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
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
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
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 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
Waste stabilisation pond system has been used more especially in developing countries for sewage treatment. The objective of this study was to investigate the hydraulic and performance efficiency of Palapye waste stab...Waste stabilisation pond system has been used more especially in developing countries for sewage treatment. The objective of this study was to investigate the hydraulic and performance efficiency of Palapye waste stabilisation ponds. The hydraulic efficiency was evaluated through drogue, pond geometry and sludge accumulation assessment. The performance efficiency was evaluated through periodic sampling and analysis of physiochemical and bacteriological parameters of individual units and of the system as a whole. Except for the maturation ponds, the depth of the anaerobic pond had reduced from 4 m to 0.45 m, for facultative ponds from 2.0 m to a range of 0.52 m - 0.91 m. The design hydraulic retention time of the system had reduced from 20 days to 7.1 days. The concentration of some physiochemical parameters in the effluent was 305 mg·L-1, 277 Nephelometric Turbidity Units (NTU), 204 mg·L-1, 156 mg·L-1, 110 mg·L-1, and 15 mg·L-1 being total suspended solids, turbidity, nitrates, chemical oxygen demand, biochemical oxygen demand and phosphate respectively. These values were more than the standard limits of the country. Effluent total coliforms concentration was 3.6 log units and within the threshold of 4.3 log units, faecal coliforms concentration was 3.5 log units, slightly higher than the threshold of 3 log units. Though Escherichia coli have no limits for discharge into other environments, the concentration in the effluent was reasonable at 2.5 log units and also within irrigation limit of 3 log counts. Palapye wastewater treatment system hydraulic efficiency is lower than the design criterion. The system was overall poor in physiochemical parameters removal but better in bacteriological removal.展开更多
Fish size and harvest density generally exhibit a negative relationship in pond culture, but the influence that pond substrate type can have on this relationship is not well understood. To evaluate the influence of po...Fish size and harvest density generally exhibit a negative relationship in pond culture, but the influence that pond substrate type can have on this relationship is not well understood. To evaluate the influence of pond substrate type on yellow perch (<i></span><i><span style="font-family:Verdana;">Perca flavescens</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;">), harvest density (number/hectare) was linearly regressed against individual fingerling size (grams) for lined (n = 48) and earthen (n = 40) substrate ponds that were treated similarly in terms of organic fertilizer use and the number of days in the pond over 12 culture seasons at Blue Dog Lake State Hatchery, South Dakota, USA. Harvest density explained 45 and 39% of the variation in yellow perch size in lined and earthen-substrate ponds (all <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> < 0.01). Comparison of regression lines indicated that fingerling size decreased as harvest density increased at a similar rate in both pond types (slope comparison, <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> = 0.62);however, fingerling size was significantly larger in lined ponds regardless of density that varied from near 0 to 700,000 per hectare (y-intercept comparison, <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> < 0.01). At the same harvest density, lined ponds will tend to produce larger yellow perch fingerlings compared to earthen ponds when similar organic fertilizers are used.展开更多
To know the bacterial communities structure in Babylonia areolata culture systems and to research and optimize the management pattem of Babylonia areola-ta culture systems of the pond mulched plastic film and sand in ...To know the bacterial communities structure in Babylonia areolata culture systems and to research and optimize the management pattem of Babylonia areola-ta culture systems of the pond mulched plastic film and sand in bottom, the bacte- rial communities in Babylonia areolata culture systems of the sub-tidal zone and the pond mulched plastic film and sand in bottom were analyzed at molecular level by adopting the denaturing gradient gel electrophoresis （DGGE）. The results indicated that the dominant bacterial communities in Babylonia areolata culture systems of the sub-tidal zone and the pond mulched plastic film and sand in bottom, which were built on the basis of the seawater in East-island of Zhanjiang, included Proteobac- teda Chloroflexi, Cyanobacteria and Actinobacteria. The dominant bacterial groups in the above pond culture system were Garnmaproteobacteria, Alphaproteobacteria, Deltaprotecbacteda, Epsilonproteobacteda, Anaerolineae, Cyanobacteria and Acti- nobacteda. The dominant bacterial communities in the subtidal zone culture system were Gammaprotecbacteda, Alphaproteobacteria, Deltaproteobacteria, Anaerolineae and Cyanobacteda, and there were less Epsilonproteobacteria and Actinobacteria in the culture system. The higher diversity was detected in the above two culture sys- tems. The results of unweighted pair group method with arithmetic average （UPG- MA） showed that the bacterial communities of the sediment samples S1 and S2 in the above two culture systems were a cluster, the similarity of bacterial communities was 54.5%. The bacterial communities of seawater samples S3 and S4 in the above culture systems were in clusters, and the similarity of the bacterial communi- ties was 84.0%. The results showed that the microorganism ecological level in the Babylonia areolata culture systems of the pond mulched plastic film and sand in bottom could be similar to the sub-tidal zone culture systems through changing the pond seawater and monitoring the microbial population.展开更多
A thorough investigation was carried out to the pond resources of a county, and Grossman-Hart-Moore （GHM） incomplete contract theory was used to do the economic analysis on the idle pond resources. The result indica...A thorough investigation was carried out to the pond resources of a county, and Grossman-Hart-Moore （GHM） incomplete contract theory was used to do the economic analysis on the idle pond resources. The result indicated that with the deepening of market-oriented economy, the human asset specificity under the incomplete contract had distorted the investment incentives to the governance of ponds that corresponding policies were required to govern the idle ponds.展开更多
1 Introduction The geothermal solar pond is a kind of special solar pond.It is different from traditional solar pond,which high temperature geothermal water can be used to heat brine.When the salt in the brine reaches...1 Introduction The geothermal solar pond is a kind of special solar pond.It is different from traditional solar pond,which high temperature geothermal water can be used to heat brine.When the salt in the brine reaches saturation temperature,it precipitate out and is separated from the brine.Compared with solar pond,the geothermal solar pond does not rely entirely on solar radiation as a heat展开更多
This paper presents the consumptive water use for freshwater pond aquaculture for semi-intensive carps farming practices. The consumptive use of water includes evaporation loss, seepage loss and water exchanges requir...This paper presents the consumptive water use for freshwater pond aquaculture for semi-intensive carps farming practices. The consumptive use of water includes evaporation loss, seepage loss and water exchanges requirements. The water requirement has been estimated to be10.3 m3/Kg of fish production under present study for semi-intensive culture and with supplemental feeding. Out of which7.6 m3/Kg of fish production is system associated requirement. On an average the evaporation loss from the pond is1498.3 mm/year and seepage loss per year is about1182.60 mm/year. Seepage and water exchange losses recharge the ground water aquifers and if they are treated and recycled, the water use in aquaculture can be reduced significantly. A further reduction in fresh water use in pond aquaculture is possible through development of intensive and superintensive culture systems and aqua feeds.展开更多
Faced with the world’s environmental and energy-related challenges,researchers are turning to innovative,sustainable and intelligent solutions to produce,store,and distribute energy.This work explores the trend of us...Faced with the world’s environmental and energy-related challenges,researchers are turning to innovative,sustainable and intelligent solutions to produce,store,and distribute energy.This work explores the trend of using a smart sensor to monitor the stability and efficiency of a salt-gradient solar pond.Several studies have been conducted to improve the thermal efficiency of salt-gradient solar ponds by introducing other materials.This study investigates the thermal and salinity behaviors of a pilot of smart salt-gradient solar ponds with(SGSP)and without(SGSPP)paraffin wax(PW)as a phase-change material(PCM).Temperature and salinity were measured experimentally using a smart sensor,with the measurements being used to investigate the stabilizing effects of placing the PCM in the solar pond’s lower convective zone.The experimental results show that the pond with the PCM(SGSPP)achieved greater thermal and salinity stability,with there being a lesser temperature and salinity gradient between the different layers when compared to a solar pond without thePCM(SGSP).The use of the PCM,therefore,helped control the maximum and minimum temperature of the pond’s storage zone.The UCZ has been found to operate approximately 4 degrees above the average ambient temperature of the day in the SGSPP and 7 degrees in SGSP.Moreover,an unstable situation is generated after 5 days from starting the operation and at 1.9 m from the bottom,and certain points have the tendency to be neutral from the upper depths in 1,3 m of the bottom.展开更多
Pampanga is the top tilapia-producing province in Philippines. One of its municipalities, Minalin, is considered as one of its major centers of production. This study aims to determine the impacts of climate change ha...Pampanga is the top tilapia-producing province in Philippines. One of its municipalities, Minalin, is considered as one of its major centers of production. This study aims to determine the impacts of climate change hazards on the economic performance of tilapia-intensive pond culture in Minalin, Pampanga considering the threats to the industry, livelihoods, and food security. Results revealed that the economic performance of tilapia pond operations using semi-intensive large-scale culture was affected by climate change, as reflected in the reduction of yield among tilapia pond operators. This makes intensive tilapia pond farming in Minalin still a viable venture but will now require more than a year to pay for investment (variable and fixed) costs if under climate change risks. The study recommends strengthening capacity building related to climate-smart tilapia farming technologies for pond operators and to implement appropriate technologies to address climate change risks.展开更多
Fry stocking density can affect harvest metrics for fingerling walleye (Stizostedion vitreum) reared in drainable ponds, but few studies have examined these relationships with the use of elevated walleye fry stocking ...Fry stocking density can affect harvest metrics for fingerling walleye (Stizostedion vitreum) reared in drainable ponds, but few studies have examined these relationships with the use of elevated walleye fry stocking densities in lined ponds. Correlation and regression analyses were used to assess how a three-fold change in walleye fry stocking density (234,375 to 703,125 per hectare) relates to harvest metrics and length of the culture period, as well as the tradeoff experienced between walleye size (grams) and harvest density in 0.32-hectare lined ponds over a nine-year period at Blue Dog State Fish Hatchery, South Dakota. As fry stocking density increased, so did harvest metrics for both number (r = 0.85, P < 0.01) and yield (r = 0.81, P < 0.01). Length of the culture period varied between 24 and 35 days and was negatively related to stocking density (r = -0.66, P The linear relationship between harvest density and yield was highly correlated (r = 0.95, P < 0.01) with highest values measuring 617,625 walleye and 173 kilograms per hectare. Harvest density explained 61% of the variation in walleye size (P 0.01) and exhibited a decreasing curvilinear relationship such that continued increases in harvest density resulted in smaller reductions in fish size. Increasing fry stocking density from 234,375 to 703,125 per hectare in lined ponds coincided with increased rearing efficiencies for number and yield, as well as a reduced culture period. Minimal reduction in walleye size occurred once harvest density exceeded 300,000 per hectare.展开更多
Aquaculture ponds are dominant features of the landscape in the coastal zone of China.Generally,aquaculture ponds are drained during the non-culture period in winter.However,the effects of such drainage on the product...Aquaculture ponds are dominant features of the landscape in the coastal zone of China.Generally,aquaculture ponds are drained during the non-culture period in winter.However,the effects of such drainage on the production and flux of greenhouse gases（GHGs）from aquaculture ponds are largely unknown.In the present study,field-based research was performed to compare the GHG fluxes between one drained pond（DP,with a water depth of 0.05 m）and one undrained pond（UDP,with a water depth of 1.16 m）during one winter in the Min River estuary of southeast China.Over the entire study period,the mean CO2flux in the DP was（0.75±0.12）mmol/（m^2·hr）,which was significantly higher than that in the UDP of（-0.49±0.09）mmol/（m^2·hr）（p0.01）.This indicates that drainage drastically transforms aquaculture ponds from a net sink to a net source of CO2in winter.Mean CH4and N2O emissions were significantly higher in the DP compared to those in the UDP（CH4=（0.66±0.31）vs.（0.07±0.06）mmol/（m^2·hr）and N2O=（19.54±2.08）vs.（0.01±0.04）μmol/（m^2·hr））（p〈0.01）,suggesting that drainage would also significantly enhance CH4and N2O emissions.Changes in environmental variables（including sediment temperature,p H,salinity,redox status,and water depth）contributed significantly to the enhanced GHG emissions following pond drainage.Furthermore,analysis of the sustained-flux global warming and cooling potentials indicated that the combined global warming potentials of the GHG fluxes were significantly higher in the DP than in the UDP（p〈0.01）,with values of739.18 and 26.46 mg CO2-eq/（m^2·hr）,respectively.Our findings suggested that drainage of aquaculture ponds can increase the emissions of potent GHGs from the coastal zone of China to the atmosphere during winter,further aggravating the problem of global warming.展开更多
Understanding phosphorus sorption phenomena in different wetland sediments is important in controlling the P output in headstream watersheds. The pond chain structure （PCS） is widespread in the headstream agricultur...Understanding phosphorus sorption phenomena in different wetland sediments is important in controlling the P output in headstream watersheds. The pond chain structure （PCS） is widespread in the headstream agricultural watersheds in the southeast of China. Phosphorus sorption characteristics were determined for pond surface sediments （0-12 cm） along a pond chain structure in Liuchahe watershed of Chaohu Lake. Results showed that P sorption capacities （expressed by P sorption index （PSI）） varied both with the landscape position of the ponds and sediment depth. From foothill ponds to riverside ponds the P sorption capacities indicated a significant gradient variability. The higher elevation ponds showed greater sorption capacities, and with the pond elevation decline, P sorption capacities gradually decreased. Some physico-chemical properties, such as pH, oxalate-extractable Fe （Feox）, organic matter （TOC） and Mehlich l-extractable Ca, Mg of pond sediments also indicated significant gradient variability from high elevation ponds to low elevation ponds. Feox was the sediment parameters most highly positively correlated with PSI and was the key factor in controlling P sorption capacity in the pond chain structure （r=0.92, p〈0.001）. Long-term hydrologic and sediment inputs can affect the distribution of sediment constituents and further affect the P sorption capacity. Making the best of the spatial difference of sorption capacities of ponds in watersheds to control nonpoint source P pollutant is necessary.展开更多
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 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.
文摘Waste stabilisation pond system has been used more especially in developing countries for sewage treatment. The objective of this study was to investigate the hydraulic and performance efficiency of Palapye waste stabilisation ponds. The hydraulic efficiency was evaluated through drogue, pond geometry and sludge accumulation assessment. The performance efficiency was evaluated through periodic sampling and analysis of physiochemical and bacteriological parameters of individual units and of the system as a whole. Except for the maturation ponds, the depth of the anaerobic pond had reduced from 4 m to 0.45 m, for facultative ponds from 2.0 m to a range of 0.52 m - 0.91 m. The design hydraulic retention time of the system had reduced from 20 days to 7.1 days. The concentration of some physiochemical parameters in the effluent was 305 mg·L-1, 277 Nephelometric Turbidity Units (NTU), 204 mg·L-1, 156 mg·L-1, 110 mg·L-1, and 15 mg·L-1 being total suspended solids, turbidity, nitrates, chemical oxygen demand, biochemical oxygen demand and phosphate respectively. These values were more than the standard limits of the country. Effluent total coliforms concentration was 3.6 log units and within the threshold of 4.3 log units, faecal coliforms concentration was 3.5 log units, slightly higher than the threshold of 3 log units. Though Escherichia coli have no limits for discharge into other environments, the concentration in the effluent was reasonable at 2.5 log units and also within irrigation limit of 3 log counts. Palapye wastewater treatment system hydraulic efficiency is lower than the design criterion. The system was overall poor in physiochemical parameters removal but better in bacteriological removal.
文摘Fish size and harvest density generally exhibit a negative relationship in pond culture, but the influence that pond substrate type can have on this relationship is not well understood. To evaluate the influence of pond substrate type on yellow perch (<i></span><i><span style="font-family:Verdana;">Perca flavescens</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;">), harvest density (number/hectare) was linearly regressed against individual fingerling size (grams) for lined (n = 48) and earthen (n = 40) substrate ponds that were treated similarly in terms of organic fertilizer use and the number of days in the pond over 12 culture seasons at Blue Dog Lake State Hatchery, South Dakota, USA. Harvest density explained 45 and 39% of the variation in yellow perch size in lined and earthen-substrate ponds (all <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> < 0.01). Comparison of regression lines indicated that fingerling size decreased as harvest density increased at a similar rate in both pond types (slope comparison, <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> = 0.62);however, fingerling size was significantly larger in lined ponds regardless of density that varied from near 0 to 700,000 per hectare (y-intercept comparison, <i></span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;"></i></span><span style="font-family:Verdana;"> < 0.01). At the same harvest density, lined ponds will tend to produce larger yellow perch fingerlings compared to earthen ponds when similar organic fertilizers are used.
基金Supported by the Special Program of Scientific and Technological Promotion of Fisheries in Guangdong(A201101I01,A201208E01)the Guangdong Scientific and Technological Planning Program(2012B020415006)~~
文摘To know the bacterial communities structure in Babylonia areolata culture systems and to research and optimize the management pattem of Babylonia areola-ta culture systems of the pond mulched plastic film and sand in bottom, the bacte- rial communities in Babylonia areolata culture systems of the sub-tidal zone and the pond mulched plastic film and sand in bottom were analyzed at molecular level by adopting the denaturing gradient gel electrophoresis （DGGE）. The results indicated that the dominant bacterial communities in Babylonia areolata culture systems of the sub-tidal zone and the pond mulched plastic film and sand in bottom, which were built on the basis of the seawater in East-island of Zhanjiang, included Proteobac- teda Chloroflexi, Cyanobacteria and Actinobacteria. The dominant bacterial groups in the above pond culture system were Garnmaproteobacteria, Alphaproteobacteria, Deltaprotecbacteda, Epsilonproteobacteda, Anaerolineae, Cyanobacteria and Acti- nobacteda. The dominant bacterial communities in the subtidal zone culture system were Gammaprotecbacteda, Alphaproteobacteria, Deltaproteobacteria, Anaerolineae and Cyanobacteda, and there were less Epsilonproteobacteria and Actinobacteria in the culture system. The higher diversity was detected in the above two culture sys- tems. The results of unweighted pair group method with arithmetic average （UPG- MA） showed that the bacterial communities of the sediment samples S1 and S2 in the above two culture systems were a cluster, the similarity of bacterial communities was 54.5%. The bacterial communities of seawater samples S3 and S4 in the above culture systems were in clusters, and the similarity of the bacterial communi- ties was 84.0%. The results showed that the microorganism ecological level in the Babylonia areolata culture systems of the pond mulched plastic film and sand in bottom could be similar to the sub-tidal zone culture systems through changing the pond seawater and monitoring the microbial population.
基金Supported by the Key Interdisciplinary Studies on "Resources,Environment and Recycling Economy" of Beijing,China (033000541212002)~~
文摘A thorough investigation was carried out to the pond resources of a county, and Grossman-Hart-Moore （GHM） incomplete contract theory was used to do the economic analysis on the idle pond resources. The result indicated that with the deepening of market-oriented economy, the human asset specificity under the incomplete contract had distorted the investment incentives to the governance of ponds that corresponding policies were required to govern the idle ponds.
文摘1 Introduction The geothermal solar pond is a kind of special solar pond.It is different from traditional solar pond,which high temperature geothermal water can be used to heat brine.When the salt in the brine reaches saturation temperature,it precipitate out and is separated from the brine.Compared with solar pond,the geothermal solar pond does not rely entirely on solar radiation as a heat
文摘This paper presents the consumptive water use for freshwater pond aquaculture for semi-intensive carps farming practices. The consumptive use of water includes evaporation loss, seepage loss and water exchanges requirements. The water requirement has been estimated to be10.3 m3/Kg of fish production under present study for semi-intensive culture and with supplemental feeding. Out of which7.6 m3/Kg of fish production is system associated requirement. On an average the evaporation loss from the pond is1498.3 mm/year and seepage loss per year is about1182.60 mm/year. Seepage and water exchange losses recharge the ground water aquifers and if they are treated and recycled, the water use in aquaculture can be reduced significantly. A further reduction in fresh water use in pond aquaculture is possible through development of intensive and superintensive culture systems and aqua feeds.
基金supported and funded by the Deanship of Scientific Research at Imam Mohammad Ibn Saud Islamic University(IMSIU)(Grant Number IMSIU-RG23098).
文摘Faced with the world’s environmental and energy-related challenges,researchers are turning to innovative,sustainable and intelligent solutions to produce,store,and distribute energy.This work explores the trend of using a smart sensor to monitor the stability and efficiency of a salt-gradient solar pond.Several studies have been conducted to improve the thermal efficiency of salt-gradient solar ponds by introducing other materials.This study investigates the thermal and salinity behaviors of a pilot of smart salt-gradient solar ponds with(SGSP)and without(SGSPP)paraffin wax(PW)as a phase-change material(PCM).Temperature and salinity were measured experimentally using a smart sensor,with the measurements being used to investigate the stabilizing effects of placing the PCM in the solar pond’s lower convective zone.The experimental results show that the pond with the PCM(SGSPP)achieved greater thermal and salinity stability,with there being a lesser temperature and salinity gradient between the different layers when compared to a solar pond without thePCM(SGSP).The use of the PCM,therefore,helped control the maximum and minimum temperature of the pond’s storage zone.The UCZ has been found to operate approximately 4 degrees above the average ambient temperature of the day in the SGSPP and 7 degrees in SGSP.Moreover,an unstable situation is generated after 5 days from starting the operation and at 1.9 m from the bottom,and certain points have the tendency to be neutral from the upper depths in 1,3 m of the bottom.
文摘Pampanga is the top tilapia-producing province in Philippines. One of its municipalities, Minalin, is considered as one of its major centers of production. This study aims to determine the impacts of climate change hazards on the economic performance of tilapia-intensive pond culture in Minalin, Pampanga considering the threats to the industry, livelihoods, and food security. Results revealed that the economic performance of tilapia pond operations using semi-intensive large-scale culture was affected by climate change, as reflected in the reduction of yield among tilapia pond operators. This makes intensive tilapia pond farming in Minalin still a viable venture but will now require more than a year to pay for investment (variable and fixed) costs if under climate change risks. The study recommends strengthening capacity building related to climate-smart tilapia farming technologies for pond operators and to implement appropriate technologies to address climate change risks.
文摘Fry stocking density can affect harvest metrics for fingerling walleye (Stizostedion vitreum) reared in drainable ponds, but few studies have examined these relationships with the use of elevated walleye fry stocking densities in lined ponds. Correlation and regression analyses were used to assess how a three-fold change in walleye fry stocking density (234,375 to 703,125 per hectare) relates to harvest metrics and length of the culture period, as well as the tradeoff experienced between walleye size (grams) and harvest density in 0.32-hectare lined ponds over a nine-year period at Blue Dog State Fish Hatchery, South Dakota. As fry stocking density increased, so did harvest metrics for both number (r = 0.85, P < 0.01) and yield (r = 0.81, P < 0.01). Length of the culture period varied between 24 and 35 days and was negatively related to stocking density (r = -0.66, P The linear relationship between harvest density and yield was highly correlated (r = 0.95, P < 0.01) with highest values measuring 617,625 walleye and 173 kilograms per hectare. Harvest density explained 61% of the variation in walleye size (P 0.01) and exhibited a decreasing curvilinear relationship such that continued increases in harvest density resulted in smaller reductions in fish size. Increasing fry stocking density from 234,375 to 703,125 per hectare in lined ponds coincided with increased rearing efficiencies for number and yield, as well as a reduced culture period. Minimal reduction in walleye size occurred once harvest density exceeded 300,000 per hectare.
基金supported by the National Science Foundation of China (Nos. 41671088 and 41371127)the Program for Innovative Research Team of Fujian Normal University (No. IRTL1205)+2 种基金the Natural Science Foundation of Fujian Province, China (No. 2014J05046)the Study-Abroad Grant Project for Graduates of the School of Geographical Sciences, (No. GY201601)the Graduated Student Science and Technology Innovation Project of the School of Geographical Science,Fujian Normal University (No. GY201601)
文摘Aquaculture ponds are dominant features of the landscape in the coastal zone of China.Generally,aquaculture ponds are drained during the non-culture period in winter.However,the effects of such drainage on the production and flux of greenhouse gases（GHGs）from aquaculture ponds are largely unknown.In the present study,field-based research was performed to compare the GHG fluxes between one drained pond（DP,with a water depth of 0.05 m）and one undrained pond（UDP,with a water depth of 1.16 m）during one winter in the Min River estuary of southeast China.Over the entire study period,the mean CO2flux in the DP was（0.75±0.12）mmol/（m^2·hr）,which was significantly higher than that in the UDP of（-0.49±0.09）mmol/（m^2·hr）（p0.01）.This indicates that drainage drastically transforms aquaculture ponds from a net sink to a net source of CO2in winter.Mean CH4and N2O emissions were significantly higher in the DP compared to those in the UDP（CH4=（0.66±0.31）vs.（0.07±0.06）mmol/（m^2·hr）and N2O=（19.54±2.08）vs.（0.01±0.04）μmol/（m^2·hr））（p〈0.01）,suggesting that drainage would also significantly enhance CH4and N2O emissions.Changes in environmental variables（including sediment temperature,p H,salinity,redox status,and water depth）contributed significantly to the enhanced GHG emissions following pond drainage.Furthermore,analysis of the sustained-flux global warming and cooling potentials indicated that the combined global warming potentials of the GHG fluxes were significantly higher in the DP than in the UDP（p〈0.01）,with values of739.18 and 26.46 mg CO2-eq/（m^2·hr）,respectively.Our findings suggested that drainage of aquaculture ponds can increase the emissions of potent GHGs from the coastal zone of China to the atmosphere during winter,further aggravating the problem of global warming.
基金The National Basic Research Program (973) of China (No. 2006CB403300, 2002CB42308) and the Key Project of KnowledgeInnovation Programme of CAS (No. KZCX1-SW-12)
文摘Understanding phosphorus sorption phenomena in different wetland sediments is important in controlling the P output in headstream watersheds. The pond chain structure （PCS） is widespread in the headstream agricultural watersheds in the southeast of China. Phosphorus sorption characteristics were determined for pond surface sediments （0-12 cm） along a pond chain structure in Liuchahe watershed of Chaohu Lake. Results showed that P sorption capacities （expressed by P sorption index （PSI）） varied both with the landscape position of the ponds and sediment depth. From foothill ponds to riverside ponds the P sorption capacities indicated a significant gradient variability. The higher elevation ponds showed greater sorption capacities, and with the pond elevation decline, P sorption capacities gradually decreased. Some physico-chemical properties, such as pH, oxalate-extractable Fe （Feox）, organic matter （TOC） and Mehlich l-extractable Ca, Mg of pond sediments also indicated significant gradient variability from high elevation ponds to low elevation ponds. Feox was the sediment parameters most highly positively correlated with PSI and was the key factor in controlling P sorption capacity in the pond chain structure （r=0.92, p〈0.001）. Long-term hydrologic and sediment inputs can affect the distribution of sediment constituents and further affect the P sorption capacity. Making the best of the spatial difference of sorption capacities of ponds in watersheds to control nonpoint source P pollutant is necessary.
