2009 Vol. 31, No. 1
Display Method:
2009, 31(1): 1-9.
Abstract:
The Taiwan Warm Current(TWC)and the Tsushima Warm Current(TSWC)flow northward over the shelf in the East China Sea(ECS).Some previous studies consider them as a Taiwan-Tsushima Warm Current(TTWC)System.It seems that the TWC is dominant in the TTWC system because it is located at the "upst ream" region of the whole system.In this paper,however,we find that the TSWC is more important in the TTWC system.Using a three-dimensional baroclinic model,we conduct several experiments to discuss the dynamic relationship between the TWC and TSWC.The results show that the TWC has little effect on the TSWC,while the TSWC has a significant effect on the TWC.We use source-sink driven mechanism along isobaths to explain this phenomenon.The perennial northward flow through the Tsushima Strait pumps the response over the northern shelf in the ECS that gives rise to the TWC.Although the TSWCis located at the "downstream" region,it could induce 0.5 Sv to TWC in annual mean. The possible mechanism can be explained here in terms of energy propagation by topographic waves.
The Taiwan Warm Current(TWC)and the Tsushima Warm Current(TSWC)flow northward over the shelf in the East China Sea(ECS).Some previous studies consider them as a Taiwan-Tsushima Warm Current(TTWC)System.It seems that the TWC is dominant in the TTWC system because it is located at the "upst ream" region of the whole system.In this paper,however,we find that the TSWC is more important in the TTWC system.Using a three-dimensional baroclinic model,we conduct several experiments to discuss the dynamic relationship between the TWC and TSWC.The results show that the TWC has little effect on the TSWC,while the TSWC has a significant effect on the TWC.We use source-sink driven mechanism along isobaths to explain this phenomenon.The perennial northward flow through the Tsushima Strait pumps the response over the northern shelf in the ECS that gives rise to the TWC.Although the TSWCis located at the "downstream" region,it could induce 0.5 Sv to TWC in annual mean. The possible mechanism can be explained here in terms of energy propagation by topographic waves.
2009, 31(1): 10-19.
Abstract:
We succeeded in implementing baroclinic 3Docean model POM(Princet on ocean model)in Changjiang River mouth and its adjacent area to simulate the tide,tide current,Taiwan Warm Current, and Taiwan Coastal Current. An interdisciplinary comprehensive survey was conducted in November 2004 with modern measurement instruments off the Changjiang River. The analysis of the observation data shows that there existhigh chlorophyll-a(Chl-a)concentration area in the surface plume on the west side of the submerged river val ley(SRV)off the Changjiang mouth. For analyzing the nutrients sources of the high Chl-a concent ration area,two numerical experiments were carried on. In one experiment,the nutrient load via the Changjiang River is considered as the only one input of nutrients. On the other hand,the nutrient load via the Changjiang River and the nutrient input from the open boundaries are coupled together to simulate the nutrients distribution. In the two experiments,the nutrients were considered as conservative mass and were calculated under diffusion and advection processes by tide,tide current,Taiwan Warm Current,and coastal current. In addition,nitrate was representative of nutrients in the simulation. Based on the analysis of the field observation data off the Changjiang River mouth in November 2004 and the calculated results of the 3D numerical model experiments,it indicates that the nutrients of the high Chl-a concent ration area comesfrom two sources. One is the input of nutrients by the upwelling on the west side of the submerged river valley off the Changjiang River mouth,which accounts for 1/2 of the total amount. The other one is the input of fishery in Shengsi and Taiwan Warm Current transport,which accounts for the same amount as the first one.
We succeeded in implementing baroclinic 3Docean model POM(Princet on ocean model)in Changjiang River mouth and its adjacent area to simulate the tide,tide current,Taiwan Warm Current, and Taiwan Coastal Current. An interdisciplinary comprehensive survey was conducted in November 2004 with modern measurement instruments off the Changjiang River. The analysis of the observation data shows that there existhigh chlorophyll-a(Chl-a)concentration area in the surface plume on the west side of the submerged river val ley(SRV)off the Changjiang mouth. For analyzing the nutrients sources of the high Chl-a concent ration area,two numerical experiments were carried on. In one experiment,the nutrient load via the Changjiang River is considered as the only one input of nutrients. On the other hand,the nutrient load via the Changjiang River and the nutrient input from the open boundaries are coupled together to simulate the nutrients distribution. In the two experiments,the nutrients were considered as conservative mass and were calculated under diffusion and advection processes by tide,tide current,Taiwan Warm Current,and coastal current. In addition,nitrate was representative of nutrients in the simulation. Based on the analysis of the field observation data off the Changjiang River mouth in November 2004 and the calculated results of the 3D numerical model experiments,it indicates that the nutrients of the high Chl-a concent ration area comesfrom two sources. One is the input of nutrients by the upwelling on the west side of the submerged river valley off the Changjiang River mouth,which accounts for 1/2 of the total amount. The other one is the input of fishery in Shengsi and Taiwan Warm Current transport,which accounts for the same amount as the first one.
2009, 31(1): 20-27.
Abstract:
During the South China Sea monsoon experiment,Taiwan University put three moored ATLAS buoys in the center deep basin of the South China Sea,in order to observe the long time serial data of water temperature,current and climate. Using almost 6 months current observation of three stations which is from October of 1998 to April of 1999,we used harmonic analysis and EOF method to study the spacial structure characteristic of tidal current in the observed sea. The results of harmonic analysis show that,in the observed sea it is dominated by the diurnal tide,the tidal ellipses rotate through the entire water column,and the tidal current is dominated by clockwise rotation,there are marked vertical variation in the tidal amplitudes. Making band-pass filtering of 10~30 hours on the real observed current and keeping the tidal period,after that using EOF to analyze the filtered tidal current,we can find that there are different vertical modes in the tidal current,which indicates that the tidal current in the deep basin of the South China Sea has strong baroclinicity.
During the South China Sea monsoon experiment,Taiwan University put three moored ATLAS buoys in the center deep basin of the South China Sea,in order to observe the long time serial data of water temperature,current and climate. Using almost 6 months current observation of three stations which is from October of 1998 to April of 1999,we used harmonic analysis and EOF method to study the spacial structure characteristic of tidal current in the observed sea. The results of harmonic analysis show that,in the observed sea it is dominated by the diurnal tide,the tidal ellipses rotate through the entire water column,and the tidal current is dominated by clockwise rotation,there are marked vertical variation in the tidal amplitudes. Making band-pass filtering of 10~30 hours on the real observed current and keeping the tidal period,after that using EOF to analyze the filtered tidal current,we can find that there are different vertical modes in the tidal current,which indicates that the tidal current in the deep basin of the South China Sea has strong baroclinicity.
2009, 31(1): 28-36.
Abstract:
Decomposing monthly sea level data at tide g auges along the coast of the Pacific Ocean in the EMD method,and combining with other data,the Pacific Ocean sea level's interannual and decadal oscillation were in vestigatel,as well as information on the sea level trends. Overall,the Pacific Ocean coastal sea level rises,with an average rate in 1.4mm/a,and shows highly non-uniform properties in geography. There are obvious interannual and decadal variability at the Pacific sea level. The interannual variations of the Pacific Ocean sea level oscillations are significantly affected by the ENSO. In the east Pacific Ocean the interannual sea level variability and Nino3 index are positive correlation,while negative correlations in the west Pacific Ocean. The correlation between both is significant in the tropical Pacific Ocean,and the correlation is weakened with latitude increasing. At different areas this correlation coefficient is different. In the west(east)Pacific Ocean sea level decadal variation performs significant negative(positive)correlation with the PDO index overall. The correlation between them is non-uniform geographically and evolves with time. Sea level decadal changes could lead to exactly the opposite sea level trend,due to decadal variation directim pact on the trends.
Decomposing monthly sea level data at tide g auges along the coast of the Pacific Ocean in the EMD method,and combining with other data,the Pacific Ocean sea level's interannual and decadal oscillation were in vestigatel,as well as information on the sea level trends. Overall,the Pacific Ocean coastal sea level rises,with an average rate in 1.4mm/a,and shows highly non-uniform properties in geography. There are obvious interannual and decadal variability at the Pacific sea level. The interannual variations of the Pacific Ocean sea level oscillations are significantly affected by the ENSO. In the east Pacific Ocean the interannual sea level variability and Nino3 index are positive correlation,while negative correlations in the west Pacific Ocean. The correlation between both is significant in the tropical Pacific Ocean,and the correlation is weakened with latitude increasing. At different areas this correlation coefficient is different. In the west(east)Pacific Ocean sea level decadal variation performs significant negative(positive)correlation with the PDO index overall. The correlation between them is non-uniform geographically and evolves with time. Sea level decadal changes could lead to exactly the opposite sea level trend,due to decadal variation directim pact on the trends.
2009, 31(1): 37-43.
Abstract:
Sea ice is a yearly occurred phenomenon in Bohai Sea of China.Optical feature of sea ice is important to the evolution of ice it self.In this study,a multi-spectral instrument system with 11 wavelengths was used to measure the incident,reflected,and transmitted radiations and their daily variations for the costal fastice in three locations near the Yingkou Harbor,west flank of the Liaodong Peninsula.Although the spectral distribution of arrived solar radiation was a double peaks structure,the reflectance and transmission were discrepant with it.Integrals of incidence,reflectance and transmission radiations are perfectly simulated by linear functions of solar height,and the albedo is simulated by a quadric function of solar height,which can revert the observation values in different time of day to that in noontime and make them comparable.The attenuation feature of sea ice for solar light is quite special that the at tenuated radiation by sea ice was independent of the solar radiation intensity and wavelength.As the ice thickness and of components in sea ice changed a little during the experiment,as a short coming of this paper,the impact from the thickness and microstructure of sea ice cannot be studied.
Sea ice is a yearly occurred phenomenon in Bohai Sea of China.Optical feature of sea ice is important to the evolution of ice it self.In this study,a multi-spectral instrument system with 11 wavelengths was used to measure the incident,reflected,and transmitted radiations and their daily variations for the costal fastice in three locations near the Yingkou Harbor,west flank of the Liaodong Peninsula.Although the spectral distribution of arrived solar radiation was a double peaks structure,the reflectance and transmission were discrepant with it.Integrals of incidence,reflectance and transmission radiations are perfectly simulated by linear functions of solar height,and the albedo is simulated by a quadric function of solar height,which can revert the observation values in different time of day to that in noontime and make them comparable.The attenuation feature of sea ice for solar light is quite special that the at tenuated radiation by sea ice was independent of the solar radiation intensity and wavelength.As the ice thickness and of components in sea ice changed a little during the experiment,as a short coming of this paper,the impact from the thickness and microstructure of sea ice cannot be studied.
2009, 31(1): 44-51.
Abstract:
To study the effect of the brine discharged from desalination plant on the distribution of salinity in Jiaozhou Bay,a numerical model for the salinity diffusion in the Jiaozhou Bay is set up based on the POM model. With the inputting conditions of existing desalination volume and the near future volume planning in 2010,the distributions and changes of the salinity in the bay are simulated. The results show that in February,May,August and October in 2010,the averaged salinity of the bay is 30.989 5, 30.80.0,30.022 1,and 30.230 6,respectively,which have an increasing about 0.027 6,0.027 42, 0.02121,and 0.020 48 than in 2008. The salinity of the local areas close to the brine discharged locations will change obviously,such as in the area near Huangdao plant,the seawater area with the salinity above 31.55 in 2010 is 0.24 km2 larger than 200.in February high tide,and the seawater area with the salinity above 32.00 turns up,It is 0.08km2;The seawater area with the salinity above 31.55 in 2010 increases 0.24 km2 than 2008 in February ebb tide,and the area with the salinity above 32.00 increase about 0.16 km2. The highest salinity values reached 40.23,36.66,37.94,37.87 in February,May,August and October respectively. Coupling with the preliminary laboratory results,we can see that in February the highest salinity is higher than 38.62,which is the no-detected toxic concentration of the brine on the phytoplankt on community in the Bay. This shows that in 2010,the brine discharged from the desalination plants will have a little effect on the distribution of average salinity in the whole bay,but it will lead to a marked increasing in salinity near to the area of the desalination plants,and will have a certain extent effect on the growth of the phytoplankton.
To study the effect of the brine discharged from desalination plant on the distribution of salinity in Jiaozhou Bay,a numerical model for the salinity diffusion in the Jiaozhou Bay is set up based on the POM model. With the inputting conditions of existing desalination volume and the near future volume planning in 2010,the distributions and changes of the salinity in the bay are simulated. The results show that in February,May,August and October in 2010,the averaged salinity of the bay is 30.989 5, 30.80.0,30.022 1,and 30.230 6,respectively,which have an increasing about 0.027 6,0.027 42, 0.02121,and 0.020 48 than in 2008. The salinity of the local areas close to the brine discharged locations will change obviously,such as in the area near Huangdao plant,the seawater area with the salinity above 31.55 in 2010 is 0.24 km2 larger than 200.in February high tide,and the seawater area with the salinity above 32.00 turns up,It is 0.08km2;The seawater area with the salinity above 31.55 in 2010 increases 0.24 km2 than 2008 in February ebb tide,and the area with the salinity above 32.00 increase about 0.16 km2. The highest salinity values reached 40.23,36.66,37.94,37.87 in February,May,August and October respectively. Coupling with the preliminary laboratory results,we can see that in February the highest salinity is higher than 38.62,which is the no-detected toxic concentration of the brine on the phytoplankt on community in the Bay. This shows that in 2010,the brine discharged from the desalination plants will have a little effect on the distribution of average salinity in the whole bay,but it will lead to a marked increasing in salinity near to the area of the desalination plants,and will have a certain extent effect on the growth of the phytoplankton.
2009, 31(1): 52-64.
Abstract:
Entermorpha prolifera outbreak is a rare kind of nature disaster in the Huanghai Sea and the East China Sea,it has a serious impact on coming Beijing Olympic sailing competition and environment near Qingdao off shore in the summer of 2008.The satellite remote sensing system used in emergency response monitoring for Entermorpha prolifera disaster was established based on the/H Y-10 satellite ground application system,MODIS data receiving and share system,and spill oil remote sensing system. More than 17 kinds of satellite from China,USA,Italy,Canada and ESA were used for dynamic monitoring of Entermorpha prolifera in all weather,day and night,many times and by many observation instruments.Overall,exact and external information about Enter morphaprolifera was got and was provided to emergency response headquarters of State Ocean Administration.
Entermorpha prolifera outbreak is a rare kind of nature disaster in the Huanghai Sea and the East China Sea,it has a serious impact on coming Beijing Olympic sailing competition and environment near Qingdao off shore in the summer of 2008.The satellite remote sensing system used in emergency response monitoring for Entermorpha prolifera disaster was established based on the/H Y-10 satellite ground application system,MODIS data receiving and share system,and spill oil remote sensing system. More than 17 kinds of satellite from China,USA,Italy,Canada and ESA were used for dynamic monitoring of Entermorpha prolifera in all weather,day and night,many times and by many observation instruments.Overall,exact and external information about Enter morphaprolifera was got and was provided to emergency response headquarters of State Ocean Administration.
2009, 31(1): 65-70.
Abstract:
High resolution sea surface wind speeds of typhoon were retrieved by using the No.0519 "Longwang" typhoon SAR image combining with the wind directions from the blended NCEP/Q SCATsea surface wind data.And also the profiles of high resolution SARsea surface wind speeds were used to analyze the features and mechanism of sea surface wind fields around the Taiwan Strait during the typhoon period. The results showed that the geography had prominent effects on the formation of wind fields features;it caused some interesting phenomena,such as the deformation of typhoon,the formation of leeward trough, corner flow and the downstream of the tips.
High resolution sea surface wind speeds of typhoon were retrieved by using the No.0519 "Longwang" typhoon SAR image combining with the wind directions from the blended NCEP/Q SCATsea surface wind data.And also the profiles of high resolution SARsea surface wind speeds were used to analyze the features and mechanism of sea surface wind fields around the Taiwan Strait during the typhoon period. The results showed that the geography had prominent effects on the formation of wind fields features;it caused some interesting phenomena,such as the deformation of typhoon,the formation of leeward trough, corner flow and the downstream of the tips.
2009, 31(1): 71-78.
Abstract:
The variation of colloidal phosphorus with salinity in esturary was studied,which was compared with that of particle and truly dissolved phosphorus with the purpose of finding out the similarities and differences between behaviors of them. Distribution patterns of phosphorus in particle,colloidal and truly dissolved phase under different salinities and their relationships with suspended particulate matter were also researched to understand the transformation and transportation of colloidal phosphorus in estuarine area. The result shows that the concentrations of total colloidal phosphorus,organic colloidal phosphorus and inorganic colloidall phosphate all descend from river-end to sea-end,illust rating their terrigenous source1 Ratios of organic to total colloidal phosphorus decreased with salinity,indicating that organic phosphor us was influenced by scavenge process of colloid more significantly compare with inorganic phosphate. Both of the phosphorus variation tendencies and the proportion between organic and inorganic phosphorus in colloidal phase were similar with that in truly dissolved phase while different from that in particle phase.
The variation of colloidal phosphorus with salinity in esturary was studied,which was compared with that of particle and truly dissolved phosphorus with the purpose of finding out the similarities and differences between behaviors of them. Distribution patterns of phosphorus in particle,colloidal and truly dissolved phase under different salinities and their relationships with suspended particulate matter were also researched to understand the transformation and transportation of colloidal phosphorus in estuarine area. The result shows that the concentrations of total colloidal phosphorus,organic colloidal phosphorus and inorganic colloidall phosphate all descend from river-end to sea-end,illust rating their terrigenous source1 Ratios of organic to total colloidal phosphorus decreased with salinity,indicating that organic phosphor us was influenced by scavenge process of colloid more significantly compare with inorganic phosphate. Both of the phosphorus variation tendencies and the proportion between organic and inorganic phosphorus in colloidal phase were similar with that in truly dissolved phase while different from that in particle phase.
2009, 31(1): 79-84.
Abstract:
Based on the China's offshore investigation and assessment in the autumn of 2007,dissolved trace metals in the sea area of the Changjiang Estuary and the Hangzhou Bay were studied and estimated with gray cluster method.According to the National Sea Water Quality Standard(GB3097-1997),the evaluation model for trace metals in seawater with gray cluster method was established.The evaluation results show that the surface seawater quality in the nearshore area of the Changjiang Estuary and the Hangzhou Bay is good as a whole,but the contents of mercury and lead are relatively high,especially mercury. The seawater quality to the north of the Changjiang Estuary,in the north of the Hangzhou Bay and in the near of Zhoushan Isle are not so good,the main reason is the drain out let.According to this study,evaluating the content of trace metals in the surface seawater using the gray cluster method was relatively objective and reasonable.
Based on the China's offshore investigation and assessment in the autumn of 2007,dissolved trace metals in the sea area of the Changjiang Estuary and the Hangzhou Bay were studied and estimated with gray cluster method.According to the National Sea Water Quality Standard(GB3097-1997),the evaluation model for trace metals in seawater with gray cluster method was established.The evaluation results show that the surface seawater quality in the nearshore area of the Changjiang Estuary and the Hangzhou Bay is good as a whole,but the contents of mercury and lead are relatively high,especially mercury. The seawater quality to the north of the Changjiang Estuary,in the north of the Hangzhou Bay and in the near of Zhoushan Isle are not so good,the main reason is the drain out let.According to this study,evaluating the content of trace metals in the surface seawater using the gray cluster method was relatively objective and reasonable.
2009, 31(1): 85-90.
Abstract:
The samples of air and water in the Liaohe Estuary in China were collected in spring and summer. The static head space and gas-chromatography method was employed to determine the concentrations of nitrous oxide in air and in seawater. The result showed a temporal and spatial characteristic of distribution of nitrous oxide dissolved in water. The result showed that the concent rations of dissolved nitrous oxide in water were higher in spring than that in summer. The concentrations of dissolved nitrous oxide in the Liaohe River were higher than in coastal area. There was a notable negative correlation between the concentrations of N2O and DO dissolved in the seawater Nitrous oxide dissolved in water was supersat urated in all surface water that was sampled in May and August Nitrous oxide released from water to air,and the Liaohe Estuary area represented a source of atmosphere nitrous oxide during the study period.
The samples of air and water in the Liaohe Estuary in China were collected in spring and summer. The static head space and gas-chromatography method was employed to determine the concentrations of nitrous oxide in air and in seawater. The result showed a temporal and spatial characteristic of distribution of nitrous oxide dissolved in water. The result showed that the concent rations of dissolved nitrous oxide in water were higher in spring than that in summer. The concentrations of dissolved nitrous oxide in the Liaohe River were higher than in coastal area. There was a notable negative correlation between the concentrations of N2O and DO dissolved in the seawater Nitrous oxide dissolved in water was supersat urated in all surface water that was sampled in May and August Nitrous oxide released from water to air,and the Liaohe Estuary area represented a source of atmosphere nitrous oxide during the study period.
2009, 31(1): 91-98.
Abstract:
2009, 31(1): 99-105.
Abstract:
A comprehensive evaluation model for water quality based on combined weights is used to evaluate the water quality of Shanghai Chenhang water resource area and Qingcaosha beach water resource area based on the investigation data from 2005 to 2007. By the comparison between the comprehensive evaluation model and the one-factorial evaluation model,the research results show that the comprehensive evaluation model is simple and suitable,it takes advant age of more comprehensive message from water samples, the grades,quality of water samples can be classed well and indexed truly,it is an effective evaluation model for water quality.
A comprehensive evaluation model for water quality based on combined weights is used to evaluate the water quality of Shanghai Chenhang water resource area and Qingcaosha beach water resource area based on the investigation data from 2005 to 2007. By the comparison between the comprehensive evaluation model and the one-factorial evaluation model,the research results show that the comprehensive evaluation model is simple and suitable,it takes advant age of more comprehensive message from water samples, the grades,quality of water samples can be classed well and indexed truly,it is an effective evaluation model for water quality.
2009, 31(1): 106-116.
Abstract:
Contents of fine grain-size,total organic matter,aluminum,iron,manganese,copper,zinc, lead,cadmium,chromium,nickel and cobalt were determined for 13 surface sediments collected from the Shantou Estuary in Guangdong Province,China in September of 2002,and the relationships of one to another among them and their distributional charact eristics were analyzed.Meanwhile,the enrichment factor of some major heavy metals in the surface sediment of Shantou Estuary was calculated according to their background value in the South China Sea.The result suggested that content ranges of iron,manganese, copper,zinc,lead,cadmium,chromium,nickel and cobalt were 2.91%~3.94%,427.85~810.96, 24.43~79.49,84.83~248.50,35.56~50.25,0.30~1.75,36.11~74.22,16.99~31.69,8.22~10.87 mg/kg,and their distribution pattern showed a decrease trend as waves from out fall of the Rongjiang River to the mouth of Shantou Estuary(exept manganese).The enrichment factor of each heavy metal were higher than one,and showed an order copper graater than cadmium graater than lead graater than zinc graater than nickel graater than chromium graater than manganese.For most heavy metals,their distribution characteristics were controlled by anthropogenic pollution,hydrodynamic process,clay and salinity.As for the element manganese,redox conditions probably play an important role in controlling distribution pattern.
Contents of fine grain-size,total organic matter,aluminum,iron,manganese,copper,zinc, lead,cadmium,chromium,nickel and cobalt were determined for 13 surface sediments collected from the Shantou Estuary in Guangdong Province,China in September of 2002,and the relationships of one to another among them and their distributional charact eristics were analyzed.Meanwhile,the enrichment factor of some major heavy metals in the surface sediment of Shantou Estuary was calculated according to their background value in the South China Sea.The result suggested that content ranges of iron,manganese, copper,zinc,lead,cadmium,chromium,nickel and cobalt were 2.91%~3.94%,427.85~810.96, 24.43~79.49,84.83~248.50,35.56~50.25,0.30~1.75,36.11~74.22,16.99~31.69,8.22~10.87 mg/kg,and their distribution pattern showed a decrease trend as waves from out fall of the Rongjiang River to the mouth of Shantou Estuary(exept manganese).The enrichment factor of each heavy metal were higher than one,and showed an order copper graater than cadmium graater than lead graater than zinc graater than nickel graater than chromium graater than manganese.For most heavy metals,their distribution characteristics were controlled by anthropogenic pollution,hydrodynamic process,clay and salinity.As for the element manganese,redox conditions probably play an important role in controlling distribution pattern.
2009, 31(1): 117-124.
Abstract:
The comprehensive analysis of historical geography and sedimentary geology can be applied for dating the sedimentary layers of this very young delta.The form of the subaqueous delta lobe is like a lens and the delt a front silt is located at the middle off the river mouth and the delta lateral(interdistributary bay)clayey silt is distributed beside the delta front.Commonly the younger distributary channel mouth is located between two abandoned river mouths.The younger delta front silt overlays the older delt a lateral (interdistributary bay)clayey silt and the younger delt a lateral(interdistributary bay)clayey silt overlays the older delta front silt simultaneously.The historical record of the location and dates of each distributary channel have been made.After determining sedimentary environments of the layers in core and sediment sources,the dates of the layers are got because the dates of the distributary channels are also the dates of the layers.
The comprehensive analysis of historical geography and sedimentary geology can be applied for dating the sedimentary layers of this very young delta.The form of the subaqueous delta lobe is like a lens and the delt a front silt is located at the middle off the river mouth and the delta lateral(interdistributary bay)clayey silt is distributed beside the delta front.Commonly the younger distributary channel mouth is located between two abandoned river mouths.The younger delta front silt overlays the older delt a lateral (interdistributary bay)clayey silt and the younger delt a lateral(interdistributary bay)clayey silt overlays the older delta front silt simultaneously.The historical record of the location and dates of each distributary channel have been made.After determining sedimentary environments of the layers in core and sediment sources,the dates of the layers are got because the dates of the distributary channels are also the dates of the layers.
2009, 31(1): 125-131.
Abstract:
The changes of nuclear behavior and external shape during fertilization and early embryonic development in Barnea dilatata were consecutively observed by optical microscope and paraffin section method.The results of cytological observation indicated that unfertilized mature eggs of Barnea dilatata were pea-rshaped or egg-shaped and remained at the prophase of the first maturation division with obvious germinal vesicle and nucleolus,while their sperm belonged to the type of flagellum(44.042±1.166)μm in total length)with the elliptical head.At water temperature of 24,sperms quickly attached to the surface of the egg after mix of sperms and eggs.From 6 min to 9 m in after insemination,germinal vesicle gradually got smaller and brokedown eventually.The fertilized eggs released the first and the second polar bodies at about the 20th min and the 30th min respectively.At completion of the second maturation division,sperm nucleus and the haploid female nucleus expanded immediately and developed into the male and female pronuclei which are loose and incompact.The formation of the male pronucleus preceded that of the female pronucleus.About 35 min,the male and female pronuclei matched into an association nucleus after their chromo somes formed respectively in the center of egg.Subsequently,the chromosomes of association nucleus arranged on the metaphase plate of first cleavage.Until about 50 min,the chromosomes were separated equally into two daughter cells which are different evidently in size.The process of the second cleavage was fundam entally similar to the first cleavage,but the cleavage direction was almost vertical to the first cleavage furrow.65~70 min after insemination,the second cleavage has finished and formed four daughter cells,one big and three small.Additionally,the abnormal phenomena of poly sperm and multi-spindles were also observed in the experiment.
The changes of nuclear behavior and external shape during fertilization and early embryonic development in Barnea dilatata were consecutively observed by optical microscope and paraffin section method.The results of cytological observation indicated that unfertilized mature eggs of Barnea dilatata were pea-rshaped or egg-shaped and remained at the prophase of the first maturation division with obvious germinal vesicle and nucleolus,while their sperm belonged to the type of flagellum(44.042±1.166)μm in total length)with the elliptical head.At water temperature of 24,sperms quickly attached to the surface of the egg after mix of sperms and eggs.From 6 min to 9 m in after insemination,germinal vesicle gradually got smaller and brokedown eventually.The fertilized eggs released the first and the second polar bodies at about the 20th min and the 30th min respectively.At completion of the second maturation division,sperm nucleus and the haploid female nucleus expanded immediately and developed into the male and female pronuclei which are loose and incompact.The formation of the male pronucleus preceded that of the female pronucleus.About 35 min,the male and female pronuclei matched into an association nucleus after their chromo somes formed respectively in the center of egg.Subsequently,the chromosomes of association nucleus arranged on the metaphase plate of first cleavage.Until about 50 min,the chromosomes were separated equally into two daughter cells which are different evidently in size.The process of the second cleavage was fundam entally similar to the first cleavage,but the cleavage direction was almost vertical to the first cleavage furrow.65~70 min after insemination,the second cleavage has finished and formed four daughter cells,one big and three small.Additionally,the abnormal phenomena of poly sperm and multi-spindles were also observed in the experiment.
2009, 31(1): 132-142.
Abstract:
Salt marsh has now been extensively concerned for its important role in estuarine and coastal eco-systems,and the rapid expanding of invaded Spartina alterniflora is also regarded as a serious problem in the Changjiang Estuary and even all the coast al region of southeast China. However,it is still difficult to evaluate the impact of the invasion of S. alterniflora on the native ecosystem for lacking of know ledge about the food web structures of salt marshes here. The relative trophic contributions of primary producers in the salt marshes of the Changjiang Estuary have been estimated by IsoSource and clustering analysis based on measurement of carbon and nitrogen stable isotopes of the dominate producers and consumers. The results indicate that the food web here is mostly supported by microphytobenthos(MPB)and native terrestrial C3 vascular plants,while the contribution of invaded C4 plants S. alterniflora is minor and its δ13C enriched production can only be utilized specifically by one gastropod in summer. The proportion of S. alterniflora in the total production of salt marshes in the Changjiang Estuary will increase during its rapid expanding,so that influence the structure and function of food web here "bottom-up" from the trophic base.
Salt marsh has now been extensively concerned for its important role in estuarine and coastal eco-systems,and the rapid expanding of invaded Spartina alterniflora is also regarded as a serious problem in the Changjiang Estuary and even all the coast al region of southeast China. However,it is still difficult to evaluate the impact of the invasion of S. alterniflora on the native ecosystem for lacking of know ledge about the food web structures of salt marshes here. The relative trophic contributions of primary producers in the salt marshes of the Changjiang Estuary have been estimated by IsoSource and clustering analysis based on measurement of carbon and nitrogen stable isotopes of the dominate producers and consumers. The results indicate that the food web here is mostly supported by microphytobenthos(MPB)and native terrestrial C3 vascular plants,while the contribution of invaded C4 plants S. alterniflora is minor and its δ13C enriched production can only be utilized specifically by one gastropod in summer. The proportion of S. alterniflora in the total production of salt marshes in the Changjiang Estuary will increase during its rapid expanding,so that influence the structure and function of food web here "bottom-up" from the trophic base.
2009, 31(1): 143-151.
Abstract:
Between April 2002 and April 2003,time series measurements of water depth,current velocity and suspended sediment content(SSC)were carried out on the marsh fringe and adjacent mudflat of Chongming eastern beach in the Changjiang Estuary.Across-shore suspended sediment flux was calculated and analyzed.Under the calm weather condition,different types of the time series of current velocity between a salt marsh and a mudflat were observed during semidiurnal tidal cycles.Marsh vegetation reduced ebb currents,current velocity enhanced in flood on the salt marsh.Owing to current velocity asymmetry,mean SSC during flood phase was 1.8 times higher than ebb phase.As a result,net onshore sediment flux controlled cross-shore suspended sediment transport process and salt marsh pioneer zone was generally accreting.There was significant positive correlation between the total sediment flux and the quartic power of maximum water depth.It indicated that tidal frces dominate suspended sediment transport and sedim entation process in the salt marsh pioneer zone under the calm weather condition.Sedimentation rate on the adjacent mudflat was higher than the salt marsh,which induced stably accreting of salt marsh towards the sea.Wind events enhanced the SSC and the current velocity during the semidiurnal tides.And remarkable onshore net sediment flux could occur on the high marsh and mudflat close to the marsh fringe during the short period under the rough weather condition.
Between April 2002 and April 2003,time series measurements of water depth,current velocity and suspended sediment content(SSC)were carried out on the marsh fringe and adjacent mudflat of Chongming eastern beach in the Changjiang Estuary.Across-shore suspended sediment flux was calculated and analyzed.Under the calm weather condition,different types of the time series of current velocity between a salt marsh and a mudflat were observed during semidiurnal tidal cycles.Marsh vegetation reduced ebb currents,current velocity enhanced in flood on the salt marsh.Owing to current velocity asymmetry,mean SSC during flood phase was 1.8 times higher than ebb phase.As a result,net onshore sediment flux controlled cross-shore suspended sediment transport process and salt marsh pioneer zone was generally accreting.There was significant positive correlation between the total sediment flux and the quartic power of maximum water depth.It indicated that tidal frces dominate suspended sediment transport and sedim entation process in the salt marsh pioneer zone under the calm weather condition.Sedimentation rate on the adjacent mudflat was higher than the salt marsh,which induced stably accreting of salt marsh towards the sea.Wind events enhanced the SSC and the current velocity during the semidiurnal tides.And remarkable onshore net sediment flux could occur on the high marsh and mudflat close to the marsh fringe during the short period under the rough weather condition.
2009, 31(1): 152-158.
Abstract:
2009, 31(1): 159-167.
Abstract:
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