The estuarine areas are under frequent influence from freshwater intrusion and ocean currents,in which zooplankton species are diversified and variable as they are sensitive to physio-chemical variations in water.Ther...The estuarine areas are under frequent influence from freshwater intrusion and ocean currents,in which zooplankton species are diversified and variable as they are sensitive to physio-chemical variations in water.Therefore,understanding the relationships between zooplankton and environmental factors help us know the water quality.To achieve co-existence with species in similar ecological group or habit,they could inevitably alter themselves to fit the ecology and adjust the function according to the competitive exclusion in ecological theory.However,information of the co-existence of dominant species in the Changjiang(Yangtze)River estuary(CRE)and adjacent waters remains scarce.We explored the relationships between dominant zooplankton and environmental factors in the study region in spring-summer from 2016 to 2020,involving particularly the composition of dominant species,ecological groups,their relationships with environmental factors,and co-existence of important species,using the non-multidimensional scale analysis(nMDS)method and redundancy analysis.Results show that Labidocera euchaeta and Tortanus vermiculus were dominant species in the study scope.The turnover rate of dominant zooplankton was greater(>50%)in spring while the species number was higher in summer.The dominant species were estuarine,offshore,and eurytopic based on the adaptation to salinity.In spring,the ecological groups were dominated by estuarine species,while in summer by estuarine and offshore species.In addition,the nMDS showed that the dominant species in the same ecological group were more dispersed and not prominently clustered;the dominant species were staggered among different ecological groups.The temperature,salinity,pH,dissolved oxygen,and chlorophyll a were the main environmental factors on the distribution of the dominant species in spring,while in summer were dissolved oxygen,temperature,salinity,and pH.The domination of medusae of Nemopsis bachei and Pleurobrachia globosa in zooplankton community in spring,and the continuous decrease in abundance of L.euchaeta reflected the effects of local climate change.The temperature and salinity changes in different years and the subsequent response of zooplankton reflected the influence of freshwater intrusion and/or ocean currents.Zooplankton in similar ecological habits exhibited the competitive exclusion in terms of co-existence.展开更多
This paper describes a dual-stroke acting hydraulic power take-off(PTO)system employed in the wave energy converter(WEC)with an inverse pendulum.The hydraulic PTO converts slow irregular reciprocating wave motions to ...This paper describes a dual-stroke acting hydraulic power take-off(PTO)system employed in the wave energy converter(WEC)with an inverse pendulum.The hydraulic PTO converts slow irregular reciprocating wave motions to relatively smooth,fast rotation of an electrical generator.The design of the hydraulic PTO system and its control are critical to maximize the generated power.A time domain simulation study and the laboratory experiment of the full-scale beach test are presented.The results of the simulation and laboratory experiments including their comparison at full-scale are also presented,which have validated the rationality of the design and the reliability of some key components of the prototype of the WEC with an inverse pendulum with the dual-stroke acting hydraulic PTO system.展开更多
Factorial kriging analysis is applied to the research on the spatial multiscale variability of heavy metals in submarine. It is used to analyze the multiscale spatial structures of seven heavy metals, Ni, Cu, Zn, Pb, ...Factorial kriging analysis is applied to the research on the spatial multiscale variability of heavy metals in submarine. It is used to analyze the multiscale spatial structures of seven heavy metals, Ni, Cu, Zn, Pb, Cr, As and Cd in the surface sediment from the northeastern of Beibu Gulf, identify and separate spatial variations at different scales of heavy metals, and discuss the provenance of heavy metals and the influencing factors. The results show that the existence of three-scale spatial variations those consist of nugget effect, a spherical structure with range of 30 km(short-range scale) and a spherical structure with range of 140 km(long-range scale) in the linear model of coregionalization fitted. The spatial distribution features of seven heavy metals at short-range scale reflect "spot-like" or "stripe-like" local-scale spatial variations; the spatial distribution features of the seven heavy metals at long-range scale represent "slice-like" regional-scale spatial variations. At local scale, Zn, Cr, Ni,Cu, Pb and Cd are derived primarily from parent materials of Hainan Island, Leizhou Peninsula and Guangxi land, whose spatial distribution characteristics are controlled by granularity of sediments, while As is influenced dominantly by human pollution components from Hainan Island and Leizhou Peninsula. At regional scale, Zn,Cr, Ni and Cu originate primarily from parent rock materials of Leizhou Peninsula and Hainan Island, secondly from Guangxi land; As originated primarily from parent rock materials from Hainan Island, secondly from Leizhou Peninsula and Guangxi land. These metals are transported and migrated with sediments dominated by the anticlockwise circulation of Beibu Gulf year-round, deposited in "convergence center", forming the whole sedimentary pattern in direction of NWW-NNW at regional scale. The difference in distribution type between As and other metals at regional scale is mainly due to their different geochemical behavior.展开更多
The vortex-induced vibration of two identical rigidly mounted risers in a parallel arrangement was studied using Ansys-CFX and model tests.The vortex shedding and force were recorded to determine the effect of spacing...The vortex-induced vibration of two identical rigidly mounted risers in a parallel arrangement was studied using Ansys-CFX and model tests.The vortex shedding and force were recorded to determine the effect of spacing on the two-degree-of-freedom oscillation of the risers.CFX was used to study the single riser and two parallel risers in 2–8D spacing considering the coupling effect.Because of the limited width of water channel,only three different riser spacings,2D,3D,and 4D,were tested to validate the characteristics of the two parallel risers by comparing to the numerical simulation.The results indicate that the lift force changes significantly with the increase in spacing,and in the case of 3D spacing,the lift force of the two parallel risers reaches the maximum.The vortex shedding of the risers in 3D spacing shows that a variable velocity field with the same frequency as the vortex shedding is generated in the overlapped area,thus equalizing the period of drag force to that of lift force.It can be concluded that the interaction between the two parallel risers is significant when the risers are brought to a small distance between them because the trajectory of riser changes from oval to curve 8 as the spacing is increased.The phase difference of lift force between the two risers is also different as the spacing changes.展开更多
Based on the monitoring results of environmental quality in the sea area near the Aojiang estuary in Wenzou during 2010-2012,the present situation of environmental quality in the sea area was analyzed and evaluated. T...Based on the monitoring results of environmental quality in the sea area near the Aojiang estuary in Wenzou during 2010-2012,the present situation of environmental quality in the sea area was analyzed and evaluated. The results show that p H,DO,CODMn,petroleum,and heavy metals( Cu,Pb,Zn,Cd,Hg,As and Cr) in the sea area near the Aojiang estuary did not exceed the second-class standard of Seawater Quality Standard( GB 3097-1997),but both inorganic nitrogen and reactive phosphate in the sea area exceeded the second-class standard seriously,and the water quality of the sea area was in an eutrophic state; domestic sewage and fertilizer loss were the main sources of nitrogen and phosphorus. The standard index of most evaluation factors of sediment quality except for Zn was smaller than 1,meeting the demands of sediment quality for environmental protection.展开更多
By using internal standard method based on gas chromatography-electron capture detector( GC-ECD),the contents of persistent organochlorine pollutants polychorinated biphenyls( PCBs) and organochlorine pesticides( OCPs...By using internal standard method based on gas chromatography-electron capture detector( GC-ECD),the contents of persistent organochlorine pollutants polychorinated biphenyls( PCBs) and organochlorine pesticides( OCPs) in eggs of seabirds( Catharacta lonnbergi,Catharacta maccormicki,Pygoscelis papua and Macronectes giganteus) breeding on King George Island,Antarctica were detected,and their ecological environment significance was discussed. The results showed that the recovery of various compounds ranged from 68. 6% to 90. 8%; relative standard deviation( RSD) was 3. 6%,and the lowest detection limits of PCBs and OCPs were 0. 8- 16 and 2- 12 pg respectively,which could meet the demands for the residue analysis of trace persistent organochlorine pollutants in the eggs of Antarctic seabirds. The contents of PCBs,DDTs,HCB and HCHs in the eggs of Antarctic seabirds were 0. 5- 515. 5,2. 0- 304. 4,0. 5- 70. 5,and 0. 5- 2. 0 ng / g respectively. In addition,the accumulation of PCBs and OCPs in the skuas was enhanced gradually through the food chain. The maximums of persistent organochlorine pollutants appeared in the eggs of C. lonnbergi,followed by the eggs of C. maccomicki. The detection of OCPs and PCBs in the eggs of Antarctic seabirds was not interfered by other compounds containing chlorine,showing that the extraction,purification and detection method was suitable for the analysis of OCPs and PCBs in the eggs of Antarctic seabirds and has high sensitivity and reliability.展开更多
Based on the monitoring results of environmental quality in Yueqing Bay during 2007-2014,the current situation of environmental quality in the bay was analyzed and assessed. The results show that pH,DO,CODMn,petroleum...Based on the monitoring results of environmental quality in Yueqing Bay during 2007-2014,the current situation of environmental quality in the bay was analyzed and assessed. The results show that pH,DO,CODMn,petroleum,and heavy metals( Cu,Pb,Zn,Cd,Hg,As and Cr)in the seawater of Yueqing Bay did not exceed the second class standard of Seawater Quality Standard( GB 3097-1997),but inorganic nitrogen and reactive phosphate in the seawater of Yueqing Bay exceeded the second class standard seriously,and the water quality of the bay was in an eutrophic state; the standard index of evaluation factors of sediment quality was smaller than 1,meeting the demands of sediment quality for environmental protection.展开更多
Combined conductivity-temperature-depth(CTD) casts and Argo profiles, 3 086 historical hydrocasts were used to quantify the water column characteristics in the northern South China Sea(SCS) and its adjacent waters. Ba...Combined conductivity-temperature-depth(CTD) casts and Argo profiles, 3 086 historical hydrocasts were used to quantify the water column characteristics in the northern South China Sea(SCS) and its adjacent waters. Based on a two-dimensional "gravest empirical mode"(GEM), a gravitational potential(, a vertically integrated variable) was used as proxy for the vertical temperature profiles TG(p,). integrated from 8 MPa to the surface shows a close relationship with the temperature, except in the deep layer greater than 15 MPa, which was caused by the bimodal deep water in the region. The GEM temperature profiles successfully revealed the bimodality of the Luzon Strait deep water, that disparate hydrophic vertical profiles can produce distinct specific volume anomaly() in the SCS and the western Philippine Sea(WPS), but failed in the Luzon Strait, where different temperature profiles may produce a same. A significant temperature divergence between the SCS water and the WPS water confirmed that the bimodal structure is strong. The deepwater bifurcation starts at about 15 MPa, and gets stronger with increasing depth. As the only deep channel connecting the bimodal-structure waters, water column characteristics in the Luzon Strait is in between, but much closer to the SCS water because of its better connectivity with the SCS. A bimodal temperature structure below 15 MPa reveals that there was a persistent baroclinic pressure gradient driving flow through the Luzon Strait. A volume flux predicted through the Bashi Channel with the hydraulic theory yields a value of 5.62×106 m3/s using all available profiles upstream and downstream of the overflow region, and 4.03×106and 2.70×106 m3/s by exclusively using the profiles collected during spring and summer, respectively. No volume flux was calculated during autumn and winter because profiles are only available for the upstream of the Bashi Channel during the corresponding period.展开更多
Based on the monitoring results of environmental quality of the waters near the Feiyun River estuary during 2011-2016, the current situation of environmental quality of the waters was analyzed and evaluated. The resul...Based on the monitoring results of environmental quality of the waters near the Feiyun River estuary during 2011-2016, the current situation of environmental quality of the waters was analyzed and evaluated. The results showed that pH, DO, COD Mn , petroleum, and heavy metals (Cu, Pb, Zn, Cd, Hg, As and Cr) in the waters near the Feiyun River estuary did not exceed the second-class standard of Seawater Quality Standard (GB 3097-1997), while both inorganic nitrogen and reactive phosphate in the waters exceeded the second-class standard obviously. The water quality of the waters near the Feiyun River estuary was in an eutrophic state. In terms of sediment quality, the standard index of most evaluation factors except for Cu was smaller than 1, meeting the demands of sediment quality for environmental protection.展开更多
Metal pollution has become an major issue governing the wetland ecosystem health.The southern coastal wetland of the Qiangtang Estuary are facing unusual perturbation due to rapid development along the embayment in re...Metal pollution has become an major issue governing the wetland ecosystem health.The southern coastal wetland of the Qiangtang Estuary are facing unusual perturbation due to rapid development along the embayment in recent decades.This study evaluated the bioavailability of metals(Cu,Pb,Cd,Cr and Zn)in the sediment of the southern coastal wetland of the Qiangtang Es-tuary using diffusive gradients in thin films(DGT)techniques and compared with several methods based on total metal content.The results showed that the contents of Cr,Pb,Cd and Cu in sediment,as detected using DGT,were considerably correlated with the exchangeable fraction and the content in Phragmites australis roots,while a weak correlation was observed for Zn.Therefore,DGT analysis could be used to evaluate the bioavailability and potential risk of Cr,Cd,Pb and Cu for P.australis.Quantitative indices,such as DGT concentration,bioaccumulation in P.australis,geoaccumulation index(Igeo)and potential ecological risk index(RI),revealed that Cd was a major potential ecological risk factor along the southern coast wetland of the Qiantang Estuary,especially in the upstream region,which is potentially more vulnerable to the anthropogenic pollution.展开更多
Based on the monitoring results of environmental quality of the waters near the Oujiang River estuary from 2010 to 2017,the present situation of environmental quality of the waters was analyzed and evaluated.The resul...Based on the monitoring results of environmental quality of the waters near the Oujiang River estuary from 2010 to 2017,the present situation of environmental quality of the waters was analyzed and evaluated.The results showed that pH,DO,COD Mn ,petroleum,and heavy metal (Cu,Pb,Zn,Cd,Hg,As and Cr) content in the waters near the Oujiang River estuary did not exceed the second-class standard of Seawater Quality Standard (GB 3097-1997),while both inorganic nitrogen and reactive phosphate in the waters greatly exceeded the second-class standard.The water quality near the Oujiang River estuary was in an eutrophic state.In terms of sediment quality,the standard index of most evaluation factors except for Cu was smaller than 1,meeting the demands of sediment quality for environmental protection.展开更多
Conspecific seagrass living in differing environments may develop different root system acclimation patterns.We applied X-ray computed tomography(CT)for imaging and quantifying roots systems of Zostera japonica collec...Conspecific seagrass living in differing environments may develop different root system acclimation patterns.We applied X-ray computed tomography(CT)for imaging and quantifying roots systems of Zostera japonica collected from typical oligotrophic and eutrophic sediments in two coastal sites of northern China,and determined sediment physicochemical properties that might influence root system morphology,density,and distribution.The trophic status of sediments had little influence on the Z.japonica root length,and diameters of root and rhizome.However,Z.japonica in oligotrophic sediment developed the root system with longer rhizome node,deeper rhizome distribution,and larger allocation to below-ground tissues in order to acquire more nutrients and relieve the N deficiency.And the lower root and rhizome densities of Z.japonica in eutrophic sediment were mainly caused by fewer shoots and shorter longevity,which was resulted from the more serious sulfide inhibition.Our results systematically revealed the effect of sediment trophic status on the phenotypic plasticity,quantity,and distribution of Z.japonica root system,and demonstrated the feasibly of X-ray CT in seagrass root system research.展开更多
Different reclamation types to be used for the tidal flat have different hydrodynamic influences on the bay. Numerical experiments based on the land reclamation(LR) and the mariculture reclamation(MR), respectively, a...Different reclamation types to be used for the tidal flat have different hydrodynamic influences on the bay. Numerical experiments based on the land reclamation(LR) and the mariculture reclamation(MR), respectively, are conducted for the same reclamation project in the Shuangpantu, for quantitative comparisons. Results show that the MR has less influence on the hydrodynamic environment than the LR. The difference is more than 50%.展开更多
基金Supported by the Innovation Team Project of Ecological Environment Monitoring and Restoration of Fishery Waters in the East China Sea of the Chinese Academy of Fishery Sciences(No.2020TD14)the National Basic Research Program of China(973 Program)(No.2010CB429005)。
文摘The estuarine areas are under frequent influence from freshwater intrusion and ocean currents,in which zooplankton species are diversified and variable as they are sensitive to physio-chemical variations in water.Therefore,understanding the relationships between zooplankton and environmental factors help us know the water quality.To achieve co-existence with species in similar ecological group or habit,they could inevitably alter themselves to fit the ecology and adjust the function according to the competitive exclusion in ecological theory.However,information of the co-existence of dominant species in the Changjiang(Yangtze)River estuary(CRE)and adjacent waters remains scarce.We explored the relationships between dominant zooplankton and environmental factors in the study region in spring-summer from 2016 to 2020,involving particularly the composition of dominant species,ecological groups,their relationships with environmental factors,and co-existence of important species,using the non-multidimensional scale analysis(nMDS)method and redundancy analysis.Results show that Labidocera euchaeta and Tortanus vermiculus were dominant species in the study scope.The turnover rate of dominant zooplankton was greater(>50%)in spring while the species number was higher in summer.The dominant species were estuarine,offshore,and eurytopic based on the adaptation to salinity.In spring,the ecological groups were dominated by estuarine species,while in summer by estuarine and offshore species.In addition,the nMDS showed that the dominant species in the same ecological group were more dispersed and not prominently clustered;the dominant species were staggered among different ecological groups.The temperature,salinity,pH,dissolved oxygen,and chlorophyll a were the main environmental factors on the distribution of the dominant species in spring,while in summer were dissolved oxygen,temperature,salinity,and pH.The domination of medusae of Nemopsis bachei and Pleurobrachia globosa in zooplankton community in spring,and the continuous decrease in abundance of L.euchaeta reflected the effects of local climate change.The temperature and salinity changes in different years and the subsequent response of zooplankton reflected the influence of freshwater intrusion and/or ocean currents.Zooplankton in similar ecological habits exhibited the competitive exclusion in terms of co-existence.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51205346 and 41206074)the National High Technology Research and Development Program of China(863 Program+3 种基金Grant No.2011AA050201)Science Fund for Creative Research Groups of National Natural Science Foundation of China(Grant No.51221004)Zhejiang Provincial Natural Science Foundation of China(Grant No.LY12E05017)Open Foundation of the State Key Laboratory of Fluid Power Transmission and Control(Grant No.GZKF-201311)
文摘This paper describes a dual-stroke acting hydraulic power take-off(PTO)system employed in the wave energy converter(WEC)with an inverse pendulum.The hydraulic PTO converts slow irregular reciprocating wave motions to relatively smooth,fast rotation of an electrical generator.The design of the hydraulic PTO system and its control are critical to maximize the generated power.A time domain simulation study and the laboratory experiment of the full-scale beach test are presented.The results of the simulation and laboratory experiments including their comparison at full-scale are also presented,which have validated the rationality of the design and the reliability of some key components of the prototype of the WEC with an inverse pendulum with the dual-stroke acting hydraulic PTO system.
基金The National Natural Science Foundation of China under contract Nos 41176045,41476050,41106047,41476047 and41106045the Scientific Research Fund of the Second Institute of Oceanography,State Oceanic Administration of China under contract No.JG1204+2 种基金the National Special Project for"Global change and air-sea interaction"under contract Nos GASI-04-01-02 and GASI-GEOGE-03Chinese Polar Environment Comprehensive Investigation and Assessment Programmes under contract Nos CHINARE2012-01-02,CHINARE2013-01-02,CHINARE2014-01-02,CHINARE2013-04-01 and CHINARE2014-04-01the Marine Public Welfare Research Project,State Oceanic Administration of China under contract No.201105003
文摘Factorial kriging analysis is applied to the research on the spatial multiscale variability of heavy metals in submarine. It is used to analyze the multiscale spatial structures of seven heavy metals, Ni, Cu, Zn, Pb, Cr, As and Cd in the surface sediment from the northeastern of Beibu Gulf, identify and separate spatial variations at different scales of heavy metals, and discuss the provenance of heavy metals and the influencing factors. The results show that the existence of three-scale spatial variations those consist of nugget effect, a spherical structure with range of 30 km(short-range scale) and a spherical structure with range of 140 km(long-range scale) in the linear model of coregionalization fitted. The spatial distribution features of seven heavy metals at short-range scale reflect "spot-like" or "stripe-like" local-scale spatial variations; the spatial distribution features of the seven heavy metals at long-range scale represent "slice-like" regional-scale spatial variations. At local scale, Zn, Cr, Ni,Cu, Pb and Cd are derived primarily from parent materials of Hainan Island, Leizhou Peninsula and Guangxi land, whose spatial distribution characteristics are controlled by granularity of sediments, while As is influenced dominantly by human pollution components from Hainan Island and Leizhou Peninsula. At regional scale, Zn,Cr, Ni and Cu originate primarily from parent rock materials of Leizhou Peninsula and Hainan Island, secondly from Guangxi land; As originated primarily from parent rock materials from Hainan Island, secondly from Leizhou Peninsula and Guangxi land. These metals are transported and migrated with sediments dominated by the anticlockwise circulation of Beibu Gulf year-round, deposited in "convergence center", forming the whole sedimentary pattern in direction of NWW-NNW at regional scale. The difference in distribution type between As and other metals at regional scale is mainly due to their different geochemical behavior.
基金This study is supported financially by the National Natural Science Foundation of China (Nos.51179179 and 51239008)
文摘The vortex-induced vibration of two identical rigidly mounted risers in a parallel arrangement was studied using Ansys-CFX and model tests.The vortex shedding and force were recorded to determine the effect of spacing on the two-degree-of-freedom oscillation of the risers.CFX was used to study the single riser and two parallel risers in 2–8D spacing considering the coupling effect.Because of the limited width of water channel,only three different riser spacings,2D,3D,and 4D,were tested to validate the characteristics of the two parallel risers by comparing to the numerical simulation.The results indicate that the lift force changes significantly with the increase in spacing,and in the case of 3D spacing,the lift force of the two parallel risers reaches the maximum.The vortex shedding of the risers in 3D spacing shows that a variable velocity field with the same frequency as the vortex shedding is generated in the overlapped area,thus equalizing the period of drag force to that of lift force.It can be concluded that the interaction between the two parallel risers is significant when the risers are brought to a small distance between them because the trajectory of riser changes from oval to curve 8 as the spacing is increased.The phase difference of lift force between the two risers is also different as the spacing changes.
文摘Based on the monitoring results of environmental quality in the sea area near the Aojiang estuary in Wenzou during 2010-2012,the present situation of environmental quality in the sea area was analyzed and evaluated. The results show that p H,DO,CODMn,petroleum,and heavy metals( Cu,Pb,Zn,Cd,Hg,As and Cr) in the sea area near the Aojiang estuary did not exceed the second-class standard of Seawater Quality Standard( GB 3097-1997),but both inorganic nitrogen and reactive phosphate in the sea area exceeded the second-class standard seriously,and the water quality of the sea area was in an eutrophic state; domestic sewage and fertilizer loss were the main sources of nitrogen and phosphorus. The standard index of most evaluation factors of sediment quality except for Zn was smaller than 1,meeting the demands of sediment quality for environmental protection.
文摘By using internal standard method based on gas chromatography-electron capture detector( GC-ECD),the contents of persistent organochlorine pollutants polychorinated biphenyls( PCBs) and organochlorine pesticides( OCPs) in eggs of seabirds( Catharacta lonnbergi,Catharacta maccormicki,Pygoscelis papua and Macronectes giganteus) breeding on King George Island,Antarctica were detected,and their ecological environment significance was discussed. The results showed that the recovery of various compounds ranged from 68. 6% to 90. 8%; relative standard deviation( RSD) was 3. 6%,and the lowest detection limits of PCBs and OCPs were 0. 8- 16 and 2- 12 pg respectively,which could meet the demands for the residue analysis of trace persistent organochlorine pollutants in the eggs of Antarctic seabirds. The contents of PCBs,DDTs,HCB and HCHs in the eggs of Antarctic seabirds were 0. 5- 515. 5,2. 0- 304. 4,0. 5- 70. 5,and 0. 5- 2. 0 ng / g respectively. In addition,the accumulation of PCBs and OCPs in the skuas was enhanced gradually through the food chain. The maximums of persistent organochlorine pollutants appeared in the eggs of C. lonnbergi,followed by the eggs of C. maccomicki. The detection of OCPs and PCBs in the eggs of Antarctic seabirds was not interfered by other compounds containing chlorine,showing that the extraction,purification and detection method was suitable for the analysis of OCPs and PCBs in the eggs of Antarctic seabirds and has high sensitivity and reliability.
基金Supported by National Natural Science Foundation of China(4127-6199)
文摘Based on the monitoring results of environmental quality in Yueqing Bay during 2007-2014,the current situation of environmental quality in the bay was analyzed and assessed. The results show that pH,DO,CODMn,petroleum,and heavy metals( Cu,Pb,Zn,Cd,Hg,As and Cr)in the seawater of Yueqing Bay did not exceed the second class standard of Seawater Quality Standard( GB 3097-1997),but inorganic nitrogen and reactive phosphate in the seawater of Yueqing Bay exceeded the second class standard seriously,and the water quality of the bay was in an eutrophic state; the standard index of evaluation factors of sediment quality was smaller than 1,meeting the demands of sediment quality for environmental protection.
基金The Zhejiang Provincial Natural Science Foundation of China under contract No.Y5110187the Scientific Research Fund of the Second Institute of Oceanography,State Oceanic Administration(SOA)of China under contract No.JG1204+1 种基金the Youth Ocean Science Foundation of SOA under contract No.2012724the Public Science and Technology Research Funds Projects of Ocean from SOA of China under contract No.201105009
文摘Combined conductivity-temperature-depth(CTD) casts and Argo profiles, 3 086 historical hydrocasts were used to quantify the water column characteristics in the northern South China Sea(SCS) and its adjacent waters. Based on a two-dimensional "gravest empirical mode"(GEM), a gravitational potential(, a vertically integrated variable) was used as proxy for the vertical temperature profiles TG(p,). integrated from 8 MPa to the surface shows a close relationship with the temperature, except in the deep layer greater than 15 MPa, which was caused by the bimodal deep water in the region. The GEM temperature profiles successfully revealed the bimodality of the Luzon Strait deep water, that disparate hydrophic vertical profiles can produce distinct specific volume anomaly() in the SCS and the western Philippine Sea(WPS), but failed in the Luzon Strait, where different temperature profiles may produce a same. A significant temperature divergence between the SCS water and the WPS water confirmed that the bimodal structure is strong. The deepwater bifurcation starts at about 15 MPa, and gets stronger with increasing depth. As the only deep channel connecting the bimodal-structure waters, water column characteristics in the Luzon Strait is in between, but much closer to the SCS water because of its better connectivity with the SCS. A bimodal temperature structure below 15 MPa reveals that there was a persistent baroclinic pressure gradient driving flow through the Luzon Strait. A volume flux predicted through the Bashi Channel with the hydraulic theory yields a value of 5.62×106 m3/s using all available profiles upstream and downstream of the overflow region, and 4.03×106and 2.70×106 m3/s by exclusively using the profiles collected during spring and summer, respectively. No volume flux was calculated during autumn and winter because profiles are only available for the upstream of the Bashi Channel during the corresponding period.
文摘Based on the monitoring results of environmental quality of the waters near the Feiyun River estuary during 2011-2016, the current situation of environmental quality of the waters was analyzed and evaluated. The results showed that pH, DO, COD Mn , petroleum, and heavy metals (Cu, Pb, Zn, Cd, Hg, As and Cr) in the waters near the Feiyun River estuary did not exceed the second-class standard of Seawater Quality Standard (GB 3097-1997), while both inorganic nitrogen and reactive phosphate in the waters exceeded the second-class standard obviously. The water quality of the waters near the Feiyun River estuary was in an eutrophic state. In terms of sediment quality, the standard index of most evaluation factors except for Cu was smaller than 1, meeting the demands of sediment quality for environmental protection.
基金the Natural Science Foun-dation of China(No.41776119)Zhejiang Provincial Natural Science Foundation of China(No.LY15D060004)for the financial support.
文摘Metal pollution has become an major issue governing the wetland ecosystem health.The southern coastal wetland of the Qiangtang Estuary are facing unusual perturbation due to rapid development along the embayment in recent decades.This study evaluated the bioavailability of metals(Cu,Pb,Cd,Cr and Zn)in the sediment of the southern coastal wetland of the Qiangtang Es-tuary using diffusive gradients in thin films(DGT)techniques and compared with several methods based on total metal content.The results showed that the contents of Cr,Pb,Cd and Cu in sediment,as detected using DGT,were considerably correlated with the exchangeable fraction and the content in Phragmites australis roots,while a weak correlation was observed for Zn.Therefore,DGT analysis could be used to evaluate the bioavailability and potential risk of Cr,Cd,Pb and Cu for P.australis.Quantitative indices,such as DGT concentration,bioaccumulation in P.australis,geoaccumulation index(Igeo)and potential ecological risk index(RI),revealed that Cd was a major potential ecological risk factor along the southern coast wetland of the Qiantang Estuary,especially in the upstream region,which is potentially more vulnerable to the anthropogenic pollution.
文摘Based on the monitoring results of environmental quality of the waters near the Oujiang River estuary from 2010 to 2017,the present situation of environmental quality of the waters was analyzed and evaluated.The results showed that pH,DO,COD Mn ,petroleum,and heavy metal (Cu,Pb,Zn,Cd,Hg,As and Cr) content in the waters near the Oujiang River estuary did not exceed the second-class standard of Seawater Quality Standard (GB 3097-1997),while both inorganic nitrogen and reactive phosphate in the waters greatly exceeded the second-class standard.The water quality near the Oujiang River estuary was in an eutrophic state.In terms of sediment quality,the standard index of most evaluation factors except for Cu was smaller than 1,meeting the demands of sediment quality for environmental protection.
基金Supported by the National Key Research and Development Program of China(Nos.2018YFD0900901,2019YFD0901300)the Scientific Research Fund of the Second Institute of Oceanography,MNR(Nos.JG1906,JG1616,JG1910)+4 种基金the National Natural Science Foundation of China(Nos.41606192/41176140,41706125,41806136)the National Science&Technology Basic Work Program of China(No.2015FY110600)the Key Projects of Philosophy and Social Sciences Research,Ministry of Education,China(No.18JZD059)the Zhejiang Qingshan Lake Innovation Platform for Marine Science and Technology(No.2017E80001)the Project of Long-term Observation and Research Plan in the Changjiang Estuary and Adjacent East China Sea(No.LORCE,14282)。
文摘Conspecific seagrass living in differing environments may develop different root system acclimation patterns.We applied X-ray computed tomography(CT)for imaging and quantifying roots systems of Zostera japonica collected from typical oligotrophic and eutrophic sediments in two coastal sites of northern China,and determined sediment physicochemical properties that might influence root system morphology,density,and distribution.The trophic status of sediments had little influence on the Z.japonica root length,and diameters of root and rhizome.However,Z.japonica in oligotrophic sediment developed the root system with longer rhizome node,deeper rhizome distribution,and larger allocation to below-ground tissues in order to acquire more nutrients and relieve the N deficiency.And the lower root and rhizome densities of Z.japonica in eutrophic sediment were mainly caused by fewer shoots and shorter longevity,which was resulted from the more serious sulfide inhibition.Our results systematically revealed the effect of sediment trophic status on the phenotypic plasticity,quantity,and distribution of Z.japonica root system,and demonstrated the feasibly of X-ray CT in seagrass root system research.
基金Project supported by the Zhejiang Provincial Natural Science Foundation(Grant No.LY17D060003)the National Natural Science Foundation of China(Grant No.41206006)
文摘Different reclamation types to be used for the tidal flat have different hydrodynamic influences on the bay. Numerical experiments based on the land reclamation(LR) and the mariculture reclamation(MR), respectively, are conducted for the same reclamation project in the Shuangpantu, for quantitative comparisons. Results show that the MR has less influence on the hydrodynamic environment than the LR. The difference is more than 50%.
