind of polycyclic-oscillatory change, which ran through the whole Cenozoic after the Late Cretaceous epoch.The tectonic movements keep closer elation with the tectonic process of the Pacific plate and have been triggered by the oscillatory change of orient and intensity of asthenospheric flow under the Pacific plate.
Since the Cenozoic, crust tectonic movement in the northern continental shelf and slope and its surrounding of the South China Sea has occurred with an uniform regional tectonic stress field, which generally appeared as a regional rifting and sinking background.The tectonic movement was charact erized by a kind of polycyclic-oscillatory change, which ran through the whole Cenozoic after the Late Cretaceous epoch.The tectonic movements keep closer elation with the tectonic process of the Pacific plate and have been triggered by the oscillatory change of orient and intensity of asthenospheric flow under the Pacific plate.
2006, 28(4): 87-95.
Abstract:
On the basis of the measurement of suspended sediment at several sites over the Dafeng tidalflat in the summer of 2002 and 2003, the northern Jiangsu coast, the spatio-temporal characteristics of grainsize distributions of suspended sediment and its response to resuspension, settling process and tidal current velocity are analyzed.The results show that the suspended sediment is mainly composed of fine and very fine silt, and the mean grain-size is 7~13 m.On the basis of the in-situ measurement data, the spatiotemporal variation models of the grain-size distributions of the suspended sediment during the tidal cycle can be summarized into two types, one is the stability type when the variation is insignificant and the other is the double-peak type when the variation is remarkable.The main factors that influence the grain-size distributions of the suspended sediment are resuspension, settling process suspended sediment imported into tidal flats during the flood phase and the grain-size distributions of seabed sediment.The resuspension can increase the coarse particles content and the mean grain-size of the suspended sediment and cause the grain-size distributions of the suspended sediment close to the seabed sediment; the effects of settling process on the suspended sediment are opposite to those of the resuspension.When the resuspension occurs, the variation of the gain-size distributions of the suspended sediment in the lower part of water column can reflect the process clearly, the mean grain-size of the suspended sediment has good linear relationships with the current velocity.Without the effects of resuspension and settling process.the grain-size distributions of the suspended sediment is inclined to be stable and invariable during the measurement period over different parts of tidal flats, the mean grain-size of the background suspended sediment over the Dafeng tidalflat is 7 μm.
On the basis of the measurement of suspended sediment at several sites over the Dafeng tidalflat in the summer of 2002 and 2003, the northern Jiangsu coast, the spatio-temporal characteristics of grainsize distributions of suspended sediment and its response to resuspension, settling process and tidal current velocity are analyzed.The results show that the suspended sediment is mainly composed of fine and very fine silt, and the mean grain-size is 7~13 m.On the basis of the in-situ measurement data, the spatiotemporal variation models of the grain-size distributions of the suspended sediment during the tidal cycle can be summarized into two types, one is the stability type when the variation is insignificant and the other is the double-peak type when the variation is remarkable.The main factors that influence the grain-size distributions of the suspended sediment are resuspension, settling process suspended sediment imported into tidal flats during the flood phase and the grain-size distributions of seabed sediment.The resuspension can increase the coarse particles content and the mean grain-size of the suspended sediment and cause the grain-size distributions of the suspended sediment close to the seabed sediment; the effects of settling process on the suspended sediment are opposite to those of the resuspension.When the resuspension occurs, the variation of the gain-size distributions of the suspended sediment in the lower part of water column can reflect the process clearly, the mean grain-size of the suspended sediment has good linear relationships with the current velocity.Without the effects of resuspension and settling process.the grain-size distributions of the suspended sediment is inclined to be stable and invariable during the measurement period over different parts of tidal flats, the mean grain-size of the background suspended sediment over the Dafeng tidalflat is 7 μm.
2006, 28(4): 96-101.
Abstract:
Two core sediments, from the Changjiang Estuary, China, were analyzed forsterols Severn sterols named as cholest-5-en-3β-ol, 5α-cholestan-3β-ol, 24-methyl-cholest-7-en-3β-ol, 4:24-methyl-5α-cholestan-3β-ol, 24-ethyl-cholest-22en-3β-ol, 24-ethyl-5α-cholestan-3β-ol and 4α, 23, 24-trimethyl-5α-cholest-22en-3β-ol were identified by means of GC-MS analysis.The relative abundance of C29 sterols, which mainly originate from terrigenous input, is the highest in all the sediment from Site 8.In Site 17, the relative abundance of C27 sterols mainly from zoo plankton input is the highest in the surface sediment, while that of C29 sterols is the highest downwards.In all the samples, the relative abundances of sterols are much higher than those of sterols at the same carbon number for the strong hydrogenation.The reductive hydrogenation of sterols is stronger downward with the depth, and that is much stronger in Site 8 than in Site 17 due to the different sedimentary circumstances.
Two core sediments, from the Changjiang Estuary, China, were analyzed forsterols Severn sterols named as cholest-5-en-3β-ol, 5α-cholestan-3β-ol, 24-methyl-cholest-7-en-3β-ol, 4:24-methyl-5α-cholestan-3β-ol, 24-ethyl-cholest-22en-3β-ol, 24-ethyl-5α-cholestan-3β-ol and 4α, 23, 24-trimethyl-5α-cholest-22en-3β-ol were identified by means of GC-MS analysis.The relative abundance of C29 sterols, which mainly originate from terrigenous input, is the highest in all the sediment from Site 8.In Site 17, the relative abundance of C27 sterols mainly from zoo plankton input is the highest in the surface sediment, while that of C29 sterols is the highest downwards.In all the samples, the relative abundances of sterols are much higher than those of sterols at the same carbon number for the strong hydrogenation.The reductive hydrogenation of sterols is stronger downward with the depth, and that is much stronger in Site 8 than in Site 17 due to the different sedimentary circumstances.
2006, 28(4): 102-107.
Abstract:
During the cruise of CHINARE-18, the concentration and profile characteristics of nutrients in the sediment interstitial water from the Southern Ocean were determined.The results show that the concentration of SiO3-Si and NH4-N are much higher than other nutrients.The profile of SiO3-Si was characterized by sharp gradients near the sediment-water interface, profile distribution of silicate show that during the diagenetic reaction of silicate, dissolution is the main part.The organic matter decomposition was occurred under the anaerobic condition.Benthic fluxes of SiO3 Si, NH4-N were from interstitial water to overlying water, and regeneration of silicate and ammonium was the main part of the nutrient regeneration in sediment interstitial water of the study area.
During the cruise of CHINARE-18, the concentration and profile characteristics of nutrients in the sediment interstitial water from the Southern Ocean were determined.The results show that the concentration of SiO3-Si and NH4-N are much higher than other nutrients.The profile of SiO3-Si was characterized by sharp gradients near the sediment-water interface, profile distribution of silicate show that during the diagenetic reaction of silicate, dissolution is the main part.The organic matter decomposition was occurred under the anaerobic condition.Benthic fluxes of SiO3 Si, NH4-N were from interstitial water to overlying water, and regeneration of silicate and ammonium was the main part of the nutrient regeneration in sediment interstitial water of the study area.
2006, 28(4): 108-114.
Abstract:
Studies on the seasonal characteristics of fish communities structure and diversity are conducted, based on data from bottom trawl surveys in 4 seasons of 2000 in the East China Sea and the Huanghai Sea.Around all survey areas there were totally 8 dominant species in 4 seasons, which were Trichiurus japonicus, Pseudosciaena polyactis, Setipinnataty, Acropoma japonicum, Apogonlineatus, Engraulis japonicus, Champsodon capensis, Psenopsisanomala.Trichiurus japonicus and Pseudosciaena polyact is were dominant around 4 seasons, and the other species were only dominant partly in 4 seasons.During the 4 seasons the fishs movement in the nor h of the Huanghai Sea was the strongest, in the middle of East China Sea the weakest and in the north of East China Sea middle.The biodiversity indexes of species richness index(D), Shannon Wiener index(H') shown the same trend:there were not apparent differences among three areas in spring and summer, but in autumn and winter the indexes of the south of yellow sea became lower, and that of the north and the middle of East China Sea became higher.Species evenness index (J') shown no apparent differences among 4 seasons and 3 areas.By comparison it was found that during summer and autumn the south fish communities are in the trend of migrating to the north, on the other hand the north fish communities are in the trend of migrating to the south during spring and winter.
Studies on the seasonal characteristics of fish communities structure and diversity are conducted, based on data from bottom trawl surveys in 4 seasons of 2000 in the East China Sea and the Huanghai Sea.Around all survey areas there were totally 8 dominant species in 4 seasons, which were Trichiurus japonicus, Pseudosciaena polyactis, Setipinnataty, Acropoma japonicum, Apogonlineatus, Engraulis japonicus, Champsodon capensis, Psenopsisanomala.Trichiurus japonicus and Pseudosciaena polyact is were dominant around 4 seasons, and the other species were only dominant partly in 4 seasons.During the 4 seasons the fishs movement in the nor h of the Huanghai Sea was the strongest, in the middle of East China Sea the weakest and in the north of East China Sea middle.The biodiversity indexes of species richness index(D), Shannon Wiener index(H') shown the same trend:there were not apparent differences among three areas in spring and summer, but in autumn and winter the indexes of the south of yellow sea became lower, and that of the north and the middle of East China Sea became higher.Species evenness index (J') shown no apparent differences among 4 seasons and 3 areas.By comparison it was found that during summer and autumn the south fish communities are in the trend of migrating to the north, on the other hand the north fish communities are in the trend of migrating to the south during spring and winter.
2006, 28(4): 115-120.
Abstract:
When male Japanese flounders were injected with alone luteinizing hormone-releasing hormone analogue(LHRH-A) (25 g/kg) or human chorionic goandotropin(hCG) (1 000 IU/kg), plasma testosterone(T) levels decreased significantly post injection 6 hour, and occurred the lowest levels post injection 12 hour, and somewhat increased postinjection 24 to 30 hour.Plasma T content declined abruptly postinjection 6 hour and appeared the least value of plasma T post injection 24 hour in that male fish injected with LHRH-A plushCG (12.5 g/kg+500IU/kg).At the same time, the plasma T levels of male fish in control group also decreased as these fish treated with LHRH-A or hCG.The plasma estradiol(E2) levels decreased significantly post injection 6 hour, and occurred the lowest levels post injection 24 hour, and somewhat increased post injection 30 hour, when female fish were injected with alone LHRH-A, whereas, the least plasma E2 levels occurred post injection 30 hour in that female fish injected with alone hCG.Plasm a E2 content decreased gradually post injection 6 hour and appeared the least value of plasma E2 postinjection 24 hour in that female fish injected with LHRH-A plus hCG.On the mean while, the plasma estradiol levels of the fish in control group also declined as these fish treated with LHRH-A or hCG.These results suggestion that the injection with alone LHRH-A or hCG or combined LHRH-A and hCG failed to increase significantly plasma testosteroneand estradiollevels, on the contrary, suppressed testosteroneand estradiolconcent ration in male and female Japanese flounder.
When male Japanese flounders were injected with alone luteinizing hormone-releasing hormone analogue(LHRH-A) (25 g/kg) or human chorionic goandotropin(hCG) (1 000 IU/kg), plasma testosterone(T) levels decreased significantly post injection 6 hour, and occurred the lowest levels post injection 12 hour, and somewhat increased postinjection 24 to 30 hour.Plasma T content declined abruptly postinjection 6 hour and appeared the least value of plasma T post injection 24 hour in that male fish injected with LHRH-A plushCG (12.5 g/kg+500IU/kg).At the same time, the plasma T levels of male fish in control group also decreased as these fish treated with LHRH-A or hCG.The plasma estradiol(E2) levels decreased significantly post injection 6 hour, and occurred the lowest levels post injection 24 hour, and somewhat increased post injection 30 hour, when female fish were injected with alone LHRH-A, whereas, the least plasma E2 levels occurred post injection 30 hour in that female fish injected with alone hCG.Plasm a E2 content decreased gradually post injection 6 hour and appeared the least value of plasma E2 postinjection 24 hour in that female fish injected with LHRH-A plus hCG.On the mean while, the plasma estradiol levels of the fish in control group also declined as these fish treated with LHRH-A or hCG.These results suggestion that the injection with alone LHRH-A or hCG or combined LHRH-A and hCG failed to increase significantly plasma testosteroneand estradiollevels, on the contrary, suppressed testosteroneand estradiolconcent ration in male and female Japanese flounder.
2006, 28(4): 121-128.
Abstract:
Diversity of bacteria was studied in deep-sea sediments from the Northwest Pacific by PCR, RFLP and sequence analysis of 16S rDNA and comparing with the published sequences in GenBank database.Based on the RFLP profile generated, 77 clones from the 16 s rDNA library were divided into 27 types.Phylogenetic analysis showed that the 27 independent clones fell into four groups:Proteobacteria (62.96%), Chloroflexi (14.81%), Planctomycetes (14.81%) and Acidobacteria (7.41%).Among all sequenced clones, 6 were related to the sulfate metabolism bacteria and the results also demonstrated that some bacteria in deep-sea sediments had relation to matter energy circulation.
Diversity of bacteria was studied in deep-sea sediments from the Northwest Pacific by PCR, RFLP and sequence analysis of 16S rDNA and comparing with the published sequences in GenBank database.Based on the RFLP profile generated, 77 clones from the 16 s rDNA library were divided into 27 types.Phylogenetic analysis showed that the 27 independent clones fell into four groups:Proteobacteria (62.96%), Chloroflexi (14.81%), Planctomycetes (14.81%) and Acidobacteria (7.41%).Among all sequenced clones, 6 were related to the sulfate metabolism bacteria and the results also demonstrated that some bacteria in deep-sea sediments had relation to matter energy circulation.
2006, 28(4): 129-137.
Abstract:
Twenty-four hour observations with three hour interval on the phytoplankton diel-rhythm at three stations in the north opening of Quauzhou Bay of Fujian were conducted seasonally from autumn of November in 2001, winter of February, spring of May and summer of August in 2002.The results show that chlorophylla varied with tidal currents with higher biomass appeared at low tide period and lower biomass during the high tide period.Chlorophyll a was in general higher at the station in the side of inner bay than the outer ones, showing a high to low gradient of phytoplankt on biomass from the inner bay to the outer.In the other hand, higher biomass was mostly found at the bottom water layer other than the upper water layer, where the biomass had partly contributed by the suspended benthic microalga, such as Paralia sulcata.Further analyses indicated that phytoplankton community changed in its structure with lower biodiversity index in the daytime than in the night.The dissimilarity of the phyt oplankt on communities between day and night was as high as 9, exhibiting an evident diel rhythm by some species, such as Skele-tonema costatum that multiplies and dominates during the day.However, some benthic algae tended to have higher density during the night, suggesting the dispersion of alga cells by the currents at night after daytime growth.Cell multiplication, resuspension and dispersion process of phyt oplankt on should be considered as control factors in the diel rhythm though tidal currents could be the stronger factor.
Twenty-four hour observations with three hour interval on the phytoplankton diel-rhythm at three stations in the north opening of Quauzhou Bay of Fujian were conducted seasonally from autumn of November in 2001, winter of February, spring of May and summer of August in 2002.The results show that chlorophylla varied with tidal currents with higher biomass appeared at low tide period and lower biomass during the high tide period.Chlorophyll a was in general higher at the station in the side of inner bay than the outer ones, showing a high to low gradient of phytoplankt on biomass from the inner bay to the outer.In the other hand, higher biomass was mostly found at the bottom water layer other than the upper water layer, where the biomass had partly contributed by the suspended benthic microalga, such as Paralia sulcata.Further analyses indicated that phytoplankton community changed in its structure with lower biodiversity index in the daytime than in the night.The dissimilarity of the phyt oplankt on communities between day and night was as high as 9, exhibiting an evident diel rhythm by some species, such as Skele-tonema costatum that multiplies and dominates during the day.However, some benthic algae tended to have higher density during the night, suggesting the dispersion of alga cells by the currents at night after daytime growth.Cell multiplication, resuspension and dispersion process of phyt oplankt on should be considered as control factors in the diel rhythm though tidal currents could be the stronger factor.
2006, 28(4): 138-144.
Abstract:
A fully nonlinear three-dimensional numerical wave tank (NWT) has been simulated by resolving Laplace equation using the finite element method in the time domain, and the fully nonlinear free surface boundary conditions are used to track free surfaces.Hexahedral element and quadratic inter polation function are used.The analytical solution of sloshing waves and the theoretical ones of second-order Stokes wave are conducted to validate the model.The results show that the model is steady and conservative and can be applied to accurately simulating the generation and transmission of nonlinear waves.
A fully nonlinear three-dimensional numerical wave tank (NWT) has been simulated by resolving Laplace equation using the finite element method in the time domain, and the fully nonlinear free surface boundary conditions are used to track free surfaces.Hexahedral element and quadratic inter polation function are used.The analytical solution of sloshing waves and the theoretical ones of second-order Stokes wave are conducted to validate the model.The results show that the model is steady and conservative and can be applied to accurately simulating the generation and transmission of nonlinear waves.
2006, 28(4): 145-152.
Abstract:
2006, 28(4): 153-158.
Abstract:
2006, 28(4): 159-166.
Abstract:
2006, 28(4): 172-177.
Abstract:
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