The Xianshuihe-Anninghe fault extends SE–S and constitutes the southeastern margin of the Tibetan Plateau.However,the Dadu River which is associated with the fault does not flow following the path,but makes a 90º...The Xianshuihe-Anninghe fault extends SE–S and constitutes the southeastern margin of the Tibetan Plateau.However,the Dadu River which is associated with the fault does not flow following the path,but makes a 90ºturn within a distance of 1 km at Shimian,heading east,and joins the Yangtze River,finally flowing into the East China Sea.Adjacent to the abrupt turn,a low and wide pass near the Daqiao reservoir at Mianning separates the N–S course of the Dadu River from the headwater of the Anning River which then flows south into the Yunnan Province along the Anninghe fault.Therefore,many previous studies assumed southward flow of the paleo-Dadu River from the Shimian to the Anning River.However,evidences for the capture of the integrated N–S paleo-Dadu-Anning River,its timing,and causes are still insufficient.This study explored the paleo-drainage pattern of the Dadu and Anning Rivers based on bulk mineral and geochemical analyses of the large quantities of fluvial/lacustrine sediments along the trunk of the Dadu and Anning Rivers.Similar with sands in the modern Dadu River,the Xigeda sediments also exhibit a granitoid affinity with the bulk major mineral compositions of quartz(>50%),anorthite(about 10%),orthoclase(about 5%),muscovite(about 5%),and clinochlore(about 4%).Correspondingly,bulk major elements show high SiO_(2),with all samples>60%,and some of them>70%,low TiO_(2)(≤0.75%),P_(2)O_(5)(≤0.55%),FeO*(≤5%),and relatively high CaO(1.02%–8.51%),Na_(2)O(1.60%–2.52%),and K_(2)O(2.17%–2.71%),with a uniform REE patterns.Therefore,synthesizing all these results indicate that these lacustrine sediments have similar material sources,which are mainly derived from its course in the Songpan-Ganzi flysch block,implying that the paleo-Dadu originally flowed southward into the Anning River and provided materials to the Xigeda ancient lake.The rearrangement of the paleo-Dadu River appears to be closely related to the locally focused uplift driven by strong activities of the XianshuiheXiaojiang fault system.展开更多
The complexity of river-tide interaction poses a significant challenge in predicting discharge in tidal rivers.Long short-term memory(LSTM)networks excel in processing and predicting crucial events with extended inter...The complexity of river-tide interaction poses a significant challenge in predicting discharge in tidal rivers.Long short-term memory(LSTM)networks excel in processing and predicting crucial events with extended intervals and time delays in time series data.Additionally,the sequence-to-sequence(Seq2Seq)model,known for handling temporal relationships,adapting to variable-length sequences,effectively capturing historical information,and accommodating various influencing factors,emerges as a robust and flexible tool in discharge forecasting.In this study,we introduce the application of LSTM-based Seq2Seq models for the first time in forecasting the discharge of a tidal reach of the Changjiang River(Yangtze River)Estuary.This study focuses on discharge forecasting using three key input characteristics:flow velocity,water level,and discharge,which means the structure of multiple input and single output is adopted.The experiment used the discharge data of the whole year of 2020,of which the first 80%is used as the training set,and the last 20%is used as the test set.This means that the data covers different tidal cycles,which helps to test the forecasting effect of different models in different tidal cycles and different runoff.The experimental results indicate that the proposed models demonstrate advantages in long-term,mid-term,and short-term discharge forecasting.The Seq2Seq models improved by 6%-60%and 5%-20%of the relative standard deviation compared to the harmonic analysis models and improved back propagation neural network models in discharge prediction,respectively.In addition,the relative accuracy of the Seq2Seq model is 1%to 3%higher than that of the LSTM model.Analytical assessment of the prediction errors shows that the Seq2Seq models are insensitive to the forecast lead time and they can capture characteristic values such as maximum flood tide flow and maximum ebb tide flow in the tidal cycle well.This indicates the significance of the Seq2Seq models.展开更多
Rivers are important habitats for wintering waterbirds.However,they are easily influenced by natural and human activities.An important approach for waterbirds to adapt to habitats is adjusting the activity time and en...Rivers are important habitats for wintering waterbirds.However,they are easily influenced by natural and human activities.An important approach for waterbirds to adapt to habitats is adjusting the activity time and energy expenditure allocation of diurnal behavior.The compensatory foraging hypothesis predicts that increased energy expenditure leads to longer foraging time,which in turn increases food intake and helps maintain a constant energy balance.However,it is unclear whether human-disturbed habitats result in increased energy expenditure related to safety or foraging.In this study,the scan sample method was used to observe the diurnal behavior of the wintering Spot-billed Duck(Anas poecilorhyncha) in two rivers in the Xin’an River Basin from October 2021 to March 2022.The allocation of time and energy expenditure for activity in both normal and disturbed environments was calculated.The results showed that foraging accounted for the highest percentage of time and energy expenditure.Additionally,foraging decreased in the disturbed environment than that in the normal environment.Resting behavior showed the opposite trend,while other behaviors were similar in both environments.The total diurnal energy expenditure of ducks in the disturbed environment was greater than that in the normal environment,with decreased foraging and resting time percentage and increased behaviors related to immediate safety(swimming and alert) and comfort.These results oppose the compensatory foraging hypothesis in favor of increased security.The optimal diurnal energy expenditure model included river width and water depth,which had a positive relationship;an increase in either of these two factors resulted in an increase in energy expenditure.This study provides a better understanding of energy allocation strategies underlying the superficial time allocation of wintering waterbirds according to environmental conditions.Exploring these changes can help understand the maximum fitness of wintering waterbirds in response to nature and human influences.展开更多
The Faleme River, a West Africa long transboundary stream (625 km) and abundant flow (>1100 million m<sup>3</sup>) is affected by severe erosion because of mining activities that takes place throughout ...The Faleme River, a West Africa long transboundary stream (625 km) and abundant flow (>1100 million m<sup>3</sup>) is affected by severe erosion because of mining activities that takes place throughout the riverbed. To preserve this important watercourse and ensure the sustainability of its services, selecting and implementing appropriates restorations techniques is vital. In this context, the purpose of this paper was to present an overview of the actions and techniques that can be implemented for the restoration/rehabilitation of the Faleme. The methodological approach includes field investigation, water sampling, literature review with cases studies and SWOT analysis of the four methods presented: river dredging, constructed wetlands, floating treatment wetlands and chemical precipitation (coagulation and flocculation). The study confirmed the pollution of the river by suspended solids (TSS > 1100 mg/L) and heavy metals such as iron, zinc, aluminium, and arsenic. For the restoration methods, it was illustrated through description of their mode of operation and through some case studies presented, that all the four methods have proven their effectiveness in treating rivers but have differences in their costs, their sustainability (detrimental to living organisms or causing a second pollution) and social acceptance. They also have weaknesses and issues that must be addressed to ensure success of rehabilitation. For the case of the Faleme river, after analysis, floating treatment wetlands are highly recommended for their low cost, good removal efficiency if the vulnerability of the raft and buoyancy to strong waves and flow is under control.展开更多
A study of toad infestation was carried out from July to December 2022, in the vicinity of the Mfilou and Ngamboulou Rivers, with the aim of determining the prevalence rate of parasitic carriage in these toads. After ...A study of toad infestation was carried out from July to December 2022, in the vicinity of the Mfilou and Ngamboulou Rivers, with the aim of determining the prevalence rate of parasitic carriage in these toads. After collecting 289 specimens, all belonging to the Anuran order and Bufonidae family, three species were identified: Sclerophrys camerunensis (Parker, 1936), Sclerophrys regularis (Reuss, 1834) and Sclerophrys sp. The most abundant species were Sclerophrys camerunensis, followed by Sclerophrys regularis. With regard to parasitological aspects, of the 289 specimens collected, 195 were parasitized, i.e. a percentage of 67.47%. The only parasitic species identified was Ascaris sp., which is preferentially located in the intestine.展开更多
In order to extend the forecasting period of flood and improve the accuracy of flood forecasting,this paper took Bailian River Reservoir which located in Huanggang City of Hubei Province as an example and carried out ...In order to extend the forecasting period of flood and improve the accuracy of flood forecasting,this paper took Bailian River Reservoir which located in Huanggang City of Hubei Province as an example and carried out basin flood simulation and forecasting by coupling the quantitative precipitation forecasting products of numerical forecast operation model of Institute of Heavy Rain in Wuhan(WRF)and the European Center for Medium-range Weather Forecasts(ECMWF)with the three water sources Xin an River model.The experimental results showed that the spatiotemporal distribution of rainfall predicted by EC is closer to the actual situation compared to WRF;the efficiency coefficient and peak time difference of EC used for flood forecasting are comparable to WRF,but the average relative error of flood peaks is about 14%smaller than WRF.Overall,the precipitation forecasting products of the two numerical models can be used for flood forecasting in the Bailian River basin.Some forecasting indicators have certain reference value,and there is still significant room for improvement in the forecasting effects of the two models.展开更多
The Islamic Republic of Iran’s principal rivers are the Karun and Shatt al-Arab. The Karun River has a 950 km length. The Karun River starting point is the convergence of the Amand, Kuhrang, and Bazoft rivers. From t...The Islamic Republic of Iran’s principal rivers are the Karun and Shatt al-Arab. The Karun River has a 950 km length. The Karun River starting point is the convergence of the Amand, Kuhrang, and Bazoft rivers. From their headwater sources in the mountains of eastern Iran, these rivers descend through valleys and gorges and flow into the plains of Iran. The Shatt al-Arab River drains an area of 879,790 square kilometers which includes land in Iran, Syria, Türkiye, Kuwait, and Iraq. The Karun joins Shatt al-Arab 110 km downriver from the confluence of the Euphrates and Tigris Rivers and flows 85 km into the Persian Gulf. The Karun river flows in a southwestern direction through the central plain and provides about 10 per cent of the water balance of Iran’s largest wetland, the Shadegan, which includes permanent marshes, lakes, and riparian habitats. The article summarizes a vast array of publications on the stated topic and this civilizationally important region in order to draw additional attention to its interdependent environmental, economic and political problems the successful resolution of which is only possible with the participation of the entire research community.展开更多
China’s low-carbon development path will make significant contributions to achieving global sustainable development goals.Due to the diverse natural and economic conditions across different regions in China,there exi...China’s low-carbon development path will make significant contributions to achieving global sustainable development goals.Due to the diverse natural and economic conditions across different regions in China,there exists an imbalance in the distribution of car-bon emissions.Therefore,regional cooperation serves as an effective means to attain low-carbon development.This study examined the pattern of carbon emissions and proposed a potential joint emission reduction strategy by utilizing the industrial carbon emission intens-ity(ICEI)as a crucial factor.We utilized social network analysis and Local Indicators of Spatial Association(LISA)space-time trans-ition matrix to investigate the spatiotemporal connections and discrepancies of ICEI in the cities of the Pearl River Basin(PRB),China from 2010 to 2020.The primary drivers of the ICEI were determined through geographical detectors and multi-scale geographically weighted regression.The results were as follows:1)the overall ICEI in the Pearl River Basin is showing a downward trend,and there is a significant spatial imbalance.2)There are numerous network connections between cities regarding the ICEI,but the network structure is relatively fragile and unstable.3)Economically developed cities such as Guangzhou,Foshan,and Dongguan are in the center of the network while playing an intermediary role.4)Energy consumption,industrialization,per capita GDP,urbanization,science and techno-logy,and productivity are found to be the most influential variables in the spatial differentiation of ICEI,and their combination in-creased the explanatory power of the geographic variation of ICEI.Finally,through the analysis of differences and connections in urban carbon emissions under different economic levels and ICEI,the study suggests joint carbon reduction strategies,which are centered on carbon transfer,financial support,and technological assistance among cities.展开更多
Summer precipitation in the Three Rivers Source Region(TRSR)of China is vital for the headwaters of the Yellow,Yangtze,and Lancang rivers and exhibits significant interdecadal variability.This study investigates the i...Summer precipitation in the Three Rivers Source Region(TRSR)of China is vital for the headwaters of the Yellow,Yangtze,and Lancang rivers and exhibits significant interdecadal variability.This study investigates the influence of the East Asian westerly jet(EAWJ)on TRSR rainfall.A strong correlation is found between TRSR summer precipitation and the Jet Zonal Position Index(JZPI)of the EAWJ from 1961 to 2019(R=0.619,p<0.01).During periods when a positive JZPI indicates a westward shift in the EAWJ,enhanced water vapor anomalies,warmer air,and low-level convergence anomalies contribute to increased TRSR summer precipitation.Using empirical orthogonal function and regression analyses,this research identifies the influence of large-scale circulation anomalies associated with the Atlantic–Eurasian teleconnection(AEA)from the North Atlantic(NA).The interdecadal variability between the NA and central tropical Pacific(CTP)significantly affects TRSR precipitation.This influence is mediated through the AEA via a Rossby wave train extending eastward along the EAWJ,and another south of 45°N.Moreover,the NA–CTP Opposite Phase Index(OPI),which quantifies the difference between the summer mean sea surface temperatures of the NA and the CTP,is identified as a critical factor in modulating the strength of this teleconnection and influencing the zonal position of the EAWJ.展开更多
Based on the practice of oil and gas exploration in the Huizhou Sag of the Pearl River Mouth Basin,the geochemical indexes of source rocks were measured,the reservoir development morphology was restored,the rocks and ...Based on the practice of oil and gas exploration in the Huizhou Sag of the Pearl River Mouth Basin,the geochemical indexes of source rocks were measured,the reservoir development morphology was restored,the rocks and minerals were characterized microscopically,the measured trap sealing indexes were compared,the biomarker compounds of crude oil were extracted,the genesis of condensate gas was identified,and the reservoir-forming conditions were examined.On this basis,the Paleogene Enping Formation in the Huizhou 26 subsag was systematically analyzed for the potential of oil and gas resources,the development characteristics of large-scale high-quality conglomerate reservoirs,the trapping effectiveness of faults,the hydrocarbon migration and accumulation model,and the formation conditions and exploration targets of large-and medium-sized glutenite-rich oil and gas fields.The research results were obtained in four aspects.First,the Paleogene Wenchang Formation in the Huizhou 26 subsag develops extensive and thick high-quality source rocks of semi-deep to deep lacustrine subfacies,which have typical hydrocarbon expulsion characteristics of"great oil generation in the early stage and huge gas expulsion in the late stage",providing a sufficient material basis for hydrocarbon accumulation in the Enping Formation.Second,under the joint control of the steep slope zone and transition zone of the fault within the sag,the large-scale near-source glutenite reservoirs are highly heterogeneous,with the development scale dominated hierarchically by three factors(favorable facies zone,particle component,and microfracture).The(subaqueous)distributary channels near the fault system,with equal grains,a low mud content(<5%),and a high content of feldspar composition,are conducive to the development of sweet spot reservoirs.Third,the strike-slip pressurization trap covered by stable lake flooding mudstone is a necessary condition for oil and gas preservation,and the NE and nearly EW faults obliquely to the principal stress have the best control on traps.Fourth,the spatiotemporal configuration of high-quality source rocks,fault transport/sealing,and glutenite reservoirs controls the degree of hydrocarbon enrichment.From top to bottom,three hydrocarbon accumulation units,i.e.low-fill zone,transition zone,and high-fill zone,are recognized.The main area of the channel in the nearly pressurized source-connecting fault zone is favorable for large-scale hydrocarbon enrichment.The research results suggest a new direction for the exploration of large-scale glutenite-rich reservoirs in the Enping Formation of the Pearl River Mouth Basin,and present a major breakthrough in oil and gas exploration.展开更多
Due to their high reliability and cost-efficiency,submarine pipelines are widely used in offshore oil and gas resource engineering.Due to the interaction of waves,currents,seabed,and pipeline structures,the soil aroun...Due to their high reliability and cost-efficiency,submarine pipelines are widely used in offshore oil and gas resource engineering.Due to the interaction of waves,currents,seabed,and pipeline structures,the soil around submarine pipelines is prone to local scour,severely affecting their operational safety.With the Yellow River Delta as the research area and based on the renormalized group(RNG)k-εturbulence model and Stokes fifth-order wave theory,this study solves the Navier-Stokes(N-S)equation using the finite difference method.The volume of fluid(VOF)method is used to describe the fluid-free surface,and a threedimensional numerical model of currents and waves-submarine pipeline-silty sandy seabed is established.The rationality of the numerical model is verified using a self-built waveflow flume.On this basis,in this study,the local scour development and characteristics of submarine pipelines in the Yellow River Delta silty sandy seabed in the prototype environment are explored and the influence of the presence of pipelines on hydrodynamic features such as surrounding flow field,shear stress,and turbulence intensity is analyzed.The results indicate that(1)local scour around submarine pipelines can be divided into three stages:rapid scour,slow scour,and stable scour.The maximum scour depth occurs directly below the pipeline,and the shape of the scour pits is asymmetric.(2)As the water depth decreases and the pipeline suspension height increases,the scour becomes more intense.(3)When currents go through a pipeline,a clear stagnation point is formed in front of the pipeline,and the flow velocity is positively correlated with the depth of scour.This study can provide a valuable reference for the protection of submarine pipelines in this area.展开更多
Human activities in a transborder watershed are complex under the influence of domestic policies,international relations,and global events.Understanding the forces driving human activity change is important for the de...Human activities in a transborder watershed are complex under the influence of domestic policies,international relations,and global events.Understanding the forces driving human activity change is important for the development of transborder watershed.In this study,we used global historical land cover data,the hemeroby index model,and synthesized major historical events to analyze how human activity intensity changed in the Heilongjiang River(Amur River in Russia)watershed(HLRW).The results showed that there was a strong spatial heterogeneity in the variation of human activity intensity in the HLRW over the past century(1900-2016).On the Chinese side,the human activity intensity change shifted from the plain areas for agricultural reclamation to the mountainous areas for timber extraction.On the Russian side,human activity intensity changes mostly concentrated along the Trans-Siberian Railway and the Baikal-Amur Mainline.Localized variation of human activity intensity tended to respond to regional events while regionalized variation tends to reflect national policy change or broad international events.The similarities and differences between China and Russia in policies and positions in international events resulted in synchronous and asynchronous changes in human activity intensity.Meanwhile,policy shifts were often confined by the natural features of the watershed.These results reveal the historical origins and fundamental connotations of watershed development and contribute to formulating regional management policies that coordinate population,eco-nomic,social,and environmental activities.展开更多
Plate subduction leads to complex exhumation processes on continents.The Huangling Massif lies at the northern margin of the South China Block.Whether the Huangling Massif was exhumed as a watershed of the middle reac...Plate subduction leads to complex exhumation processes on continents.The Huangling Massif lies at the northern margin of the South China Block.Whether the Huangling Massif was exhumed as a watershed of the middle reaches of the Paleo-Yangtze River during the Mesozoic remains under debate.We examined the exhumation history of the Huangling Massif based on six granite bedrock samples,using apatite fission track(AFT)and apatite and zircon(U-Th)/He(AHe and ZHe)thermochronology.These samples yielded ages of 157–132 Ma(ZHe),119–106 Ma(AFT),and 114–72 Ma(AHe),respectively.Thermal modeling revealed that three phases of rapid cooling occurred during the Late Jurassic–Early Cretaceous,late Early Cretaceous,and Late Cretaceous.These exhumation processes led to the high topographic relief responsible for the emergence of the Huangling Massif.The integrated of our new data with published sedimentological records suggests that the Huangling Massif might have been the watershed of the middle reaches of the Paleo-Yangtze River since the Cretaceous.At that time,the rivers flowed westward into the Sichuan Basin and eastward into the Jianghan Basin.The subduction of the Pacific Plate beneath the Asian continent in the Mesozoic deeply influenced the geomorphic evolution of the South China Block.展开更多
Pollution of rivers is mainly caused by anthropogenic activities such as discharge of effluent from industrial facilities,maintenance of sewage/effluent treatment plants,and dumping of solid waste on river banks.This ...Pollution of rivers is mainly caused by anthropogenic activities such as discharge of effluent from industrial facilities,maintenance of sewage/effluent treatment plants,and dumping of solid waste on river banks.This study dealt with the pollution issues of the Cooum River in the well-known city of Chennai in South India.Water samples from 27 locations were collected and analyzed for 12 elements,including Ba,B,and Al,as well as heavy metals such as Pb,Cr,Mn,Fe,Co,Ni,Cu,Zn,and Cd.The samples showed levels of these elements that exceeded World Health Organization recommendations.Pearson correlation analysis revealed the inter-dependency among elements,and the contribution of each element based on factor loadings showed its percentage contribution compared to others.Water samples from six significant locations were chosen for remediation with three algae:Chlorella vulgaris,Scenedesmus dimorphus,and Phormedium sp.The uptake of pollutants led to the continuous growth of algae during the incubation period of 15 d,effectively removing heavy metals from the river water.The increasing levels of algal counts and the chlorophyll a content confirmed the algal growth during the incubation period,followed by a declining stage after the incubation period.The scanning electron microscopic images of algae before and after the remediation showed no remarkable modification of morphological patterns.This study showed that the uptake of heavy metals using algae is an effective water pollution remediation measure,making the process practicable in the field on a large scale in the near future.展开更多
To investigate the dominant species and interspecific association in the phytoplankton community of the Feiyun River basin in Zhejiang Province,East China,the main stream and the Shanxi Zhaoshandu Reservoir in the dow...To investigate the dominant species and interspecific association in the phytoplankton community of the Feiyun River basin in Zhejiang Province,East China,the main stream and the Shanxi Zhaoshandu Reservoir in the downstream were chosen as the study area,for which 22 sampling sites were designated.Sampling was conducted in September 2021,January,May,and July 2022.Phytoplankton species were identified from both quantitative samples and in-vivo observations.Phytoplankton was quantified by direct counting.Results show that there were 98 species belonging to 6 phyla and 78 genera.In addition,to clarify the niches of the dominant phytoplankton species and their interspecific association,the dominance index was calculated,and a comprehensive analysis was conducted including niche width,niche overlap value,ecological response rate,overall association,chi-square test,and the stability.The phytoplankton community exhibited characteristics of a Cyanobacteria-Chlorophyta-Diatom type community,showing higher diversity in spring and lower diversity in summer.Among 11 dominants phytoplankton species from 3 phyla,both frequency and dominance degree varied seasonally,of which Microcystis sp.was the dominant species in Spring,Autumn,and Winter.The niche widths of the dominant species ranged from 0.234 to 0.933,and were categorized into three groups.The niche overlap values of the 11 dominant species ranged from 0.359 to 0.959,exhibiting significant seasonal differences-highest in winter followed by autumn,spring,and summer in turn.The overall correlation among dominant species in all four seasons revealed a non-significant negative association,resulting in an unstable community structure.A significant portion(84.2%)of species pairs displayed positive associations,suggesting a successional pattern where Diatoms dominated while other dominant species shared resources and space.Despite this pattern,stability measurements indicated that the dominant species community remained unstable.Therefore,careful monitoring is recommended for potential water environment issues arising from abnormal proliferation of dominant species in the watershed during winter.This research built a theoretical foundation with a data support to the early warning of eutrophication and provided a reference for water resources management in similar watersheds along the eastern coast of China.展开更多
Water scarcity and pollution pose a threat to the sustainable development of cities and society.Therefore,it is crucial to analyze the hydrochemical characteristics and carbon dynamics of waterdeficient areas.Taking t...Water scarcity and pollution pose a threat to the sustainable development of cities and society.Therefore,it is crucial to analyze the hydrochemical characteristics and carbon dynamics of waterdeficient areas.Taking the Taiyuan section of Fenhe River as the research object,we systematically explored the hydrochemical characteristics of surface water and its evolutionary processes,as well as the ecological effect of algal carbonic anhydrase in carbon cycle using the hydrochemical evolution method and correlation analysis.The ternary diagram demonstrates that the main water chemical type in Fenhe River was SO^(2-)_(4)·Cl^(-)-Na^(+).The Gibbs and end-member diagrams of each ion display that the chemical composition of surface water was mainly controlled by silicate decomposition.The chemical ions originated mainly from dissolution of some minerals,such as plagioclase,halite,dolomite,calcite,and gypsum.The diatoms had a lower CO_(2)requirement because they exhibited a higher abundance at a lower partial pressure of CO_(2)(p CO_(2)).However,high CO_(2)concentration had a positive effect on cyanobacteria,which reduced the active transport of HCO_(3)^(-),saved the energy needed for this part of active transport,and indirectly improved the overall photosynthetic efficiency of algae.Carbonic anhydrase(CA)activity was significantly negatively correlated with p CO_(2)and positively correlated with HCO_(3)^(-)concentration,indicating that CA in water promoted the conversion of CO_(2)to HCO_(3)^(-).The HCO_(3)^(-)generated from this process continued to participate in the erosion of silicate rocks,sequestering CO_(2)in the form of Ca CO_(3),which has a non-negligible impact on the carbon sink in the Fenhe River.These consequences may have important implications for the biogeochemical cycling occurring in urban water.展开更多
This study investigated the distribution of microplastics and heavy metals,along with the interaction between the two in the sediments of urban rivers in China.Results showed that the abundance of microplastics ranged...This study investigated the distribution of microplastics and heavy metals,along with the interaction between the two in the sediments of urban rivers in China.Results showed that the abundance of microplastics ranged from 2412±187.5 to 7638±1312items kg^(-1)dry sediment across different survey stations,with an average abundance at(4388±713)items kg^(-1)dry sediment.Upon further categorization,it was found that transparent fragments were the primary color and type of microplastics present.The potential ecological risk index(RI)of heavy metals in sediments suggested a low level of ecological risk within a majority of the urban rivers studied.Cd was identified as the main potential ecological risk factor in the sediments of the studied areas.There was a relatively good significant linear relationship between the RI of heavy metals and the abundance of microplastics,bolstering the linkage between these two environmental pollutants.However,the concentrations of heavy metals in microplastics were not dependent on their corresponding contents in sediments.In fact,the concentration of Cu,Cd,and As in microplastics were higher than those in the sediments.This finding confirmed that microplastics could serve as carriers of heavy metals and introduce potential risks to aquatic wildlife and human through the food chain.展开更多
In our recent investigations of diatom diversity,we studied three species,namely,Skeletonema costatum,Skeletonema subsalsum,and Skeletonema potamos.Although they have been found frequently in Changjiang(Yangtze)River ...In our recent investigations of diatom diversity,we studied three species,namely,Skeletonema costatum,Skeletonema subsalsum,and Skeletonema potamos.Although they have been found frequently in Changjiang(Yangtze)River Basin,their morphological and molecular identification is difficult in taxonomy.Therefore,to integrate morphological and molecular biological approaches,we compared systematically their morphological characters and performed phylogenetic analysis.Twelve strains of Skeletonema were collected and isolated from Shanghai and Jiangsu,China,and their morphological characteristics were examined by light microscopy(LM)and the scanning electron microscopy(SEM).Based on morphological comparison,we determined that S.potamos is easy to distinguish from the other two species.The heavily silicified areolae,undulated or cleft distal ends of terminal fultoportula processes(TFPPs),absence of basal pores of fultoportula processes(FPPs),the rootlike protrusions of FPPs,and no interlocking connection are the stable characteristics that can be used to identify S.potamos.However,there are only two features that can distinguish S.costatum from S.subsalsum,namely the location of terminal rimoportulae(TRPs)and the distal shape of TFPPs.In addition,we amplified and sequenced nine common genetic markers from the strains,from which 101 sequences were obtained,constructed phylogenetic trees based on the nine genes and evaluated that seven genes can be used to identify S.potamos,and revealed that S.subsalsum is the closest known relative of S.costatum,and only ATP synthetase beta-subunit gene(atp B)is able to distinguish them from each other,which strongly support that it is an effective molecular marker for Skeletonema.This work provided a theoretical basis for the taxonomic study of Skeletonema.展开更多
In the summer of 2022,China(especially the Yangtze River Valley,YRV)suffered its strongest heatwave(HW)event since 1961.In this study,we examined the influences of multiscale variabilities on the 2022 extreme HW in th...In the summer of 2022,China(especially the Yangtze River Valley,YRV)suffered its strongest heatwave(HW)event since 1961.In this study,we examined the influences of multiscale variabilities on the 2022 extreme HW in the lower reaches of the YRV,focusing on the city of Shanghai.We found that about 1/3 of the 2022 HW days in Shanghai can be attributed to the long-term warming trend of global warming.During mid-summer of 2022,an enhanced western Pacific subtropical high(WPSH)and anomalous double blockings over the Ural Mountains and Sea of Okhotsk,respectively,were associated with the persistently anomalous high pressure over the YRV,leading to the extreme HW.The Pacific Decadal Oscillation played a major role in the anomalous blocking pattern associated with the HW at the decadal time scale.Also,the positive phase of the Atlantic Multidecadal Oscillation may have contributed to regulating the formation of the double-blocking pattern.Anomalous warming of both the warm pool of the western Pacific and tropical North Atlantic at the interannual time scale may also have favored the persistency of the double blocking and the anomalously strong WPSH.At the subseasonal time scale,the anomalously frequent phases 2-5 of the canonical northward propagating variability of boreal summer intraseasonal oscillation associated with the anomalous propagation of a weak Madden-Julian Oscillation suppressed the convection over the YRV and also contributed to the HW.Therefore,the 2022 extreme HW originated from multiscale forcing including both the climate warming trend and air-sea interaction at multiple time scales.展开更多
基金financially supported by the Natural Science Foundation of China(41941016,42072240,41830217)Ministry of Science and Technology of China(2019QZKK0901,2021FY100101)+2 种基金Key Special Project for Introduced Talents Team of the Southern Marine Science and Engineering Guangdong Laboratory(GML2019ZD0201)China Geological Survey(DD20221630)Special Fund of the Institute of Geophysics,China Earthquake Administration(DQJB20B21).
文摘The Xianshuihe-Anninghe fault extends SE–S and constitutes the southeastern margin of the Tibetan Plateau.However,the Dadu River which is associated with the fault does not flow following the path,but makes a 90ºturn within a distance of 1 km at Shimian,heading east,and joins the Yangtze River,finally flowing into the East China Sea.Adjacent to the abrupt turn,a low and wide pass near the Daqiao reservoir at Mianning separates the N–S course of the Dadu River from the headwater of the Anning River which then flows south into the Yunnan Province along the Anninghe fault.Therefore,many previous studies assumed southward flow of the paleo-Dadu River from the Shimian to the Anning River.However,evidences for the capture of the integrated N–S paleo-Dadu-Anning River,its timing,and causes are still insufficient.This study explored the paleo-drainage pattern of the Dadu and Anning Rivers based on bulk mineral and geochemical analyses of the large quantities of fluvial/lacustrine sediments along the trunk of the Dadu and Anning Rivers.Similar with sands in the modern Dadu River,the Xigeda sediments also exhibit a granitoid affinity with the bulk major mineral compositions of quartz(>50%),anorthite(about 10%),orthoclase(about 5%),muscovite(about 5%),and clinochlore(about 4%).Correspondingly,bulk major elements show high SiO_(2),with all samples>60%,and some of them>70%,low TiO_(2)(≤0.75%),P_(2)O_(5)(≤0.55%),FeO*(≤5%),and relatively high CaO(1.02%–8.51%),Na_(2)O(1.60%–2.52%),and K_(2)O(2.17%–2.71%),with a uniform REE patterns.Therefore,synthesizing all these results indicate that these lacustrine sediments have similar material sources,which are mainly derived from its course in the Songpan-Ganzi flysch block,implying that the paleo-Dadu originally flowed southward into the Anning River and provided materials to the Xigeda ancient lake.The rearrangement of the paleo-Dadu River appears to be closely related to the locally focused uplift driven by strong activities of the XianshuiheXiaojiang fault system.
基金The National Natural Science Foundation of China under contract Nos 42266006 and 41806114the Jiangxi Provincial Natural Science Foundation under contract Nos 20232BAB204089 and 20202ACBL214019.
文摘The complexity of river-tide interaction poses a significant challenge in predicting discharge in tidal rivers.Long short-term memory(LSTM)networks excel in processing and predicting crucial events with extended intervals and time delays in time series data.Additionally,the sequence-to-sequence(Seq2Seq)model,known for handling temporal relationships,adapting to variable-length sequences,effectively capturing historical information,and accommodating various influencing factors,emerges as a robust and flexible tool in discharge forecasting.In this study,we introduce the application of LSTM-based Seq2Seq models for the first time in forecasting the discharge of a tidal reach of the Changjiang River(Yangtze River)Estuary.This study focuses on discharge forecasting using three key input characteristics:flow velocity,water level,and discharge,which means the structure of multiple input and single output is adopted.The experiment used the discharge data of the whole year of 2020,of which the first 80%is used as the training set,and the last 20%is used as the test set.This means that the data covers different tidal cycles,which helps to test the forecasting effect of different models in different tidal cycles and different runoff.The experimental results indicate that the proposed models demonstrate advantages in long-term,mid-term,and short-term discharge forecasting.The Seq2Seq models improved by 6%-60%and 5%-20%of the relative standard deviation compared to the harmonic analysis models and improved back propagation neural network models in discharge prediction,respectively.In addition,the relative accuracy of the Seq2Seq model is 1%to 3%higher than that of the LSTM model.Analytical assessment of the prediction errors shows that the Seq2Seq models are insensitive to the forecast lead time and they can capture characteristic values such as maximum flood tide flow and maximum ebb tide flow in the tidal cycle well.This indicates the significance of the Seq2Seq models.
基金supported by the National Natural Science Foundation of China (Grant No. 32100400)Huangshan University Startup Project of Scientific Research (2020xkjq013)Environment Conservation Research Centre of Xin’an River Basin (kypt202002)。
文摘Rivers are important habitats for wintering waterbirds.However,they are easily influenced by natural and human activities.An important approach for waterbirds to adapt to habitats is adjusting the activity time and energy expenditure allocation of diurnal behavior.The compensatory foraging hypothesis predicts that increased energy expenditure leads to longer foraging time,which in turn increases food intake and helps maintain a constant energy balance.However,it is unclear whether human-disturbed habitats result in increased energy expenditure related to safety or foraging.In this study,the scan sample method was used to observe the diurnal behavior of the wintering Spot-billed Duck(Anas poecilorhyncha) in two rivers in the Xin’an River Basin from October 2021 to March 2022.The allocation of time and energy expenditure for activity in both normal and disturbed environments was calculated.The results showed that foraging accounted for the highest percentage of time and energy expenditure.Additionally,foraging decreased in the disturbed environment than that in the normal environment.Resting behavior showed the opposite trend,while other behaviors were similar in both environments.The total diurnal energy expenditure of ducks in the disturbed environment was greater than that in the normal environment,with decreased foraging and resting time percentage and increased behaviors related to immediate safety(swimming and alert) and comfort.These results oppose the compensatory foraging hypothesis in favor of increased security.The optimal diurnal energy expenditure model included river width and water depth,which had a positive relationship;an increase in either of these two factors resulted in an increase in energy expenditure.This study provides a better understanding of energy allocation strategies underlying the superficial time allocation of wintering waterbirds according to environmental conditions.Exploring these changes can help understand the maximum fitness of wintering waterbirds in response to nature and human influences.
文摘The Faleme River, a West Africa long transboundary stream (625 km) and abundant flow (>1100 million m<sup>3</sup>) is affected by severe erosion because of mining activities that takes place throughout the riverbed. To preserve this important watercourse and ensure the sustainability of its services, selecting and implementing appropriates restorations techniques is vital. In this context, the purpose of this paper was to present an overview of the actions and techniques that can be implemented for the restoration/rehabilitation of the Faleme. The methodological approach includes field investigation, water sampling, literature review with cases studies and SWOT analysis of the four methods presented: river dredging, constructed wetlands, floating treatment wetlands and chemical precipitation (coagulation and flocculation). The study confirmed the pollution of the river by suspended solids (TSS > 1100 mg/L) and heavy metals such as iron, zinc, aluminium, and arsenic. For the restoration methods, it was illustrated through description of their mode of operation and through some case studies presented, that all the four methods have proven their effectiveness in treating rivers but have differences in their costs, their sustainability (detrimental to living organisms or causing a second pollution) and social acceptance. They also have weaknesses and issues that must be addressed to ensure success of rehabilitation. For the case of the Faleme river, after analysis, floating treatment wetlands are highly recommended for their low cost, good removal efficiency if the vulnerability of the raft and buoyancy to strong waves and flow is under control.
文摘A study of toad infestation was carried out from July to December 2022, in the vicinity of the Mfilou and Ngamboulou Rivers, with the aim of determining the prevalence rate of parasitic carriage in these toads. After collecting 289 specimens, all belonging to the Anuran order and Bufonidae family, three species were identified: Sclerophrys camerunensis (Parker, 1936), Sclerophrys regularis (Reuss, 1834) and Sclerophrys sp. The most abundant species were Sclerophrys camerunensis, followed by Sclerophrys regularis. With regard to parasitological aspects, of the 289 specimens collected, 195 were parasitized, i.e. a percentage of 67.47%. The only parasitic species identified was Ascaris sp., which is preferentially located in the intestine.
基金Supported by Open Project Fund of China Meteorological Administration Basin Heavy Rainfall Key Laboratory(2023BHR-Y26)Innovation Project Fund of Wuhan Metropolitan Area Meteorological Joint Science and Technology(WHCSQY202305)+1 种基金Innovation and Development Special Project of China Meteorological Administration(CXFZ2022J019)Project of Huanggang Meteorological Bureau's Scientific Research(2022Y02).
文摘In order to extend the forecasting period of flood and improve the accuracy of flood forecasting,this paper took Bailian River Reservoir which located in Huanggang City of Hubei Province as an example and carried out basin flood simulation and forecasting by coupling the quantitative precipitation forecasting products of numerical forecast operation model of Institute of Heavy Rain in Wuhan(WRF)and the European Center for Medium-range Weather Forecasts(ECMWF)with the three water sources Xin an River model.The experimental results showed that the spatiotemporal distribution of rainfall predicted by EC is closer to the actual situation compared to WRF;the efficiency coefficient and peak time difference of EC used for flood forecasting are comparable to WRF,but the average relative error of flood peaks is about 14%smaller than WRF.Overall,the precipitation forecasting products of the two numerical models can be used for flood forecasting in the Bailian River basin.Some forecasting indicators have certain reference value,and there is still significant room for improvement in the forecasting effects of the two models.
文摘The Islamic Republic of Iran’s principal rivers are the Karun and Shatt al-Arab. The Karun River has a 950 km length. The Karun River starting point is the convergence of the Amand, Kuhrang, and Bazoft rivers. From their headwater sources in the mountains of eastern Iran, these rivers descend through valleys and gorges and flow into the plains of Iran. The Shatt al-Arab River drains an area of 879,790 square kilometers which includes land in Iran, Syria, Türkiye, Kuwait, and Iraq. The Karun joins Shatt al-Arab 110 km downriver from the confluence of the Euphrates and Tigris Rivers and flows 85 km into the Persian Gulf. The Karun river flows in a southwestern direction through the central plain and provides about 10 per cent of the water balance of Iran’s largest wetland, the Shadegan, which includes permanent marshes, lakes, and riparian habitats. The article summarizes a vast array of publications on the stated topic and this civilizationally important region in order to draw additional attention to its interdependent environmental, economic and political problems the successful resolution of which is only possible with the participation of the entire research community.
基金Under the auspices of the Philosophy and Social Science Planning Project of Guizhou,China(No.21GZZD59)。
文摘China’s low-carbon development path will make significant contributions to achieving global sustainable development goals.Due to the diverse natural and economic conditions across different regions in China,there exists an imbalance in the distribution of car-bon emissions.Therefore,regional cooperation serves as an effective means to attain low-carbon development.This study examined the pattern of carbon emissions and proposed a potential joint emission reduction strategy by utilizing the industrial carbon emission intens-ity(ICEI)as a crucial factor.We utilized social network analysis and Local Indicators of Spatial Association(LISA)space-time trans-ition matrix to investigate the spatiotemporal connections and discrepancies of ICEI in the cities of the Pearl River Basin(PRB),China from 2010 to 2020.The primary drivers of the ICEI were determined through geographical detectors and multi-scale geographically weighted regression.The results were as follows:1)the overall ICEI in the Pearl River Basin is showing a downward trend,and there is a significant spatial imbalance.2)There are numerous network connections between cities regarding the ICEI,but the network structure is relatively fragile and unstable.3)Economically developed cities such as Guangzhou,Foshan,and Dongguan are in the center of the network while playing an intermediary role.4)Energy consumption,industrialization,per capita GDP,urbanization,science and techno-logy,and productivity are found to be the most influential variables in the spatial differentiation of ICEI,and their combination in-creased the explanatory power of the geographic variation of ICEI.Finally,through the analysis of differences and connections in urban carbon emissions under different economic levels and ICEI,the study suggests joint carbon reduction strategies,which are centered on carbon transfer,financial support,and technological assistance among cities.
基金supported by the 2nd Scientific Expedition to the Qinghai–Tibet Plateau[grant number 2019QZKK0102]the National Natural Science Foundation of China[grant number 42275045,41975012]+3 种基金the West Light Foundation of the Chinese Academy of Sciences[grant number xbzg-zdsys-202215]the Science and Technology Research Plan of Gansu Province[grant number 20JR10RA070]the Youth Innovation Promotion Association of the Chinese Academy of Sciences[grant number QCH2019004]iLEAPs(integrated Land Ecosystem–Atmosphere Processes Study).
文摘Summer precipitation in the Three Rivers Source Region(TRSR)of China is vital for the headwaters of the Yellow,Yangtze,and Lancang rivers and exhibits significant interdecadal variability.This study investigates the influence of the East Asian westerly jet(EAWJ)on TRSR rainfall.A strong correlation is found between TRSR summer precipitation and the Jet Zonal Position Index(JZPI)of the EAWJ from 1961 to 2019(R=0.619,p<0.01).During periods when a positive JZPI indicates a westward shift in the EAWJ,enhanced water vapor anomalies,warmer air,and low-level convergence anomalies contribute to increased TRSR summer precipitation.Using empirical orthogonal function and regression analyses,this research identifies the influence of large-scale circulation anomalies associated with the Atlantic–Eurasian teleconnection(AEA)from the North Atlantic(NA).The interdecadal variability between the NA and central tropical Pacific(CTP)significantly affects TRSR precipitation.This influence is mediated through the AEA via a Rossby wave train extending eastward along the EAWJ,and another south of 45°N.Moreover,the NA–CTP Opposite Phase Index(OPI),which quantifies the difference between the summer mean sea surface temperatures of the NA and the CTP,is identified as a critical factor in modulating the strength of this teleconnection and influencing the zonal position of the EAWJ.
基金Supported by the CNOOC Major Technology Project During the 14th FIVE-YEAR PLAN PERIOD(KJGG2022-0403)CNOOC Major Technology Project(KJZH-2021-0003-00).
文摘Based on the practice of oil and gas exploration in the Huizhou Sag of the Pearl River Mouth Basin,the geochemical indexes of source rocks were measured,the reservoir development morphology was restored,the rocks and minerals were characterized microscopically,the measured trap sealing indexes were compared,the biomarker compounds of crude oil were extracted,the genesis of condensate gas was identified,and the reservoir-forming conditions were examined.On this basis,the Paleogene Enping Formation in the Huizhou 26 subsag was systematically analyzed for the potential of oil and gas resources,the development characteristics of large-scale high-quality conglomerate reservoirs,the trapping effectiveness of faults,the hydrocarbon migration and accumulation model,and the formation conditions and exploration targets of large-and medium-sized glutenite-rich oil and gas fields.The research results were obtained in four aspects.First,the Paleogene Wenchang Formation in the Huizhou 26 subsag develops extensive and thick high-quality source rocks of semi-deep to deep lacustrine subfacies,which have typical hydrocarbon expulsion characteristics of"great oil generation in the early stage and huge gas expulsion in the late stage",providing a sufficient material basis for hydrocarbon accumulation in the Enping Formation.Second,under the joint control of the steep slope zone and transition zone of the fault within the sag,the large-scale near-source glutenite reservoirs are highly heterogeneous,with the development scale dominated hierarchically by three factors(favorable facies zone,particle component,and microfracture).The(subaqueous)distributary channels near the fault system,with equal grains,a low mud content(<5%),and a high content of feldspar composition,are conducive to the development of sweet spot reservoirs.Third,the strike-slip pressurization trap covered by stable lake flooding mudstone is a necessary condition for oil and gas preservation,and the NE and nearly EW faults obliquely to the principal stress have the best control on traps.Fourth,the spatiotemporal configuration of high-quality source rocks,fault transport/sealing,and glutenite reservoirs controls the degree of hydrocarbon enrichment.From top to bottom,three hydrocarbon accumulation units,i.e.low-fill zone,transition zone,and high-fill zone,are recognized.The main area of the channel in the nearly pressurized source-connecting fault zone is favorable for large-scale hydrocarbon enrichment.The research results suggest a new direction for the exploration of large-scale glutenite-rich reservoirs in the Enping Formation of the Pearl River Mouth Basin,and present a major breakthrough in oil and gas exploration.
基金China Postdoctoral Science Foundation,Grant/Award Number:2023M731999National Natural Science Foundation of China,Grant/Award Number:52301326。
文摘Due to their high reliability and cost-efficiency,submarine pipelines are widely used in offshore oil and gas resource engineering.Due to the interaction of waves,currents,seabed,and pipeline structures,the soil around submarine pipelines is prone to local scour,severely affecting their operational safety.With the Yellow River Delta as the research area and based on the renormalized group(RNG)k-εturbulence model and Stokes fifth-order wave theory,this study solves the Navier-Stokes(N-S)equation using the finite difference method.The volume of fluid(VOF)method is used to describe the fluid-free surface,and a threedimensional numerical model of currents and waves-submarine pipeline-silty sandy seabed is established.The rationality of the numerical model is verified using a self-built waveflow flume.On this basis,in this study,the local scour development and characteristics of submarine pipelines in the Yellow River Delta silty sandy seabed in the prototype environment are explored and the influence of the presence of pipelines on hydrodynamic features such as surrounding flow field,shear stress,and turbulence intensity is analyzed.The results indicate that(1)local scour around submarine pipelines can be divided into three stages:rapid scour,slow scour,and stable scour.The maximum scour depth occurs directly below the pipeline,and the shape of the scour pits is asymmetric.(2)As the water depth decreases and the pipeline suspension height increases,the scour becomes more intense.(3)When currents go through a pipeline,a clear stagnation point is formed in front of the pipeline,and the flow velocity is positively correlated with the depth of scour.This study can provide a valuable reference for the protection of submarine pipelines in this area.
基金Under the auspices of National Key Research and Development Program of China(No.2017YFA0604403)National Natural Science Foundation of China(No.41801108)。
文摘Human activities in a transborder watershed are complex under the influence of domestic policies,international relations,and global events.Understanding the forces driving human activity change is important for the development of transborder watershed.In this study,we used global historical land cover data,the hemeroby index model,and synthesized major historical events to analyze how human activity intensity changed in the Heilongjiang River(Amur River in Russia)watershed(HLRW).The results showed that there was a strong spatial heterogeneity in the variation of human activity intensity in the HLRW over the past century(1900-2016).On the Chinese side,the human activity intensity change shifted from the plain areas for agricultural reclamation to the mountainous areas for timber extraction.On the Russian side,human activity intensity changes mostly concentrated along the Trans-Siberian Railway and the Baikal-Amur Mainline.Localized variation of human activity intensity tended to respond to regional events while regionalized variation tends to reflect national policy change or broad international events.The similarities and differences between China and Russia in policies and positions in international events resulted in synchronous and asynchronous changes in human activity intensity.Meanwhile,policy shifts were often confined by the natural features of the watershed.These results reveal the historical origins and fundamental connotations of watershed development and contribute to formulating regional management policies that coordinate population,eco-nomic,social,and environmental activities.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.41671011,41871019,41877292,41972212)Research Foundation of Chutian Scholars Program of Hubei Province(Grant No.8210403)Shanxi Key Research and Development program:Feng Cheng(Grant No.2021SF2-03).
文摘Plate subduction leads to complex exhumation processes on continents.The Huangling Massif lies at the northern margin of the South China Block.Whether the Huangling Massif was exhumed as a watershed of the middle reaches of the Paleo-Yangtze River during the Mesozoic remains under debate.We examined the exhumation history of the Huangling Massif based on six granite bedrock samples,using apatite fission track(AFT)and apatite and zircon(U-Th)/He(AHe and ZHe)thermochronology.These samples yielded ages of 157–132 Ma(ZHe),119–106 Ma(AFT),and 114–72 Ma(AHe),respectively.Thermal modeling revealed that three phases of rapid cooling occurred during the Late Jurassic–Early Cretaceous,late Early Cretaceous,and Late Cretaceous.These exhumation processes led to the high topographic relief responsible for the emergence of the Huangling Massif.The integrated of our new data with published sedimentological records suggests that the Huangling Massif might have been the watershed of the middle reaches of the Paleo-Yangtze River since the Cretaceous.At that time,the rivers flowed westward into the Sichuan Basin and eastward into the Jianghan Basin.The subduction of the Pacific Plate beneath the Asian continent in the Mesozoic deeply influenced the geomorphic evolution of the South China Block.
文摘Pollution of rivers is mainly caused by anthropogenic activities such as discharge of effluent from industrial facilities,maintenance of sewage/effluent treatment plants,and dumping of solid waste on river banks.This study dealt with the pollution issues of the Cooum River in the well-known city of Chennai in South India.Water samples from 27 locations were collected and analyzed for 12 elements,including Ba,B,and Al,as well as heavy metals such as Pb,Cr,Mn,Fe,Co,Ni,Cu,Zn,and Cd.The samples showed levels of these elements that exceeded World Health Organization recommendations.Pearson correlation analysis revealed the inter-dependency among elements,and the contribution of each element based on factor loadings showed its percentage contribution compared to others.Water samples from six significant locations were chosen for remediation with three algae:Chlorella vulgaris,Scenedesmus dimorphus,and Phormedium sp.The uptake of pollutants led to the continuous growth of algae during the incubation period of 15 d,effectively removing heavy metals from the river water.The increasing levels of algal counts and the chlorophyll a content confirmed the algal growth during the incubation period,followed by a declining stage after the incubation period.The scanning electron microscopic images of algae before and after the remediation showed no remarkable modification of morphological patterns.This study showed that the uptake of heavy metals using algae is an effective water pollution remediation measure,making the process practicable in the field on a large scale in the near future.
基金Supported by the National Key Scientific Research Project(No.2018YFC1508200)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX 23_0714)+1 种基金the China Scholarship Council(No.202206710066)the Construction Project of Wenzhou Hydrology High quality Development Pilot Zone(No.WZSW-GZLFZXXQ-202105)。
文摘To investigate the dominant species and interspecific association in the phytoplankton community of the Feiyun River basin in Zhejiang Province,East China,the main stream and the Shanxi Zhaoshandu Reservoir in the downstream were chosen as the study area,for which 22 sampling sites were designated.Sampling was conducted in September 2021,January,May,and July 2022.Phytoplankton species were identified from both quantitative samples and in-vivo observations.Phytoplankton was quantified by direct counting.Results show that there were 98 species belonging to 6 phyla and 78 genera.In addition,to clarify the niches of the dominant phytoplankton species and their interspecific association,the dominance index was calculated,and a comprehensive analysis was conducted including niche width,niche overlap value,ecological response rate,overall association,chi-square test,and the stability.The phytoplankton community exhibited characteristics of a Cyanobacteria-Chlorophyta-Diatom type community,showing higher diversity in spring and lower diversity in summer.Among 11 dominants phytoplankton species from 3 phyla,both frequency and dominance degree varied seasonally,of which Microcystis sp.was the dominant species in Spring,Autumn,and Winter.The niche widths of the dominant species ranged from 0.234 to 0.933,and were categorized into three groups.The niche overlap values of the 11 dominant species ranged from 0.359 to 0.959,exhibiting significant seasonal differences-highest in winter followed by autumn,spring,and summer in turn.The overall correlation among dominant species in all four seasons revealed a non-significant negative association,resulting in an unstable community structure.A significant portion(84.2%)of species pairs displayed positive associations,suggesting a successional pattern where Diatoms dominated while other dominant species shared resources and space.Despite this pattern,stability measurements indicated that the dominant species community remained unstable.Therefore,careful monitoring is recommended for potential water environment issues arising from abnormal proliferation of dominant species in the watershed during winter.This research built a theoretical foundation with a data support to the early warning of eutrophication and provided a reference for water resources management in similar watersheds along the eastern coast of China.
基金Supported by the Fundamental Research Program of Shanxi Province(Nos.202103021223266,202203021211313,202303021211114,202303021222246)the Excellent Doctoral Research Project in Shanxi Province(No.QZX-2023005)the Shanxi Scientific and Technological Innovation Team of Halophiles Resources Utilization(No.202204051001035)。
文摘Water scarcity and pollution pose a threat to the sustainable development of cities and society.Therefore,it is crucial to analyze the hydrochemical characteristics and carbon dynamics of waterdeficient areas.Taking the Taiyuan section of Fenhe River as the research object,we systematically explored the hydrochemical characteristics of surface water and its evolutionary processes,as well as the ecological effect of algal carbonic anhydrase in carbon cycle using the hydrochemical evolution method and correlation analysis.The ternary diagram demonstrates that the main water chemical type in Fenhe River was SO^(2-)_(4)·Cl^(-)-Na^(+).The Gibbs and end-member diagrams of each ion display that the chemical composition of surface water was mainly controlled by silicate decomposition.The chemical ions originated mainly from dissolution of some minerals,such as plagioclase,halite,dolomite,calcite,and gypsum.The diatoms had a lower CO_(2)requirement because they exhibited a higher abundance at a lower partial pressure of CO_(2)(p CO_(2)).However,high CO_(2)concentration had a positive effect on cyanobacteria,which reduced the active transport of HCO_(3)^(-),saved the energy needed for this part of active transport,and indirectly improved the overall photosynthetic efficiency of algae.Carbonic anhydrase(CA)activity was significantly negatively correlated with p CO_(2)and positively correlated with HCO_(3)^(-)concentration,indicating that CA in water promoted the conversion of CO_(2)to HCO_(3)^(-).The HCO_(3)^(-)generated from this process continued to participate in the erosion of silicate rocks,sequestering CO_(2)in the form of Ca CO_(3),which has a non-negligible impact on the carbon sink in the Fenhe River.These consequences may have important implications for the biogeochemical cycling occurring in urban water.
基金supported by the Key Research and Development Program (Scientific and Technological Project)of Henan Province (Nos.212102310080,222102320294,and 232102231062)the Fundamental Research Funds for the Central Universities (No.220602024)the Major Focus Project of Henan Academy of Sciences (No.220102002)。
文摘This study investigated the distribution of microplastics and heavy metals,along with the interaction between the two in the sediments of urban rivers in China.Results showed that the abundance of microplastics ranged from 2412±187.5 to 7638±1312items kg^(-1)dry sediment across different survey stations,with an average abundance at(4388±713)items kg^(-1)dry sediment.Upon further categorization,it was found that transparent fragments were the primary color and type of microplastics present.The potential ecological risk index(RI)of heavy metals in sediments suggested a low level of ecological risk within a majority of the urban rivers studied.Cd was identified as the main potential ecological risk factor in the sediments of the studied areas.There was a relatively good significant linear relationship between the RI of heavy metals and the abundance of microplastics,bolstering the linkage between these two environmental pollutants.However,the concentrations of heavy metals in microplastics were not dependent on their corresponding contents in sediments.In fact,the concentration of Cu,Cd,and As in microplastics were higher than those in the sediments.This finding confirmed that microplastics could serve as carriers of heavy metals and introduce potential risks to aquatic wildlife and human through the food chain.
基金Supported by the National Natural Science Foundation of China(No.32170205)the Natural Science Foundation of Shanghai(No.21ZR144730)。
文摘In our recent investigations of diatom diversity,we studied three species,namely,Skeletonema costatum,Skeletonema subsalsum,and Skeletonema potamos.Although they have been found frequently in Changjiang(Yangtze)River Basin,their morphological and molecular identification is difficult in taxonomy.Therefore,to integrate morphological and molecular biological approaches,we compared systematically their morphological characters and performed phylogenetic analysis.Twelve strains of Skeletonema were collected and isolated from Shanghai and Jiangsu,China,and their morphological characteristics were examined by light microscopy(LM)and the scanning electron microscopy(SEM).Based on morphological comparison,we determined that S.potamos is easy to distinguish from the other two species.The heavily silicified areolae,undulated or cleft distal ends of terminal fultoportula processes(TFPPs),absence of basal pores of fultoportula processes(FPPs),the rootlike protrusions of FPPs,and no interlocking connection are the stable characteristics that can be used to identify S.potamos.However,there are only two features that can distinguish S.costatum from S.subsalsum,namely the location of terminal rimoportulae(TRPs)and the distal shape of TFPPs.In addition,we amplified and sequenced nine common genetic markers from the strains,from which 101 sequences were obtained,constructed phylogenetic trees based on the nine genes and evaluated that seven genes can be used to identify S.potamos,and revealed that S.subsalsum is the closest known relative of S.costatum,and only ATP synthetase beta-subunit gene(atp B)is able to distinguish them from each other,which strongly support that it is an effective molecular marker for Skeletonema.This work provided a theoretical basis for the taxonomic study of Skeletonema.
基金the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030004)the National Natural Science Foundation of China(Grant No.42175056)+3 种基金the Natural Science Foundation of Shanghai(Grant No.21ZR1457600)Review and Summary Project of China Meteorological Administration(Grant No.FPZJ2023-044)the China Meteorological Administration Innovation and Development Project(Grant No.CXFZ2022J009)the Key Innovation Team of Climate Prediction of the China Meteorological Administration(Grant No.CMA2023ZD03).
文摘In the summer of 2022,China(especially the Yangtze River Valley,YRV)suffered its strongest heatwave(HW)event since 1961.In this study,we examined the influences of multiscale variabilities on the 2022 extreme HW in the lower reaches of the YRV,focusing on the city of Shanghai.We found that about 1/3 of the 2022 HW days in Shanghai can be attributed to the long-term warming trend of global warming.During mid-summer of 2022,an enhanced western Pacific subtropical high(WPSH)and anomalous double blockings over the Ural Mountains and Sea of Okhotsk,respectively,were associated with the persistently anomalous high pressure over the YRV,leading to the extreme HW.The Pacific Decadal Oscillation played a major role in the anomalous blocking pattern associated with the HW at the decadal time scale.Also,the positive phase of the Atlantic Multidecadal Oscillation may have contributed to regulating the formation of the double-blocking pattern.Anomalous warming of both the warm pool of the western Pacific and tropical North Atlantic at the interannual time scale may also have favored the persistency of the double blocking and the anomalously strong WPSH.At the subseasonal time scale,the anomalously frequent phases 2-5 of the canonical northward propagating variability of boreal summer intraseasonal oscillation associated with the anomalous propagation of a weak Madden-Julian Oscillation suppressed the convection over the YRV and also contributed to the HW.Therefore,the 2022 extreme HW originated from multiscale forcing including both the climate warming trend and air-sea interaction at multiple time scales.
