In order to characterize the features of radium isotopes in estuaries of Tianjin,a continuous survey and sampling of typical estuaries were conducted from 2013 to 2017 in this study.The activities of natural radioacti...In order to characterize the features of radium isotopes in estuaries of Tianjin,a continuous survey and sampling of typical estuaries were conducted from 2013 to 2017 in this study.The activities of natural radioactive radium isotopes(^(223)Ra,^(224)Ra,and ^(228)Ra)in groundwater and surface water were measured by the radium-delayed coincidence counting(RaDeCC)system.The non-conservative behavior of the radium isotopes was investigated under hydrogeochemical conditions and urbanization.The results indicated that in terms of horizontal distribution,the activities of radium in groundwater(Hangu,Tanggu,and Dagang)showed an upward trend from north to south and demonstrated a higher figure than surface water(Haihe River and Duliujian River).Concerning the vertical distribution,the activitives of radium at a 15 m burial depth was higher than that at a 30 m burial depth in all measurements.The activities of radium isotopes in the study area increased with the increase of total dissolved solids,and their desorption behavior on Fe-Mn oxides was constrained by the redox intensity.Different hydrogeological conditions resulted in variations in the vertical profile of radium activities.The activity of radium was regulated by seasonal variation and precipitation in groundwater and surface water.In addition,the rapid urbanization has caused a significant impact on the features of radium isotopes in typical estuaries of Tianjin.Meanwhile,radium isotopes can be applied to reflect the impact of urbanization on surface watergroundwater systems.Clarifying and cleverly utilizing the relationship between behavior of radium isotopes and urbanization will promote the development of the Tianjin Binhai New Area in a healthy way.展开更多
Springer has recently published the book entitled “Studies of the Biogeochemistry of Typical Estuaries and Bays in China”. Professor Shen Zhiliang from the Institute of Oceanology, Chinese Academy of Sciences, China...Springer has recently published the book entitled “Studies of the Biogeochemistry of Typical Estuaries and Bays in China”. Professor Shen Zhiliang from the Institute of Oceanology, Chinese Academy of Sciences, China, authored and complied this book. The new book collects, compiles, and summarizes the studies on the biogeochemical cycling of the biogenic elements in mainly two typical regions in China, i.e., the Changjiang (Yangtze) River estuary and Jiaozhou Bay, and other regions are touched in the aspects of nutrients, suspended particulate matter, phytoplankton, and heavy metals, etc., in biogeochemistry, ecology, environmental science, oceanography, and biology etc.展开更多
由中国科学院海洋研究所沈志良研究员主编的《Studies of the Biogeochemistry of Typical Estuaries and Bays in China》将由Springer出版社出版。这是一部专门论述中国典型河口、海湾生物地球化学研究的书籍,以长江口和胶州湾为主要...由中国科学院海洋研究所沈志良研究员主编的《Studies of the Biogeochemistry of Typical Estuaries and Bays in China》将由Springer出版社出版。这是一部专门论述中国典型河口、海湾生物地球化学研究的书籍,以长江口和胶州湾为主要研究区域,研究内容包括营养盐、悬浮颗粒物、浮游植物、重金属等,涉及生物地球化学、生态学、环境科学、海洋化学、海洋生物学等多个学科。展开更多
Based on 2-dimensional vertically governing equations of salt water intrusion at estuaries, a method is obtained, which can predict quantitatively current velocity and salinity distribution along depth when the intrus...Based on 2-dimensional vertically governing equations of salt water intrusion at estuaries, a method is obtained, which can predict quantitatively current velocity and salinity distribution along depth when the intrusion occurs. The volume-controlling method proposed by Patanker and Spalding is used to form the computational pattern and the Power- Law Scheme is used as the diversion pattern of the diffusion term. The comparison between the computational results and the measured ones gives a satisfactory agreement.展开更多
Persistent organic pollutants(POPs) such as organochlorine pesticides are of global concern due to their widespread occurrence and persistence. This paper reports recent research studying the distribution and fate of ...Persistent organic pollutants(POPs) such as organochlorine pesticides are of global concern due to their widespread occurrence and persistence. This paper reports recent research studying the distribution and fate of organochlorine pesticides in the Jiulong River, the Minjiang River and the Pearl River estuaries in Southeast China. Eighteen organochlorine pesticides were extracted from water, pore water and sediment samples, followed by analysis by GC ECD. The results showed that the contamination levels were similar in these three estuaries. The levels of the total organochlorine pesticides in porewater were significantly higher than those in surface water, due to the high affinity of these hydrophobic compounds for sediment phase. Among the hexachlorocyclohexane(HCH) compounds, β HCH was found to be the most important isomer. The analysis of 1,1,1 trichloro 2,2 bis chlorophenyl ethane(DDT) and its metabolites showed that 1,1 dichloro 2[ o chlorophenyl] 2[ p chlorophenyl] ethylene(DDE) was dominant in the group.展开更多
Zooplankton was major indicator species of the environment. To explore the effect of marine environment on zooplankton distribution in the coast of China, the zooplankton samples from stations in Guanhe Estuary(GE), C...Zooplankton was major indicator species of the environment. To explore the effect of marine environment on zooplankton distribution in the coast of China, the zooplankton samples from stations in Guanhe Estuary(GE), Changjiang(Yangtze River) Estuary(CE), Oujiang Estuary(OE), Jiulongjiang Estuary(JE) and Beilun Estuary(BE)(covering 14 latitudes) in spring were surveyed and the variation of zooplankton ecological group was researched. According to the adaptability temperature, the zooplankton was divided into two ecological groups: warm-temperate species and subtropical species. The warm-temperate species was the main dominant species and subtropical species was only dominant species in BE. Calanus sinicus, a warm-temperate species, was the only dominant species in all five estuaries. From north to south, the proportion of warm-temperate species in the five estuaries gradually decreased depends on the number, were 83.33%, 48.39%, 45.00%, 43.75% and 30.43%, respectively. In contrary, the proportion of subtropical species was gradually increased. The warm-temperate species predominated over the total abundance and the percentage was whopping high in the north estuaries, including GE(96.16%), CE(95.57%), OE(97.83%) and JE(95.53%). The abundance percentage of subtropical species have remarkably higher(82.39%) in BE. Five estuaries zooplankton community was subdivided into three zooplankton groups, which were the northern warm temperate zooplankton group, the southern subtropical zooplankton group and the estuarine brackish-water group. The water temperature and coastal current of China Sea are recognized as the main factors determining the distribution and community structure of estuarine zooplankton in spring.展开更多
The distinctive estuary hydrodynamics and nutrient input make the estuary ecosystem play a key role in lake ecosystems.The Nanfei River and Zhaohe River are two main inlets of Chaohu Lake,Anhui,East China.We selected ...The distinctive estuary hydrodynamics and nutrient input make the estuary ecosystem play a key role in lake ecosystems.The Nanfei River and Zhaohe River are two main inlets of Chaohu Lake,Anhui,East China.We selected estuaries of the two rivers as representative areas to study temporal and spatial changes of bacterial communities.In August(summer)and November(autumn)2016 and February(winter)and May(spring)2017,16 water and sediment samples were collected from the estuaries.Physicochemical characteristics indicate significant differences in the nutritional status and eutrophication index of the estuaries due mainly to organic input.Examination of the number of operational taxonomic units,the diversity index,the community composition,and redundancy analysis revealed the following.First,the existence of varying degrees of seasonal differences in the distribution of almost all bacteria.In addition,the species diversity in the sediment samples was higher than that in the water samples,and the dominant species differed also among these samples.Second,a large number of unknown genera were detected,especially in the sediment samples,such as unclassified Xanthomonadales incertae sedis,unclassified Anaerolineaceae,and unclassified Alcaligenaceae.Last,TP,TN,and TOC were the main influential factors that affected the bacterial community structure.展开更多
Based on the one-dimensional salinity transport equation with constant diffusion coefficient, and separated water flow velocity into runoff and tidal current with the single-frequency in an idealized estuary, the simp...Based on the one-dimensional salinity transport equation with constant diffusion coefficient, and separated water flow velocity into runoff and tidal current with the single-frequency in an idealized estuary, the simplest unsteady analytical so- lution of salinity intrusion is deduced and the estimation formula of diffusion coefficient is obtained in this paper. The unsteady solution indicates that salinity process in estuaries results from the interaction of runoff and tidal current, and its amplitude is in direct proportion to the product of the velocity of runoff water and the amplitude of tidal flow velocity and in inverse proportion to the diffusion coefficient and the tidal angular frequency, and its phase lag tidal flow with 7/2 which reveals the basic features of the maximum salinity appearing after flood slack and the minimum salinity appearing before ebb slack under the effect of runoff （the advance or lag time is relative to the magnitude of runoff and tidal flow）. According to the measured flow velocity and salinity data, the salinity diffusion coefficient could be estimated. Finally, with the field data of observing sites on the deepwater navigation channel of the Yangtze Estuary, the diffusion coefficient is calculated and a comparative analysis of simulated and measured of salinity process is made. The results show that the solution can comprehensively reflects the basic characteristics and processes of salinity intrusion under the interaction of runoff and tidal flow in estuaries. The solution is not only suitable for theoretical research, but also convenient for estimating reasonable physical parameters and giving the initial condition in the salinity intrusion numerical simulation.展开更多
Based on literature and survery data of fish composition collected by bottom trawl investigation from 2006 to 2007 infour main estuaries of China southeastern coastal areas and their adjacent waters,changes of the tax...Based on literature and survery data of fish composition collected by bottom trawl investigation from 2006 to 2007 infour main estuaries of China southeastern coastal areas and their adjacent waters,changes of the taxonomic diversity across spatialand temporal scales of fish community were analyzed by taxonomic diversity indices.The results are as follows:a total number of1397 fish species(including some freshwater species),belonging to 2 classes,42 orders,186 families and 593 genera,were collected inthe studied sea areas.The species richness increased with lower latitudes,particularly so with Perciformes.There were 339 fish spe-cies in the Yangtze River Estuary and adjacent waters,belonging to 2 classes,31 orders,101 families and 231 genera.There were 535fish species in the Minjiang River Estuary and adjacent waters,belonging to 2 classes,33 orders,133 families and 323 genera.A totalnumber of 803 fish species were collected in the Jiulongjiang River Estuary and adjacent waters,which belonged to 2 classes,35 orders,155 families and 419 genera.And 1021 fish species which belonged to 2 classes,32 orders,153 families,and 466 genera were collectedin the Pearl River Estuary and adjacent waters.The numbers of orders and families of fish species from the northern to the southern wa-ters first increased and then decreased.The average variation in taxonomic distinctness(Λ+)gradually decreased with lower latitudes inthe four estuaries and adjacent waters.There were no significant differences in the average taxonomic distinctness(△+)among the fourestuaries and adjacent waters,and fish fauna were closely related with each other,and all of them belonged to the same zoogeographicalfauna(Indian-Malaysia fauna).Fish composition in the Minjiang River Estuary and adjacent waters was more similar to that in the Jiu-longjiang River Estuary and adjacent waters among the four estuaries.Compared with the historical data,the average taxonomic dis-tinctness of fish community showed a great decrease in the Minjiang River Estuary and the Jiulongjiang River Estuary and their adjacentwaters.展开更多
Aggregation is used to represent the real world in a model at an appropriate level of abstraction.We used the convection-diffusion equation to examine the implications of aggregation progressing from a three-dimension...Aggregation is used to represent the real world in a model at an appropriate level of abstraction.We used the convection-diffusion equation to examine the implications of aggregation progressing from a three-dimensional(3D)spatial description to a model representing a system as a single box that exchanges sediment with the adjacent environment.We highlight how all models depend on some forms of parametric closure,which need to be chosen to suit the scale of aggregation adopted in the model.All such models are therefore aggregated and make use of some empirical relationships to deal with sub-scale processes.One such appropriately aggregated model,the model for the aggregated scale morphological interaction between tidal basin and adjacent coast(ASMITA),is examined in more detail and used to illustrate the insight that this level of aggregation can bring to a problem by considering how tidal inlets and estuaries are impacted by sea level rise.展开更多
Based on the principle of conservative matter removal in estuary,a new method is proposed for estimating the ratio of sediment resuspension in estuaries with fine suspended sediments in the turbidity maximum zone(TMZ)...Based on the principle of conservative matter removal in estuary,a new method is proposed for estimating the ratio of sediment resuspension in estuaries with fine suspended sediments in the turbidity maximum zone(TMZ) of the Changjiang(Yangtze) estuary during 2005.Results show that there was a range of 18.7%±27.9% to 73.9%±22.5% per annum of total suspended particulate matter(SPM),with an average of 49.2%.Nearly half of the particulate matter in the TMZ originates from sediment resuspension.This indicates that sediment resuspension is one of the major mechanisms involved in formation of the TMZ.Compared with traditional method for calculating these ratios in the estuary,this new method evaluates the dynamic variation of SPM content carried by river runoff from the river mouth to the ocean.The new method produced more reliable results than the traditional one and could produce a better estimation of resuspension flux for particulate matter in estuaries.展开更多
China’s eastern coastal area marine hazards (storm surge, erosion and deposition by tidal currents and seawater intrusion) and the history, present situation, experiences and problems of inhabitants in their fight ag...China’s eastern coastal area marine hazards (storm surge, erosion and deposition by tidal currents and seawater intrusion) and the history, present situation, experiences and problems of inhabitants in their fight against marine hazards are discussed in this paper, which also suggests countermeasures against, and scientific and rational management of , coastal area marine hazards in order to protect the coastal and estuarine ecosystems.展开更多
In China,the water quality standards in operation include the Environmental Quality Standard for Surface Water（GB3838-2002）and Water Quality Standards for Seawater（GB3097-1997）.However,these two standards are curr...In China,the water quality standards in operation include the Environmental Quality Standard for Surface Water（GB3838-2002）and Water Quality Standards for Seawater（GB3097-1997）.However,these two standards are currently not suitable for the estuarial zones of China because of the unique properties of water environment in estuaries.We proposed preliminarily a basic idea and technical workflow in formulating water quality standards for the estuaries of China based on analyzing the water environment properties of estuaries comprehensively and comparing various parameters and their standard values mentioned in these two standards above.Issues pertinent to the formulation of the water quality standards for estuaries,e.g.nutrient,heavy metals and persistent organic pollutants（POPs）,are highly concerned.The objective of this paper is to provide technical support for the formulation of scientific water quality standards and the assessment of water quality of the estuaries of China.展开更多
Vegetation and soil within estuarine ecosystems play an integral role in ecological processes within pocket estuaries. However, physical barriers, caused by culverts diminish hydrological inputs, sediment exchange, an...Vegetation and soil within estuarine ecosystems play an integral role in ecological processes within pocket estuaries. However, physical barriers, caused by culverts diminish hydrological inputs, sediment exchange, and habitat connectivity. The restoration of estuaries by bridge replacement reconnects <span>the aquatic corridor, however, the recovery of plant communities and soil s</span>ubstrate is not well understood. This observational study monitored four estuary restoration sites of variable ages (0 - 12 years) in Western Washington, USA. Plant community composition, soil organic carbon, organic matter, and soil nutrients were assessed. Percent soil carbon was different among the pre-restoration and youngest (3-year) post-restoration site (<i>P</i> = 0.03), suggesting an initial decrease in carbon and organic matter during restoration. Both N and P were deficient at the newest, lower restoration site, presumably linked to the lack of organic matter required for adequate cation exchange capacity and nutrient/plant exchange (<i>P</i> < 0.05). Plant species diversity was higher at the intermediate (9-year) and oldest post-restoration sites (12-year;<i>P</i> = 0.02). Vegetation composition was primarily native species with few invasive plants present. The results of this study illustrate that tidal marsh plant communities are influenced by the development of salinity and vertical gradients with older sites having an increase in species diversity. Future surveys are ongoing to <span>better understand how these sites recover organic matter and tidal marsh co</span>mmunities to form adequate estuarine habitat over time.展开更多
Inconsistencies between datasets are examined with reference to flood tidal elevations in the Tamar River estuary, Tasmania Australia. Errors in a 30-year-old commonly cited dataset have been perpetuated in subsequent...Inconsistencies between datasets are examined with reference to flood tidal elevations in the Tamar River estuary, Tasmania Australia. Errors in a 30-year-old commonly cited dataset have been perpetuated in subsequent publications and datasets, and a clarification is herein provided. Elevation of the flood tidal wave as it propagates the estuary is evident in mean tide level and mean sea level, although the analysis is compromised by the temporal differences of the datasets. As sea levels rise due to global warming, the importance of accurate on-going sea level data in any estuary will become more acute.展开更多
An analytic model is developed to investigate the barotropic tidally driven residual exchange flow in shallow estuaries. Ebb dominated flow in deep channel and flood dominated flow on the shoals produced by the model ...An analytic model is developed to investigate the barotropic tidally driven residual exchange flow in shallow estuaries. Ebb dominated flow in deep channel and flood dominated flow on the shoals produced by the model are consistent with some observations in tidal rivers and shallow estuaries . Analysis shows that this type of exchange flow is caused by the combined effect of nonlinearity and the lateral variation of the depth. The inward flux is mainly due to the surface elevation of the wave . A seaward residual pressure gradient has to be maintained to drive the water outward for mass balance. Since the surface elevation in an estuary has only small lateral variation , the depth integrated pressure force is mainly dependent on the depth whose value in the channel is larger than that on the shoals. As a result, theretum flow in the channel is larger than that on the shoals. An ebb-flood flow spstem is thus generated.展开更多
A theoretical expression for vertical profile of horizontal velocity in tenns of its depth-average is derived based on oscillatory boundary layer theory and estuarine flow characteristics. The derived theoretical prof...A theoretical expression for vertical profile of horizontal velocity in tenns of its depth-average is derived based on oscillatory boundary layer theory and estuarine flow characteristics. The derived theoretical profile is then incorporated into a vertical quasi-two-dimensional model, which is proved advantageous in more physical implications and less CPU time demand. To validate the proposed model, the calculated results are compared to the field data in the Yangtze River Estuary, exhibiting good agreement with observations. The proposed quasi-two-dimensional vertical model is used to study mixing process, especially dependence of salinity distribution and salt front strength on runoff and tides in estuaries.展开更多
The Laizhou Bay(LB)represents a substantial ecological area that is vulnerable to human activities and confronts diverse environmental challenges.This study provides a comprehensive characterization of nutrients,petro...The Laizhou Bay(LB)represents a substantial ecological area that is vulnerable to human activities and confronts diverse environmental challenges.This study provides a comprehensive characterization of nutrients,petroleum,heavy metals,and phytoplankton community structure across seven distinct areas in LB.The results indicate relatively high concentrations of NO_(2)-N,SiO_(4)-Si,and NO_(3)-N in the Southwest Laizhou Bay(SWLB)and Huanghe River Estuary(HRE).In contrast,the East Laizhou bay(ELB)and the North of Huanghe River Estuary(NHRE)exhibit the highest concentrations of heavy metals(As,Cr and Hg).The areas with high phytoplankton density and community diversity are mainly located in the SWLB.After adjusting for basic environmental factors,phytoplankton density and Margalef richness index D are significantly associated with nutrients(NO_(3)-N,NO_(2)-N,NH_(4)-N,SiO_(4)-Si),and heavy metal(Cr)concentrations.We highlight that,in addition to Xiaoqinghe River,nutrients brought by the Mihe River in the SWLB and heavy metal(Cr)pollution in the ELB resulting from industrial and mining activities along the coast significantly influence phytoplankton growth and community structure.Therefore,it is recommended that more monitoring and management efforts be focused on these regions in the future.展开更多
Hypoxia off the Changjiang River Estuary has been the subject of much attention,yet systematic observations have been lacking,resulting in a lack of knowledge regarding its long-term change and drivers.By revisiting t...Hypoxia off the Changjiang River Estuary has been the subject of much attention,yet systematic observations have been lacking,resulting in a lack of knowledge regarding its long-term change and drivers.By revisiting the repeated surveys of dissolved oxygen(DO) and other relevant hydrographic parameters along the section from the Changjiang River Estuary to the Jeju-do in the summer from 1997 to 2014,rather different trends were revealed for the dual low-DO cores.The nearshore low-DO core,located close to the river mouth and relatively stable,shows that hypoxia has become more severe with the lowest DO descen ding at a rate of -0.07 mg/(L·a) and the thickness of low-DO zone rising at a rate of 0.43 m/a.The offshore core,centered around 40-m isobath but moving back and forth between 123.5°-125°E,shows large fluctuations in the minimum DO concentration,with the thickness of low-DO zone falling at a rate of -1.55 m/a.The probable factors affecting the minimum DO concentration in the two regions also vary.In the nearshore region,the decreasing minimum DO is driven by the increase in both stratification and primary productivity,with the enhanced extension of the Changjiang River Diluted Water(CDW) strengthening stratification.In the offshore region,the fluctuating trend of the minimum DO concentration indicates that both DO loss and DO supplement are distinct.The DO loss is primarily attributed to bottom apparent oxygen utilization caused by the organic matter decay and is also relevant to the advection of low-DO water from the nearshore region.The DO supplement is primarily due to weakened stratification.Our analysis also shows that the minimum DO concentration in the nearshore region was extremely low in 1998,2003,2007 and 2010,related to El Ni?o signal in these summers.展开更多
基金The National Natural Science Foundation of China under contract No.42172273.
文摘In order to characterize the features of radium isotopes in estuaries of Tianjin,a continuous survey and sampling of typical estuaries were conducted from 2013 to 2017 in this study.The activities of natural radioactive radium isotopes(^(223)Ra,^(224)Ra,and ^(228)Ra)in groundwater and surface water were measured by the radium-delayed coincidence counting(RaDeCC)system.The non-conservative behavior of the radium isotopes was investigated under hydrogeochemical conditions and urbanization.The results indicated that in terms of horizontal distribution,the activities of radium in groundwater(Hangu,Tanggu,and Dagang)showed an upward trend from north to south and demonstrated a higher figure than surface water(Haihe River and Duliujian River).Concerning the vertical distribution,the activitives of radium at a 15 m burial depth was higher than that at a 30 m burial depth in all measurements.The activities of radium isotopes in the study area increased with the increase of total dissolved solids,and their desorption behavior on Fe-Mn oxides was constrained by the redox intensity.Different hydrogeological conditions resulted in variations in the vertical profile of radium activities.The activity of radium was regulated by seasonal variation and precipitation in groundwater and surface water.In addition,the rapid urbanization has caused a significant impact on the features of radium isotopes in typical estuaries of Tianjin.Meanwhile,radium isotopes can be applied to reflect the impact of urbanization on surface watergroundwater systems.Clarifying and cleverly utilizing the relationship between behavior of radium isotopes and urbanization will promote the development of the Tianjin Binhai New Area in a healthy way.
文摘Springer has recently published the book entitled “Studies of the Biogeochemistry of Typical Estuaries and Bays in China”. Professor Shen Zhiliang from the Institute of Oceanology, Chinese Academy of Sciences, China, authored and complied this book. The new book collects, compiles, and summarizes the studies on the biogeochemical cycling of the biogenic elements in mainly two typical regions in China, i.e., the Changjiang (Yangtze) River estuary and Jiaozhou Bay, and other regions are touched in the aspects of nutrients, suspended particulate matter, phytoplankton, and heavy metals, etc., in biogeochemistry, ecology, environmental science, oceanography, and biology etc.
文摘由中国科学院海洋研究所沈志良研究员主编的《Studies of the Biogeochemistry of Typical Estuaries and Bays in China》将由Springer出版社出版。这是一部专门论述中国典型河口、海湾生物地球化学研究的书籍,以长江口和胶州湾为主要研究区域,研究内容包括营养盐、悬浮颗粒物、浮游植物、重金属等,涉及生物地球化学、生态学、环境科学、海洋化学、海洋生物学等多个学科。
文摘Based on 2-dimensional vertically governing equations of salt water intrusion at estuaries, a method is obtained, which can predict quantitatively current velocity and salinity distribution along depth when the intrusion occurs. The volume-controlling method proposed by Patanker and Spalding is used to form the computational pattern and the Power- Law Scheme is used as the diversion pattern of the diffusion term. The comparison between the computational results and the measured ones gives a satisfactory agreement.
文摘Persistent organic pollutants(POPs) such as organochlorine pesticides are of global concern due to their widespread occurrence and persistence. This paper reports recent research studying the distribution and fate of organochlorine pesticides in the Jiulong River, the Minjiang River and the Pearl River estuaries in Southeast China. Eighteen organochlorine pesticides were extracted from water, pore water and sediment samples, followed by analysis by GC ECD. The results showed that the contamination levels were similar in these three estuaries. The levels of the total organochlorine pesticides in porewater were significantly higher than those in surface water, due to the high affinity of these hydrophobic compounds for sediment phase. Among the hexachlorocyclohexane(HCH) compounds, β HCH was found to be the most important isomer. The analysis of 1,1,1 trichloro 2,2 bis chlorophenyl ethane(DDT) and its metabolites showed that 1,1 dichloro 2[ o chlorophenyl] 2[ p chlorophenyl] ethylene(DDE) was dominant in the group.
基金funded by the National Natural Science Foundation of China (No. G41176131)the National Marine Public Welfare Research Project of China (No. 201305027-8)the Young Ocean Science Fund of East China Sea branch of State Oceanic Administration (No. 201708)
文摘Zooplankton was major indicator species of the environment. To explore the effect of marine environment on zooplankton distribution in the coast of China, the zooplankton samples from stations in Guanhe Estuary(GE), Changjiang(Yangtze River) Estuary(CE), Oujiang Estuary(OE), Jiulongjiang Estuary(JE) and Beilun Estuary(BE)(covering 14 latitudes) in spring were surveyed and the variation of zooplankton ecological group was researched. According to the adaptability temperature, the zooplankton was divided into two ecological groups: warm-temperate species and subtropical species. The warm-temperate species was the main dominant species and subtropical species was only dominant species in BE. Calanus sinicus, a warm-temperate species, was the only dominant species in all five estuaries. From north to south, the proportion of warm-temperate species in the five estuaries gradually decreased depends on the number, were 83.33%, 48.39%, 45.00%, 43.75% and 30.43%, respectively. In contrary, the proportion of subtropical species was gradually increased. The warm-temperate species predominated over the total abundance and the percentage was whopping high in the north estuaries, including GE(96.16%), CE(95.57%), OE(97.83%) and JE(95.53%). The abundance percentage of subtropical species have remarkably higher(82.39%) in BE. Five estuaries zooplankton community was subdivided into three zooplankton groups, which were the northern warm temperate zooplankton group, the southern subtropical zooplankton group and the estuarine brackish-water group. The water temperature and coastal current of China Sea are recognized as the main factors determining the distribution and community structure of estuarine zooplankton in spring.
基金Supported by the National Natural Science Foundation of China(Nos.41601573,41771235)the Key University Science Research Project of Anhui Province(No.KJ2019A0641)+1 种基金the Linkage Project of Anhui Public Welfare Technology Application Research(No.1704f0804053)the Science and the Technology Innovation Strategy and Soft Science Research Special Project of Anhui Province(No.1706a02020048)。
文摘The distinctive estuary hydrodynamics and nutrient input make the estuary ecosystem play a key role in lake ecosystems.The Nanfei River and Zhaohe River are two main inlets of Chaohu Lake,Anhui,East China.We selected estuaries of the two rivers as representative areas to study temporal and spatial changes of bacterial communities.In August(summer)and November(autumn)2016 and February(winter)and May(spring)2017,16 water and sediment samples were collected from the estuaries.Physicochemical characteristics indicate significant differences in the nutritional status and eutrophication index of the estuaries due mainly to organic input.Examination of the number of operational taxonomic units,the diversity index,the community composition,and redundancy analysis revealed the following.First,the existence of varying degrees of seasonal differences in the distribution of almost all bacteria.In addition,the species diversity in the sediment samples was higher than that in the water samples,and the dominant species differed also among these samples.Second,a large number of unknown genera were detected,especially in the sediment samples,such as unclassified Xanthomonadales incertae sedis,unclassified Anaerolineaceae,and unclassified Alcaligenaceae.Last,TP,TN,and TOC were the main influential factors that affected the bacterial community structure.
基金The research is partly supported by the Key Project of National Natural Science Foundation of China (Grant No.50339010)
文摘Based on the one-dimensional salinity transport equation with constant diffusion coefficient, and separated water flow velocity into runoff and tidal current with the single-frequency in an idealized estuary, the simplest unsteady analytical so- lution of salinity intrusion is deduced and the estimation formula of diffusion coefficient is obtained in this paper. The unsteady solution indicates that salinity process in estuaries results from the interaction of runoff and tidal current, and its amplitude is in direct proportion to the product of the velocity of runoff water and the amplitude of tidal flow velocity and in inverse proportion to the diffusion coefficient and the tidal angular frequency, and its phase lag tidal flow with 7/2 which reveals the basic features of the maximum salinity appearing after flood slack and the minimum salinity appearing before ebb slack under the effect of runoff （the advance or lag time is relative to the magnitude of runoff and tidal flow）. According to the measured flow velocity and salinity data, the salinity diffusion coefficient could be estimated. Finally, with the field data of observing sites on the deepwater navigation channel of the Yangtze Estuary, the diffusion coefficient is calculated and a comparative analysis of simulated and measured of salinity process is made. The results show that the solution can comprehensively reflects the basic characteristics and processes of salinity intrusion under the interaction of runoff and tidal flow in estuaries. The solution is not only suitable for theoretical research, but also convenient for estimating reasonable physical parameters and giving the initial condition in the salinity intrusion numerical simulation.
基金supported by the Natural Science Foundation of Fujian Province(No.D0410021)by the‘908’Marine Survey Project of Fujian Province(No:FJ908-01-01-HS)
文摘Based on literature and survery data of fish composition collected by bottom trawl investigation from 2006 to 2007 infour main estuaries of China southeastern coastal areas and their adjacent waters,changes of the taxonomic diversity across spatialand temporal scales of fish community were analyzed by taxonomic diversity indices.The results are as follows:a total number of1397 fish species(including some freshwater species),belonging to 2 classes,42 orders,186 families and 593 genera,were collected inthe studied sea areas.The species richness increased with lower latitudes,particularly so with Perciformes.There were 339 fish spe-cies in the Yangtze River Estuary and adjacent waters,belonging to 2 classes,31 orders,101 families and 231 genera.There were 535fish species in the Minjiang River Estuary and adjacent waters,belonging to 2 classes,33 orders,133 families and 323 genera.A totalnumber of 803 fish species were collected in the Jiulongjiang River Estuary and adjacent waters,which belonged to 2 classes,35 orders,155 families and 419 genera.And 1021 fish species which belonged to 2 classes,32 orders,153 families,and 466 genera were collectedin the Pearl River Estuary and adjacent waters.The numbers of orders and families of fish species from the northern to the southern wa-ters first increased and then decreased.The average variation in taxonomic distinctness(Λ+)gradually decreased with lower latitudes inthe four estuaries and adjacent waters.There were no significant differences in the average taxonomic distinctness(△+)among the fourestuaries and adjacent waters,and fish fauna were closely related with each other,and all of them belonged to the same zoogeographicalfauna(Indian-Malaysia fauna).Fish composition in the Minjiang River Estuary and adjacent waters was more similar to that in the Jiu-longjiang River Estuary and adjacent waters among the four estuaries.Compared with the historical data,the average taxonomic dis-tinctness of fish community showed a great decrease in the Minjiang River Estuary and the Jiulongjiang River Estuary and their adjacentwaters.
文摘Aggregation is used to represent the real world in a model at an appropriate level of abstraction.We used the convection-diffusion equation to examine the implications of aggregation progressing from a three-dimensional(3D)spatial description to a model representing a system as a single box that exchanges sediment with the adjacent environment.We highlight how all models depend on some forms of parametric closure,which need to be chosen to suit the scale of aggregation adopted in the model.All such models are therefore aggregated and make use of some empirical relationships to deal with sub-scale processes.One such appropriately aggregated model,the model for the aggregated scale morphological interaction between tidal basin and adjacent coast(ASMITA),is examined in more detail and used to illustrate the insight that this level of aggregation can bring to a problem by considering how tidal inlets and estuaries are impacted by sea level rise.
基金Supported by National Natural Science Foundation of China for Creative Research Groups(No.41121064) and NSFC(No.41176138)the Program from Three Gorges Engineering Construction Committee of the State Council,China(No.SX2004-010)
文摘Based on the principle of conservative matter removal in estuary,a new method is proposed for estimating the ratio of sediment resuspension in estuaries with fine suspended sediments in the turbidity maximum zone(TMZ) of the Changjiang(Yangtze) estuary during 2005.Results show that there was a range of 18.7%±27.9% to 73.9%±22.5% per annum of total suspended particulate matter(SPM),with an average of 49.2%.Nearly half of the particulate matter in the TMZ originates from sediment resuspension.This indicates that sediment resuspension is one of the major mechanisms involved in formation of the TMZ.Compared with traditional method for calculating these ratios in the estuary,this new method evaluates the dynamic variation of SPM content carried by river runoff from the river mouth to the ocean.The new method produced more reliable results than the traditional one and could produce a better estimation of resuspension flux for particulate matter in estuaries.
文摘China’s eastern coastal area marine hazards (storm surge, erosion and deposition by tidal currents and seawater intrusion) and the history, present situation, experiences and problems of inhabitants in their fight against marine hazards are discussed in this paper, which also suggests countermeasures against, and scientific and rational management of , coastal area marine hazards in order to protect the coastal and estuarine ecosystems.
基金Supported by the Special Fund for Environmental Protection Research in the Pubic Interest(201309007)
文摘In China,the water quality standards in operation include the Environmental Quality Standard for Surface Water（GB3838-2002）and Water Quality Standards for Seawater（GB3097-1997）.However,these two standards are currently not suitable for the estuarial zones of China because of the unique properties of water environment in estuaries.We proposed preliminarily a basic idea and technical workflow in formulating water quality standards for the estuaries of China based on analyzing the water environment properties of estuaries comprehensively and comparing various parameters and their standard values mentioned in these two standards above.Issues pertinent to the formulation of the water quality standards for estuaries,e.g.nutrient,heavy metals and persistent organic pollutants（POPs）,are highly concerned.The objective of this paper is to provide technical support for the formulation of scientific water quality standards and the assessment of water quality of the estuaries of China.
文摘Vegetation and soil within estuarine ecosystems play an integral role in ecological processes within pocket estuaries. However, physical barriers, caused by culverts diminish hydrological inputs, sediment exchange, and habitat connectivity. The restoration of estuaries by bridge replacement reconnects <span>the aquatic corridor, however, the recovery of plant communities and soil s</span>ubstrate is not well understood. This observational study monitored four estuary restoration sites of variable ages (0 - 12 years) in Western Washington, USA. Plant community composition, soil organic carbon, organic matter, and soil nutrients were assessed. Percent soil carbon was different among the pre-restoration and youngest (3-year) post-restoration site (<i>P</i> = 0.03), suggesting an initial decrease in carbon and organic matter during restoration. Both N and P were deficient at the newest, lower restoration site, presumably linked to the lack of organic matter required for adequate cation exchange capacity and nutrient/plant exchange (<i>P</i> < 0.05). Plant species diversity was higher at the intermediate (9-year) and oldest post-restoration sites (12-year;<i>P</i> = 0.02). Vegetation composition was primarily native species with few invasive plants present. The results of this study illustrate that tidal marsh plant communities are influenced by the development of salinity and vertical gradients with older sites having an increase in species diversity. Future surveys are ongoing to <span>better understand how these sites recover organic matter and tidal marsh co</span>mmunities to form adequate estuarine habitat over time.
文摘Inconsistencies between datasets are examined with reference to flood tidal elevations in the Tamar River estuary, Tasmania Australia. Errors in a 30-year-old commonly cited dataset have been perpetuated in subsequent publications and datasets, and a clarification is herein provided. Elevation of the flood tidal wave as it propagates the estuary is evident in mean tide level and mean sea level, although the analysis is compromised by the temporal differences of the datasets. As sea levels rise due to global warming, the importance of accurate on-going sea level data in any estuary will become more acute.
文摘An analytic model is developed to investigate the barotropic tidally driven residual exchange flow in shallow estuaries. Ebb dominated flow in deep channel and flood dominated flow on the shoals produced by the model are consistent with some observations in tidal rivers and shallow estuaries . Analysis shows that this type of exchange flow is caused by the combined effect of nonlinearity and the lateral variation of the depth. The inward flux is mainly due to the surface elevation of the wave . A seaward residual pressure gradient has to be maintained to drive the water outward for mass balance. Since the surface elevation in an estuary has only small lateral variation , the depth integrated pressure force is mainly dependent on the depth whose value in the channel is larger than that on the shoals. As a result, theretum flow in the channel is larger than that on the shoals. An ebb-flood flow spstem is thus generated.
基金Project supported by the National Natural Science Foundation of China (Grant No. 59879025)the National Climbing Project of the Ministry of Science and Technology of China the Director Foundation of Institute of Mechanics, Chinese Academy of Scien
文摘A theoretical expression for vertical profile of horizontal velocity in tenns of its depth-average is derived based on oscillatory boundary layer theory and estuarine flow characteristics. The derived theoretical profile is then incorporated into a vertical quasi-two-dimensional model, which is proved advantageous in more physical implications and less CPU time demand. To validate the proposed model, the calculated results are compared to the field data in the Yangtze River Estuary, exhibiting good agreement with observations. The proposed quasi-two-dimensional vertical model is used to study mixing process, especially dependence of salinity distribution and salt front strength on runoff and tides in estuaries.
基金the National Natural Science Foundation of China(Nos.42176234 and 42130403)the Chinese Arctic and Antarctic Creative Program(No.JDXT2018-01)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0402).
文摘The Laizhou Bay(LB)represents a substantial ecological area that is vulnerable to human activities and confronts diverse environmental challenges.This study provides a comprehensive characterization of nutrients,petroleum,heavy metals,and phytoplankton community structure across seven distinct areas in LB.The results indicate relatively high concentrations of NO_(2)-N,SiO_(4)-Si,and NO_(3)-N in the Southwest Laizhou Bay(SWLB)and Huanghe River Estuary(HRE).In contrast,the East Laizhou bay(ELB)and the North of Huanghe River Estuary(NHRE)exhibit the highest concentrations of heavy metals(As,Cr and Hg).The areas with high phytoplankton density and community diversity are mainly located in the SWLB.After adjusting for basic environmental factors,phytoplankton density and Margalef richness index D are significantly associated with nutrients(NO_(3)-N,NO_(2)-N,NH_(4)-N,SiO_(4)-Si),and heavy metal(Cr)concentrations.We highlight that,in addition to Xiaoqinghe River,nutrients brought by the Mihe River in the SWLB and heavy metal(Cr)pollution in the ELB resulting from industrial and mining activities along the coast significantly influence phytoplankton growth and community structure.Therefore,it is recommended that more monitoring and management efforts be focused on these regions in the future.
基金The National Key Research&Development Program of China under contract No.2023YFC3108003 in Project No.2023YFC3108000the National Natural Science Foundation of China under contract No.41876026+3 种基金the Scientific Research Fund of the Second Institute of Oceanography,Ministry of Natural Resources under contract No.YJJC2201the National Programme on Global Change and Air–Sea Interaction Phase Ⅱ under contract No.GASI-01-CJKthe Zhejiang Provincial Ten Thousand Talents Program under contract No.2020R52038the Project of State Key Laboratory of Satellite Ocean Environment Dynamics under contract No.SOEDZZ2105。
文摘Hypoxia off the Changjiang River Estuary has been the subject of much attention,yet systematic observations have been lacking,resulting in a lack of knowledge regarding its long-term change and drivers.By revisiting the repeated surveys of dissolved oxygen(DO) and other relevant hydrographic parameters along the section from the Changjiang River Estuary to the Jeju-do in the summer from 1997 to 2014,rather different trends were revealed for the dual low-DO cores.The nearshore low-DO core,located close to the river mouth and relatively stable,shows that hypoxia has become more severe with the lowest DO descen ding at a rate of -0.07 mg/(L·a) and the thickness of low-DO zone rising at a rate of 0.43 m/a.The offshore core,centered around 40-m isobath but moving back and forth between 123.5°-125°E,shows large fluctuations in the minimum DO concentration,with the thickness of low-DO zone falling at a rate of -1.55 m/a.The probable factors affecting the minimum DO concentration in the two regions also vary.In the nearshore region,the decreasing minimum DO is driven by the increase in both stratification and primary productivity,with the enhanced extension of the Changjiang River Diluted Water(CDW) strengthening stratification.In the offshore region,the fluctuating trend of the minimum DO concentration indicates that both DO loss and DO supplement are distinct.The DO loss is primarily attributed to bottom apparent oxygen utilization caused by the organic matter decay and is also relevant to the advection of low-DO water from the nearshore region.The DO supplement is primarily due to weakened stratification.Our analysis also shows that the minimum DO concentration in the nearshore region was extremely low in 1998,2003,2007 and 2010,related to El Ni?o signal in these summers.
