[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in t...[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in the Upper Yangtze River.This study initiated continuous monitoring of natural spawning habitats from February 2022 to assess these ecological changes.[Methods]Environmental DNA(eDNA)metabarcoding was employed to analyze fish species composition,biodiversity patterns,and niche parameters of dominant species.Water sampling followed the CEN/TS 19461 standard across five monitoring transects(ZT1-ZT5).[Results]The eDNA analysis detected 45 species of fish belonging to 38 genera,13 families,and 3 orders were detected through environmental DNA(eDNA)in this survey,including 10 species endemic to the upper reaches of the Yangtze River,such as Procypris rabaudi and Myxocyprinus asiaticus.The fish community was mainly composed of bottom-dwelling,settling ovum-producing,omnivorous fish.The variation ranges of the Chao1 index,ACE index,Shannon index,and Simpson index are 736~996,719~965,1.58~3.23,and 0.83~0.99,respectively,indicating that fish species in spawning sites are abundant and community distribution uniformity is high.All indexes are highest at ZT1 monitoring points.Cluster analysis showed that,at a certain similarity level,fish community types in spawning sites could be basically divided into two groups:ZT1,ZT3,and ZT5 clustered together,and ZT2 and ZT4 clustered together,indicating similar fish community habitats.There are 9 dominant fish species in typical deep pool habitats in the reserve,with niche widths(Bi)ranging from 1.13 to 3.87.The dominant fish species are broad and medium niche fish,such as Cyprinus carpio and Hemiculter tchangi,with the niche overlap index(Oik)of some dominant fish species reaching more than 0.95.This indicates fierce competition for resources among the fish in this spawning ground.[Conclusion]The Zhutuo spawning ground demonstrates high species richness with homogeneous community structure and intense resource competition.This study establishes an eDNA-based monitoring framework that enhances conventional survey method,providing critical baseline data for adaptive management under the fishing moratorium regime.展开更多
For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological...For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological index(RSEI)was calculated for the Lijiang River Basin in Guangxi Zhuang Autonomous Region for 1991,2001,2011,and 2021.Spatial autocorrelation analysis was employed to investigate spatiotemporal variations in the ecological environmental quality of the Lijiang River Basin.Furthermore,geographic detectors were used to quantitatively analyze influencing factors and their interaction effects on ecological environmental quality.The results verified that:1)From 1991 to 2021,the ecological environmental quality of the Lijiang River Basin demonstrated significant improvement.The area with good and excellent ecological environmental quality in proportion increased by 19.69%(3406.57 km^(2)),while the area with fair and poor ecological environmental quality in proportion decreased by 10.76%(1860.36 km^(2)).2)Spatially,the ecological environmental quality of the Lijiang River Basin exhibited a pattern of low quality in the central region and high quality in the periphery.Specifically,poor ecological environmental quality characterized the Guilin urban area,Pingle County,and Lingchuan County.3)From 1991 to 2021,a significant positive spatial correlation was observed in ecological environmental quality of the Lijiang River Basin.Areas with high-high agglomeration were predominantly forests and grasslands,indicating good ecological environmental quality,whereas areas with low-low agglomeration were dominated by cultivated land and construction land,indicating poor ecological environmental quality.4)Annual average precipitation and temperature exerted the most significant influence on the ecological environmental quality of the basin,and their interactions with other factors had the great influence.This study aimed to enhance understanding of the evolution of the ecological environment in the Lijiang River Basin of Guangxi Zhuang Autonomous Region and provide scientific guidance for decision-making and management related to ecology in the region.展开更多
The authors demonstrate the importance of the simulation of the water quantity exchange between river water and groundwater to a better understanding of the hydrologic relations between a river and nearby aquifer wher...The authors demonstrate the importance of the simulation of the water quantity exchange between river water and groundwater to a better understanding of the hydrologic relations between a river and nearby aquifer where groundwater is pumped extensively but only seasonally. And MODFLOW is used to design the stream aquifer model in which the pumpage of more than 1000 wells was simulated. The river gaining and river losing processes were analyzed. Simulation results suggest that continuation of over extraction of groundwater will gradually increase the depletion volume in the river year after year and more depletion will occur in later years. The exchange manner between groundwater and the Platte River differs from place to place. The Platte River loses water to the adjacent aquifer in the west part of the study area, and gains water from the adjacent aquifer in the east part of the study area.展开更多
Gezhouba hydroproject was impounded and put into operation in 1981. In order to analyse the impact on the downstream river course, Jingjiang Hydrologic and Water Resources Survey Bureau of Changjiang Water Resources C...Gezhouba hydroproject was impounded and put into operation in 1981. In order to analyse the impact on the downstream river course, Jingjiang Hydrologic and Water Resources Survey Bureau of Changjiang Water Resources Commission has conducted prototype observation on the Yichang-Chenglingji river stretch. On basis of the observed data, the change in river regime and scour-sedimentation evolution and water surface profile below the dam are analysed systematically. The results show that the scouring of downstream river course mainly stretches from Yichang to Ouchikou, mainly occurring in 1980～1987; the scourring mainly takes place in the river channel and the water surface profile drops significantly in dry season,but not quite in high flood season.展开更多
The contamination and environmental risk assessment of the toxic elements in sediments from the middle-downstream (Zhuzhou-Changsha section) of the Xiangjiang River in Hunan Province of China were studied. The results...The contamination and environmental risk assessment of the toxic elements in sediments from the middle-downstream (Zhuzhou-Changsha section) of the Xiangjiang River in Hunan Province of China were studied. The results show that As, Cd, Pb and Zn are major contaminants in sediments, and average concentrations of these elements significantly exceed both the Control Standards for Pollutants in Sludge of China (GB4284-84) for agricultural use in acidic soils and the effect range median (ERM) values. The average concentrations of As, Cd and Pb in the river water slightly exceed the limit of Surface Water Environment Quality Standard (GB3838-2002). The concentrations of As and Cr in depth profiles extensively change, but slight changes are observed in Pb and Zn. Cd and Zn in most sediment samples can easily enter the food-chain and bring possible ecotoxicological risk to organisms living in sediments according to the risk assessment code.展开更多
A gram negative bacterium,named JDC-16,which can grow well on the substrate of phthalic acid esters(PAEs) as the sole source of carbon and energy,was isolated from river sludge.Based on the morphology,physiological an...A gram negative bacterium,named JDC-16,which can grow well on the substrate of phthalic acid esters(PAEs) as the sole source of carbon and energy,was isolated from river sludge.Based on the morphology,physiological and biochemical properties and analysis of 16S rRNA gene sequence,it was preliminarily identified belonging to the genus Acinetobacter.The result of substrates utilization range indicates that strain JDC-16 can utilize a variety of phthalates except for diisononyl phthalate(DINP) .The degradation tests using diethyl phthalate(DEP) as the model compound show that the optimal pH and temperature for DEP degradation by Acinetobacter sp.JDC-16 is 8.0 and 35℃,respectively.Meanwhile,degradation kinetics under various initial concentrations of DEP reveals that substrate depletion curves fit well with the modified Gompertz model with high correlation coefficient(R 2 >0.99) .Furthermore,the substrate induction test indicates that DEP-induction can apparently shorten the lag phase and enhance the degradation rate.This work highlights the potential of this isolate for bioremediation of phthalates-contaminated environments.展开更多
The Changsha-Xiangtan-Zhuzhou City Group is a heavy industrial district and accepted as the serious pollution area in the Xiangjiang River basin.In this study,7 metals(Pb,Hg,Cd,As,Zn,Cu and Se)and the river water qual...The Changsha-Xiangtan-Zhuzhou City Group is a heavy industrial district and accepted as the serious pollution area in the Xiangjiang River basin.In this study,7 metals(Pb,Hg,Cd,As,Zn,Cu and Se)and the river water quality parameters including pH,dissolved oxygen(DO),Escherichia coli(E.coli),potassium permanganate index(CODMn),dichromate oxidizability(CODCr),five-day biochemical oxygen demand(BOD5),ammonia nitrogen(NH4+-N),total nitrogen(TN),total phosphorus(TP)and fluoride(F)in 18 sampling sites of the Changsha-Xiangtan-Zhuzhou section are monthly monitored in 2016,which is the year to step into the second stage of the“Xiangjiang River Heavy Metal Pollution Control Implementation Plan”.It is found that E.coli,TN and TP are the main pollutants in the Changsha-Zhuzhou-Xiangtan section,and the pollution of heavy metal is not serious but As with potential risk to local people especially children should be concerned.In addition,Xiangtan city is mainly featured with heavy metal pollution,while Zhuzhou and Changsha city are both featured with other pollutants from municipal domestic sewage.展开更多
Frothing is a main disease of highways in Yellow River Flood Field, due to the loss of dynamic strength of roadbed soils under the couple effects of temperature, salt, and vehicle traffic load. This is strongly linked...Frothing is a main disease of highways in Yellow River Flood Field, due to the loss of dynamic strength of roadbed soils under the couple effects of temperature, salt, and vehicle traffic load. This is strongly linked to the dynamic characteristics of silt in this region. To analyze these couple effects on the dynamic characteristics of silt, a series of tests(i.e., freeze-thaw cycling tests, vibration triaxial tests and ultrasonic wave velocity tests) were conducted and two kinds of silt(i.e., salt-free and 3%-salt silt) were designed. The results indicate that the dynamic shear strength and dynamic modulus decrease with increasing freeze-thaw cycles, while the damping ratio simultaneously increases. Furthermore, compared to salt-free silt, the decrement of dynamic shear strength and dynamic modulus of silt with 3% salt is more significant, but the damping ratio of 3%-salt silt is larger. In ultrasonic wave velocity tests, ultrasonic wave velocity of frozen soil specimens decreases as the number of freeze-thaw cycles increases. Based on the results of ultrasonic wave velocity tests, a preliminary model is proposed to evaluate damage of silt through field measurement ultrasonic data. The study could provide a theoretical basis for the treatment of silty soil highway.展开更多
Chinese mitten crab （Eriocheir sinensis） is an indigenous and ecologically and economically important species in the Liao River area, but its identification and genetic diversity remain poorly understood. To evaluat...Chinese mitten crab （Eriocheir sinensis） is an indigenous and ecologically and economically important species in the Liao River area, but its identification and genetic diversity remain poorly understood. To evaluate the germplasm resources of this species, samples were collected from these locations： four sub-populations from the Liao River area and one population from the Yangtze River area; one primer was used to distinguish between the Liao River and the Yangtze River crabs. Thirteen loci were used for crab genetic diversity analysis, and basic statistics showed that the collecting samples were purebred in the Liao River area. The average observed heterozygosity （H0） of the Liao River population was 0.5931, and the expected heterozygosity （He） was 0.8064. The polymorphism information content （PIC） was 0.7753, which showed that the Liao River population had high genetic diversity. The genetic differentiation index （FST） averaged 0.0342, meaning a low degree of differentiation; cluster analysis indicated that Hujia （HJ）, Xinli （XL） and Chenjia （CJ） sub-populations were allocated to the same cluster, while Baqiangzi （BQZ） sub-population was isolated. In summary, these data demonstrated that the crabs in the Liao River had high genetic diversity, but low genetic differentiation. Thus, the Liao River population had the potential for breeding selection. Furthermore, this study also provided valuable genetic information for the conservation of Chinese mitten crab.展开更多
In order to evaluate objectively and accurately the integrity, safety and operating conditions in real time for the Nanjing Yangtze River Bridge, a large structural safety monitoring system was described. The monitori...In order to evaluate objectively and accurately the integrity, safety and operating conditions in real time for the Nanjing Yangtze River Bridge, a large structural safety monitoring system was described. The monitoring system is composed of three parts: sensor system, signal sampling and processing system, and safety monitoring and assessment system. Combining theoretical analysis with measured data analysis, main monitoring contents and layout of measuring points were determined. The vibration response monitoring was significantly investigated. The main contents of safety monitoring on vibration response monitoring are vibration of the main body of the Nanjing Yangtze river bridge, collision avoidance of the bridge piers, vibration of girders on high piers for the bridge approach and earthquake. As a field laboratory, the safety monitorying system also provides information to investigate the unknown and indeterminate problems on bridge structures and specific environment around bridges.展开更多
The hydrodynamic conditions present in a river delta's formation are a highly important factor in the variation between its sedimentary regulation and characteristics. In the case of the lacustrine basin river-dom...The hydrodynamic conditions present in a river delta's formation are a highly important factor in the variation between its sedimentary regulation and characteristics. In the case of the lacustrine basin river-dominated delta, water level fluctuations and fluviation, are both important controlling factors of the sedimentary characteristics and reservoir architecture. To discuss the effects of water level fluctuation on sediment characteristics and reservoir architecture of this delta, the Fangniugou section in the east of the Songliao Basin was selected for study. Based on an outcrop investigation of the lacustrine basin river-dominated delta, combining with an analysis of the major and trace chemical elements in the sediments to determine the relative water depth, through architecture bounding surfaces and lithofacies division, sedimentary microfacies recognition and architectural element research, this work illustrated the effects of water level fluctuation on the reservoir architecture and established sedimentary models for the lacustrine basin river-dominated delta under various water level conditions. The results show that there are 8 lithofacies in the Fangniugou section. The fan delta front, which is the main object of this study, develops four sedimentary microfacies that include the underwater distributary channel, river mouth bar, sheet sand and interdistributary bay. The effects of water level fluctuation on different orders geographic architecture elements are respectively reflected in the vertical combination of the composite sand bodies, the plane combination of the single sand bodies, the particle size changes in the vertical of hyperplasia in the single sand body, the coset and lamina. In the case of the sand body development of the petroliferous basin, varying water level conditions and research locations resulted in significant variation in the distribution and combination of the sand bodies in the lacustrine basin.展开更多
Multivariate statistical techniques,such as cluster analysis(CA),discriminant analysis(DA),principal component analysis(PCA) and factor analysis(FA),were applied to evaluate and interpret the surface water quality dat...Multivariate statistical techniques,such as cluster analysis(CA),discriminant analysis(DA),principal component analysis(PCA) and factor analysis(FA),were applied to evaluate and interpret the surface water quality data sets of the Second Songhua River(SSHR) basin in China,obtained during two years(2012-2013) of monitoring of 10 physicochemical parameters at 15 different sites.The results showed that most of physicochemical parameters varied significantly among the sampling sites.Three significant groups,highly polluted(HP),moderately polluted(MP) and less polluted(LP),of sampling sites were obtained through Hierarchical agglomerative CA on the basis of similarity of water quality characteristics.DA identified p H,F,DO,NH3-N,COD and VPhs were the most important parameters contributing to spatial variations of surface water quality.However,DA did not give a considerable data reduction(40% reduction).PCA/FA resulted in three,three and four latent factors explaining 70%,62% and 71% of the total variance in water quality data sets of HP,MP and LP regions,respectively.FA revealed that the SSHR water chemistry was strongly affected by anthropogenic activities(point sources:industrial effluents and wastewater treatment plants;non-point sources:domestic sewage,livestock operations and agricultural activities) and natural processes(seasonal effect,and natural inputs).PCA/FA in the whole basin showed the best results for data reduction because it used only two parameters(about 80% reduction) as the most important parameters to explain 72% of the data variation.Thus,this work illustrated the utility of multivariate statistical techniques for analysis and interpretation of datasets and,in water quality assessment,identification of pollution sources/factors and understanding spatial variations in water quality for effective stream water quality management.展开更多
A series of researches were carried out for the soil samples in the Pearl River Delta under the action of consolidation loads,such as the quantitative analyses of the pore scale,shape and size distributions of micro-s...A series of researches were carried out for the soil samples in the Pearl River Delta under the action of consolidation loads,such as the quantitative analyses of the pore scale,shape and size distributions of micro-structure units,with an environmental scanning electron microscope (ESEM),a mercury intrusion analyzer and a mineral diffractometer. The experimental results show that the consolidation pressures remarkably change the pore sizes and distribution characteristics of the silt,thus changing its compressibility and permeability. This can be proved by the fact that,in the earlier stage with a consolidation pressure of p<200 kPa,the pore sizes are greater and the compressibility and permeability coefficients are larger. However,they rapidly decrease with the increase in consolidation pressure. And in the later stage with a consolidation pressure of p>200 kPa,the pore sizes are smaller and the compressibility and permeability coefficients are less. Therefore,the empirical formulas of compression coefficient and permeability coefficient vs consolidation load and average pore diameter are deduced.展开更多
Following the basin wide heavy flood on Changjiang River in 1998, a significant flood occurred in 1999. Comparative analysis of both floods in terms of flows and flooding situations shows that both floods had one comm...Following the basin wide heavy flood on Changjiang River in 1998, a significant flood occurred in 1999. Comparative analysis of both floods in terms of flows and flooding situations shows that both floods had one common feature, that is, the flood stages were fairly high. But they differed greatly at the same time, that is, the 1998 flood was a basin wide heavy one while the 1999 flood was a significant local one. At Yichang station there occurred eight flood peaks in 1998, while in 1999 only three peaks took place. The maximum peak discharge at this station in 1999 was 57 600 cubic meters per second, which was smaller than that in 1998. The maximum flood-volume in 30 d of the 1998 flood at this station equaled that in 1954, when an extraordinary heavy flood happened on the River, while the maximum flood-volume in 30 d in 1999 was 25.8 billion cubic meters per second smaller than the 1998 one. It is seen that inflow floods from the upstream Changjiang River (above Yichang) in 1999 were not so big. Comparison of flood volumes in longer period shows that the 1999 flood was relatively concentrated while the 1998 one had lasted longer duration. Analysis shows that flooding situations in both years differed significantly in terms of the flood volumes diverted from river channels due to dyke breaches and collapses, the cases of polder embankment collapses, the areas of inundated cultivated land and the numbers of dangerous events for hydraulic structures. These differences had been resulted from the different properties of both floods and the dyke strengthening efforts made after the 1998 flood. It is seen that flood control engineering constructions initiated in the days following the 1998 flood have played an important role in fighting the 1999 flood.展开更多
文摘[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in the Upper Yangtze River.This study initiated continuous monitoring of natural spawning habitats from February 2022 to assess these ecological changes.[Methods]Environmental DNA(eDNA)metabarcoding was employed to analyze fish species composition,biodiversity patterns,and niche parameters of dominant species.Water sampling followed the CEN/TS 19461 standard across five monitoring transects(ZT1-ZT5).[Results]The eDNA analysis detected 45 species of fish belonging to 38 genera,13 families,and 3 orders were detected through environmental DNA(eDNA)in this survey,including 10 species endemic to the upper reaches of the Yangtze River,such as Procypris rabaudi and Myxocyprinus asiaticus.The fish community was mainly composed of bottom-dwelling,settling ovum-producing,omnivorous fish.The variation ranges of the Chao1 index,ACE index,Shannon index,and Simpson index are 736~996,719~965,1.58~3.23,and 0.83~0.99,respectively,indicating that fish species in spawning sites are abundant and community distribution uniformity is high.All indexes are highest at ZT1 monitoring points.Cluster analysis showed that,at a certain similarity level,fish community types in spawning sites could be basically divided into two groups:ZT1,ZT3,and ZT5 clustered together,and ZT2 and ZT4 clustered together,indicating similar fish community habitats.There are 9 dominant fish species in typical deep pool habitats in the reserve,with niche widths(Bi)ranging from 1.13 to 3.87.The dominant fish species are broad and medium niche fish,such as Cyprinus carpio and Hemiculter tchangi,with the niche overlap index(Oik)of some dominant fish species reaching more than 0.95.This indicates fierce competition for resources among the fish in this spawning ground.[Conclusion]The Zhutuo spawning ground demonstrates high species richness with homogeneous community structure and intense resource competition.This study establishes an eDNA-based monitoring framework that enhances conventional survey method,providing critical baseline data for adaptive management under the fishing moratorium regime.
基金supported by the Guangxi Natural Science Foundation(2020GXNSFAA297266)Doctoral Research Foundation of Guilin University of Technology(GUTQDJJ2007059)Guangxi Hidden Metallic Mineral Exploration Key Laboratory。
文摘For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological index(RSEI)was calculated for the Lijiang River Basin in Guangxi Zhuang Autonomous Region for 1991,2001,2011,and 2021.Spatial autocorrelation analysis was employed to investigate spatiotemporal variations in the ecological environmental quality of the Lijiang River Basin.Furthermore,geographic detectors were used to quantitatively analyze influencing factors and their interaction effects on ecological environmental quality.The results verified that:1)From 1991 to 2021,the ecological environmental quality of the Lijiang River Basin demonstrated significant improvement.The area with good and excellent ecological environmental quality in proportion increased by 19.69%(3406.57 km^(2)),while the area with fair and poor ecological environmental quality in proportion decreased by 10.76%(1860.36 km^(2)).2)Spatially,the ecological environmental quality of the Lijiang River Basin exhibited a pattern of low quality in the central region and high quality in the periphery.Specifically,poor ecological environmental quality characterized the Guilin urban area,Pingle County,and Lingchuan County.3)From 1991 to 2021,a significant positive spatial correlation was observed in ecological environmental quality of the Lijiang River Basin.Areas with high-high agglomeration were predominantly forests and grasslands,indicating good ecological environmental quality,whereas areas with low-low agglomeration were dominated by cultivated land and construction land,indicating poor ecological environmental quality.4)Annual average precipitation and temperature exerted the most significant influence on the ecological environmental quality of the basin,and their interactions with other factors had the great influence.This study aimed to enhance understanding of the evolution of the ecological environment in the Lijiang River Basin of Guangxi Zhuang Autonomous Region and provide scientific guidance for decision-making and management related to ecology in the region.
基金UnitedStateGeologicalSurveyGrant(No.1 4 34 HQ 96 GR 0 2 683)
文摘The authors demonstrate the importance of the simulation of the water quantity exchange between river water and groundwater to a better understanding of the hydrologic relations between a river and nearby aquifer where groundwater is pumped extensively but only seasonally. And MODFLOW is used to design the stream aquifer model in which the pumpage of more than 1000 wells was simulated. The river gaining and river losing processes were analyzed. Simulation results suggest that continuation of over extraction of groundwater will gradually increase the depletion volume in the river year after year and more depletion will occur in later years. The exchange manner between groundwater and the Platte River differs from place to place. The Platte River loses water to the adjacent aquifer in the west part of the study area, and gains water from the adjacent aquifer in the east part of the study area.
文摘Gezhouba hydroproject was impounded and put into operation in 1981. In order to analyse the impact on the downstream river course, Jingjiang Hydrologic and Water Resources Survey Bureau of Changjiang Water Resources Commission has conducted prototype observation on the Yichang-Chenglingji river stretch. On basis of the observed data, the change in river regime and scour-sedimentation evolution and water surface profile below the dam are analysed systematically. The results show that the scouring of downstream river course mainly stretches from Yichang to Ouchikou, mainly occurring in 1980～1987; the scourring mainly takes place in the river channel and the water surface profile drops significantly in dry season,but not quite in high flood season.
基金Project (20507022) supported by the National Natural Science Foundation of ChinaProject (EREH050303) supported by the Foundation of Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health
文摘The contamination and environmental risk assessment of the toxic elements in sediments from the middle-downstream (Zhuzhou-Changsha section) of the Xiangjiang River in Hunan Province of China were studied. The results show that As, Cd, Pb and Zn are major contaminants in sediments, and average concentrations of these elements significantly exceed both the Control Standards for Pollutants in Sludge of China (GB4284-84) for agricultural use in acidic soils and the effect range median (ERM) values. The average concentrations of As, Cd and Pb in the river water slightly exceed the limit of Surface Water Environment Quality Standard (GB3838-2002). The concentrations of As and Cr in depth profiles extensively change, but slight changes are observed in Pb and Zn. Cd and Zn in most sediment samples can easily enter the food-chain and bring possible ecotoxicological risk to organisms living in sediments according to the risk assessment code.
基金Project(30770388) supported by the National Natural Science Foundation of China
文摘A gram negative bacterium,named JDC-16,which can grow well on the substrate of phthalic acid esters(PAEs) as the sole source of carbon and energy,was isolated from river sludge.Based on the morphology,physiological and biochemical properties and analysis of 16S rRNA gene sequence,it was preliminarily identified belonging to the genus Acinetobacter.The result of substrates utilization range indicates that strain JDC-16 can utilize a variety of phthalates except for diisononyl phthalate(DINP) .The degradation tests using diethyl phthalate(DEP) as the model compound show that the optimal pH and temperature for DEP degradation by Acinetobacter sp.JDC-16 is 8.0 and 35℃,respectively.Meanwhile,degradation kinetics under various initial concentrations of DEP reveals that substrate depletion curves fit well with the modified Gompertz model with high correlation coefficient(R 2 >0.99) .Furthermore,the substrate induction test indicates that DEP-induction can apparently shorten the lag phase and enhance the degradation rate.This work highlights the potential of this isolate for bioremediation of phthalates-contaminated environments.
基金Projects(2018YFC1903301,2018YFC1801805)supported by the National Key R&D Program of China
文摘The Changsha-Xiangtan-Zhuzhou City Group is a heavy industrial district and accepted as the serious pollution area in the Xiangjiang River basin.In this study,7 metals(Pb,Hg,Cd,As,Zn,Cu and Se)and the river water quality parameters including pH,dissolved oxygen(DO),Escherichia coli(E.coli),potassium permanganate index(CODMn),dichromate oxidizability(CODCr),five-day biochemical oxygen demand(BOD5),ammonia nitrogen(NH4+-N),total nitrogen(TN),total phosphorus(TP)and fluoride(F)in 18 sampling sites of the Changsha-Xiangtan-Zhuzhou section are monthly monitored in 2016,which is the year to step into the second stage of the“Xiangjiang River Heavy Metal Pollution Control Implementation Plan”.It is found that E.coli,TN and TP are the main pollutants in the Changsha-Zhuzhou-Xiangtan section,and the pollution of heavy metal is not serious but As with potential risk to local people especially children should be concerned.In addition,Xiangtan city is mainly featured with heavy metal pollution,while Zhuzhou and Changsha city are both featured with other pollutants from municipal domestic sewage.
基金Project(2018YFB1600100) supported by the National Key Research and Development Project of ChinaProjects(51778346, 51508310) supported by the National Natural Science Foundation of ChinaProject(2019GSF111007) supported by Key Research and Development Project of Shandong Province, China。
文摘Frothing is a main disease of highways in Yellow River Flood Field, due to the loss of dynamic strength of roadbed soils under the couple effects of temperature, salt, and vehicle traffic load. This is strongly linked to the dynamic characteristics of silt in this region. To analyze these couple effects on the dynamic characteristics of silt, a series of tests(i.e., freeze-thaw cycling tests, vibration triaxial tests and ultrasonic wave velocity tests) were conducted and two kinds of silt(i.e., salt-free and 3%-salt silt) were designed. The results indicate that the dynamic shear strength and dynamic modulus decrease with increasing freeze-thaw cycles, while the damping ratio simultaneously increases. Furthermore, compared to salt-free silt, the decrement of dynamic shear strength and dynamic modulus of silt with 3% salt is more significant, but the damping ratio of 3%-salt silt is larger. In ultrasonic wave velocity tests, ultrasonic wave velocity of frozen soil specimens decreases as the number of freeze-thaw cycles increases. Based on the results of ultrasonic wave velocity tests, a preliminary model is proposed to evaluate damage of silt through field measurement ultrasonic data. The study could provide a theoretical basis for the treatment of silty soil highway.
基金Supported by Open Project Program of Key Laboratory of Freshwater Aquatic Biotechnology and Breeding,Ministry of Agriculture,Heilongjiang Fisheries Research Institute,Chinese Academy of Fishery Sciences(FBB2016-01)
文摘Chinese mitten crab （Eriocheir sinensis） is an indigenous and ecologically and economically important species in the Liao River area, but its identification and genetic diversity remain poorly understood. To evaluate the germplasm resources of this species, samples were collected from these locations： four sub-populations from the Liao River area and one population from the Yangtze River area; one primer was used to distinguish between the Liao River and the Yangtze River crabs. Thirteen loci were used for crab genetic diversity analysis, and basic statistics showed that the collecting samples were purebred in the Liao River area. The average observed heterozygosity （H0） of the Liao River population was 0.5931, and the expected heterozygosity （He） was 0.8064. The polymorphism information content （PIC） was 0.7753, which showed that the Liao River population had high genetic diversity. The genetic differentiation index （FST） averaged 0.0342, meaning a low degree of differentiation; cluster analysis indicated that Hujia （HJ）, Xinli （XL） and Chenjia （CJ） sub-populations were allocated to the same cluster, while Baqiangzi （BQZ） sub-population was isolated. In summary, these data demonstrated that the crabs in the Liao River had high genetic diversity, but low genetic differentiation. Thus, the Liao River population had the potential for breeding selection. Furthermore, this study also provided valuable genetic information for the conservation of Chinese mitten crab.
文摘In order to evaluate objectively and accurately the integrity, safety and operating conditions in real time for the Nanjing Yangtze River Bridge, a large structural safety monitoring system was described. The monitoring system is composed of three parts: sensor system, signal sampling and processing system, and safety monitoring and assessment system. Combining theoretical analysis with measured data analysis, main monitoring contents and layout of measuring points were determined. The vibration response monitoring was significantly investigated. The main contents of safety monitoring on vibration response monitoring are vibration of the main body of the Nanjing Yangtze river bridge, collision avoidance of the bridge piers, vibration of girders on high piers for the bridge approach and earthquake. As a field laboratory, the safety monitorying system also provides information to investigate the unknown and indeterminate problems on bridge structures and specific environment around bridges.
基金Project(2011ZX05009-002)supported by the National Key Oil&Gas Project,ChinaProject(15CX06010A)supported by the Fundamental Research Funds for the Central Universities,China
文摘The hydrodynamic conditions present in a river delta's formation are a highly important factor in the variation between its sedimentary regulation and characteristics. In the case of the lacustrine basin river-dominated delta, water level fluctuations and fluviation, are both important controlling factors of the sedimentary characteristics and reservoir architecture. To discuss the effects of water level fluctuation on sediment characteristics and reservoir architecture of this delta, the Fangniugou section in the east of the Songliao Basin was selected for study. Based on an outcrop investigation of the lacustrine basin river-dominated delta, combining with an analysis of the major and trace chemical elements in the sediments to determine the relative water depth, through architecture bounding surfaces and lithofacies division, sedimentary microfacies recognition and architectural element research, this work illustrated the effects of water level fluctuation on the reservoir architecture and established sedimentary models for the lacustrine basin river-dominated delta under various water level conditions. The results show that there are 8 lithofacies in the Fangniugou section. The fan delta front, which is the main object of this study, develops four sedimentary microfacies that include the underwater distributary channel, river mouth bar, sheet sand and interdistributary bay. The effects of water level fluctuation on different orders geographic architecture elements are respectively reflected in the vertical combination of the composite sand bodies, the plane combination of the single sand bodies, the particle size changes in the vertical of hyperplasia in the single sand body, the coset and lamina. In the case of the sand body development of the petroliferous basin, varying water level conditions and research locations resulted in significant variation in the distribution and combination of the sand bodies in the lacustrine basin.
基金Project (2012ZX07501002-001) supported by the Ministry of Science and Technology of China
文摘Multivariate statistical techniques,such as cluster analysis(CA),discriminant analysis(DA),principal component analysis(PCA) and factor analysis(FA),were applied to evaluate and interpret the surface water quality data sets of the Second Songhua River(SSHR) basin in China,obtained during two years(2012-2013) of monitoring of 10 physicochemical parameters at 15 different sites.The results showed that most of physicochemical parameters varied significantly among the sampling sites.Three significant groups,highly polluted(HP),moderately polluted(MP) and less polluted(LP),of sampling sites were obtained through Hierarchical agglomerative CA on the basis of similarity of water quality characteristics.DA identified p H,F,DO,NH3-N,COD and VPhs were the most important parameters contributing to spatial variations of surface water quality.However,DA did not give a considerable data reduction(40% reduction).PCA/FA resulted in three,three and four latent factors explaining 70%,62% and 71% of the total variance in water quality data sets of HP,MP and LP regions,respectively.FA revealed that the SSHR water chemistry was strongly affected by anthropogenic activities(point sources:industrial effluents and wastewater treatment plants;non-point sources:domestic sewage,livestock operations and agricultural activities) and natural processes(seasonal effect,and natural inputs).PCA/FA in the whole basin showed the best results for data reduction because it used only two parameters(about 80% reduction) as the most important parameters to explain 72% of the data variation.Thus,this work illustrated the utility of multivariate statistical techniques for analysis and interpretation of datasets and,in water quality assessment,identification of pollution sources/factors and understanding spatial variations in water quality for effective stream water quality management.
基金Project(2008ZA11) supported by State Key Laboratory of Subtropical Building Science in South China University of Technology, ChinaProject(20080430815) supported by China Postdoctoral Science Foundation
文摘A series of researches were carried out for the soil samples in the Pearl River Delta under the action of consolidation loads,such as the quantitative analyses of the pore scale,shape and size distributions of micro-structure units,with an environmental scanning electron microscope (ESEM),a mercury intrusion analyzer and a mineral diffractometer. The experimental results show that the consolidation pressures remarkably change the pore sizes and distribution characteristics of the silt,thus changing its compressibility and permeability. This can be proved by the fact that,in the earlier stage with a consolidation pressure of p<200 kPa,the pore sizes are greater and the compressibility and permeability coefficients are larger. However,they rapidly decrease with the increase in consolidation pressure. And in the later stage with a consolidation pressure of p>200 kPa,the pore sizes are smaller and the compressibility and permeability coefficients are less. Therefore,the empirical formulas of compression coefficient and permeability coefficient vs consolidation load and average pore diameter are deduced.
文摘Following the basin wide heavy flood on Changjiang River in 1998, a significant flood occurred in 1999. Comparative analysis of both floods in terms of flows and flooding situations shows that both floods had one common feature, that is, the flood stages were fairly high. But they differed greatly at the same time, that is, the 1998 flood was a basin wide heavy one while the 1999 flood was a significant local one. At Yichang station there occurred eight flood peaks in 1998, while in 1999 only three peaks took place. The maximum peak discharge at this station in 1999 was 57 600 cubic meters per second, which was smaller than that in 1998. The maximum flood-volume in 30 d of the 1998 flood at this station equaled that in 1954, when an extraordinary heavy flood happened on the River, while the maximum flood-volume in 30 d in 1999 was 25.8 billion cubic meters per second smaller than the 1998 one. It is seen that inflow floods from the upstream Changjiang River (above Yichang) in 1999 were not so big. Comparison of flood volumes in longer period shows that the 1999 flood was relatively concentrated while the 1998 one had lasted longer duration. Analysis shows that flooding situations in both years differed significantly in terms of the flood volumes diverted from river channels due to dyke breaches and collapses, the cases of polder embankment collapses, the areas of inundated cultivated land and the numbers of dangerous events for hydraulic structures. These differences had been resulted from the different properties of both floods and the dyke strengthening efforts made after the 1998 flood. It is seen that flood control engineering constructions initiated in the days following the 1998 flood have played an important role in fighting the 1999 flood.
