The original landform along the China Russia Crude Oil Pipeline(CRCOP,line 2)was disturbed during installation of pavement for the pipeline.Forest and vegetation coverage is dense,and runoff develops along the pipe.Si...The original landform along the China Russia Crude Oil Pipeline(CRCOP,line 2)was disturbed during installation of pavement for the pipeline.Forest and vegetation coverage is dense,and runoff develops along the pipe.Since the opera tion of the CRCOP(line 2)began in 2018,ponding has appeared on both sides of the pipeline.If there is no drainage,ponding can hardly dissipate,due to the low permeability of the permafrost layer.With the supply of surface flow and the transportation of oil at positive temperatures,ponding promotes an increase in temperature and changes the boundary ther mal conditions of the pipeline.Meanwhile,when the ponding freezes and thaws,frost heave threatens operational safety of the pipeline.Furthermore,the ponding can affect the thermal condition of line 1.In this paper,the distribution of pond ing along the CRCOP was obtained by field investigation.The type and cause of ponding were summarized,and the catch ment and stream order were extracted by the Digital Elevation Model(DEM).According to the statistical results in attri butes for topographic factors,it is known that ponding along the pipeline is relative to elevation,slope,aspect,and the Topographic Wetness Index(TWI).Water easily accumulates at altitudes of 300450 m,slopes within 3°5°,aspect in the northeast or south,TWI within 1316,flow direction in north east south,and flow length within 90150 km.This paper proposes a theoretical basis for the cause and characteristics of ponding along the pipeline.展开更多
Buried pipelines are widely used for transporting oil in remote cold regions. However, the warm oil can induce considerable thermal influence on the surrounding frozen soils and result in severe maintenance problems. ...Buried pipelines are widely used for transporting oil in remote cold regions. However, the warm oil can induce considerable thermal influence on the surrounding frozen soils and result in severe maintenance problems. This paper presents a case study of the thermal influence of ponding and buried warm-oil pipelines on permafrost along the China-Russia Crude Oil Pipeline(CRCOP) in Northeast China. Since its operation in 2011, the operation of the warm-oil pipelines has led to rapid warming and thawing of the surrounding permafrost and development of sizable ponding along the pipeline route,which, in return, exacerbates the permafrost degradation. A field study was conducted along a 400-km long segment of the CRCOP in permafrost regions of Northeast China to collect the location and size information of ponding. A two-dimensional heat transfer model coupled with phase change was established to analyze the thermal influence of ponding and the operation of warm-oil pipelines on the surrounding permafrost. In-situ measured ground temperatures from a monitoring site were obtained to validate the numerical model. The simulation results show that ponding accelerates the development of the thaw bulb around the pipeline. The maximum thaw depth below the pipeline increases from 4 m for the case without ponding to 9 m for the case with ponding after 50 years of operation, and ponding directly above the pipe induces the maximum thaw depth. Engineering measures should be adopted to control the size or even eliminate surface water-rich ponding for the long-term performance of buried warm-oil pipelines.展开更多
The study area is located in the Lower Yom River Basin covering an area of about 970 km^2 in the lower part of Northern Thailand, which is underlain by sequences of unconsolidated alluvial deposits derived from the Yo...The study area is located in the Lower Yom River Basin covering an area of about 970 km^2 in the lower part of Northern Thailand, which is underlain by sequences of unconsolidated alluvial deposits derived from the Yom and Nan River floodplains. Groundwater has been heavily exploited largely for agriculture from the shallow gravel, sand and silt aquifer in the basin. Drastically declining water levels, up to 10 m in some areas, has been observed within the past decade, creating difficulties with lift irrigation for the local farmers. Therefore, the Department of Groundwater Resources, Thailand, considers that groundwater artificial recharge may be useful for recovering the static water levels within the most hydrogeological suitable areas. The objective of the paper is to rank the suitability of sub-watershed in the Lower Yom River Basin for conducting a pilot-scale testing of MAR （managed aquifer recharge） by ponding system. Hydrogeological and non-hydrogeological parameters were used to formulate the site selection criteria. Boolean logic and Fuzzy logic were used for delineating the 19 sub-watersheds in the Lan Ba watershed. Detailed hydrogeological investigations were conducted in the 10 most prospective sub-watersheds. Of these, the Nong Na 3 sub-watershed covering an area of about 500 hectares was determined to be the most appropriate site for the MAR pilot construction and testing.展开更多
Information on the Arctic sea ice climate indicators is crucial to business strategic planning and climate monitoring.Data on the evolvement of the Arctic sea ice and decadal trends of phenology factors during melt se...Information on the Arctic sea ice climate indicators is crucial to business strategic planning and climate monitoring.Data on the evolvement of the Arctic sea ice and decadal trends of phenology factors during melt season are necessary for climate prediction under global warming.Previous studies on Arctic sea ice phenology did not involve melt ponds that dramatically lower the ice surface albedo and tremendously affect the process of sea ice surface melt.Temporal means and trends of the Arctic sea ice phenology from 1982 to 2017 were examined based on satellite-derived sea ice concentration and albedo measurements.Moreover,the timing of ice ponding and two periods corresponding to it were newly proposed as key stages in the melt season.Therefore,four timings,i.e.,date of snow and ice surface melt onset(MO),date of pond onset(PO),date of sea ice opening(DOO),and date of sea ice retreat(DOR);and three durations,i.e.,melt pond formation period(MPFP,i.e.,MO–PO),melt pond extension period(MPEP,i.e.,PO–DOR),and seasonal loss of ice period(SLIP,i.e.,DOO–DOR),were used.PO ranged from late April in the peripheral seas to late June in the central Arctic Ocean in Bootstrap results,whereas the pan-Arctic was observed nearly 4 days later in NASA Team results.Significant negative trends were presented in the MPEP in the Hudson Bay,the Baffin Bay,the Greenland Sea,the Kara and Barents seas in both results,indicating that the Arctic sea ice undergoes a quick transition from ice to open water,thereby extending the melt season year to year.The high correlation coefficient between MO and PO,MPFP illustrated that MO predominates the process of pond formation.展开更多
This research optimized the structure of lithium extraction solar ponds to enhance the crystallization rate and yield of Li_(2)CO_(3).Using the response surface methodology in Design-Expert 10.0.3,the authors conducte...This research optimized the structure of lithium extraction solar ponds to enhance the crystallization rate and yield of Li_(2)CO_(3).Using the response surface methodology in Design-Expert 10.0.3,the authors conducted experiments to investigate the influence of four factors related to solar pond structure on the crystallization of Li_(2)CO_(3) and their pairwise interactions.Computational Fluid Dynamics(CFD)simulations of the flow field within the solar pond were performed using COMSOL Multiphysics software to compare temperature distributions before and after optimization.The results indicate that the optimal structure for lithium extraction from the Zabuye Salt Lake solar ponds includes UCZ(Upper Convective Zone)thickness of 53.63 cm,an LCZ(Lower Convective Zone)direct heating temperature of 57.39℃,a CO32−concentration of 32.21 g/L,and an added soda ash concentration of 6.52 g/L.Following this optimized pathway,the Li_(2)CO_(3) precipitation increased by 7.34% compared to the initial solar pond process,with a 33.33% improvement in lithium carbonate crystallization rate.This study demonstrates the feasibility of optimizing lithium extraction solar pond structures,offering a new approach for constructing such ponds in salt lakes.It provides valuable guidance for the efficient extraction of lithium resources from carbonate-type salt lake brines.展开更多
Activity 1 Think about the following questions and write down your answers before reading the text.1.Suppose you are planning a trip to Antarctica and want to visit Don Juan Pond,what special preparations would you ne...Activity 1 Think about the following questions and write down your answers before reading the text.1.Suppose you are planning a trip to Antarctica and want to visit Don Juan Pond,what special preparations would you need to make compared to a normal trip?2.In your opinion,how could the unique features of Don Juan Pond be used to develop educational programs for high school students?展开更多
Insects represent an important taxon for the functioning of ecosystems. They also contribute to human and animal nutrition and are vector agents of several diseases. In Congo-Brazzaville the diversity of entomofauna i...Insects represent an important taxon for the functioning of ecosystems. They also contribute to human and animal nutrition and are vector agents of several diseases. In Congo-Brazzaville the diversity of entomofauna is very little known. The present study aimed to investigate ponds. The inventory of insects was conducted in ponds Ngatsouéné and Yo, the first one was located in the center of Djambala and the last one was 2 km from the center of the city. The insects were caught with an entomological net from 23rd to 24th December 2012. The study identifies 37 species belonging to 17 families and 7 orders. This entomofauna study showed a high proportion of the Orthoptera order (27.20%). Family Mantidae has the largest species number (13.51%). Mantis sp is the most abundant species (13.51%). This is a database and therefore, should be extended to different aquatic ecosystems of the Department of Plateaux. The results obtained during this study will contribute to the development of a database for the management of entomofauna in Congo.展开更多
This study evaluates the dynamics of trace metals impacts on the ecosystems of the Bartlett Pond, a small shallow wetland pond located in Laredo, Texas by analyzing sediment samples taken from four quadrants of the po...This study evaluates the dynamics of trace metals impacts on the ecosystems of the Bartlett Pond, a small shallow wetland pond located in Laredo, Texas by analyzing sediment samples taken from four quadrants of the pond. The concentrations of trace elements in sediment samples are highest for iron (Fe), followed by chromium (Cr), then lead (Pb), with lower concentration of antimony (Sb), cobalt (Co), arsenic (As), cadmium (Cd), and the lowest concentration being thallium (Tl) within Bartlett Pond. The sediment quality of the pond is acceptable for organisms and the environment as trace element concentrations (e.g. As, Cd, Cr, and Pb) are within the probable effect concentration (PEC) of National Ocean and Atmospheric Administration (NOAA) guidelines although the PEC values for Co, Fe, Sb and Tl are not given. Bivariate and multivariate correlation analysis shows that most trace elements exhibit a strong positive correlation among them indicating the same anthropogenic sources and biogeochemical processes control these trace elements concentrations within the pond. We provided a comprehensive snapshot of trace element concentrations in sediments through descriptive analysis, laying the foundation for future environmental risk assessments. Correlation analysis of eight trace elements helped identify relationships, offering insights into pollution sources and potential health impacts. Additionally, univariate and multivariate predictive analyses generated numerous models, extending beyond the interpretation of partial and full regression coefficients. We also included graphical analyses of trace element variations, which are critical for understanding environmental processes and geochemical patterns. These findings advance our understanding about trace metals dynamics in sediments and may be a valuable reference for ecosystems and environmental management of different landscapes.展开更多
Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cyc...Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cycle of wintering populations. The ongoing degradation and loss of optimal habitats have forced wintering waterbirds to increasingly rely on alternative foraging sites and modify their behavioral adaptation strategies to cope with food scarcity. The Siberian Crane (Leucogeranus leucogeranus), a large-bodied endangered waterbird species characterized by specialized dietary preferences, demonstrates particular sensitivity to environmental alterations. Faced with diminishing suitable habitats and declining natural food resources, this species has progressively adapted to utilizing artificial habitats, including agricultural landscapes such as paddy fields and lotus ponds, as supplementary wintering foraging grounds to fulfill their energetic requirements. This study examines the hypothesis that Siberian Cranes adapt their foraging behavior through plastic behavioral strategies in artificial habitats under conditions of limited food availability, thereby enhancing population fitness. A comparative analysis of crane foraging behaviors was conducted between mudflats and lotus ponds throughout the 2023–2024 wintering period. This investigation focused on three critical environmental factors: food abundance, food burial depth, and sediment penetrability, examining their influence on foraging patterns across these distinct habitats. The results revealed significant inter-habitat differences: foraging success rates were substantially higher (p < 0.05) and food handling times markedly longer in lotus ponds compared to mudflats, whereas foraging effort and attempt frequency were significantly elevated in mudflat habitats. The superior food availability in lotus ponds facilitated enhanced foraging success rates, enabling cranes to accumulate essential energy reserves for winter survival. However, the deeper burial depth of lotus roots in these habitats required more intensive processing behaviors, including prolonged digging, breaking, and swallowing activities, which consequently increased handling time by approximately 40% and reduced foraging attempts by 25–30% compared to mudflat conditions. These behavioral trade-offs suggest that while lotus ponds provide adequate food resources, their structural characteristics may impose physiological constraints that limit their effectiveness as optimal foraging grounds for Siberian Cranes. These findings offer valuable insights into the behavioral plasticity of wintering Siberian Cranes response to spatial variations in food resource distribution, while contributing to our understanding of the ecological value of lotus roots as alternative winter food sources in artificial wetland ecosystems.展开更多
Wetlands are unique ecological environments capable of harboring high biodiversity.However,urbanization can degrade,eliminate,or transformthese habitats.Although amphibians utilize habitats created by humans in urban ...Wetlands are unique ecological environments capable of harboring high biodiversity.However,urbanization can degrade,eliminate,or transformthese habitats.Although amphibians utilize habitats created by humans in urban landscapes,few studies have investigated the infuence of thehabitat quality on the life history of anurans.We assessed life history traits such as snout-vent length(SVL),body condition,and reproductiveinvestment in the South American common toad Rhinella arenarum,to determine whether urbanization is harmful or benefcial to this species.We sampled wetlands with different levels of urbanization in Río Cuarto city,Córdoba,Argentina.We recorded males with lower SVL in mediumurbanized wetlands and those with the highest SVL in both low and high urbanization categories,similar to what was found for body conditionswith males with low body conditions inhabiting wetlands with a medium degree of urbanization.In females,lower SVL was recorded in mediumurbanization and highest SVL in high and low urbanization.It is observed that females recorded in highly urbanized wetlands have a very lowbody condition.The reproductive investment parameters were not signifcantly different,but we observed an association between a greaternumber of eggs and clutch size with wetlands of low urbanization.These results show a variability of responses of R.arenarum to urbanization,which could be due to phenotypic plasticity in its life history parameters,allowing it to inhabit urban areas.Continuous monitoring of the speciesin these wetlands is needed to determine if these biological responses are temporary or persistent.展开更多
Melt ponds are significant physical features on the ice surface throughout the Arctic summer,and the scarcity of observational data has resulted in a vague understanding about it.This study employs satellite data and ...Melt ponds are significant physical features on the ice surface throughout the Arctic summer,and the scarcity of observational data has resulted in a vague understanding about it.This study employs satellite data and multi-model averaged outputs from Coupled Model Intercomparison Project Phase 6(CMIP6)to analyze the spatiotemporal evolution characteristics of Arctic melt ponds and their relationship with sea ice thickness(SIT)and atmospheric energy flux.The ponds first emerge at lower latitudes and gradually extend to cover central ice areas as the season progresses,then persisting longer and covering larger total areas in the central region,with peak areas exceeding 0.6×10^(6)km^(2),which is four to five times that of other marginal areas.Over the past two decades,pond coverage has exhibited markedly different trends with slight decreases in the marginal seas but significant increases in the central area.Both CMIP6 and satellite data indicate that the sea ice carrying capacity,related to thickness,plays a crucial role in creating these differences.There is a marked increasing pond in areas with thicker ice.When the SIT falls below a certain threshold,however,sea ice melting results in decreased pond coverage.Additionally,the energy balance on the ice surface also dramatically impacts pond changes.For instance,the overall pond changes in central area are influenced by net longwave radiation and latent heat,with anomalies in these fluxes correlating highly(up to 0.8)with pond anomalies.Meanwhile,net shortwave radiation primarily causes local pond anomalies through the pond-shortwave feedback only under the clear weather conditions.展开更多
The environmental issues confronted by traditional freshwater aquaculture are increasingly sedous, promoting development of ecological remediation technolo- gies. The in-situ remediation represented by fish-vegetable ...The environmental issues confronted by traditional freshwater aquaculture are increasingly sedous, promoting development of ecological remediation technolo- gies. The in-situ remediation represented by fish-vegetable mutualism mode （FVMM） and ex-situ remediation represented by recirculating aquaculture system （RAS） are highlights of related researches. In the paper, the advantages and disadvantages of FVMM and RAS were analyzed and area allocation was discussed in terms of eu- trophication and pond nitrogen cycle. The results showed that the FVMM could re- duce pollutant-discharge coefficient of fish ponds, but the ecological balance would still be hard to be achieved nationwide. In contrast, although the extra cost and land resources would produce inevitably, the application is of great significance in small regions, especially for eutrophication areas thanks for zero-discharge.展开更多
A dissolved oxygen fuzzy system predicting model based on neural network was put forward in this study. 106 groups of data were used to confirm the fitness of the predicting model. The first 80 groups of data were act...A dissolved oxygen fuzzy system predicting model based on neural network was put forward in this study. 106 groups of data were used to confirm the fitness of the predicting model. The first 80 groups of data were acted as training input and the other 26 groups of data were acted as the confirmed data in the system. The result showed that the testing data was approximately the same as the predicted data. So it gave a new way to solve the problem that the status of the water quality couldn＇t be predicted in time and it＇s hard to watching and measuring the factors dynamic.展开更多
With Biolog Eco microplate, metabolic characteristics and functional diver-sity of carbon source in microflora of ponds were researched based on recitculating ponds and control ponds in order to explore effects of eco...With Biolog Eco microplate, metabolic characteristics and functional diver-sity of carbon source in microflora of ponds were researched based on recitculating ponds and control ponds in order to explore effects of eco-adjustments on microflo-ra in ponds. The results indicate that total number of bacterium, microbial metabolism activity, and diversity index in P7, P8, P1 and P2 kept higher, fol owed by P3, P4, P5 and P6. The utilization rate of microbes on sugars achieved the highest （31.0%-48.7%）, fol owed by carboxylic acid （13.4%-18.0%）, amino acid （10.1%-20.5%）, polymers （9.4%-17.0%）, biopolymer （5.7%-9.7%） and phenol （4.95%-7.50%）. Principal component analysis divided microflora in different ponds, suggesting that microbial community has varied carbon source characteristics and nitrogen-containing compound and biopolymer metabolisms are most affected.展开更多
The establishment of water circulation aquaculture system realized the hi- erarchical use of nitrogen, phosphorus and other eutrophic substances in aquaculture wastewater and the recirculation use of water resource. H...The establishment of water circulation aquaculture system realized the hi- erarchical use of nitrogen, phosphorus and other eutrophic substances in aquaculture wastewater and the recirculation use of water resource. However, no research has been reported on the detailed calculation of the relationship between the area of aquaculture pond and purification pond. In this study, referring to the absorption ability of aquatic plants to pollutants in aquaculture wastewater and pollutant generation and discharge coefficient in aquaculture pond, based on the general rules of water quality management in freshwater aquaculture system, a calculation mode was es- tablished to investigate the relationship between the area of aquaculture pond and purification pond in freshwater recirculation aquaculture system, which was feasible to explain related cases and would provide theoretical basis to reduce the economic costs in the construction of water circulation aquaculture system and realize the bal- ance between the ecological benefits and the economic benefits.展开更多
The aquaculture pond water quality was taken as research objects,based on the general analysis of factors influencing the pond water quality,the system of index estimation and assessment standard were established afte...The aquaculture pond water quality was taken as research objects,based on the general analysis of factors influencing the pond water quality,the system of index estimation and assessment standard were established after sorting by importance of the factors by means of Delphi and expert investigation.In this study,index weight was confirmed according to the importance of the factors and relative membership grade of the measured values,thus and the fuzzy comprehensive evaluation model of aquaculture pond water quality was constructed,and the fuzzy comprehensive evaluation system of freshwater aquaculture pond water quality was designed and implemented.The application of this system in the assessment of aquaculture pond water quality by a company had achieved better result.展开更多
[Objective] This study was to provide references for the evaluation of water quality in aquaculture ponds by evaluating the pond water quality using fuzzy comprehensive evaluation method based on entropy weight. [Meth...[Objective] This study was to provide references for the evaluation of water quality in aquaculture ponds by evaluating the pond water quality using fuzzy comprehensive evaluation method based on entropy weight. [Method] The fuzzy compre- hensive evaluation method based on entropy weight was used to evaluate the water quality in the ponds with Ukraine scale carp （Cyprinus carpio） as the main cultivated fish. The average size of the fish was 71.4 g/ind, and totally three groups of pond were set with the population density of 6 000, 9 000, 12 000 ind/hm2. [Result] According to the GB3838-2002 Environmental Quality Standards for Surface Water of China, the water quality of 6 000 ind/hm2 group was Grade I, and the water quality of 9 000 and 12 000 ind/hm2 were Grade V. [Conclusion] With the increasing of feeding density, the pond water quality would worsen, however, there is no difference on water quality between 9 000 and 12 000 ind/hm2 groups.展开更多
The arsenic contamination in soil-water-plant systems is a major concern of where, the groundwater is being contaminated with arsenic （above 0.01 mg/L） in the Indian subcontinent. The study was conducted with organi...The arsenic contamination in soil-water-plant systems is a major concern of where, the groundwater is being contaminated with arsenic （above 0.01 mg/L） in the Indian subcontinent. The study was conducted with organic matter to find out the reducing effect on arsenic load to rice （cv. Khitish）. It was observed that intermittent ponding reduced arsenic uptake （23.33% in root, 13.84% in shoot and 19.84% in leaf） at panicle initiation stage, instead of continuous ponding. A decreasing trend of arsenic accumulation （root straw husk whole grain milled grain） was observed in different plant parts at harvest. Combined applications of lathyrus ＋ vermicompost ＋ poultry manure reduced arsenic transport in plant parts （root, straw, husk, whole grains and milled grain） which was significantly at par （p 0.05） with chopped rice straw （5 tons/ha ） ＋ lathyrus green manuring （5 tons/ha） in comparison to control and corresponding soils. A significant negative correlation of arsenic with phosphorus （grain P with arsenic in different parts R 2 = 0.627–0.726 at p 0.01） was observed. Similarly, soil arsenic had a negative correlation with soil available phosphorus （R 2 = 0.822 at p 0.001） followed by soil nitrogen （R 2 = 0.762 at p 0.01） and soil potassium （R 2 = 0.626 at p 0.01）. Hence, effective management of contaminated irrigation water along with organic matter could reduce the arsenic build up to plants and soil.展开更多
Infiltration–runoff–slope instability mechanism of macropore slope under heavy rainfall is unclear.This paper studied its instability mechanism with an improved Green–Ampt(GA)model considering the dual-porosity(i.e...Infiltration–runoff–slope instability mechanism of macropore slope under heavy rainfall is unclear.This paper studied its instability mechanism with an improved Green–Ampt(GA)model considering the dual-porosity(i.e.,matrix and macropore)and ponding condition,and proposed the infiltration equations,infiltration–runoff coupled model,and safety factor calculation method.Results show that the infiltration processes of macropore slope can be divided into three stages,and the proposed model is rational by a comparative analysis.The wetting front depth of the traditional unsaturated slope is 17.2%larger than that of the macropore slope in the early rainfall stage and 27%smaller than that of the macropore slope in the late rainfall stage.Then,macropores benefit the slope stability in the early rainfall but not in the latter.Macropore flow does not occur initially but becomes pronounced with increasing rainfall duration.The equal depth of the wetting front in the two domains is regarded as the onset criteria of macropore flow.Parameter analysis shows that macropore flow is delayed by increasing proportion of macropore domain(ω_(f)),whereas promoted by increasing ratio of saturated permeability coefficients between the two domains(μ).The increasing trend of ponding depth is sharp at first and then grows slowly.Finally,when rainfall duration is less than 3 h,ωf andμhave no significant effect on the safety factor,whereas it decreases with increasingωf and increases with increasingμunder longer duration(≥3 h).With the increase ofω_(f),the slope maximum instability time advances by 10.5 h,and with the increase ofμ,the slope maximum instability time delays by 3.1 h.展开更多
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA2003020102)the National Natural Science Foundation of China (No. 41630636 and No. 41772325)the China Postdoctoral Science Foundation (No. 2019M653797)
文摘The original landform along the China Russia Crude Oil Pipeline(CRCOP,line 2)was disturbed during installation of pavement for the pipeline.Forest and vegetation coverage is dense,and runoff develops along the pipe.Since the opera tion of the CRCOP(line 2)began in 2018,ponding has appeared on both sides of the pipeline.If there is no drainage,ponding can hardly dissipate,due to the low permeability of the permafrost layer.With the supply of surface flow and the transportation of oil at positive temperatures,ponding promotes an increase in temperature and changes the boundary ther mal conditions of the pipeline.Meanwhile,when the ponding freezes and thaws,frost heave threatens operational safety of the pipeline.Furthermore,the ponding can affect the thermal condition of line 1.In this paper,the distribution of pond ing along the CRCOP was obtained by field investigation.The type and cause of ponding were summarized,and the catch ment and stream order were extracted by the Digital Elevation Model(DEM).According to the statistical results in attri butes for topographic factors,it is known that ponding along the pipeline is relative to elevation,slope,aspect,and the Topographic Wetness Index(TWI).Water easily accumulates at altitudes of 300450 m,slopes within 3°5°,aspect in the northeast or south,TWI within 1316,flow direction in north east south,and flow length within 90150 km.This paper proposes a theoretical basis for the cause and characteristics of ponding along the pipeline.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA2003020102)the China Postdoctoral Science Foundation(No.2019M653797)+1 种基金the National Natural Science Foundation of China(No.41630636 and No.41772325)the Major Program of the Bureau of International Cooperation,the Chinese Academy of Sciences(131B62KYSB20170012).
文摘Buried pipelines are widely used for transporting oil in remote cold regions. However, the warm oil can induce considerable thermal influence on the surrounding frozen soils and result in severe maintenance problems. This paper presents a case study of the thermal influence of ponding and buried warm-oil pipelines on permafrost along the China-Russia Crude Oil Pipeline(CRCOP) in Northeast China. Since its operation in 2011, the operation of the warm-oil pipelines has led to rapid warming and thawing of the surrounding permafrost and development of sizable ponding along the pipeline route,which, in return, exacerbates the permafrost degradation. A field study was conducted along a 400-km long segment of the CRCOP in permafrost regions of Northeast China to collect the location and size information of ponding. A two-dimensional heat transfer model coupled with phase change was established to analyze the thermal influence of ponding and the operation of warm-oil pipelines on the surrounding permafrost. In-situ measured ground temperatures from a monitoring site were obtained to validate the numerical model. The simulation results show that ponding accelerates the development of the thaw bulb around the pipeline. The maximum thaw depth below the pipeline increases from 4 m for the case without ponding to 9 m for the case with ponding after 50 years of operation, and ponding directly above the pipe induces the maximum thaw depth. Engineering measures should be adopted to control the size or even eliminate surface water-rich ponding for the long-term performance of buried warm-oil pipelines.
文摘The study area is located in the Lower Yom River Basin covering an area of about 970 km^2 in the lower part of Northern Thailand, which is underlain by sequences of unconsolidated alluvial deposits derived from the Yom and Nan River floodplains. Groundwater has been heavily exploited largely for agriculture from the shallow gravel, sand and silt aquifer in the basin. Drastically declining water levels, up to 10 m in some areas, has been observed within the past decade, creating difficulties with lift irrigation for the local farmers. Therefore, the Department of Groundwater Resources, Thailand, considers that groundwater artificial recharge may be useful for recovering the static water levels within the most hydrogeological suitable areas. The objective of the paper is to rank the suitability of sub-watershed in the Lower Yom River Basin for conducting a pilot-scale testing of MAR （managed aquifer recharge） by ponding system. Hydrogeological and non-hydrogeological parameters were used to formulate the site selection criteria. Boolean logic and Fuzzy logic were used for delineating the 19 sub-watersheds in the Lan Ba watershed. Detailed hydrogeological investigations were conducted in the 10 most prospective sub-watersheds. Of these, the Nong Na 3 sub-watershed covering an area of about 500 hectares was determined to be the most appropriate site for the MAR pilot construction and testing.
基金The National Key Research and Development Program of China under contract No.2018YFC1406102the Funds for the Distinguished Young Scientists of Hubei Province(China)under contract No.2019CFA057the National Natural Science Foundation of China under contract Nos 41941010 and 41776200。
文摘Information on the Arctic sea ice climate indicators is crucial to business strategic planning and climate monitoring.Data on the evolvement of the Arctic sea ice and decadal trends of phenology factors during melt season are necessary for climate prediction under global warming.Previous studies on Arctic sea ice phenology did not involve melt ponds that dramatically lower the ice surface albedo and tremendously affect the process of sea ice surface melt.Temporal means and trends of the Arctic sea ice phenology from 1982 to 2017 were examined based on satellite-derived sea ice concentration and albedo measurements.Moreover,the timing of ice ponding and two periods corresponding to it were newly proposed as key stages in the melt season.Therefore,four timings,i.e.,date of snow and ice surface melt onset(MO),date of pond onset(PO),date of sea ice opening(DOO),and date of sea ice retreat(DOR);and three durations,i.e.,melt pond formation period(MPFP,i.e.,MO–PO),melt pond extension period(MPEP,i.e.,PO–DOR),and seasonal loss of ice period(SLIP,i.e.,DOO–DOR),were used.PO ranged from late April in the peripheral seas to late June in the central Arctic Ocean in Bootstrap results,whereas the pan-Arctic was observed nearly 4 days later in NASA Team results.Significant negative trends were presented in the MPEP in the Hudson Bay,the Baffin Bay,the Greenland Sea,the Kara and Barents seas in both results,indicating that the Arctic sea ice undergoes a quick transition from ice to open water,thereby extending the melt season year to year.The high correlation coefficient between MO and PO,MPFP illustrated that MO predominates the process of pond formation.
基金This study was supported by the National Natural Science Foundation of China(U20A20148)the Major Science and Technology Projects of the Xizang(Tibet)Autonomous Region(XZ202201ZD0004G and XZ202201ZD0004G01).
文摘This research optimized the structure of lithium extraction solar ponds to enhance the crystallization rate and yield of Li_(2)CO_(3).Using the response surface methodology in Design-Expert 10.0.3,the authors conducted experiments to investigate the influence of four factors related to solar pond structure on the crystallization of Li_(2)CO_(3) and their pairwise interactions.Computational Fluid Dynamics(CFD)simulations of the flow field within the solar pond were performed using COMSOL Multiphysics software to compare temperature distributions before and after optimization.The results indicate that the optimal structure for lithium extraction from the Zabuye Salt Lake solar ponds includes UCZ(Upper Convective Zone)thickness of 53.63 cm,an LCZ(Lower Convective Zone)direct heating temperature of 57.39℃,a CO32−concentration of 32.21 g/L,and an added soda ash concentration of 6.52 g/L.Following this optimized pathway,the Li_(2)CO_(3) precipitation increased by 7.34% compared to the initial solar pond process,with a 33.33% improvement in lithium carbonate crystallization rate.This study demonstrates the feasibility of optimizing lithium extraction solar pond structures,offering a new approach for constructing such ponds in salt lakes.It provides valuable guidance for the efficient extraction of lithium resources from carbonate-type salt lake brines.
文摘Activity 1 Think about the following questions and write down your answers before reading the text.1.Suppose you are planning a trip to Antarctica and want to visit Don Juan Pond,what special preparations would you need to make compared to a normal trip?2.In your opinion,how could the unique features of Don Juan Pond be used to develop educational programs for high school students?
文摘Insects represent an important taxon for the functioning of ecosystems. They also contribute to human and animal nutrition and are vector agents of several diseases. In Congo-Brazzaville the diversity of entomofauna is very little known. The present study aimed to investigate ponds. The inventory of insects was conducted in ponds Ngatsouéné and Yo, the first one was located in the center of Djambala and the last one was 2 km from the center of the city. The insects were caught with an entomological net from 23rd to 24th December 2012. The study identifies 37 species belonging to 17 families and 7 orders. This entomofauna study showed a high proportion of the Orthoptera order (27.20%). Family Mantidae has the largest species number (13.51%). Mantis sp is the most abundant species (13.51%). This is a database and therefore, should be extended to different aquatic ecosystems of the Department of Plateaux. The results obtained during this study will contribute to the development of a database for the management of entomofauna in Congo.
文摘This study evaluates the dynamics of trace metals impacts on the ecosystems of the Bartlett Pond, a small shallow wetland pond located in Laredo, Texas by analyzing sediment samples taken from four quadrants of the pond. The concentrations of trace elements in sediment samples are highest for iron (Fe), followed by chromium (Cr), then lead (Pb), with lower concentration of antimony (Sb), cobalt (Co), arsenic (As), cadmium (Cd), and the lowest concentration being thallium (Tl) within Bartlett Pond. The sediment quality of the pond is acceptable for organisms and the environment as trace element concentrations (e.g. As, Cd, Cr, and Pb) are within the probable effect concentration (PEC) of National Ocean and Atmospheric Administration (NOAA) guidelines although the PEC values for Co, Fe, Sb and Tl are not given. Bivariate and multivariate correlation analysis shows that most trace elements exhibit a strong positive correlation among them indicating the same anthropogenic sources and biogeochemical processes control these trace elements concentrations within the pond. We provided a comprehensive snapshot of trace element concentrations in sediments through descriptive analysis, laying the foundation for future environmental risk assessments. Correlation analysis of eight trace elements helped identify relationships, offering insights into pollution sources and potential health impacts. Additionally, univariate and multivariate predictive analyses generated numerous models, extending beyond the interpretation of partial and full regression coefficients. We also included graphical analyses of trace element variations, which are critical for understanding environmental processes and geochemical patterns. These findings advance our understanding about trace metals dynamics in sediments and may be a valuable reference for ecosystems and environmental management of different landscapes.
基金funded by the National Natural Science Foundation of China(No.32470553).
文摘Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cycle of wintering populations. The ongoing degradation and loss of optimal habitats have forced wintering waterbirds to increasingly rely on alternative foraging sites and modify their behavioral adaptation strategies to cope with food scarcity. The Siberian Crane (Leucogeranus leucogeranus), a large-bodied endangered waterbird species characterized by specialized dietary preferences, demonstrates particular sensitivity to environmental alterations. Faced with diminishing suitable habitats and declining natural food resources, this species has progressively adapted to utilizing artificial habitats, including agricultural landscapes such as paddy fields and lotus ponds, as supplementary wintering foraging grounds to fulfill their energetic requirements. This study examines the hypothesis that Siberian Cranes adapt their foraging behavior through plastic behavioral strategies in artificial habitats under conditions of limited food availability, thereby enhancing population fitness. A comparative analysis of crane foraging behaviors was conducted between mudflats and lotus ponds throughout the 2023–2024 wintering period. This investigation focused on three critical environmental factors: food abundance, food burial depth, and sediment penetrability, examining their influence on foraging patterns across these distinct habitats. The results revealed significant inter-habitat differences: foraging success rates were substantially higher (p < 0.05) and food handling times markedly longer in lotus ponds compared to mudflats, whereas foraging effort and attempt frequency were significantly elevated in mudflat habitats. The superior food availability in lotus ponds facilitated enhanced foraging success rates, enabling cranes to accumulate essential energy reserves for winter survival. However, the deeper burial depth of lotus roots in these habitats required more intensive processing behaviors, including prolonged digging, breaking, and swallowing activities, which consequently increased handling time by approximately 40% and reduced foraging attempts by 25–30% compared to mudflat conditions. These behavioral trade-offs suggest that while lotus ponds provide adequate food resources, their structural characteristics may impose physiological constraints that limit their effectiveness as optimal foraging grounds for Siberian Cranes. These findings offer valuable insights into the behavioral plasticity of wintering Siberian Cranes response to spatial variations in food resource distribution, while contributing to our understanding of the ecological value of lotus roots as alternative winter food sources in artificial wetland ecosystems.
基金Financial support was provided by Secretaría de Cienciay Técnica-Universidad Nacional de Río Cuarto(SECyTUNRC,Grant PPI 18/C416)Fondo para la Investigación Científca y Tecnológica(FONCyT,Grant PICT BIDPICT 0981-20182530-2019).
文摘Wetlands are unique ecological environments capable of harboring high biodiversity.However,urbanization can degrade,eliminate,or transformthese habitats.Although amphibians utilize habitats created by humans in urban landscapes,few studies have investigated the infuence of thehabitat quality on the life history of anurans.We assessed life history traits such as snout-vent length(SVL),body condition,and reproductiveinvestment in the South American common toad Rhinella arenarum,to determine whether urbanization is harmful or benefcial to this species.We sampled wetlands with different levels of urbanization in Río Cuarto city,Córdoba,Argentina.We recorded males with lower SVL in mediumurbanized wetlands and those with the highest SVL in both low and high urbanization categories,similar to what was found for body conditionswith males with low body conditions inhabiting wetlands with a medium degree of urbanization.In females,lower SVL was recorded in mediumurbanization and highest SVL in high and low urbanization.It is observed that females recorded in highly urbanized wetlands have a very lowbody condition.The reproductive investment parameters were not signifcantly different,but we observed an association between a greaternumber of eggs and clutch size with wetlands of low urbanization.These results show a variability of responses of R.arenarum to urbanization,which could be due to phenotypic plasticity in its life history parameters,allowing it to inhabit urban areas.Continuous monitoring of the speciesin these wetlands is needed to determine if these biological responses are temporary or persistent.
基金The National Natural Science Foundation of China under contract Nos 42175172 and 41975134.
文摘Melt ponds are significant physical features on the ice surface throughout the Arctic summer,and the scarcity of observational data has resulted in a vague understanding about it.This study employs satellite data and multi-model averaged outputs from Coupled Model Intercomparison Project Phase 6(CMIP6)to analyze the spatiotemporal evolution characteristics of Arctic melt ponds and their relationship with sea ice thickness(SIT)and atmospheric energy flux.The ponds first emerge at lower latitudes and gradually extend to cover central ice areas as the season progresses,then persisting longer and covering larger total areas in the central region,with peak areas exceeding 0.6×10^(6)km^(2),which is four to five times that of other marginal areas.Over the past two decades,pond coverage has exhibited markedly different trends with slight decreases in the marginal seas but significant increases in the central area.Both CMIP6 and satellite data indicate that the sea ice carrying capacity,related to thickness,plays a crucial role in creating these differences.There is a marked increasing pond in areas with thicker ice.When the SIT falls below a certain threshold,however,sea ice melting results in decreased pond coverage.Additionally,the energy balance on the ice surface also dramatically impacts pond changes.For instance,the overall pond changes in central area are influenced by net longwave radiation and latent heat,with anomalies in these fluxes correlating highly(up to 0.8)with pond anomalies.Meanwhile,net shortwave radiation primarily causes local pond anomalies through the pond-shortwave feedback only under the clear weather conditions.
基金Supported China Agriculture Research System (CARS-49)National Nonprofit InstituteResearch Grant of Freshwater Fisheries Research Center,CAFS (2011JBFA15)~~
文摘The environmental issues confronted by traditional freshwater aquaculture are increasingly sedous, promoting development of ecological remediation technolo- gies. The in-situ remediation represented by fish-vegetable mutualism mode （FVMM） and ex-situ remediation represented by recirculating aquaculture system （RAS） are highlights of related researches. In the paper, the advantages and disadvantages of FVMM and RAS were analyzed and area allocation was discussed in terms of eu- trophication and pond nitrogen cycle. The results showed that the FVMM could re- duce pollutant-discharge coefficient of fish ponds, but the ecological balance would still be hard to be achieved nationwide. In contrast, although the extra cost and land resources would produce inevitably, the application is of great significance in small regions, especially for eutrophication areas thanks for zero-discharge.
基金Supported by National Natural Science Foundation of China (40801227)Open Foundation of Marine and Estuarine Fisheries Resources of Ministry of Agriculture and the Key Laboratory of Ecology (Open-2-04-09)~~
文摘A dissolved oxygen fuzzy system predicting model based on neural network was put forward in this study. 106 groups of data were used to confirm the fitness of the predicting model. The first 80 groups of data were acted as training input and the other 26 groups of data were acted as the confirmed data in the system. The result showed that the testing data was approximately the same as the predicted data. So it gave a new way to solve the problem that the status of the water quality couldn＇t be predicted in time and it＇s hard to watching and measuring the factors dynamic.
基金Supported by National Modern Agricultural Technology System(CARS-46)NationalSci-tech Support Plan(2012BAD25B05,2012BAD25B01)National Department PublicBenefit Research Foundation(201203083)~~
文摘With Biolog Eco microplate, metabolic characteristics and functional diver-sity of carbon source in microflora of ponds were researched based on recitculating ponds and control ponds in order to explore effects of eco-adjustments on microflo-ra in ponds. The results indicate that total number of bacterium, microbial metabolism activity, and diversity index in P7, P8, P1 and P2 kept higher, fol owed by P3, P4, P5 and P6. The utilization rate of microbes on sugars achieved the highest （31.0%-48.7%）, fol owed by carboxylic acid （13.4%-18.0%）, amino acid （10.1%-20.5%）, polymers （9.4%-17.0%）, biopolymer （5.7%-9.7%） and phenol （4.95%-7.50%）. Principal component analysis divided microflora in different ponds, suggesting that microbial community has varied carbon source characteristics and nitrogen-containing compound and biopolymer metabolisms are most affected.
基金Supported by Special Fund for the Construction of Modern Agricultural Industry Technology System(CARS-46)Special Fund for Basic Research and Operating Expenses of Central-level Research Institutes(2007JBFA03)~~
文摘The establishment of water circulation aquaculture system realized the hi- erarchical use of nitrogen, phosphorus and other eutrophic substances in aquaculture wastewater and the recirculation use of water resource. However, no research has been reported on the detailed calculation of the relationship between the area of aquaculture pond and purification pond. In this study, referring to the absorption ability of aquatic plants to pollutants in aquaculture wastewater and pollutant generation and discharge coefficient in aquaculture pond, based on the general rules of water quality management in freshwater aquaculture system, a calculation mode was es- tablished to investigate the relationship between the area of aquaculture pond and purification pond in freshwater recirculation aquaculture system, which was feasible to explain related cases and would provide theoretical basis to reduce the economic costs in the construction of water circulation aquaculture system and realize the bal- ance between the ecological benefits and the economic benefits.
基金Supported by National Natural Science Foundation of China(40801227)Open Foundation of Key Open Laboratory of Marine and Estuarine Fishery Resources and Ecology, Ministry of Agriculture (Open-2-04-09)~~
文摘The aquaculture pond water quality was taken as research objects,based on the general analysis of factors influencing the pond water quality,the system of index estimation and assessment standard were established after sorting by importance of the factors by means of Delphi and expert investigation.In this study,index weight was confirmed according to the importance of the factors and relative membership grade of the measured values,thus and the fuzzy comprehensive evaluation model of aquaculture pond water quality was constructed,and the fuzzy comprehensive evaluation system of freshwater aquaculture pond water quality was designed and implemented.The application of this system in the assessment of aquaculture pond water quality by a company had achieved better result.
基金Supported by the Major Project of Application Foundation and Advanced Technology of Tianjin (the Natural Science Foundation of Tianjin) (09JCZDJC19200),China~~
文摘[Objective] This study was to provide references for the evaluation of water quality in aquaculture ponds by evaluating the pond water quality using fuzzy comprehensive evaluation method based on entropy weight. [Method] The fuzzy compre- hensive evaluation method based on entropy weight was used to evaluate the water quality in the ponds with Ukraine scale carp （Cyprinus carpio） as the main cultivated fish. The average size of the fish was 71.4 g/ind, and totally three groups of pond were set with the population density of 6 000, 9 000, 12 000 ind/hm2. [Result] According to the GB3838-2002 Environmental Quality Standards for Surface Water of China, the water quality of 6 000 ind/hm2 group was Grade I, and the water quality of 9 000 and 12 000 ind/hm2 were Grade V. [Conclusion] With the increasing of feeding density, the pond water quality would worsen, however, there is no difference on water quality between 9 000 and 12 000 ind/hm2 groups.
基金supported by the National Agricultural Innovation Project Component-IV(NAIP/C4/C1005/2006-07),Indian Council of Agricultural Research,Pusa,New Delhi,India
文摘The arsenic contamination in soil-water-plant systems is a major concern of where, the groundwater is being contaminated with arsenic （above 0.01 mg/L） in the Indian subcontinent. The study was conducted with organic matter to find out the reducing effect on arsenic load to rice （cv. Khitish）. It was observed that intermittent ponding reduced arsenic uptake （23.33% in root, 13.84% in shoot and 19.84% in leaf） at panicle initiation stage, instead of continuous ponding. A decreasing trend of arsenic accumulation （root straw husk whole grain milled grain） was observed in different plant parts at harvest. Combined applications of lathyrus ＋ vermicompost ＋ poultry manure reduced arsenic transport in plant parts （root, straw, husk, whole grains and milled grain） which was significantly at par （p 0.05） with chopped rice straw （5 tons/ha ） ＋ lathyrus green manuring （5 tons/ha） in comparison to control and corresponding soils. A significant negative correlation of arsenic with phosphorus （grain P with arsenic in different parts R 2 = 0.627–0.726 at p 0.01） was observed. Similarly, soil arsenic had a negative correlation with soil available phosphorus （R 2 = 0.822 at p 0.001） followed by soil nitrogen （R 2 = 0.762 at p 0.01） and soil potassium （R 2 = 0.626 at p 0.01）. Hence, effective management of contaminated irrigation water along with organic matter could reduce the arsenic build up to plants and soil.
基金funded by the Natural Science Foundation of Fujian Province(Grant No.2023J011133)。
文摘Infiltration–runoff–slope instability mechanism of macropore slope under heavy rainfall is unclear.This paper studied its instability mechanism with an improved Green–Ampt(GA)model considering the dual-porosity(i.e.,matrix and macropore)and ponding condition,and proposed the infiltration equations,infiltration–runoff coupled model,and safety factor calculation method.Results show that the infiltration processes of macropore slope can be divided into three stages,and the proposed model is rational by a comparative analysis.The wetting front depth of the traditional unsaturated slope is 17.2%larger than that of the macropore slope in the early rainfall stage and 27%smaller than that of the macropore slope in the late rainfall stage.Then,macropores benefit the slope stability in the early rainfall but not in the latter.Macropore flow does not occur initially but becomes pronounced with increasing rainfall duration.The equal depth of the wetting front in the two domains is regarded as the onset criteria of macropore flow.Parameter analysis shows that macropore flow is delayed by increasing proportion of macropore domain(ω_(f)),whereas promoted by increasing ratio of saturated permeability coefficients between the two domains(μ).The increasing trend of ponding depth is sharp at first and then grows slowly.Finally,when rainfall duration is less than 3 h,ωf andμhave no significant effect on the safety factor,whereas it decreases with increasingωf and increases with increasingμunder longer duration(≥3 h).With the increase ofω_(f),the slope maximum instability time advances by 10.5 h,and with the increase ofμ,the slope maximum instability time delays by 3.1 h.
