1.Introduction The availability of reliable information describing our natural and anthropogenic environment—and its changes in particular—is crucial for understanding the complexity of structures and processes with...1.Introduction The availability of reliable information describing our natural and anthropogenic environment—and its changes in particular—is crucial for understanding the complexity of structures and processes within environmental systems.Modern remote sensing and monitoring methods provide an increasing amount of environmental data that can be used for a variety of management purposes[1,2].展开更多
Environmental pollution and energy shortage has been regarded as the two major challenges because of the rapid development of urbanization and industrialization.Considering these challenges,providing green environment...Environmental pollution and energy shortage has been regarded as the two major challenges because of the rapid development of urbanization and industrialization.Considering these challenges,providing green environment and energy for human beings are pivotal for future sustainable development.Nanostructured catalysts(photocatalysts,thermal catalysts and electrocatalysts)with unique physiochemical properties could offer numerous opportunities to solve these issues of environmental and energetic sustainability.In recent years,significant advances have been made on the synthesis,mechanistic understanding and innovative applications of the new catalysts for environmental and energetic problems.These new catalysts have found wide applications in different fashions.展开更多
While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are r...While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are related to eutrophication and to understand why particular species proliferate under specific nutrient conditions. The overall goal of this brief review is to describe why nutrient loads are not changing in stoichiometric proportion to the "Redfield ratio", and why this has important consequences for algal growth. Many types of harmful algae appear to be able to thrive, and/or increase their production of toxins, when nutrient loads are not in proportion classically identified as Redfield ratios. Here we also describe some of the physiological mechanisms of different species to take up nutrients and to thrive under conditions of nutrient imbalance.展开更多
A field experiment, involving lime N (calcium cyanamide, CaCN2) fertilization as a control measure, was conducted to study environmental problems induced by long-term heavy N application in Japanese tea fields. Long-t...A field experiment, involving lime N (calcium cyanamide, CaCN2) fertilization as a control measure, was conducted to study environmental problems induced by long-term heavy N application in Japanese tea fields. Long-term tea cultivation caused serious soil acidification. Seventy-seven percent of the 70 tea fields investigated had soil pH values below 4.0, and 9% below 3.0, with the lowest value of 2.7. Moreover, excess N application in tea fields put a threat to plant growth, induced serious nitrate contamination to local water, and caused high nitrous oxide loss. Compared with the conventional high N application treatment (1100 kg N ha-1) without lime N, the low N application (400 kg N ha-1) with calcium cyanamide effectively stopped soil acidification as well as achieved the same or slightly higher levels in tea yield and in total N and amino acid contents of tea shoots. The application of calcium cyanamide could be a suitable fertilization for the prevention of environmental problems in tea cultivation.展开更多
The presence of emerging pharmaceutical pollutants at low concentration levels in the surface and ground water has caused a potential threat to the marine and human lives.The emerging pharmaceutical pollutants general...The presence of emerging pharmaceutical pollutants at low concentration levels in the surface and ground water has caused a potential threat to the marine and human lives.The emerging pharmaceutical pollutants generally include analgesics and anti-inflammatories,lipid-lowering drugs,antiepileptics,antibiotics,and β-blockers compounds.In recent years,various processes have been developed and advanced oxidation process is the most effective for decontamination of emerging pharmaceutical pollutants till date.Semiconductor based photocatalysis technology has recently received a great interest for the removal of new emerging pharmaceutical pollutants.This review article highlights the removal of emerging pharmaceutical pollutants especially through photocatalysis as well as recent progress using different nanostructures.Additional focus has been given over fundamental key dynamics processes of nanomaterials and degradation pathways of emerging pharmaceutical pollutants.Finally,this review concludes with the perspectives and outlook over future developments in photocatalysis technology for the degradation of emerging pharmaceutical pollutants leading to a solution for realworld in near future.展开更多
For simulating water wave propagation in coastal areas, various Boussinesq-type equations with improved properties in intermediate or deep water have been presented in the past several decades. How to choose proper Bo...For simulating water wave propagation in coastal areas, various Boussinesq-type equations with improved properties in intermediate or deep water have been presented in the past several decades. How to choose proper Boussinesq-type equations has been a practical problem for engineers. In this paper, approaches of improving the characteristics of the equations, i.e. linear dispersion, shoaling gradient and nonlinearity, are reviewed and the advantages and disadvantages of several different Boussinesq-type equations are compared for the applications of these Boussinesq-type equations in coastal engineering with relatively large sea areas. Then for improving the properties of Boussinesq-type equations, a new set of fully nonlinear Boussinseq-type equations with modified representative velocity are derived, which can be used for better linear dispersion and nonlinearity. Based on the method of minimizing the overall error in different ranges of applications, sets of parameters are determined with optimized linear dispersion, linear shoaling and nonlinearity, respectively. Finally, a test example is given for validating the results of this study. Both results show that the equations with optimized parameters display better characteristics than the ones obtained by matching with pad6 approximation.展开更多
As the pressures on water resources are ever increasing,the organization of complex disparate data and scientific information to inform the actions to protect and enhance the resilience of freshwater resources is key ...As the pressures on water resources are ever increasing,the organization of complex disparate data and scientific information to inform the actions to protect and enhance the resilience of freshwater resources is key for sustainable development and implementation of integrated water resource management(IWRM).Methodologies supporting IWRM implementation have largely focused on water management and governance,with less attention to evaluation methods of ecologic,economic,and social conditions.To assist in assessing water resource sustainability,the Integrated Hydro-Environment Assessment Tool(IHEAT)has been developed to create a framework for different disciplines and interests to engage in structured dialogue.The IHEAT builds on the considerable body of knowledge developed around IWRM and seeks to place this information into a single framework that facilitates the cogeneration of knowledge between managers,stakeholders,and the communities affected by management decisions with the understanding that there is a need to merge expert analysis with traditional knowledge and the lived experience of communities.IHEAT merges the driver-pressure-state-impact-response(DPSIR)framework,the Millennium Ecosystem Assessment's ecosystem services and human well-being(HWB)framework,sustainability criteria for water resource systems,and water resources indexes and sets of indicators to better understand spatiotemporal interactions between hydrologic,socioeconomic,and ecologic systems and evaluate impacts of disturbances on ecological goods and services and HWB.IHEAT consists of a Conceptual Template(IHEAT-CT)which provides a systematic framework for assessing basin conditions and guiding indicator selection as well as an Assessment Interface(IHEAT-AI)for organizing,processing,and assessing analytical results.The IHEAT-CT,presented herein,is a rapid screening tool that connects water use directly,or through ecosystem goods and services(EGS),to constituents of HWB.Disturbance Templates for eight pressure types,such as land-use change,climate change,and population growth,are provided to guide practitioners regarding potential changes to landscape elements in the hydrological cycle,impacts on EGS,and societal implications on HWB.The basin screening results in a summary report card illuminating key freshwater ecosystems,the EGS they provide,and potential responses to drivers and pressures acting on the hydrologic system.This screening provides a common understanding by technical and nontechnical parties and provides the foundation for more complex conceptual models should they be required.An indicator list guides the selection of hydrologic,ecologic,economic,and social analytical methods to support IWRM technical input.展开更多
Applying catalysts for electrochemical energy conversion holds great promise for developing clean and sustainable energy sources.One of the main advantages of electrocatalysis is its ability to reduce conversion energ...Applying catalysts for electrochemical energy conversion holds great promise for developing clean and sustainable energy sources.One of the main advantages of electrocatalysis is its ability to reduce conversion energy loss significantly.However,the wide application of electrocatalysts in these conversion processes has been hindered by poor catalytic performance and limited resources of catalyst materials.To overcome these challenges,researchers have turned to two-dimensional(2D)materials,which possess large specific surface areas and can easily be engineered to have desirable electronic structures,making them promising candidates for high-performance electrocatalysis in various reactions.This comprehensive review focuses on engineering novel 2D material-based electrocatalysts and their application to seawater splitting.The review briefly introduces the mechanism of seawater splitting and the primary challenges of 2D materials.Then,we highlight the unique advantages and regulating strategies for seawater electrolysis based on recent advancements.We also review various 2D catalyst families for direct seawater splitting and delve into the physicochemical properties of these catalysts to provide valuable insights.Finally,we outline the vital future challenges and discuss the perspectives on seawater electrolysis.This review provides valuable insights for the rational design and development of cutting-edge 2D material electrocatalysts for seawater-electrolysis applications.展开更多
An experiment was carried out to study the transport process of nitrogen （N） assimilation from tea roots by monitoring the dynamic composition of N compounds in xylem sap after 15^N-NO3 and 15^N-NH4 were fed to the ...An experiment was carried out to study the transport process of nitrogen （N） assimilation from tea roots by monitoring the dynamic composition of N compounds in xylem sap after 15^N-NO3 and 15^N-NH4 were fed to the root of tea plants （Camellia sinensis L.）. Results showed that the main amino acids were glutamine, theanine, axginine, asparic acid and glutamic acid, which accounted for 49%, 17%, 8%, 7%, and 4%, respectively, of the total amino acids in the xylem sap. After the tea plants were fed with 15^N-NO3 and 15^N-NH4 for 48 h, the amount of total amino acids in xylem sap significantly increased and those fed with 15^N-NH4 had higher increment than those with 15^N-NOa. Two hours after 15^N- NO3 and 15^N-NH4 were fed, 15N abundance in glutamine, asparagine, glutamic acid, alanine, and arginine were detected and increased quickly over time. This indicated that it took less than 2 h for NO3-N and NH4-N to be absorbed by tea roots, incorporated into the above amino acids and transported to the xylem sap. Rapid increase in 15^N-NO3 in the xylem sap of tea plants fed with 15^N-NO3 indicated that nitrate could be directly transported to the xylem sap. Glutamine, theanine, and alanine were the main amino acids transported in xylem sap of tea plants fed with both 15^N-NO3 and 15^N-NH4.展开更多
The main objectives of this study were to introduce an integrated method for effectively identifying soil heavy metal pollution sources and apportioning their contributions, and apply it to a case study. The method co...The main objectives of this study were to introduce an integrated method for effectively identifying soil heavy metal pollution sources and apportioning their contributions, and apply it to a case study. The method combines the principal component analysis/absolute principal component scores (PCA/APCS) receptor model and geostatistics. The case study was conducted in an area of 31 km2 in the urban-rural transition zone of Wuhan, a metropolis of central China. 124 topsoil samples were collected for measuring the concentrations of eight heavy metal elements (Mn, Cu, Zn, Pb, Cd, Cr, Ni and Co). PCA results revealed that three major factors were responsible for soil heavy metal pollution, which were initially identified as "steel production", "agronomic input" and "coal consumption". The APCS technique, combined with multiple linear regression analysis, was then applied for source apportionment. Steel production appeared to be the main source for Ni, Co, Cd, Zn and Mn, agronomic input for Cu, and coal consumption for Pb and Cr. Geostatistical interpolation using ordinary kriging was finally used to map the spatial distributions of the contributions of pollution sources and further confirm the result interpretations. The introduced method appears to be an effective tool in soil pollution source apportionment and identification, and might provide valuable reference information for pollution control and environmental management.展开更多
Dimethylsulfide(DMS) measurements in the surface seawater of China eastern coastline were conducted during March 9—10, 1993 in Bohai Sea along the cruise from Dalian to Tianjin and during September 24—25, 1994 in Ye...Dimethylsulfide(DMS) measurements in the surface seawater of China eastern coastline were conducted during March 9—10, 1993 in Bohai Sea along the cruise from Dalian to Tianjin and during September 24—25, 1994 in Yellow Sea along the cruise from Shanghai to Qingdao. On the cruise in Bohai Sea DMS concentrations varied from 0.11 to 2.63 nmol/L with an average of 1.31 nmol/L, while DMS flux was estimated to be 0.85 μmol/(m 2·d) with the range of 0.04—3.12 μmol/(m 2·d). On the cruise in Yellow Sea DMS concentrations varied from 0.95 to 7.48 nmol/L with an average of 2.89 nmol/L, and DMS flux was estimated to be 7.94 μmol/(m 2·d) with the range of 0.11—18.88 μmol/(m 2·d). Variations in DMS concentrations along the latitude in Yellow Sea were observed larger than those along the longitude in Bohai Sea. DMS concentrations and fluxes had a similar spatial trend both in Bohai Sea and Yellow Sea with the correlation coefficients of 0.75 and 0.64, respectively.展开更多
The Subei Shoal is a special coastal area with complex physical oceanographic properties in the Yellow Sea.In the present study,the distribution of phytoplankton and its correlation with environmental factors were stu...The Subei Shoal is a special coastal area with complex physical oceanographic properties in the Yellow Sea.In the present study,the distribution of phytoplankton and its correlation with environmental factors were studied during spring and summer of 2012 in the Subei Shoal of the Yellow Sea.Phytoplankton species composition and abundance data were accomplished by Utermohl method.Diatoms represented the greatest cellular abundance during the study period.In spring,the phytoplankton cell abundance ranged from 1.59×10^3 to 269.78×10^3 cell/L with an average of 41.80×10^3 cell/L,and Skeletonema sp.and Paralia sulcata was the most dominant species.In summer,the average phytoplankton cell abundance was 72.59×10^3 cell/L with the range of 1.78×10^3 to 574.96×10^3 cell/L,and the main dominant species was Pseudo-nitzschia pungens,Skeletonema sp.,Dactyliosolen fragilissima and Chaetoceros curvisetus.The results of a redundancy analysis(RDA)showed that turbidity,temperature,salinity,pH,dissolved oxygen(DO),the ratio of dissolved inorganic nitrogen to silicate and SiO4-Si(DIN/SiO4-Si)were the most important environmental factors controlling phytoplankton assemblages in spring or summer in the Subei Shoal of the Yellow Sea.展开更多
The effects of varying nitrogen （N）： phosphorus （P） ratios on the growth and N-uptake and assimilation of the harmful dinoflagellates Prorocentrum minimum and Prorocentrum donghaiense were examined in turbidistat...The effects of varying nitrogen （N）： phosphorus （P） ratios on the growth and N-uptake and assimilation of the harmful dinoflagellates Prorocentrum minimum and Prorocentrum donghaiense were examined in turbidistat culture experiments. Algal cultures were supplied with media containing PO4^3- in various concentrations to obtain a wide range of N：P ratios. Experiments to determine rates of N uptake and assimilation of different N sources （NO^3-, NH4^＋, urea and glycine by P. minimum and NO3^-, NH4^＋ by P. donghaiense） were conducted using ^15-N tracer techniques at each N：P ratio. The growth rates suggested nutrient limitation at both high and low N：P ratios relative to the Redfield ratio. On a diel basis, the growth of both species was regulated by the light-dark cycle, which may be a result of regulation of both lightdependent growth and light-independent nutrient uptake. Maximum growth rates of both species always occurred at the beginning of light phase. In P-rich medium （low N：P ratio）, both species had higher N assimilation rates, suggesting N limitation. Low assimilation coefficients at high N：P ratios suggested P limitation of N uptake and assimilation. NO3 ^-and NH4^＋ contributed more than 90% of the total N uptake of P. minimum. Reduced N sources were more quickly assimilated than NO3^-. Highest average daily growth rates were recorded near an N：P ratio of 12 for both species. The N uptake rates of cultures at N：P ratios near Redfield ratio were more balanced with growth rates. The linkage between growth rates and N uptake/assimilation rates were conceptually described by the variation of cell N quota. The N：P ratios affect the N uptake and growth of Prorocentrum spp., and may regulate their bloom progression in eutrophic ecosystems.展开更多
Mesoscale eddy activity and its modulation mechanism in the South China Sea （SCS） are inves- tigated with newly reprocessed satellite altimetry observations and hydrographic data. The eddy kinetic energy （EKE） lev...Mesoscale eddy activity and its modulation mechanism in the South China Sea （SCS） are inves- tigated with newly reprocessed satellite altimetry observations and hydrographic data. The eddy kinetic energy （EKE） level of basin-wide averages show a distinct seasonal cycle with the maximum in August-December and the minimum in February-May. Furthermore, the seasonal pattern of EKE in the basin is dominated by region offshore of central Vietnam （OCV）, southwest of Taiwan Island （SWT）, and southwest of Luzon （SWL）, which are also the breeding grounds of mesoscale eddies in the SCS. Instability theory analysis suggests that the seasonal cycle of EKE is modulated by the baroclinic instability of the mean flow. High eddy growth rate （EGR） is found in the active eddy regions. Vertical velocity shear in the upper 50-500 m is crucial for the growth of baroclinic instability, leading to seasonal EKE evolution in the SCS.展开更多
Surface plasmon resonance(SPR)of metals may provide a way to improve light absorption and utilization of semiconductors,achieving better solar light conversion and photocatalysis efficiency.This study uses the advanta...Surface plasmon resonance(SPR)of metals may provide a way to improve light absorption and utilization of semiconductors,achieving better solar light conversion and photocatalysis efficiency.This study uses the advantages of SPR in metallic Bi and artificial defects to cooperatively enhance the photocatalytic performance of BiOI.The catalysts were prepared by partial reduction of BiOI to form Bi@defective BiOI,which showed highly enhanced visible photocatalytic activity for NOx removal.The effects of reductant quantity on the photocatalytic performance of Bi@defective BiOI were investigated.The as-prepared photocatalyst(Bi/BiOI-2)using 2 mmol of reductant NaBH4 showed the most efficient visible light photocatalytic activity.This enhanced activity can be ascribed to the synergistic effects of metallic Bi and oxygen vacancies.The electrons from the valence band tend to accumulate at vacancy states;therefore,the increased charge density would cause the adsorbed oxygen to transform more easily into superoxide radicals and,further,into hydroxyl radicals.These radicals are the main active species that oxidize NO into final products.The SPR effect of elemental Bi enables the improvement of visible light absorption efficiency and the promotion of charge carrier separation,which are crucial factors in boosting photocatalysis.NO adsorption and reaction processes on Bi/BiOI-2 were dynamically monitored by in situ infrared spectroscopy(FT-IR).The Bi/BiOI photocatalysis mechanism co-mediated by elemental Bi and oxygen vacancies was proposed based on the analysis of intermediate products and DFT calculations.This present work could provide new insights into the design of high-performance photocatalysts and understanding of the photocatalysis reaction mechanism for air-purification applications.展开更多
The BiOCl/Bi12O17Cl2@MoS2(BOC-MS)composites were successfully synthesized by a facile method at room temperature.The physicochemical properties of the as-obtained samples were characterized by X-ray diffractometer(XRD...The BiOCl/Bi12O17Cl2@MoS2(BOC-MS)composites were successfully synthesized by a facile method at room temperature.The physicochemical properties of the as-obtained samples were characterized by X-ray diffractometer(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),ultraviolet–visible diffuse reflection spectra(UV–Vis DRS),photoluminescence(PL),Brunauer–Emmett–Teller–Barrett–Joyner–Halenda(BET–BJH),and electron spin resonance(ESR)in detail.Moreover,the in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)was applied to elucidate the adsorption and photocatalytic reaction mechanism.The optimized BOC-MS-1.0 composites exhibited excellent visible light photocatalytic capability(51.1%)and photochemical stability for removal of NO.Based on the DMPOESR spin trapping,the·O2-radicals andáOH radicals were identified as the main active species generated from BOCMS-1.0 under visible light irradiation.The enhanced photocatalytic performance can be ascribed to the positive synergetic effect of the MoS2 and the effective carrier separation ability.展开更多
Beef consumption in China has increased substantially from 5.0 million tons in 2000 to 7.7 million tons in 2019 thanks to rapid income growth,but still remains low compared to pork and poultry consumption.Improving th...Beef consumption in China has increased substantially from 5.0 million tons in 2000 to 7.7 million tons in 2019 thanks to rapid income growth,but still remains low compared to pork and poultry consumption.Improving the understanding about the impacts of household income on beef consumption in China is necessary to forecast future beef demand and inform the domestic beef industry,especially in the context of unprecedented expansion of middle income class in China.Based on survey data of 32878 urban households collected by the National Bureau of Statistics of China,we employed the inverse hyperbolic sine(IHS)double-hurdle model to estimate income elasticities of beef demand across different income groups and simulated possible trends of future beef consumption of Chinese urban residents.The empirical results showed that the unconditional income elasticities of beef consumption at home vary between 0.169 for the lowincome group and 0.671 for the high-income group.The simulated results indicated that beef consumption is expected to increase by 12.0 to 38.8%in 10 years and by 18.6 to 70.5%in 15 years under distinct income growth scenarios.Our findings provide practical insights for policy makers and other stakeholders about future beef demand,such as potential opportunities embedded in rising beef demand for domestic producers and world beef exporters as well as the urgency of improving the supply chain resilience of beef in China.展开更多
The dinoflagellate Noctiluca scintillans is one of the most important and abundant red tide organisms and it is distributed world-wide. It occurs in two forms. Red Noctiluca is heterotrophic and fills the role of one ...The dinoflagellate Noctiluca scintillans is one of the most important and abundant red tide organisms and it is distributed world-wide. It occurs in two forms. Red Noctiluca is heterotrophic and fills the role of one of the microzooplankton grazers in the foodweb. In contrast, green Noctiluca contains a photosynthetic symbiont Pedinomonas noctilucae （a prasinophyte）, but it also feeds on other plankton when the food supply is abundant. In this review, we document the global distribution of these two forms and include the first maps of their global distribution. Red Noctiluca occurs widely in the temperate to sub-tropical coastal regions of the world. It occurs over a wide temperature range of about 10℃ to 25℃ and at higher salinities （generally not in estuaries）. It is particularly abundant in high productivity areas such as upwelling or eutrophic areas where diatoms dominate since they are its preferred food source. Green Noctiluca is much more restricted to a temperature range of 25℃-30℃ and mainly occurs in tropical waters of Southeast Asia, Bay of Bengal （east coast of India）, in the eastern, western and northern Arabian Sea, the Red Sea, and recently it has become very abundant in the Gulf of Oman. Red and green Noctiluca do overlap in their distribution in the eastern, northern and western Arabian Sea with a seasonal shift from green Noctiluca in the cooler winter convective mixing, higher productivity season, to red Noctiluca in the more oligotrophic warmer summer season.展开更多
基金the German Federal Ministry of Education and Research(BMBF)for funding the Chaohu Lake project in the frame of the Chinese Major Water Program(02WCL1337A-E)the Sino-German Center for Science Promotion(CDZ)for the Poyang Lake project(GZ1167)+1 种基金the Helmholtz Association for supporting the establishment of Center for Environmental Information Science(HIRN 0002)the Chinese Academy of Sciences(CAS)for providing support to various activities through the CAS President’s International Fellowship Initiative(PIFI)
文摘1.Introduction The availability of reliable information describing our natural and anthropogenic environment—and its changes in particular—is crucial for understanding the complexity of structures and processes within environmental systems.Modern remote sensing and monitoring methods provide an increasing amount of environmental data that can be used for a variety of management purposes[1,2].
文摘Environmental pollution and energy shortage has been regarded as the two major challenges because of the rapid development of urbanization and industrialization.Considering these challenges,providing green environment and energy for human beings are pivotal for future sustainable development.Nanostructured catalysts(photocatalysts,thermal catalysts and electrocatalysts)with unique physiochemical properties could offer numerous opportunities to solve these issues of environmental and energetic sustainability.In recent years,significant advances have been made on the synthesis,mechanistic understanding and innovative applications of the new catalysts for environmental and energetic problems.These new catalysts have found wide applications in different fashions.
文摘While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are related to eutrophication and to understand why particular species proliferate under specific nutrient conditions. The overall goal of this brief review is to describe why nutrient loads are not changing in stoichiometric proportion to the "Redfield ratio", and why this has important consequences for algal growth. Many types of harmful algae appear to be able to thrive, and/or increase their production of toxins, when nutrient loads are not in proportion classically identified as Redfield ratios. Here we also describe some of the physiological mechanisms of different species to take up nutrients and to thrive under conditions of nutrient imbalance.
基金Project supported by the National Natural Science Foundation of China (No. 40471066)the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KZCX3-SW-417)
文摘A field experiment, involving lime N (calcium cyanamide, CaCN2) fertilization as a control measure, was conducted to study environmental problems induced by long-term heavy N application in Japanese tea fields. Long-term tea cultivation caused serious soil acidification. Seventy-seven percent of the 70 tea fields investigated had soil pH values below 4.0, and 9% below 3.0, with the lowest value of 2.7. Moreover, excess N application in tea fields put a threat to plant growth, induced serious nitrate contamination to local water, and caused high nitrous oxide loss. Compared with the conventional high N application treatment (1100 kg N ha-1) without lime N, the low N application (400 kg N ha-1) with calcium cyanamide effectively stopped soil acidification as well as achieved the same or slightly higher levels in tea yield and in total N and amino acid contents of tea shoots. The application of calcium cyanamide could be a suitable fertilization for the prevention of environmental problems in tea cultivation.
基金RKG acknowledges financial assistance from Department of Science and Technology(DST)India,through the INSPIRE Faculty Award(Project No.IFA-13 ENG-57)Grant No.DST/TM/WTI/2K16/23(G).PK thanks IIT Kanpur for Institute Postdoctoral Fellowship.
文摘The presence of emerging pharmaceutical pollutants at low concentration levels in the surface and ground water has caused a potential threat to the marine and human lives.The emerging pharmaceutical pollutants generally include analgesics and anti-inflammatories,lipid-lowering drugs,antiepileptics,antibiotics,and β-blockers compounds.In recent years,various processes have been developed and advanced oxidation process is the most effective for decontamination of emerging pharmaceutical pollutants till date.Semiconductor based photocatalysis technology has recently received a great interest for the removal of new emerging pharmaceutical pollutants.This review article highlights the removal of emerging pharmaceutical pollutants especially through photocatalysis as well as recent progress using different nanostructures.Additional focus has been given over fundamental key dynamics processes of nanomaterials and degradation pathways of emerging pharmaceutical pollutants.Finally,this review concludes with the perspectives and outlook over future developments in photocatalysis technology for the degradation of emerging pharmaceutical pollutants leading to a solution for realworld in near future.
基金financially supported by the National Science and Technology Support Program of China(Grant No.2010BAC68B04)
文摘For simulating water wave propagation in coastal areas, various Boussinesq-type equations with improved properties in intermediate or deep water have been presented in the past several decades. How to choose proper Boussinesq-type equations has been a practical problem for engineers. In this paper, approaches of improving the characteristics of the equations, i.e. linear dispersion, shoaling gradient and nonlinearity, are reviewed and the advantages and disadvantages of several different Boussinesq-type equations are compared for the applications of these Boussinesq-type equations in coastal engineering with relatively large sea areas. Then for improving the properties of Boussinesq-type equations, a new set of fully nonlinear Boussinseq-type equations with modified representative velocity are derived, which can be used for better linear dispersion and nonlinearity. Based on the method of minimizing the overall error in different ranges of applications, sets of parameters are determined with optimized linear dispersion, linear shoaling and nonlinearity, respectively. Finally, a test example is given for validating the results of this study. Both results show that the equations with optimized parameters display better characteristics than the ones obtained by matching with pad6 approximation.
文摘As the pressures on water resources are ever increasing,the organization of complex disparate data and scientific information to inform the actions to protect and enhance the resilience of freshwater resources is key for sustainable development and implementation of integrated water resource management(IWRM).Methodologies supporting IWRM implementation have largely focused on water management and governance,with less attention to evaluation methods of ecologic,economic,and social conditions.To assist in assessing water resource sustainability,the Integrated Hydro-Environment Assessment Tool(IHEAT)has been developed to create a framework for different disciplines and interests to engage in structured dialogue.The IHEAT builds on the considerable body of knowledge developed around IWRM and seeks to place this information into a single framework that facilitates the cogeneration of knowledge between managers,stakeholders,and the communities affected by management decisions with the understanding that there is a need to merge expert analysis with traditional knowledge and the lived experience of communities.IHEAT merges the driver-pressure-state-impact-response(DPSIR)framework,the Millennium Ecosystem Assessment's ecosystem services and human well-being(HWB)framework,sustainability criteria for water resource systems,and water resources indexes and sets of indicators to better understand spatiotemporal interactions between hydrologic,socioeconomic,and ecologic systems and evaluate impacts of disturbances on ecological goods and services and HWB.IHEAT consists of a Conceptual Template(IHEAT-CT)which provides a systematic framework for assessing basin conditions and guiding indicator selection as well as an Assessment Interface(IHEAT-AI)for organizing,processing,and assessing analytical results.The IHEAT-CT,presented herein,is a rapid screening tool that connects water use directly,or through ecosystem goods and services(EGS),to constituents of HWB.Disturbance Templates for eight pressure types,such as land-use change,climate change,and population growth,are provided to guide practitioners regarding potential changes to landscape elements in the hydrological cycle,impacts on EGS,and societal implications on HWB.The basin screening results in a summary report card illuminating key freshwater ecosystems,the EGS they provide,and potential responses to drivers and pressures acting on the hydrologic system.This screening provides a common understanding by technical and nontechnical parties and provides the foundation for more complex conceptual models should they be required.An indicator list guides the selection of hydrologic,ecologic,economic,and social analytical methods to support IWRM technical input.
基金supported by funding from the Natural Science Foundation of China(Grant Nos.52373266 and 22105129)the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2024A1515012334 and 2022A1515011048)+1 种基金the Science and Technology Innovation Commission of Shenzhen(Grant No.KQTD20170810105439418)We are grateful to the Guangdong Basic and Applied Basic Research Committee Foundation(Grant Nos.2023A1515110316 and 2024A1515011848).
文摘Applying catalysts for electrochemical energy conversion holds great promise for developing clean and sustainable energy sources.One of the main advantages of electrocatalysis is its ability to reduce conversion energy loss significantly.However,the wide application of electrocatalysts in these conversion processes has been hindered by poor catalytic performance and limited resources of catalyst materials.To overcome these challenges,researchers have turned to two-dimensional(2D)materials,which possess large specific surface areas and can easily be engineered to have desirable electronic structures,making them promising candidates for high-performance electrocatalysis in various reactions.This comprehensive review focuses on engineering novel 2D material-based electrocatalysts and their application to seawater splitting.The review briefly introduces the mechanism of seawater splitting and the primary challenges of 2D materials.Then,we highlight the unique advantages and regulating strategies for seawater electrolysis based on recent advancements.We also review various 2D catalyst families for direct seawater splitting and delve into the physicochemical properties of these catalysts to provide valuable insights.Finally,we outline the vital future challenges and discuss the perspectives on seawater electrolysis.This review provides valuable insights for the rational design and development of cutting-edge 2D material electrocatalysts for seawater-electrolysis applications.
文摘An experiment was carried out to study the transport process of nitrogen （N） assimilation from tea roots by monitoring the dynamic composition of N compounds in xylem sap after 15^N-NO3 and 15^N-NH4 were fed to the root of tea plants （Camellia sinensis L.）. Results showed that the main amino acids were glutamine, theanine, axginine, asparic acid and glutamic acid, which accounted for 49%, 17%, 8%, 7%, and 4%, respectively, of the total amino acids in the xylem sap. After the tea plants were fed with 15^N-NO3 and 15^N-NH4 for 48 h, the amount of total amino acids in xylem sap significantly increased and those fed with 15^N-NH4 had higher increment than those with 15^N-NOa. Two hours after 15^N- NO3 and 15^N-NH4 were fed, 15N abundance in glutamine, asparagine, glutamic acid, alanine, and arginine were detected and increased quickly over time. This indicated that it took less than 2 h for NO3-N and NH4-N to be absorbed by tea roots, incorporated into the above amino acids and transported to the xylem sap. Rapid increase in 15^N-NO3 in the xylem sap of tea plants fed with 15^N-NO3 indicated that nitrate could be directly transported to the xylem sap. Glutamine, theanine, and alanine were the main amino acids transported in xylem sap of tea plants fed with both 15^N-NO3 and 15^N-NH4.
基金Supported by the National Natural Science Foundation of China (No. 40971269)
文摘The main objectives of this study were to introduce an integrated method for effectively identifying soil heavy metal pollution sources and apportioning their contributions, and apply it to a case study. The method combines the principal component analysis/absolute principal component scores (PCA/APCS) receptor model and geostatistics. The case study was conducted in an area of 31 km2 in the urban-rural transition zone of Wuhan, a metropolis of central China. 124 topsoil samples were collected for measuring the concentrations of eight heavy metal elements (Mn, Cu, Zn, Pb, Cd, Cr, Ni and Co). PCA results revealed that three major factors were responsible for soil heavy metal pollution, which were initially identified as "steel production", "agronomic input" and "coal consumption". The APCS technique, combined with multiple linear regression analysis, was then applied for source apportionment. Steel production appeared to be the main source for Ni, Co, Cd, Zn and Mn, agronomic input for Cu, and coal consumption for Pb and Cr. Geostatistical interpolation using ordinary kriging was finally used to map the spatial distributions of the contributions of pollution sources and further confirm the result interpretations. The introduced method appears to be an effective tool in soil pollution source apportionment and identification, and might provide valuable reference information for pollution control and environmental management.
文摘Dimethylsulfide(DMS) measurements in the surface seawater of China eastern coastline were conducted during March 9—10, 1993 in Bohai Sea along the cruise from Dalian to Tianjin and during September 24—25, 1994 in Yellow Sea along the cruise from Shanghai to Qingdao. On the cruise in Bohai Sea DMS concentrations varied from 0.11 to 2.63 nmol/L with an average of 1.31 nmol/L, while DMS flux was estimated to be 0.85 μmol/(m 2·d) with the range of 0.04—3.12 μmol/(m 2·d). On the cruise in Yellow Sea DMS concentrations varied from 0.95 to 7.48 nmol/L with an average of 2.89 nmol/L, and DMS flux was estimated to be 7.94 μmol/(m 2·d) with the range of 0.11—18.88 μmol/(m 2·d). Variations in DMS concentrations along the latitude in Yellow Sea were observed larger than those along the longitude in Bohai Sea. DMS concentrations and fluxes had a similar spatial trend both in Bohai Sea and Yellow Sea with the correlation coefficients of 0.75 and 0.64, respectively.
基金The Public Science and Technology Research Funds Projects of the Ocean under contract Nos 201205010 and201205009-5the National Science&Technology Pillar Program under contract No.2012BAC07B03+3 种基金the National Natural Science Foundation of China under contract No.41206111the Chinese Science and Technology Base Projects under contract No.2012FY112500the Shanghai Universities First-class Disciplines Project(Disapline name:Marine Science(0707))the Plateau Peak Disciplines Project of Shanghai Universities(Marine Science 0707)
文摘The Subei Shoal is a special coastal area with complex physical oceanographic properties in the Yellow Sea.In the present study,the distribution of phytoplankton and its correlation with environmental factors were studied during spring and summer of 2012 in the Subei Shoal of the Yellow Sea.Phytoplankton species composition and abundance data were accomplished by Utermohl method.Diatoms represented the greatest cellular abundance during the study period.In spring,the phytoplankton cell abundance ranged from 1.59×10^3 to 269.78×10^3 cell/L with an average of 41.80×10^3 cell/L,and Skeletonema sp.and Paralia sulcata was the most dominant species.In summer,the average phytoplankton cell abundance was 72.59×10^3 cell/L with the range of 1.78×10^3 to 574.96×10^3 cell/L,and the main dominant species was Pseudo-nitzschia pungens,Skeletonema sp.,Dactyliosolen fragilissima and Chaetoceros curvisetus.The results of a redundancy analysis(RDA)showed that turbidity,temperature,salinity,pH,dissolved oxygen(DO),the ratio of dissolved inorganic nitrogen to silicate and SiO4-Si(DIN/SiO4-Si)were the most important environmental factors controlling phytoplankton assemblages in spring or summer in the Subei Shoal of the Yellow Sea.
基金supported by the University of Maryland Center for Environmental Science (UMCES), Horn Point Laboratory. This is UMCES contribution number 4503
文摘The effects of varying nitrogen （N）： phosphorus （P） ratios on the growth and N-uptake and assimilation of the harmful dinoflagellates Prorocentrum minimum and Prorocentrum donghaiense were examined in turbidistat culture experiments. Algal cultures were supplied with media containing PO4^3- in various concentrations to obtain a wide range of N：P ratios. Experiments to determine rates of N uptake and assimilation of different N sources （NO^3-, NH4^＋, urea and glycine by P. minimum and NO3^-, NH4^＋ by P. donghaiense） were conducted using ^15-N tracer techniques at each N：P ratio. The growth rates suggested nutrient limitation at both high and low N：P ratios relative to the Redfield ratio. On a diel basis, the growth of both species was regulated by the light-dark cycle, which may be a result of regulation of both lightdependent growth and light-independent nutrient uptake. Maximum growth rates of both species always occurred at the beginning of light phase. In P-rich medium （low N：P ratio）, both species had higher N assimilation rates, suggesting N limitation. Low assimilation coefficients at high N：P ratios suggested P limitation of N uptake and assimilation. NO3 ^-and NH4^＋ contributed more than 90% of the total N uptake of P. minimum. Reduced N sources were more quickly assimilated than NO3^-. Highest average daily growth rates were recorded near an N：P ratio of 12 for both species. The N uptake rates of cultures at N：P ratios near Redfield ratio were more balanced with growth rates. The linkage between growth rates and N uptake/assimilation rates were conceptually described by the variation of cell N quota. The N：P ratios affect the N uptake and growth of Prorocentrum spp., and may regulate their bloom progression in eutrophic ecosystems.
基金The National Natural Science Foundation of China under contract No.41076011,40531006,41106024 and40976014the National Basic Research Program of China under contract No.2011CB403600
文摘Mesoscale eddy activity and its modulation mechanism in the South China Sea （SCS） are inves- tigated with newly reprocessed satellite altimetry observations and hydrographic data. The eddy kinetic energy （EKE） level of basin-wide averages show a distinct seasonal cycle with the maximum in August-December and the minimum in February-May. Furthermore, the seasonal pattern of EKE in the basin is dominated by region offshore of central Vietnam （OCV）, southwest of Taiwan Island （SWT）, and southwest of Luzon （SWL）, which are also the breeding grounds of mesoscale eddies in the SCS. Instability theory analysis suggests that the seasonal cycle of EKE is modulated by the baroclinic instability of the mean flow. High eddy growth rate （EGR） is found in the active eddy regions. Vertical velocity shear in the upper 50-500 m is crucial for the growth of baroclinic instability, leading to seasonal EKE evolution in the SCS.
基金supported by the National Natural Science Foundation of China(21501016,21777011 and 21822601)the National Key R&D Program of China(2016YFC02047)+2 种基金the Innovative Research Team of Chongqing(CXTDG201602014)the Key Natural Science Foundation of Chongqing(cstc2017jcyj BX0052)the National Ten Thousand Talent Program of China~~
文摘Surface plasmon resonance(SPR)of metals may provide a way to improve light absorption and utilization of semiconductors,achieving better solar light conversion and photocatalysis efficiency.This study uses the advantages of SPR in metallic Bi and artificial defects to cooperatively enhance the photocatalytic performance of BiOI.The catalysts were prepared by partial reduction of BiOI to form Bi@defective BiOI,which showed highly enhanced visible photocatalytic activity for NOx removal.The effects of reductant quantity on the photocatalytic performance of Bi@defective BiOI were investigated.The as-prepared photocatalyst(Bi/BiOI-2)using 2 mmol of reductant NaBH4 showed the most efficient visible light photocatalytic activity.This enhanced activity can be ascribed to the synergistic effects of metallic Bi and oxygen vacancies.The electrons from the valence band tend to accumulate at vacancy states;therefore,the increased charge density would cause the adsorbed oxygen to transform more easily into superoxide radicals and,further,into hydroxyl radicals.These radicals are the main active species that oxidize NO into final products.The SPR effect of elemental Bi enables the improvement of visible light absorption efficiency and the promotion of charge carrier separation,which are crucial factors in boosting photocatalysis.NO adsorption and reaction processes on Bi/BiOI-2 were dynamically monitored by in situ infrared spectroscopy(FT-IR).The Bi/BiOI photocatalysis mechanism co-mediated by elemental Bi and oxygen vacancies was proposed based on the analysis of intermediate products and DFT calculations.This present work could provide new insights into the design of high-performance photocatalysts and understanding of the photocatalysis reaction mechanism for air-purification applications.
基金financially supported by the National Natural Science Foundation of China (Nos. 51708078 and 41801063)the Natural Science Foundation of Chongqing (No. 2018jcyjA1040)
文摘The BiOCl/Bi12O17Cl2@MoS2(BOC-MS)composites were successfully synthesized by a facile method at room temperature.The physicochemical properties of the as-obtained samples were characterized by X-ray diffractometer(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),ultraviolet–visible diffuse reflection spectra(UV–Vis DRS),photoluminescence(PL),Brunauer–Emmett–Teller–Barrett–Joyner–Halenda(BET–BJH),and electron spin resonance(ESR)in detail.Moreover,the in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)was applied to elucidate the adsorption and photocatalytic reaction mechanism.The optimized BOC-MS-1.0 composites exhibited excellent visible light photocatalytic capability(51.1%)and photochemical stability for removal of NO.Based on the DMPOESR spin trapping,the·O2-radicals andáOH radicals were identified as the main active species generated from BOCMS-1.0 under visible light irradiation.The enhanced photocatalytic performance can be ascribed to the positive synergetic effect of the MoS2 and the effective carrier separation ability.
基金the National Natural Science Foundation of China(71473251)。
文摘Beef consumption in China has increased substantially from 5.0 million tons in 2000 to 7.7 million tons in 2019 thanks to rapid income growth,but still remains low compared to pork and poultry consumption.Improving the understanding about the impacts of household income on beef consumption in China is necessary to forecast future beef demand and inform the domestic beef industry,especially in the context of unprecedented expansion of middle income class in China.Based on survey data of 32878 urban households collected by the National Bureau of Statistics of China,we employed the inverse hyperbolic sine(IHS)double-hurdle model to estimate income elasticities of beef demand across different income groups and simulated possible trends of future beef consumption of Chinese urban residents.The empirical results showed that the unconditional income elasticities of beef consumption at home vary between 0.169 for the lowincome group and 0.671 for the high-income group.The simulated results indicated that beef consumption is expected to increase by 12.0 to 38.8%in 10 years and by 18.6 to 70.5%in 15 years under distinct income growth scenarios.Our findings provide practical insights for policy makers and other stakeholders about future beef demand,such as potential opportunities embedded in rising beef demand for domestic producers and world beef exporters as well as the urgency of improving the supply chain resilience of beef in China.
基金the University Grants Council of Hong Kong and its Area of Excellence Program to PJH. KF was supported by a JSPS grant on the ecophysiology of green Noctiluca in the Gulf of Thailand. PMG received funding from NSF （No. OCE-1015980）This is contribution number 4502 from the University of Maryland Center for Environmental Studies. KY Acknowledges Support from the CAS/SAFEA International Partnership Program for Creative Research Teams （No. KZCXZYW-T001）. DMA received partial funding through the NSF/NIEHS Centers for Oceans and Human Health （No. NIEHS P50 ES012742, NSF OCE- 043072 and OCE-0911031）, and through NSF Grant （No. OCE-0850421）+1 种基金 This paper is based on work partially supported by SCOR/LOICZ Working Group 132, supported by the Scientific Committee on Oceanographic Research （SCOR） through grants from the U.S. National Science Foundation （No OCE-0938349 and OCE-0813697） from the Land-Ocean Interactions in the Coastal Zone （LOICZ） Project and the Chinese Academy of Sciences. We thank A. KANA for assistance with the GIS produced maps and LIU Hao for his assistance with the tables and references.
文摘The dinoflagellate Noctiluca scintillans is one of the most important and abundant red tide organisms and it is distributed world-wide. It occurs in two forms. Red Noctiluca is heterotrophic and fills the role of one of the microzooplankton grazers in the foodweb. In contrast, green Noctiluca contains a photosynthetic symbiont Pedinomonas noctilucae （a prasinophyte）, but it also feeds on other plankton when the food supply is abundant. In this review, we document the global distribution of these two forms and include the first maps of their global distribution. Red Noctiluca occurs widely in the temperate to sub-tropical coastal regions of the world. It occurs over a wide temperature range of about 10℃ to 25℃ and at higher salinities （generally not in estuaries）. It is particularly abundant in high productivity areas such as upwelling or eutrophic areas where diatoms dominate since they are its preferred food source. Green Noctiluca is much more restricted to a temperature range of 25℃-30℃ and mainly occurs in tropical waters of Southeast Asia, Bay of Bengal （east coast of India）, in the eastern, western and northern Arabian Sea, the Red Sea, and recently it has become very abundant in the Gulf of Oman. Red and green Noctiluca do overlap in their distribution in the eastern, northern and western Arabian Sea with a seasonal shift from green Noctiluca in the cooler winter convective mixing, higher productivity season, to red Noctiluca in the more oligotrophic warmer summer season.
