2005 Vol. 27, No. 4
Display Method:
2005, 27(4): 1-9.
Abstract:
On the basis of the current measurements at 200,500 and 800 m from moored current meters with the time series data from March 17 to April 15 at the mooring station(20°49'57"N,120°48'12"E) in Luzon Strait during spring of 2002 cruise,the spectral analy ses and calculation have been made.The major observed results are as follows:(1) the average velocity in the observing days is(47.4cm/s,346°) at the 200 m levels.The maximum observed current velocity Vmax and maximum daily current velocity Vd,max are(103.8 cm/s,10°) and(71.6 cm/s,339°) at 200 m level,respectively.The averag evelocity in the observing days is(20.3 cm/s,350°) at the 500 m level.Vmax and Vd,max are(74.1 cm/s,17°) and(39.1 cm/s, 317°) at 500 m level,respectively.The above results mean that the Kuroshio intrudes north west ward at the 200 and 500 m levels of moored station through the Luzon Strait in SCS.(2) The average velocity in the observing days is(1.2 cm/s,35b) at the 800 m level.Vmax and Vd,max are(10.8 cm/s,76°) and(4.7 cm/s,46°) at 800 m level,respectively.i.e.,their directions are north east ward.This means that the flow condition at the 800 m levels very differs from that at the 200 and 500 m levels,and their velocities decease with depth and their directions rotate clockwise with the change of depth.(3) The currents are stronger in April than these in March.(4) There exists the prominent fluctuations of tidal current.There exists also variation of tidal current with the change of depth.At 200,500 and 800 m levels,the semidiurnal peak is higher than the diurnal peak and the clockwise component is dominant in their fluctuations except for the height of diurnal peak is higher than that of semidiurnal peak for the clockwise component and the count erclockwise component is dominant in their fluctuations for semidiurnal peak at the 500 m level.(5) There is the prominent fluctuation of period of more than 15 d or about 14 d at the 200,500 and 800 m levels.For example,when f>0(the counterclockwise component),there are the prominent fluctuations of about 19 d periods at the 200 and 500 m levels,and there is the prominent fluctuations of about 14 d periods for clockwise component at the 800 m levels,respectively.(6) At 200,500 and 800 m levels,there are also the following prominent peaks:1) the fluctuation in the period range of about 4~6 d,which occurs in the weather process;2) the fluctuation in the period range of about 2~3 d;3) the inertial period of about 34.5 h,whose fluctuation is clockwise,and soon.(7) From the cross spectral estimates between two time series,it is shown that 1) there are significant coherence peaks for the periods of more than 15 d and 2~3 d and the diurnal and semidiurnal peaks and so on between the two time series of currents at 200 and 500 m dept hs.Bot h the current fluctuations at 200 and 500 m dept hs are synchro nous for the period of more than 15 d.2) t here ar e significant coher ence peaks for the periods of about 4~6 d,which occurs in the weather process,and 2~3 d and the diurnal and semidiurnal peaks and so on between the two time series of currents at 500 and 800 m depths.However,the phase difference of current fluctuations between two time series at 500 and 800 m levels have the time lags and forward phenomena for the above periods.
On the basis of the current measurements at 200,500 and 800 m from moored current meters with the time series data from March 17 to April 15 at the mooring station(20°49'57"N,120°48'12"E) in Luzon Strait during spring of 2002 cruise,the spectral analy ses and calculation have been made.The major observed results are as follows:(1) the average velocity in the observing days is(47.4cm/s,346°) at the 200 m levels.The maximum observed current velocity Vmax and maximum daily current velocity Vd,max are(103.8 cm/s,10°) and(71.6 cm/s,339°) at 200 m level,respectively.The averag evelocity in the observing days is(20.3 cm/s,350°) at the 500 m level.Vmax and Vd,max are(74.1 cm/s,17°) and(39.1 cm/s, 317°) at 500 m level,respectively.The above results mean that the Kuroshio intrudes north west ward at the 200 and 500 m levels of moored station through the Luzon Strait in SCS.(2) The average velocity in the observing days is(1.2 cm/s,35b) at the 800 m level.Vmax and Vd,max are(10.8 cm/s,76°) and(4.7 cm/s,46°) at 800 m level,respectively.i.e.,their directions are north east ward.This means that the flow condition at the 800 m levels very differs from that at the 200 and 500 m levels,and their velocities decease with depth and their directions rotate clockwise with the change of depth.(3) The currents are stronger in April than these in March.(4) There exists the prominent fluctuations of tidal current.There exists also variation of tidal current with the change of depth.At 200,500 and 800 m levels,the semidiurnal peak is higher than the diurnal peak and the clockwise component is dominant in their fluctuations except for the height of diurnal peak is higher than that of semidiurnal peak for the clockwise component and the count erclockwise component is dominant in their fluctuations for semidiurnal peak at the 500 m level.(5) There is the prominent fluctuation of period of more than 15 d or about 14 d at the 200,500 and 800 m levels.For example,when f>0(the counterclockwise component),there are the prominent fluctuations of about 19 d periods at the 200 and 500 m levels,and there is the prominent fluctuations of about 14 d periods for clockwise component at the 800 m levels,respectively.(6) At 200,500 and 800 m levels,there are also the following prominent peaks:1) the fluctuation in the period range of about 4~6 d,which occurs in the weather process;2) the fluctuation in the period range of about 2~3 d;3) the inertial period of about 34.5 h,whose fluctuation is clockwise,and soon.(7) From the cross spectral estimates between two time series,it is shown that 1) there are significant coherence peaks for the periods of more than 15 d and 2~3 d and the diurnal and semidiurnal peaks and so on between the two time series of currents at 200 and 500 m dept hs.Bot h the current fluctuations at 200 and 500 m dept hs are synchro nous for the period of more than 15 d.2) t here ar e significant coher ence peaks for the periods of about 4~6 d,which occurs in the weather process,and 2~3 d and the diurnal and semidiurnal peaks and so on between the two time series of currents at 500 and 800 m depths.However,the phase difference of current fluctuations between two time series at 500 and 800 m levels have the time lags and forward phenomena for the above periods.
2005, 27(4): 10-18.
Abstract:
Tidal constituents,which are extracted from about 10-year TOPEX/Poseidon altimetry data along track points,are assimilated into an two-dimension non-linear tidal model with the adjoint assimilation method.Tidal constituents M2,S2,O1 and K1 are simulated in the Huanghai and Bohai Seas,then Co-tidal maps are obtained.The bias between calculations and observations are also provided and the results tell that calculations agree well with observations.Moreover,there are two experiments in this paper:one is tooptimize different coefficient,the other is to assimilate different data.The first experiment shows that it is better to optimize the open boundary conditions and the bottom friction coefficients at the same time than to optimize the open boundary conditions only.The second experiment shows that the results are better when assimilating the altimetry data and the tidal constants from tidal gauges simult aneously than assimilating anyone separately.The results also show that it is useful to simulate the tidal system in the Huanghai and Bohai Seas by assimilating T/Paltimetry data and tidal constants from tidal gauges with adjoint assimilation method.
Tidal constituents,which are extracted from about 10-year TOPEX/Poseidon altimetry data along track points,are assimilated into an two-dimension non-linear tidal model with the adjoint assimilation method.Tidal constituents M2,S2,O1 and K1 are simulated in the Huanghai and Bohai Seas,then Co-tidal maps are obtained.The bias between calculations and observations are also provided and the results tell that calculations agree well with observations.Moreover,there are two experiments in this paper:one is tooptimize different coefficient,the other is to assimilate different data.The first experiment shows that it is better to optimize the open boundary conditions and the bottom friction coefficients at the same time than to optimize the open boundary conditions only.The second experiment shows that the results are better when assimilating the altimetry data and the tidal constants from tidal gauges simult aneously than assimilating anyone separately.The results also show that it is useful to simulate the tidal system in the Huanghai and Bohai Seas by assimilating T/Paltimetry data and tidal constants from tidal gauges with adjoint assimilation method.
2005, 27(4): 19-30.
Abstract:
A new viscoelastic-plastic(VEP) constitutive model for seaice dynamics is developed based on continuum mechanics.This model consists of four components:Kelvin-Vogit viscoelastic model,Mohr-Coulomb yielding criterion,associated normality flow rule for plastic rheology,and hydrostatic pressure.The numerical simulations for ice motion in an idealized rectangular basin are carried out using smoothed particle hydrodynamics(SPH) method,and compared with the analytical solution as well as those based on the modified viscous plastic(VP) model and static ice jam theory.These simulations show that the new VEP model can simulate ice dynamics accurately.The new constitutive model is further applied to simulating ice dynamics of the Bohai Sea and compared with the traditional V P,and modified VP models.The results of VEP model are compared better with the satellite remote sensing images,and the simulating ice conditions in the JZ20-2 Oil Plat form area are more reaso nable.
A new viscoelastic-plastic(VEP) constitutive model for seaice dynamics is developed based on continuum mechanics.This model consists of four components:Kelvin-Vogit viscoelastic model,Mohr-Coulomb yielding criterion,associated normality flow rule for plastic rheology,and hydrostatic pressure.The numerical simulations for ice motion in an idealized rectangular basin are carried out using smoothed particle hydrodynamics(SPH) method,and compared with the analytical solution as well as those based on the modified viscous plastic(VP) model and static ice jam theory.These simulations show that the new VEP model can simulate ice dynamics accurately.The new constitutive model is further applied to simulating ice dynamics of the Bohai Sea and compared with the traditional V P,and modified VP models.The results of VEP model are compared better with the satellite remote sensing images,and the simulating ice conditions in the JZ20-2 Oil Plat form area are more reaso nable.
2005, 27(4): 31-37.
Abstract:
To get sea surface temperature by remote sensing has high real-timeliness,but the data quality varies with the at mospheric environment.To solve sea surface temperature by the assimilation technology has high local precision,but the coverage and real timeliness are poor.As the two technologies suit to different situations,it is proposed to apply the data fusing technology so that the two technologies can complement each other with their respective advantages,i.e.,can carry out consistence evaluation and weighted fusing calculation of the data points according to their respective advantages and limitations.While the precision is improved,the result's uncertainty is quantified and evaluated.The results of the sampling test taking the China's eastern sea area as an example show that the fusing method fits the complex environment better.
To get sea surface temperature by remote sensing has high real-timeliness,but the data quality varies with the at mospheric environment.To solve sea surface temperature by the assimilation technology has high local precision,but the coverage and real timeliness are poor.As the two technologies suit to different situations,it is proposed to apply the data fusing technology so that the two technologies can complement each other with their respective advantages,i.e.,can carry out consistence evaluation and weighted fusing calculation of the data points according to their respective advantages and limitations.While the precision is improved,the result's uncertainty is quantified and evaluated.The results of the sampling test taking the China's eastern sea area as an example show that the fusing method fits the complex environment better.
2005, 27(4): 38-44.
Abstract:
Inverse algorithms of ocean constituents for 4 bands HY-1/CCD imager were developed using in-situ data which acquired in the Huanghai Sea and the East China Sea in the spring time of 2003.There trieved ocean constituents include total suspended matter(TSM),suspended sediment(SS) and chlorophylla(Chl a) of surface water,broadband characterist ics of CCD baffled the inversion of colored dissolved organic matter(CDOM).In-situ remote sensing reflectance spectra were acquired using ASD spect roradiometer,standard fluorometric method was used for extracting Chl a concentration in-situ,and filt erpad samples were brought back to the laboratory for analysis of TSM and SS.For these constituents retrieval,correlation coefficient values are over 0.88 and average relative error values are under 40%.The error sensitivity of the inverse algorithms is also tested,it shows that the inverse algorithms of TSM,SS and Chl a concentration in the middle low turbid water can meet daily operation,but it needs furt her research for the retrieval algorithm of Chl a concentration in the high turbid water.
Inverse algorithms of ocean constituents for 4 bands HY-1/CCD imager were developed using in-situ data which acquired in the Huanghai Sea and the East China Sea in the spring time of 2003.There trieved ocean constituents include total suspended matter(TSM),suspended sediment(SS) and chlorophylla(Chl a) of surface water,broadband characterist ics of CCD baffled the inversion of colored dissolved organic matter(CDOM).In-situ remote sensing reflectance spectra were acquired using ASD spect roradiometer,standard fluorometric method was used for extracting Chl a concentration in-situ,and filt erpad samples were brought back to the laboratory for analysis of TSM and SS.For these constituents retrieval,correlation coefficient values are over 0.88 and average relative error values are under 40%.The error sensitivity of the inverse algorithms is also tested,it shows that the inverse algorithms of TSM,SS and Chl a concentration in the middle low turbid water can meet daily operation,but it needs furt her research for the retrieval algorithm of Chl a concentration in the high turbid water.
2005, 27(4): 45-52.
Abstract:
On the basis of the chlorophyll-a data remote sensed by SeaWiFS from October 1997 to September 2002,the spatial and temporal distributions of the monthly mean chlorophyll-a concentration in the South China Sea(SCS) are presented,and their results show that the chlorophyll-a concentrations are usually high in winter and low in spring in the mostareas of the SCS;the minimum monthly mean of chlorophyll-a concentration in the SCS generally appears in April or May,but their maximums in different areas appear in different months,that is,the maximum appears in December in the center of the sea basin,and in July along the coast area of Guangdong Province,and there are two peaks in August and Decem berre-spectively in the sout heast in shore area of Vietnam;it is special in the wester narea of the Luzon Strait that the maximum appears in December and the minimum in July.Spatially,the chlorophyll-a concentrations in in shore areas are higher than those in the central sea basin obviously,and higher in the wester nareas of the SCS than those in the eastern areas generally.The spat ial and temporal feat ures of the chloro phyl-l a concentration in the SCS can be affected by the variations of the circulation(such as upwelling),sea surface temperature and wind field,and related to the nutrient transport from land.
On the basis of the chlorophyll-a data remote sensed by SeaWiFS from October 1997 to September 2002,the spatial and temporal distributions of the monthly mean chlorophyll-a concentration in the South China Sea(SCS) are presented,and their results show that the chlorophyll-a concentrations are usually high in winter and low in spring in the mostareas of the SCS;the minimum monthly mean of chlorophyll-a concentration in the SCS generally appears in April or May,but their maximums in different areas appear in different months,that is,the maximum appears in December in the center of the sea basin,and in July along the coast area of Guangdong Province,and there are two peaks in August and Decem berre-spectively in the sout heast in shore area of Vietnam;it is special in the wester narea of the Luzon Strait that the maximum appears in December and the minimum in July.Spatially,the chlorophyll-a concentrations in in shore areas are higher than those in the central sea basin obviously,and higher in the wester nareas of the SCS than those in the eastern areas generally.The spat ial and temporal feat ures of the chloro phyl-l a concentration in the SCS can be affected by the variations of the circulation(such as upwelling),sea surface temperature and wind field,and related to the nutrient transport from land.
2005, 27(4): 53-58.
Abstract:
During the cruise of Nansha Islands sea areas investigation in 2002,three sediments cores were obtained using gravity box method,then barium,titanium,REE and other trace elements in these samples were examined on ICPMS,at the same time the sedimentage was measured with AMS-14Corc(organic carbon) method.The distribution characteristics of barium and titanium both in plane and vertical direction were studied.It is found that biobarium variation at NS02-21 and NS02-50 is obvious,begining to increase at about 2 800 a BP.However,the situation is fairly complex and no obvious trend is found at another site(NS02-1),combining with related REE data and other trace element tracers,may be due to its high contents of terrigenous substance in this core.The paleoproductivity using bariumas a reconstructing proxy was calculated adapting Francois model subsequently.The paleoproductivity(export productivity) at Site NS02-21 is 0.78~2.41 g/(cm2·a),the average value is 1.06 g/(cm2·a).The paleoproductivity at NS02-50 site is 3.72~4.57 g/(cm2·a),the average value is 4.13 g/(cm2·a).Lots of researches have indicated that the variations of paleopro ductivity in Nansha Islands sea area are mainly caused by variation of paleo monso on and sea level.Here the paleo productivity records at Sites NS02-21 and NS02-50 mainly reflect the paleo ecological environment variation since Mid Holocene.During that period there was an obvious cold period between 4 000 a BP and 2 000 a BP according to related resear chresults,and the winter trade wind streng thened at that time.The increasing of paleoproductivity in these two sam pling sites mainly corresponds to the cold period in the late Holocene.
During the cruise of Nansha Islands sea areas investigation in 2002,three sediments cores were obtained using gravity box method,then barium,titanium,REE and other trace elements in these samples were examined on ICPMS,at the same time the sedimentage was measured with AMS-14Corc(organic carbon) method.The distribution characteristics of barium and titanium both in plane and vertical direction were studied.It is found that biobarium variation at NS02-21 and NS02-50 is obvious,begining to increase at about 2 800 a BP.However,the situation is fairly complex and no obvious trend is found at another site(NS02-1),combining with related REE data and other trace element tracers,may be due to its high contents of terrigenous substance in this core.The paleoproductivity using bariumas a reconstructing proxy was calculated adapting Francois model subsequently.The paleoproductivity(export productivity) at Site NS02-21 is 0.78~2.41 g/(cm2·a),the average value is 1.06 g/(cm2·a).The paleoproductivity at NS02-50 site is 3.72~4.57 g/(cm2·a),the average value is 4.13 g/(cm2·a).Lots of researches have indicated that the variations of paleopro ductivity in Nansha Islands sea area are mainly caused by variation of paleo monso on and sea level.Here the paleo productivity records at Sites NS02-21 and NS02-50 mainly reflect the paleo ecological environment variation since Mid Holocene.During that period there was an obvious cold period between 4 000 a BP and 2 000 a BP according to related resear chresults,and the winter trade wind streng thened at that time.The increasing of paleoproductivity in these two sam pling sites mainly corresponds to the cold period in the late Holocene.
2005, 27(4): 59-67.
Abstract:
Concentration and composition feature of n-alkanes in modern sediments from the Chang jiang Estuary and adjacent area are reported.Factor statistical analysis method is used to study the source of n-alkanes.The result shows that n-alkanes distribution patterns are charact erized by three modes:the beside peak mode which indicates abundant of terrest rial plant origin,dual peaks mode indicating both terrestrial plant and marine biological input and petroleum contamination mode.The chromatogram proxies mutation of n-alkanes in border the stations of at Changjiang Estuary is the objective reflection of sediment diversity resulting from two types of different water masses.Relationship between E n-Alk and TOC retains a postcor relation at all stations except P4,and TER-Alk,PL-1 and CPI are all highly correlated to the distance at the ZJ section.Factor statistical analysis reveals 4 types of input,among those the contribution of ter restrial plantinput is the largest one(51.5%),and among the terrestrial plantinputs the contribution of the Changjiang River discharge is the largest one(49.1%).In terms of diversity of factor load,it is supposed that the sedimentaryorganic matter in the area of middle-northern East China Sea is mostly trans-ported from North Jiangsu Province Coast and the old Huanghe River subaqueus delta,but a majority of sedimentary organic matter in Okinawa Trough may be come from Changjiang River and the inner shelf of East China Sea,and then its migration mechanism is discussed.
Concentration and composition feature of n-alkanes in modern sediments from the Chang jiang Estuary and adjacent area are reported.Factor statistical analysis method is used to study the source of n-alkanes.The result shows that n-alkanes distribution patterns are charact erized by three modes:the beside peak mode which indicates abundant of terrest rial plant origin,dual peaks mode indicating both terrestrial plant and marine biological input and petroleum contamination mode.The chromatogram proxies mutation of n-alkanes in border the stations of at Changjiang Estuary is the objective reflection of sediment diversity resulting from two types of different water masses.Relationship between E n-Alk and TOC retains a postcor relation at all stations except P4,and TER-Alk,PL-1 and CPI are all highly correlated to the distance at the ZJ section.Factor statistical analysis reveals 4 types of input,among those the contribution of ter restrial plantinput is the largest one(51.5%),and among the terrestrial plantinputs the contribution of the Changjiang River discharge is the largest one(49.1%).In terms of diversity of factor load,it is supposed that the sedimentaryorganic matter in the area of middle-northern East China Sea is mostly trans-ported from North Jiangsu Province Coast and the old Huanghe River subaqueus delta,but a majority of sedimentary organic matter in Okinawa Trough may be come from Changjiang River and the inner shelf of East China Sea,and then its migration mechanism is discussed.
MnO2 precipitation and direct beta counting technique for determining 234Th in small-volume seawater
2005, 27(4): 68-75.
Abstract:
A method for 234Th deter mination in small-volume seawater was established by using the alpha/bet a counter with scintillating solid detectors.This method is based on the coprecipitation of thorium with Mn oxides followed by direct beta counting of the precipitation.A series of experiments were conducted in order to examine the blank,chemical yield,detector efficiency of the procedure.Besides,the effect of the amount of MnO2 precipitation on total yields was tested.Hal-flife determination was used to verify the reliability of the method.The results show that this procedure has stable blanks and total yields,high detector efficiencies and chemical yields.The half-life of the measuring nuclide is consistent with that of 234Th.This technique has been used to measure 234Th in surface seawater samples from the subtropical North Pacific.Comparing with previous classic methods,this new technique has the advantage of minimal sample volume,easier processing prior to beta counting,and suitable for ship-board analysis.By using this method for 234Th determination,much higher spatial and temporal resolution data can be obtained,and knowledge of POC export in the ocean may greatly be increased.
A method for 234Th deter mination in small-volume seawater was established by using the alpha/bet a counter with scintillating solid detectors.This method is based on the coprecipitation of thorium with Mn oxides followed by direct beta counting of the precipitation.A series of experiments were conducted in order to examine the blank,chemical yield,detector efficiency of the procedure.Besides,the effect of the amount of MnO2 precipitation on total yields was tested.Hal-flife determination was used to verify the reliability of the method.The results show that this procedure has stable blanks and total yields,high detector efficiencies and chemical yields.The half-life of the measuring nuclide is consistent with that of 234Th.This technique has been used to measure 234Th in surface seawater samples from the subtropical North Pacific.Comparing with previous classic methods,this new technique has the advantage of minimal sample volume,easier processing prior to beta counting,and suitable for ship-board analysis.By using this method for 234Th determination,much higher spatial and temporal resolution data can be obtained,and knowledge of POC export in the ocean may greatly be increased.
2005, 27(4): 76-81.
Abstract:
In recenty ears,along with the reduction of the silt and sand transported by the rivers to the sea, the erosion to the bank of the China's coastturns to be worse and worse.So it is important and urgent and of realistic significance to study the rule of shoal evolution and thus to establish a reasonable and feasible forecasting model.A for ecasting model suitable to the evolution of tide-type coast beach is established by applying Professor U da's theory of equal-depth-line forecasting model.A key point in establishing the model is to find a reasonable solution in calculating the quantity of near-bank silt and sand along the equal-depth-line.The concept of the distribution of wave-breaking time in intertidal zones is introdued and thus the quantity of sand transpo rtation in the intertidal zones in the half-tide period is put forward as well as its distribution along the profile of shoal.Aforecasting calculation of the bank in South Shandong Province is made by using the model and its result is verified.It shows that the result is reasonable and basically reflects the characteristics of the evolution of that section of shoal.
In recenty ears,along with the reduction of the silt and sand transported by the rivers to the sea, the erosion to the bank of the China's coastturns to be worse and worse.So it is important and urgent and of realistic significance to study the rule of shoal evolution and thus to establish a reasonable and feasible forecasting model.A for ecasting model suitable to the evolution of tide-type coast beach is established by applying Professor U da's theory of equal-depth-line forecasting model.A key point in establishing the model is to find a reasonable solution in calculating the quantity of near-bank silt and sand along the equal-depth-line.The concept of the distribution of wave-breaking time in intertidal zones is introdued and thus the quantity of sand transpo rtation in the intertidal zones in the half-tide period is put forward as well as its distribution along the profile of shoal.Aforecasting calculation of the bank in South Shandong Province is made by using the model and its result is verified.It shows that the result is reasonable and basically reflects the characteristics of the evolution of that section of shoal.
2005, 27(4): 82-87.
Abstract:
Six palynolo gical assemblages were disting uished through an intensive study on pollen and spores from Cores G2 and XT2 at the frontedge of the Changjiang River Delta.Combined with the data from other cores nearby,six stages about the evolution of vegetation and climate were reconst ructed for the Late Quaternary on this area as follows:mixed sparse forest of conifers and deciduous broad-leave trees,reflecting a cold and dryclimate(Late Pleist ocene);mixed forest of conifers and broad-leave tree-sgrassland,reflecting a temperate and little moist climate(sub-arctic period);mixed forest of conifers and broad-leave trees with a fewevergreen broad-leave trees,reflecting a temperate and slightly dryclimate(the boreal period);evergreen broad-leave forest being mainly composed of Castanopsis and Quercus(evergreen),indicating a hot and moist climate(the Atlantic period);mixed forest of conifers and broad-leave trees,indicated by Quercus,Pinus and Artemisi a as main elementin palynological assem blages,reflecting a warm and little dryclimate(the sub-boreal period);mixed forest of deciduous broad-leaves,evergreen broad-leaves and conifers,Quercus(deciduous,evergreen) and pines,being the main components,reflecting a warm and wet climate(the sub-Atlantic period).These fluctuations coincide with the global climatic changes.The present study provides reliable evidence for biostratig raphy and reconstructions of paleo vegetaton,paleoclimate and paleoenvironment in this area from the Late Quaternary on.
Six palynolo gical assemblages were disting uished through an intensive study on pollen and spores from Cores G2 and XT2 at the frontedge of the Changjiang River Delta.Combined with the data from other cores nearby,six stages about the evolution of vegetation and climate were reconst ructed for the Late Quaternary on this area as follows:mixed sparse forest of conifers and deciduous broad-leave trees,reflecting a cold and dryclimate(Late Pleist ocene);mixed forest of conifers and broad-leave tree-sgrassland,reflecting a temperate and little moist climate(sub-arctic period);mixed forest of conifers and broad-leave trees with a fewevergreen broad-leave trees,reflecting a temperate and slightly dryclimate(the boreal period);evergreen broad-leave forest being mainly composed of Castanopsis and Quercus(evergreen),indicating a hot and moist climate(the Atlantic period);mixed forest of conifers and broad-leave trees,indicated by Quercus,Pinus and Artemisi a as main elementin palynological assem blages,reflecting a warm and little dryclimate(the sub-boreal period);mixed forest of deciduous broad-leaves,evergreen broad-leaves and conifers,Quercus(deciduous,evergreen) and pines,being the main components,reflecting a warm and wet climate(the sub-Atlantic period).These fluctuations coincide with the global climatic changes.The present study provides reliable evidence for biostratig raphy and reconstructions of paleo vegetaton,paleoclimate and paleoenvironment in this area from the Late Quaternary on.
2005, 27(4): 88-94.
Abstract:
The error of marginal beams mainly influences the quality of multi beam sounding data.The precision of multi-beam sounding data influences their reliability and application,and it is the base of correlative study.The key control factors of marginal beams quality are accurate multi-beam sonar parameters, accurate sound profiles and sounding noises compilation.If inaccurate multi-beam sonar parameters or inaccurate sound profiles are used in flatarea during the multi beam survey,unreality submarine topography will be got such as belt along the survey line.It is difficult to improve the quality of multi-beam sounding data using single method during post processing,because the error of multi-beam sounding is caused by different factors.On the basis of multi-beam survey principles and the acoustics theory,the multi-beam sounding error data have been researched and processed,the soft ware of man machine conversation to process the multi-beam error sounding data has been designed and estahlished with oriented object method of GIS at last.The study result has been used in to pographic mapping of marin project.
The error of marginal beams mainly influences the quality of multi beam sounding data.The precision of multi-beam sounding data influences their reliability and application,and it is the base of correlative study.The key control factors of marginal beams quality are accurate multi-beam sonar parameters, accurate sound profiles and sounding noises compilation.If inaccurate multi-beam sonar parameters or inaccurate sound profiles are used in flatarea during the multi beam survey,unreality submarine topography will be got such as belt along the survey line.It is difficult to improve the quality of multi-beam sounding data using single method during post processing,because the error of multi-beam sounding is caused by different factors.On the basis of multi-beam survey principles and the acoustics theory,the multi-beam sounding error data have been researched and processed,the soft ware of man machine conversation to process the multi-beam error sounding data has been designed and estahlished with oriented object method of GIS at last.The study result has been used in to pographic mapping of marin project.
2005, 27(4): 95-101.
Abstract:
The rapid siltation of deep trough means the suspended sediment sinking very fast to the bottom of the trough within a quite limited period,and it makes up of fluid mud layer.A comprehensive analysis is done based on the data of duplicate measurement of seabed profile depth,topogr aphy,hydrology and suspended sediment in the Hangzhou,Sanmen and Xiangshan Bays.The results show that rapid accumulation happens under three conditions:(1) fine sediment is very abundant;(2) hydrology diminishes quickly;and(3) there exists a obviously concave landform.These three factors must be satisfied at the same time, other wise the rapid siltation cannotoccur at the deep trough.Since the Hangzhou Bay is full of fine sediment,the suspended sediment concentration is high all the year and it is influenced by the secondary Changjiang plume front and the Qiantang plume front at the east trial dredged trough,the rapid deposition can be measured when the hydrology turns weak from spring to neap tidal period.The suspended sediment is plenty comparatively in the Sanmen Bay,the seabed of tidal flat is kept stable with a little siltation and the trough is nearly in the equilibrium of erosion and siltation wit hina normal year.Only when the storm hits the bay and the following day sare between middle and neaptidal period after the storm past,a large number of suspended sedimenter odedobvio usly from tidal flat will sink quickly to the deep trough.However,the Xiangshan Bay is sheltered with hills around the bay and islands in bay mouth,the water is very limpid and the suspended sediment is quite little,so the rapid accumulation cannot be happened in the innerbay trough even with the impact of storm.
The rapid siltation of deep trough means the suspended sediment sinking very fast to the bottom of the trough within a quite limited period,and it makes up of fluid mud layer.A comprehensive analysis is done based on the data of duplicate measurement of seabed profile depth,topogr aphy,hydrology and suspended sediment in the Hangzhou,Sanmen and Xiangshan Bays.The results show that rapid accumulation happens under three conditions:(1) fine sediment is very abundant;(2) hydrology diminishes quickly;and(3) there exists a obviously concave landform.These three factors must be satisfied at the same time, other wise the rapid siltation cannotoccur at the deep trough.Since the Hangzhou Bay is full of fine sediment,the suspended sediment concentration is high all the year and it is influenced by the secondary Changjiang plume front and the Qiantang plume front at the east trial dredged trough,the rapid deposition can be measured when the hydrology turns weak from spring to neap tidal period.The suspended sediment is plenty comparatively in the Sanmen Bay,the seabed of tidal flat is kept stable with a little siltation and the trough is nearly in the equilibrium of erosion and siltation wit hina normal year.Only when the storm hits the bay and the following day sare between middle and neaptidal period after the storm past,a large number of suspended sedimenter odedobvio usly from tidal flat will sink quickly to the deep trough.However,the Xiangshan Bay is sheltered with hills around the bay and islands in bay mouth,the water is very limpid and the suspended sediment is quite little,so the rapid accumulation cannot be happened in the innerbay trough even with the impact of storm.
2005, 27(4): 102-107.
Abstract:
The reproductive season,embryo development and larval culture of amphioxus in the National Natural Protective Area of Xiamen were studied in detail by the methods of histology and embryology.The results indicate that the reproductive season of amphioxus in the National Natural Protective Area of Xiamen maybe divided into two breeding stages.One is the breeding peak stage which starts from June to the end of July,and another is small breeding stage which is in August and September.The observation on the artificial breeding suggests that amphioxus spawned initially at about 07:00 PM,and the spawning and spermiation behaviours in female and male amphioxus could be seen.The male amphioxus left firstly the sand,rushed up to the water surface,and swam as well as released sperms.Then,the fmale swam to the water surface,and all eggs passed out from broken wall of ovary into the at rial cavity and through the atriopore to the water.The fertility rate is about 98.5%.At the same time,the whole process of the development from larvae to young fish is observed with metamorphosis(length:1.05~13.50 mm).
The reproductive season,embryo development and larval culture of amphioxus in the National Natural Protective Area of Xiamen were studied in detail by the methods of histology and embryology.The results indicate that the reproductive season of amphioxus in the National Natural Protective Area of Xiamen maybe divided into two breeding stages.One is the breeding peak stage which starts from June to the end of July,and another is small breeding stage which is in August and September.The observation on the artificial breeding suggests that amphioxus spawned initially at about 07:00 PM,and the spawning and spermiation behaviours in female and male amphioxus could be seen.The male amphioxus left firstly the sand,rushed up to the water surface,and swam as well as released sperms.Then,the fmale swam to the water surface,and all eggs passed out from broken wall of ovary into the at rial cavity and through the atriopore to the water.The fertility rate is about 98.5%.At the same time,the whole process of the development from larvae to young fish is observed with metamorphosis(length:1.05~13.50 mm).
2005, 27(4): 108-113.
Abstract:
Seasonal investigations were carried out on a fish net-cage cultural area and a contrasting area.41 species from study areas were identified.39 species were collected from the cultural area and 9 species from the contrasting area.No any macrobenthos species was found in the center of fish net-cage cultural area.The average biomass and density in the net-cage cultural area are 91.92 g/m2 and 115 ind/m2,higher than those in the contrasting area(10.61 g/m2 and 48 ind/m2).They are change obviously with the variety of season.Community structure in the net-cage cultural area is more complex than the contrasting area.Main environment factors in the net-cage cultural area such as sulfide and organic compound are higher than the contrasting area.Relationship of macrobent hos and environment factors is discussed.There was not any macrobenthos in the center of fish net-cage cultural area in which the sediment was piled up at the rate of 25 cm/a.
Seasonal investigations were carried out on a fish net-cage cultural area and a contrasting area.41 species from study areas were identified.39 species were collected from the cultural area and 9 species from the contrasting area.No any macrobenthos species was found in the center of fish net-cage cultural area.The average biomass and density in the net-cage cultural area are 91.92 g/m2 and 115 ind/m2,higher than those in the contrasting area(10.61 g/m2 and 48 ind/m2).They are change obviously with the variety of season.Community structure in the net-cage cultural area is more complex than the contrasting area.Main environment factors in the net-cage cultural area such as sulfide and organic compound are higher than the contrasting area.Relationship of macrobent hos and environment factors is discussed.There was not any macrobenthos in the center of fish net-cage cultural area in which the sediment was piled up at the rate of 25 cm/a.
2005, 27(4): 114-120.
Abstract:
By enriching with diesel fUel as a sole carbon source,two microbial consortia were obtained from different marine environment samples:one,colleted from the Huanghe Dock of Shengli Oil Field,and the other,from the Oil storage Dock Xiamen.Nine bacteria and one fungus were screened out from the two samples.All of the isolates show considerable biodeg radability to diesel fuelex cept for M-5,while it shows degradability to several kinds of PAHs.Sequence analysis of 16S rDNA identifies that the 9 bacteria belong to Bacillus cereus,Pseudomonas stutzeri,Staphylococcus arlettae,Alcanivorax sp.,Alcaligenes denitrificans and alpha proteobacterium(iso late M-5),respectively.A mong them,each of isolates B-5 and M-5 belongs to a novel species.Two alkane monoxyg enase fragments ware amplified from isolate B-5 and Pseudomonas stutzeri M-2.And the fragmentret rieved from isolate B-5 seems to encode a partial novel alkane monoxyg enase.
By enriching with diesel fUel as a sole carbon source,two microbial consortia were obtained from different marine environment samples:one,colleted from the Huanghe Dock of Shengli Oil Field,and the other,from the Oil storage Dock Xiamen.Nine bacteria and one fungus were screened out from the two samples.All of the isolates show considerable biodeg radability to diesel fuelex cept for M-5,while it shows degradability to several kinds of PAHs.Sequence analysis of 16S rDNA identifies that the 9 bacteria belong to Bacillus cereus,Pseudomonas stutzeri,Staphylococcus arlettae,Alcanivorax sp.,Alcaligenes denitrificans and alpha proteobacterium(iso late M-5),respectively.A mong them,each of isolates B-5 and M-5 belongs to a novel species.Two alkane monoxyg enase fragments ware amplified from isolate B-5 and Pseudomonas stutzeri M-2.And the fragmentret rieved from isolate B-5 seems to encode a partial novel alkane monoxyg enase.
2005, 27(4): 121-126.
Abstract:
There is an unknown microalga(ZM2020) which has been used widely and proved to be nutritious as feed.In order to evaluate its nutrition value based on fatty acids and sterols,the alga has been cultured in two modes as standing and air bubbling conditions,simultaneo us analysis of fatty acids and sterols has been carried out on agas chromatography mass spectrometer by applying a new step-wise derivetization method.The results indicate that the microalg a is abundant in EPA,C14:0,C16:0,C16:1,as well as some conceivable amount of DH A,C22:5(n-6) and C18 unsaturated fatty acids.Eleven C27 to C30 sterols have been identified with major ones including 24-methyl(ethyl)-cholesterol.The existence of unusual sterols of methylpavlovol and ethyl pavlovol has been observed unam biguously.Based on the composition analysis of fatty acids and sterols,this alga can be classified into Prymnesiophy ceae,Pavlovales,Pavlo vaceae.It is also demonstrated here that lipid analysis can be a useful tool for microalgal chemotaxonomy.
There is an unknown microalga(ZM2020) which has been used widely and proved to be nutritious as feed.In order to evaluate its nutrition value based on fatty acids and sterols,the alga has been cultured in two modes as standing and air bubbling conditions,simultaneo us analysis of fatty acids and sterols has been carried out on agas chromatography mass spectrometer by applying a new step-wise derivetization method.The results indicate that the microalg a is abundant in EPA,C14:0,C16:0,C16:1,as well as some conceivable amount of DH A,C22:5(n-6) and C18 unsaturated fatty acids.Eleven C27 to C30 sterols have been identified with major ones including 24-methyl(ethyl)-cholesterol.The existence of unusual sterols of methylpavlovol and ethyl pavlovol has been observed unam biguously.Based on the composition analysis of fatty acids and sterols,this alga can be classified into Prymnesiophy ceae,Pavlovales,Pavlo vaceae.It is also demonstrated here that lipid analysis can be a useful tool for microalgal chemotaxonomy.
2005, 27(4): 127-134.
Abstract:
The abundance,biomass and distribution characteristics of bacteria and protozoa and their ecological role in the planktonic community of the Bering Sea were investigated between 21 July and 1 August 1999.Bacterial carbon biomass in the surface waters ranges from 1.5 to 20.2 μg/dm3,which accounts for 30% of phytoplankton biomass on average.The biomass of bacteria integrated over the depth from 0 to 100 m of the water column varies from 720 to 3123 mg/m2 and accounts for 67% of the total phytoplankton biomass.The biomass of protozoa ranges from 1.2 to 27.4 μg/dm3 in the surface layers,and varies from 189 to 1698 mg/m2 in the upper 100 m of the water column,which constitutes 21% of integrated biomass of phytoplankton.The integrated biomass of protozoa in being less than 5 μm,5~20 μm and being greater than 20 μm size fractions accounts for 13%,47% and 40% of the total biomass,respectively.As a main protozoan assemblage,the integrated biomass of dinoflagellates constituts 39% of the total biomass of protozoa.The biomass of bacteria and protozoa decreases from western to north eastern and eastern regions of the Bering Sea,and the biomass of these organisms also decreases with depth.Such distribution characteristics might be influenced by both the therm ocline observed at a depth from 20 to 25 m and the water current existed in the surface layers in the investigation area.The great biomass of macrozooplankton in the investigation area suggests that it might be an important cause for the lower relative biomass of protozoa, which limits the role of the microbial loop in the Bering Sea in summer.
The abundance,biomass and distribution characteristics of bacteria and protozoa and their ecological role in the planktonic community of the Bering Sea were investigated between 21 July and 1 August 1999.Bacterial carbon biomass in the surface waters ranges from 1.5 to 20.2 μg/dm3,which accounts for 30% of phytoplankton biomass on average.The biomass of bacteria integrated over the depth from 0 to 100 m of the water column varies from 720 to 3123 mg/m2 and accounts for 67% of the total phytoplankton biomass.The biomass of protozoa ranges from 1.2 to 27.4 μg/dm3 in the surface layers,and varies from 189 to 1698 mg/m2 in the upper 100 m of the water column,which constitutes 21% of integrated biomass of phytoplankton.The integrated biomass of protozoa in being less than 5 μm,5~20 μm and being greater than 20 μm size fractions accounts for 13%,47% and 40% of the total biomass,respectively.As a main protozoan assemblage,the integrated biomass of dinoflagellates constituts 39% of the total biomass of protozoa.The biomass of bacteria and protozoa decreases from western to north eastern and eastern regions of the Bering Sea,and the biomass of these organisms also decreases with depth.Such distribution characteristics might be influenced by both the therm ocline observed at a depth from 20 to 25 m and the water current existed in the surface layers in the investigation area.The great biomass of macrozooplankton in the investigation area suggests that it might be an important cause for the lower relative biomass of protozoa, which limits the role of the microbial loop in the Bering Sea in summer.
2005, 27(4): 135-147.
Abstract:
The cell abundance,the composition of dominant species,size fractionated biomass and productivity of phytoplankton,new production,the environmentally rest ricted mechanism are studied in the Prydz Bay and the adjacent Indian sector of the Southern Ocean during the austral summer of 1998/1999.The results show that there is marked feature of spatial zonation in the sea areas investig ated.In the Prydz Bay and its adjacent continental shelf,the biomass and productivity of phytoplankton are high;those of continental slope and open ocean area are obviously low.The nut rient concent ration has opposite distribution trend,due to the consumption of phytoplankton.It is mainly affected by the vertical stability of water column,grazing pressure of zooplankton,temperature and light,etc.The results of size-fractionation show that the average contribution of netplankton to total chlorophyll a in the studiy sea areas is 52.2%,those of nano-and picoplankton are 29.4% and 18.4%,respectively.The average contribution of netplankton to total primary production is 52.4%,those of nano-and picoplankton are 28.7% and 18.9%,separately.It is the same as previous conclusion that the contribution of picoplankton to productivity is slightly larger than that to biomass of phytoplankton communities.The average new production and f-ratio are 230.6 mg/(m2·d) and 0.43,respectively.
The cell abundance,the composition of dominant species,size fractionated biomass and productivity of phytoplankton,new production,the environmentally rest ricted mechanism are studied in the Prydz Bay and the adjacent Indian sector of the Southern Ocean during the austral summer of 1998/1999.The results show that there is marked feature of spatial zonation in the sea areas investig ated.In the Prydz Bay and its adjacent continental shelf,the biomass and productivity of phytoplankton are high;those of continental slope and open ocean area are obviously low.The nut rient concent ration has opposite distribution trend,due to the consumption of phytoplankton.It is mainly affected by the vertical stability of water column,grazing pressure of zooplankton,temperature and light,etc.The results of size-fractionation show that the average contribution of netplankton to total chlorophyll a in the studiy sea areas is 52.2%,those of nano-and picoplankton are 29.4% and 18.4%,respectively.The average contribution of netplankton to total primary production is 52.4%,those of nano-and picoplankton are 28.7% and 18.9%,separately.It is the same as previous conclusion that the contribution of picoplankton to productivity is slightly larger than that to biomass of phytoplankton communities.The average new production and f-ratio are 230.6 mg/(m2·d) and 0.43,respectively.
2005, 27(4): 148-154.
Abstract:
On the basis of data of four seasonal investigations in the East China Sea(23°30'～33°00'N,118°30'～128°00'E) in 1997~2000,the distribution and the seasonal variation of Pteropods abundance and the environmental factors on Pteropods abundance as well as the regression contribution of the abundance of dominant species to total abundance were discussed through qualitative and quantitative methods.Results show a clear seasonal change of Pteropods abundance with the following order:autumn(108×10-2～500×10-2ind/m3) being greater than summer(33×10-2ind/m3) being greater than winter(28×10-2ind/m3) beingg reater than spring(10×10-2ind/m3).Pteropods were not observed in north shallow waters of the East China Sea(29°30'~33°N,123°30'~125°E) in winter and spring.The seasonal changes of Pteropods show that the Pteropods abundance in the south is higher than that in the north and that in the out shore higher than that in the off shore.On the basis of the analysis results of dominance and regression contribution,the Pteropods abundance distribution is decided mainly by the distribution of Creseis acicul a in spring,C.virgula in summer,Desmopterus papilio in autumn and Limacinat rochi formis in winter.The variation of Pteropods abundance shows a clear linear correlation with surface water temperature and 10 m water temperature but no significant correlation with bottom water temperature or salinity.In summer,the high-abundance distribution area of Pteropods is located in the place where the Taiwan Warm Currentorig inates from Kuroshio.In autumn,the distribution area with abundance higher than 250×10-2ind/m3 expands with the Taiwan Warm Current north ward within the mixing area where the Changjiang fresh water,the Zhejiang-Fujian coastal water and the cold water of Huanghai Sea meettogether.Water temperature and warm currents are the mostimportant environmental factors that influenced the changes of Ptero pods abundance in the East China Sea.
On the basis of data of four seasonal investigations in the East China Sea(23°30'～33°00'N,118°30'～128°00'E) in 1997~2000,the distribution and the seasonal variation of Pteropods abundance and the environmental factors on Pteropods abundance as well as the regression contribution of the abundance of dominant species to total abundance were discussed through qualitative and quantitative methods.Results show a clear seasonal change of Pteropods abundance with the following order:autumn(108×10-2～500×10-2ind/m3) being greater than summer(33×10-2ind/m3) being greater than winter(28×10-2ind/m3) beingg reater than spring(10×10-2ind/m3).Pteropods were not observed in north shallow waters of the East China Sea(29°30'~33°N,123°30'~125°E) in winter and spring.The seasonal changes of Pteropods show that the Pteropods abundance in the south is higher than that in the north and that in the out shore higher than that in the off shore.On the basis of the analysis results of dominance and regression contribution,the Pteropods abundance distribution is decided mainly by the distribution of Creseis acicul a in spring,C.virgula in summer,Desmopterus papilio in autumn and Limacinat rochi formis in winter.The variation of Pteropods abundance shows a clear linear correlation with surface water temperature and 10 m water temperature but no significant correlation with bottom water temperature or salinity.In summer,the high-abundance distribution area of Pteropods is located in the place where the Taiwan Warm Currentorig inates from Kuroshio.In autumn,the distribution area with abundance higher than 250×10-2ind/m3 expands with the Taiwan Warm Current north ward within the mixing area where the Changjiang fresh water,the Zhejiang-Fujian coastal water and the cold water of Huanghai Sea meettogether.Water temperature and warm currents are the mostimportant environmental factors that influenced the changes of Ptero pods abundance in the East China Sea.
2005, 27(4): 155-160.
Abstract:
A two-dimensional bottom jet discharged into a cross-flow is simulated by the standard two-equation k-ε model with VOF method.By comparing with experimental results,it is shown that the recirculation zones calculated using the model generally agree with the experimental results.Velocity and concentration's trajectories are expressed by simple form ulas and compared with experimental results.Some conclusions are also draw by analyzing the velocity and concentration distributions.
A two-dimensional bottom jet discharged into a cross-flow is simulated by the standard two-equation k-ε model with VOF method.By comparing with experimental results,it is shown that the recirculation zones calculated using the model generally agree with the experimental results.Velocity and concentration's trajectories are expressed by simple form ulas and compared with experimental results.Some conclusions are also draw by analyzing the velocity and concentration distributions.
2005, 27(4): 161-166.
Abstract:
2005, 27(4): 167-173.
Abstract:
2005, 27(4): 174-180.
Abstract:
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