Open earthen pond-based larviculture is the main method for rearing Chinese mitten crab(Eriocheir sinensis)larvae in China.Bacterioplankton play a vital role in aquaculture ecosystems,but their community succession th...Open earthen pond-based larviculture is the main method for rearing Chinese mitten crab(Eriocheir sinensis)larvae in China.Bacterioplankton play a vital role in aquaculture ecosystems,but their community succession throughout the larval nursery stages of E.sinensis in such systems is still poorly understood.Using 16S rRNA gene amplicon sequencing,this study characterized the dynamics of bacterioplankton communities during a complete E.sinensis larval rearing cycle in open earthen ponds.Results presented a distinct,unidirectional succession in bacterioplankton composition,characterized by a decrease in Alphaproteobacteria and an increase in Actinobacteria.Live feeds(Brachionus plicatilis and Artemia salina)significantly affected bacterioplankton communities directly through their biological activities and indirectly by modifying the structure of phytoplankton composition.In addition to live feeds,water temperature and dissolved oxygen were key environmental factors affecting the structure of bacterioplankton communities.Biotic interactions,specifically with phytoplankton and copepods,were key drivers of bacterioplankton succession.Routine feeding practices during larval cultivation decreased bacterioplankton network complexity and strengthened community stability.Keystone taxa,specifically OTU783(Rhodobacteraceae)and OTU1235(Microbacteriaceae),played an essential role in maintaining the community stability through recruiting more rare species during the later stages despite their low abundances.These outcomes advance our understanding of the mechanisms central to bacterioplankton community succession and stability in E.sinensis larviculture systems,offering critical insights for developing sustainable aquaculture management strategies.展开更多
Aquaculture ponds have emerged as a significant contributor to greenhouse gas(GHG)emissions.We measured methane(CH_(4)),carbon dioxide(CO_(2)),and nitrous oxide(N_(2)O)emissions in ponds,all located in Jiangsu Provinc...Aquaculture ponds have emerged as a significant contributor to greenhouse gas(GHG)emissions.We measured methane(CH_(4)),carbon dioxide(CO_(2)),and nitrous oxide(N_(2)O)emissions in ponds,all located in Jiangsu Province,with different fish and management practices over an entire cycle.All ponds emitted these gases,with higher CH_(4) and N_(2)O levels during fish growth than stocking period.The highest CH_(4) and N_(2)O fluxes were found in the Crucian carp(Carassius auratus)pond with up to 16,512±3015μmol/(m^(2)·h)and 5.54±0.31μmol/(m^(2)·h),respectively.CH_(4) was the primary contributor to the global warming potential in traditional earthen ponds,accounting for an average contribution rate of 87.7%.The dissolved oxygen(DO)concentration was the water quality parameter that most significantly influenced the CO_(2)flux,while pH acted as its primary regulator.The GHG emission intensity per unit of fish production in traditional earthen ponds was 197 times higher than that in-pond raceway systems.Largemouth bass(Micropterus salmoides)and Crucian carp ponds exhibited CH_(4) diffusion fluxes at the sediment-water interface,which were>20 times higher than those at the water-air interface.Our results further suggest that stocking density and feed amount significantly influence the variations in GHG emissions among the ponds with the in-pond raceway system having low carbon emissions and being high yield aquaculture system compared to traditional earthen ponds.The water depth and DO concentration can be manipulated to reduce GHG emissions across the various interfaces.展开更多
Leakage of electrolytic manganese slag(EMS)ponds is a long-lasting and serious threat to environmental health worldwide,particularly in karst areas where the ecosystems are highly sensitive to geochemical perturbation...Leakage of electrolytic manganese slag(EMS)ponds is a long-lasting and serious threat to environmental health worldwide,particularly in karst areas where the ecosystems are highly sensitive to geochemical perturbations.However,the mechanisms of Mn mobilization and migration are insufficiently known.In this study,we combine systematic field investigations,laboratory column experiments and geochemical analyses to clarify the environmental geochemistry and controlling factors of leaching of Mn in the karst areas of southwestern China.While the Mn slag ponds as a whole had shown a low permeability,release of free Mn^(2+)and NH_(3)-N is significantly facilitated by the synergies of seepage infiltration,microbial activities and environmental acidification.With the increase of depth,the mineralogical composition of the slag undergoes significant alteration,and redox conditions change from acidic-oxidizing to acidic-reducing environments,which will accelerate the mobilization of Mn further and increase the risk of groundwater contamination.In addition,the presence of clay mineral colloids in Mn slag changes the migration properties of Mn,which introduces complexity in the geochemical behavior of Mn.Our findings highlight that Mn transformation and migration are controlled by dynamic,depth-dependent geochemical processes and the interplay of both internal and external factors.This research consolidates mechanistic foundation of deciphering Mn environmental behaviors in karst regions,reinforcing the urgency of preventing and rehabilitating electrolytic Mn slag leakage.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
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
Mining tailing ponds are large infrastructure objects whose life cycle spans over several decades.They are indispensable for certain types of mines where technological process produces and rejects mud.They also have p...Mining tailing ponds are large infrastructure objects whose life cycle spans over several decades.They are indispensable for certain types of mines where technological process produces and rejects mud.They also have potential to generate risks for human life,property and environment.For that reason,it is essential to adequately manage them throughout all the stages of their life cycle.The phase of their closure and abandonment is less studied and understood.The paper proposes a holistic resilience-based approach for analyzing this phase of their life cycle.The proposed methodology is validated through a case study at an actual surface iron ore mine in Bosnia and Herzegovina.展开更多
The performance of the Dongying multi-stage ponds-wetlands ecosystem was investigated in this work. Study of the removal of different pollutants (BOD5, COD, SS, TP, TN, NH3-N, etc.) in different temperature seasons an...The performance of the Dongying multi-stage ponds-wetlands ecosystem was investigated in this work. Study of the removal of different pollutants (BOD5, COD, SS, TP, TN, NH3-N, etc.) in different temperature seasons and different units in this system indicated that effluent BOD5 and SS were constant to less than 11 mg/L and 14 mg/L throughout the experimental proc- esses; but that the removal efficiencies of pollutants such as TP, TN, NH3-N, COD varied greatly with season. The higher the temperature was, the higher was the observed removal in this system. Additionally, each unit of the system functioned differently in removing pollutants. BOD5 and SS were mainly removed in the first three units (hybrid facultative ponds, aeration ponds and aerated fish ponds), whereas nitrogen and phosphates were mainly removed in hydrophyte ponds and constructed reed wetlands. The multi-stage ponds-wetlands ecosystem exhibits good potential of removing different pollutants, and the effluent quality meet several standards for wastewater reuse.展开更多
Aquaculture ponds are one of the fastest-growing land use types in valuable and fertile coastal areas and have caused serious environmental problems. Quantitative assessment of the extent, spatial distribution, and dy...Aquaculture ponds are one of the fastest-growing land use types in valuable and fertile coastal areas and have caused serious environmental problems. Quantitative assessment of the extent, spatial distribution, and dynamics of aquaculture ponds is of utmost importance for sustainable economic development and scientific management of land and water resources in the coastal area. An object-oriented classification approach was applied to Landsat images acquired over three decades to investigate the long-term change of aquaculture ponds in the coastal region of the Yellow River Delta. The results indicated that the aquaculture ponds in the study area undergone a sharp expansion from 40.38 km^2 in 1983 to 1406.89 km^2 in 2015, and the fast expansion occurred during the period of 2010–2015 and 1990–2000. Natural wetlands, especially mudflat, and cropland were main land use types contributing to the increase of aquaculture ponds. The patches of aquaculture ponds were consequently prevalence in the north of the Yellow River Estuary and landscape metrics indicated an increase of the aquaculture ponds of the study area in the quantity and complexity. The expansion of aquaculture ponds inevitably had negative effects on the coastal environment, including loss of natural wetlands, water pollution and land subsidence, etc. The results from this study provide baseline data and valuable information for efficiently planning and managing aquaculture practices and for effectively implementing adequate regulations and protection measures.展开更多
This study investigated the relationships among the parameters of dissolved oxygen, chlorophyll-a and phytoplankton composition in tilapia ponds. Each pond (a total of 18 ponds) was sampled once in the dry, winter sea...This study investigated the relationships among the parameters of dissolved oxygen, chlorophyll-a and phytoplankton composition in tilapia ponds. Each pond (a total of 18 ponds) was sampled once in the dry, winter season between January and March and again early in the rainy season between May and June. The data were analyzed by examining correlations among parameters as affected by season, altitude and culture system. Observations were made at sites located in 5 selected provinces of northern Thailand: Chiangrai, Chiangmai, Phayao, Lampang and Nakornsawan. Mean elevation of these areas range from 25 to 582 meters above sea level (masl) and were categorized into low (400 masl) elevation sites. Ponds were 0.8 - 2.0 m deep, 0.16 - 0.64 ha in area and could be further categorized into high and low input systems.Mean air temperature in winter ranged between 16.5°C - 35.8°C while mean water temperature ranged between 25.5°C - 27.1°C. In rainy season, air temperature ranged between 22.0°C - 37.3°C and water temperature ranged between 29.4°C - 31.8°C. The amount of chlorophyll-a in both seasons were comparable (p > 0.05), but chlorophyll-a in high input system was significantly higher (p 0.05) than in low input ponds. Only weak correlation was found between chlorophyll-a, DOmax and DOmin. Multifactor-ANOVA was used to analyze the difference of total bacteria and filamentous cyanobacteria in ponds based upon elevation, culture systems and season. Result shows that there is a significant interaction observed between elevation, culture system and season (p 0.05). Species diversity and composition of phytoplankton in fish ponds in 2 seasons revealed the presence of 90 genera of phytoplankton under all 7 divisions. Divisions Chlorophyta and Cyanophyta had the most number of genera identified in both seasons with Pediastrum spp., and Scendesmus spp., and Anabaena spp. as dominant genera/genus, respectively.展开更多
Eriocheirsinensis, Portunus trituberculatus and Scylla paramamosain are important commercial culture crab species in China. Traditional factory breeding of crabs depends on Artemia nauplius. The rising price of Artemi...Eriocheirsinensis, Portunus trituberculatus and Scylla paramamosain are important commercial culture crab species in China. Traditional factory breeding of crabs depends on Artemia nauplius. The rising price of Artemia cysts has led to the decline of the economic benefit of the crab breeding factory. Factory crab breeding has been gradually replaced by pond breeding in recent years. E. sinensis and P. trituberculatus have been bred mainly in ponds. Meanwhile, S. paramamosain is still mainly bred in factories because of the crudeness of pond breeding. The research progress on food organism utilization in the three species of commercially bred crabs was reviewed in this paper. In the workshop seeds production, rotifer and Artemia nauplii were necessary in the early stages from zoea I to zoea II in the three crab species. Adult artemia, minced fish and shellfish were fed to the larvae in the later zoea stages from zoea III to Megalopa.?The rising of the price of artemia eggs made people find other feed organism to replace artemia. Copepods have been used in crab seeds production in pond from zoea III stage to replace artemia in recent years, which has reduced the cost of seeds production.展开更多
A total of 26 isolates were obtained from solar salt ponds of different salinities(100, 150, 200, and 250) in Hangu Saltworks Co. Ltd., Tianjin, China. Phylogenetic analysis of 16 SrRNA gene sequences indicated that f...A total of 26 isolates were obtained from solar salt ponds of different salinities(100, 150, 200, and 250) in Hangu Saltworks Co. Ltd., Tianjin, China. Phylogenetic analysis of 16 SrRNA gene sequences indicated that five bacteria genera H alomonas, Salinicoccus, Oceanobacillus, Gracibacillus, and Salimicrobium and one archaea genera H alorubrum were present. The genus H alomonas was predominant with eight strains distributed in a salinity range of 100–200, followed by H alorubrum with six strains in salinity 250. Based on the genus and original sampling salinity, eight bacterial and two archaeal isolates were selected for further morphological, physiological, and biochemical characterization. All of the bacterial strains were moderately halophilic with the optimal salinity for growth being either 50 or 100, while two archaeal strains were extremely halophilic with an optimal growth salinity of 200. Additionally, we put forth strain SM.200-5 as a new candidate S alimicrobium species based on the phylogenic analysis of the 16 SrRNA gene sequence and its biochemical characteristics when compared with known related species.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
In Japan, various countermeasures have been taken to improve the water quality of public waters such as rivers and lakes. Though water quality has improved, it is still insufficient. In summer, eutrophication is seen ...In Japan, various countermeasures have been taken to improve the water quality of public waters such as rivers and lakes. Though water quality has improved, it is still insufficient. In summer, eutrophication is seen in lakes and inner bays, as well as rivers. As a countermeasure to prevent eutrophication, the removal treatment of nutrient salts such as nitrogen and phosphorus is done, in addition to organic substance elimination in the domestic sewerage system. This report will show the water quality characteristics of rivers and ponds in Japan. It is considered that these investigative results are effective when the water quality improvement of the stabilization ponds where eutrophication occurs are examined in China.展开更多
Nowadays, rainwater harvesting (RWH) technology is increasingly adopted as a strategic pathway for reducing poverty in rural drought prone areas for enhancing agricultural productivity and boosting farm income. The ai...Nowadays, rainwater harvesting (RWH) technology is increasingly adopted as a strategic pathway for reducing poverty in rural drought prone areas for enhancing agricultural productivity and boosting farm income. The aim of this study is to assess the level of adoption and the impacts of RWH ponds on farm income in Ntarama sector of Bugesera District in Eastern Province of Rwanda. Fifteen farm ponds were visited and the level at which households adopted RWH ponds, their impact on farm income and performance in storing water were assessed. Interviews and questionnaires methods were used to farm ponds beneficiaries and the storage capacity of farm ponds was calculated to ensure that they meet irrigation water demand. Then, Microsoft excel was used as a data analysis tool. The results show that 42.5% of households have adopted RWH ponds and the adoption level of RWH ponds fails due to the lack of training about the role and use of RWH ponds before their implementation. Beside this the low level of public involvement during the site selection for ponds associated with social conflicts among water users was observed. However, it is further revealed that the use of RWH ponds positively impacts on agricultural income on 1/4 hectare per year by about 2,325,000 RWF (3100USD). The studied portion of area can bear 222 ponds of 120 m<sup>3</sup> each if all the rain is harvested throughout the year instead of being three ponds. Furthermore, we found that the quantity of rainwater harvested of 328.5 m<sup>3</sup> as a total of the 3 ponds was still too less to meet irrigation water demand. As negative impacts, the RWH technology can cause dangerous effects such as social conflicts, breeding site for mosquitoes, water related diseases, accidents and others with a level of severity of 32%, 24%, 20%, 16% and 8%, respectively. This happens when the RWH ponds are not properly managed.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
By measuring water temperature,salinity,pH,dissolved oxygen,nitrite and ammonia nitrogen,the annual variation regularity of water quality in the aquaculture ponds for sea cucumbers Apostichopus japonicus in Dalian wer...By measuring water temperature,salinity,pH,dissolved oxygen,nitrite and ammonia nitrogen,the annual variation regularity of water quality in the aquaculture ponds for sea cucumbers Apostichopus japonicus in Dalian were studied.Results showed that the physicochemical indicators kept changing in the year,and the various ranges of water temperature,salinity,pH,dissolved oxygen,nitrite,and ammonia nitrogen were 6.38-27.27℃,29.20‰-33.78‰,7.86-8.38,5.19-13.36 mg/L,0.0037-0.0090 mg/L and 0.0171-0.0908 mg/L,respectively.Analysis indicated that there was an extremely significant negative correlation between water temperature and dissolved oxygen(P<0.01),an extremely significant positive correlation between water temperature and ammonia nitrogen(P<0.01),a significant negative correlation between salinity and nitrite(P<0.05),a significant negative correlation between dissolved oxygen and nitrite(P<0.05),and an extremely significant negative correlation between dissolved oxygen and ammonia nitrogen(P<0.01)in the aquaculture ponds for sea cucumber in Dalian.Research showed that the water quality of aquaculture ponds kept fluctuating all the time during the tested period,there were complicated and close relationships among physicochemical indicators,and a slight variation of external factors would bring consecutive reactions to different indicators in the water quality of aquaculture ponds.A reference for the production and management of sea cucumbers could be provided from the results.展开更多
Climate warming has a significant impact on the sea ice and ecosystem of the Arctic Ocean.Under the increasing numbers of melt ponds in Arctic sea ice,the phytoplankton communities associated with the ice system are c...Climate warming has a significant impact on the sea ice and ecosystem of the Arctic Ocean.Under the increasing numbers of melt ponds in Arctic sea ice,the phytoplankton communities associated with the ice system are changing.During the 7th Chinese National Arctic Research Expedition cruise in summer 2016,photosynthesis pigments and nutrients were analyzed,revealing differences in phytoplankton communities between melt ponds and open water in the central Arctic.Photosynthetic pigment analysis suggested that Fuco(5-91μg m^-3)and Diadino(4-21μg m^-3)were the main pigments in the open water.However,the melt ponds had high concentrations of Viola(7-30μg m^-3),Lut(4-59μg m^-3)and Chl b(11-38μg m^-3),suggesting that green algae dominated phytoplankton communities in the melt ponds.The significant differences in phytoplankton communities between melt ponds and open water might be due to the salinity difference.Moreover,green algae may play a more important role in Arctic sea ice ecosystems with the expected growing number of melt ponds in the central Arctic Ocean.展开更多
This paper presents a method for in situ determining sediment oxygen demand (SOD) in cultivation pond. This method based on sediment surface structure, temperature, and other determining conditions like those in shrim...This paper presents a method for in situ determining sediment oxygen demand (SOD) in cultivation pond. This method based on sediment surface structure, temperature, and other determining conditions like those in shrimp cultivation environments, overcomes defects of old methods and provides more accurate estimation of SOD’s effect on dissolved oxygen in culture waters. Our experiment shows that the sediment surface structure and temperature had important effect on SOD in culture water. Different SOD values were derived from different parts of oxygen consumption curves of sediment, because the curves were not linear. According to the oxygen consumption curves of sediment and saturated DO in culture water, it was thought more suitable to calculate SOD with dissolved oxygen reduction from 5.0 to 2.0 mg/l. This method to determine the SOD of shrimp ponds yielded satisfactory results.展开更多
Phosphorus overenrichment of shallow ponds prevailing in wetlands leads to their eutrophication causing the collapse of those vulnerable habitats.The potential of phosphorus accumulation by periphyton developed on art...Phosphorus overenrichment of shallow ponds prevailing in wetlands leads to their eutrophication causing the collapse of those vulnerable habitats.The potential of phosphorus accumulation by periphyton developed on artificial substrata has been investigated in two shallow ponds(Bara?ka and?iroki Rit)in northwest Serbia and compared to the same ability of plankton and metaphyton.The periphyton substrate carrier has been submerged from May to October.Both continuously(CS)and monthly developed(MS)periphyton were sampled.Autotrophic component of all investigated communities has been qualitatively assessed.Maximum accumulation of only 14.7 mg TP/m^(2) was recorded in three-month exposed periphyton CS.MS exposed from July to August reached maximal 12.7 mg TP/m^(2).Plankton community that was characterized by more diverse and abundantly developed algal component was more effective in phosphorus accumulation(0.7 mg/g dry weight)in comparison with dominantly inorganic and diatom-dominated periphyton in Bara?ka.Unstable conditions caused by recent revitalization(dredging organic matter and mud from pond basin—redigging)as well as rapid desiccation of?iroki Rit disabled making an unambiguous conclusion about the efficiency of phosphorus accumulation among different communities,but suggested slight potential of phosphorus harvesting by metaphyton in this pond.Due to the shorter exposure time that brings the reduced risk of unpredictable changes in the ecosystem,as well as the considerable amount of accumulated phosphorus,large-scale application of one-month exposed periphyton developed on artificial substrates would be more advisable for phosphorus harvesting in nutrient affected shallow ponds.展开更多
基金supported by the National Key R&D Program(No.2022YFD2400700)from the Ministry of Science and Technology of Chinathe Open Competition Project(No.JBGS[2021]127)from the Department of Agriculture and Rural Affairs of Jiangsu Provincepartially supported by the platform project of Shanghai Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture Animals(No.2021-KJ-02-12)。
文摘Open earthen pond-based larviculture is the main method for rearing Chinese mitten crab(Eriocheir sinensis)larvae in China.Bacterioplankton play a vital role in aquaculture ecosystems,but their community succession throughout the larval nursery stages of E.sinensis in such systems is still poorly understood.Using 16S rRNA gene amplicon sequencing,this study characterized the dynamics of bacterioplankton communities during a complete E.sinensis larval rearing cycle in open earthen ponds.Results presented a distinct,unidirectional succession in bacterioplankton composition,characterized by a decrease in Alphaproteobacteria and an increase in Actinobacteria.Live feeds(Brachionus plicatilis and Artemia salina)significantly affected bacterioplankton communities directly through their biological activities and indirectly by modifying the structure of phytoplankton composition.In addition to live feeds,water temperature and dissolved oxygen were key environmental factors affecting the structure of bacterioplankton communities.Biotic interactions,specifically with phytoplankton and copepods,were key drivers of bacterioplankton succession.Routine feeding practices during larval cultivation decreased bacterioplankton network complexity and strengthened community stability.Keystone taxa,specifically OTU783(Rhodobacteraceae)and OTU1235(Microbacteriaceae),played an essential role in maintaining the community stability through recruiting more rare species during the later stages despite their low abundances.These outcomes advance our understanding of the mechanisms central to bacterioplankton community succession and stability in E.sinensis larviculture systems,offering critical insights for developing sustainable aquaculture management strategies.
基金supported by the National Key Research and Development Program of China(No.SQ2024YFE0102696)the Provincial Science and Technology Innovative Program for Carbon Peak and Carbon Neutrality of Jiangsu of China(No.BE2022422)supported by the TÜBITAK program BIDEB2232(No.118C250).
文摘Aquaculture ponds have emerged as a significant contributor to greenhouse gas(GHG)emissions.We measured methane(CH_(4)),carbon dioxide(CO_(2)),and nitrous oxide(N_(2)O)emissions in ponds,all located in Jiangsu Province,with different fish and management practices over an entire cycle.All ponds emitted these gases,with higher CH_(4) and N_(2)O levels during fish growth than stocking period.The highest CH_(4) and N_(2)O fluxes were found in the Crucian carp(Carassius auratus)pond with up to 16,512±3015μmol/(m^(2)·h)and 5.54±0.31μmol/(m^(2)·h),respectively.CH_(4) was the primary contributor to the global warming potential in traditional earthen ponds,accounting for an average contribution rate of 87.7%.The dissolved oxygen(DO)concentration was the water quality parameter that most significantly influenced the CO_(2)flux,while pH acted as its primary regulator.The GHG emission intensity per unit of fish production in traditional earthen ponds was 197 times higher than that in-pond raceway systems.Largemouth bass(Micropterus salmoides)and Crucian carp ponds exhibited CH_(4) diffusion fluxes at the sediment-water interface,which were>20 times higher than those at the water-air interface.Our results further suggest that stocking density and feed amount significantly influence the variations in GHG emissions among the ponds with the in-pond raceway system having low carbon emissions and being high yield aquaculture system compared to traditional earthen ponds.The water depth and DO concentration can be manipulated to reduce GHG emissions across the various interfaces.
基金financially supported by the National Natural Science Foundation of China(No.42077184)Guizhou Institute of Technology's Research Initiation Fund Project for High-Level Talents(No.XJGC20190602)。
文摘Leakage of electrolytic manganese slag(EMS)ponds is a long-lasting and serious threat to environmental health worldwide,particularly in karst areas where the ecosystems are highly sensitive to geochemical perturbations.However,the mechanisms of Mn mobilization and migration are insufficiently known.In this study,we combine systematic field investigations,laboratory column experiments and geochemical analyses to clarify the environmental geochemistry and controlling factors of leaching of Mn in the karst areas of southwestern China.While the Mn slag ponds as a whole had shown a low permeability,release of free Mn^(2+)and NH_(3)-N is significantly facilitated by the synergies of seepage infiltration,microbial activities and environmental acidification.With the increase of depth,the mineralogical composition of the slag undergoes significant alteration,and redox conditions change from acidic-oxidizing to acidic-reducing environments,which will accelerate the mobilization of Mn further and increase the risk of groundwater contamination.In addition,the presence of clay mineral colloids in Mn slag changes the migration properties of Mn,which introduces complexity in the geochemical behavior of Mn.Our findings highlight that Mn transformation and migration are controlled by dynamic,depth-dependent geochemical processes and the interplay of both internal and external factors.This research consolidates mechanistic foundation of deciphering Mn environmental behaviors in karst regions,reinforcing the urgency of preventing and rehabilitating electrolytic Mn slag leakage.
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 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.
文摘Mining tailing ponds are large infrastructure objects whose life cycle spans over several decades.They are indispensable for certain types of mines where technological process produces and rejects mud.They also have potential to generate risks for human life,property and environment.For that reason,it is essential to adequately manage them throughout all the stages of their life cycle.The phase of their closure and abandonment is less studied and understood.The paper proposes a holistic resilience-based approach for analyzing this phase of their life cycle.The proposed methodology is validated through a case study at an actual surface iron ore mine in Bosnia and Herzegovina.
基金Project (No. GA02C201) supported by the Key Project of Scienceand Technology Commission of Heilongjiang Province China
文摘The performance of the Dongying multi-stage ponds-wetlands ecosystem was investigated in this work. Study of the removal of different pollutants (BOD5, COD, SS, TP, TN, NH3-N, etc.) in different temperature seasons and different units in this system indicated that effluent BOD5 and SS were constant to less than 11 mg/L and 14 mg/L throughout the experimental proc- esses; but that the removal efficiencies of pollutants such as TP, TN, NH3-N, COD varied greatly with season. The higher the temperature was, the higher was the observed removal in this system. Additionally, each unit of the system functioned differently in removing pollutants. BOD5 and SS were mainly removed in the first three units (hybrid facultative ponds, aeration ponds and aerated fish ponds), whereas nitrogen and phosphates were mainly removed in hydrophyte ponds and constructed reed wetlands. The multi-stage ponds-wetlands ecosystem exhibits good potential of removing different pollutants, and the effluent quality meet several standards for wastewater reuse.
基金Under the auspices of National Program on Key Basic Research Project(No.2013CB430401)
文摘Aquaculture ponds are one of the fastest-growing land use types in valuable and fertile coastal areas and have caused serious environmental problems. Quantitative assessment of the extent, spatial distribution, and dynamics of aquaculture ponds is of utmost importance for sustainable economic development and scientific management of land and water resources in the coastal area. An object-oriented classification approach was applied to Landsat images acquired over three decades to investigate the long-term change of aquaculture ponds in the coastal region of the Yellow River Delta. The results indicated that the aquaculture ponds in the study area undergone a sharp expansion from 40.38 km^2 in 1983 to 1406.89 km^2 in 2015, and the fast expansion occurred during the period of 2010–2015 and 1990–2000. Natural wetlands, especially mudflat, and cropland were main land use types contributing to the increase of aquaculture ponds. The patches of aquaculture ponds were consequently prevalence in the north of the Yellow River Estuary and landscape metrics indicated an increase of the aquaculture ponds of the study area in the quantity and complexity. The expansion of aquaculture ponds inevitably had negative effects on the coastal environment, including loss of natural wetlands, water pollution and land subsidence, etc. The results from this study provide baseline data and valuable information for efficiently planning and managing aquaculture practices and for effectively implementing adequate regulations and protection measures.
文摘This study investigated the relationships among the parameters of dissolved oxygen, chlorophyll-a and phytoplankton composition in tilapia ponds. Each pond (a total of 18 ponds) was sampled once in the dry, winter season between January and March and again early in the rainy season between May and June. The data were analyzed by examining correlations among parameters as affected by season, altitude and culture system. Observations were made at sites located in 5 selected provinces of northern Thailand: Chiangrai, Chiangmai, Phayao, Lampang and Nakornsawan. Mean elevation of these areas range from 25 to 582 meters above sea level (masl) and were categorized into low (400 masl) elevation sites. Ponds were 0.8 - 2.0 m deep, 0.16 - 0.64 ha in area and could be further categorized into high and low input systems.Mean air temperature in winter ranged between 16.5°C - 35.8°C while mean water temperature ranged between 25.5°C - 27.1°C. In rainy season, air temperature ranged between 22.0°C - 37.3°C and water temperature ranged between 29.4°C - 31.8°C. The amount of chlorophyll-a in both seasons were comparable (p > 0.05), but chlorophyll-a in high input system was significantly higher (p 0.05) than in low input ponds. Only weak correlation was found between chlorophyll-a, DOmax and DOmin. Multifactor-ANOVA was used to analyze the difference of total bacteria and filamentous cyanobacteria in ponds based upon elevation, culture systems and season. Result shows that there is a significant interaction observed between elevation, culture system and season (p 0.05). Species diversity and composition of phytoplankton in fish ponds in 2 seasons revealed the presence of 90 genera of phytoplankton under all 7 divisions. Divisions Chlorophyta and Cyanophyta had the most number of genera identified in both seasons with Pediastrum spp., and Scendesmus spp., and Anabaena spp. as dominant genera/genus, respectively.
文摘Eriocheirsinensis, Portunus trituberculatus and Scylla paramamosain are important commercial culture crab species in China. Traditional factory breeding of crabs depends on Artemia nauplius. The rising price of Artemia cysts has led to the decline of the economic benefit of the crab breeding factory. Factory crab breeding has been gradually replaced by pond breeding in recent years. E. sinensis and P. trituberculatus have been bred mainly in ponds. Meanwhile, S. paramamosain is still mainly bred in factories because of the crudeness of pond breeding. The research progress on food organism utilization in the three species of commercially bred crabs was reviewed in this paper. In the workshop seeds production, rotifer and Artemia nauplii were necessary in the early stages from zoea I to zoea II in the three crab species. Adult artemia, minced fish and shellfish were fed to the larvae in the later zoea stages from zoea III to Megalopa.?The rising of the price of artemia eggs made people find other feed organism to replace artemia. Copepods have been used in crab seeds production in pond from zoea III stage to replace artemia in recent years, which has reduced the cost of seeds production.
基金Supported by the International Cooperation Research Program of the Ministry of Science & Technology of China(No.2010DFA32300)the Natural Science Foundation of Tianjin(No.13JCZDJC28700)the Foundation of Tianjin Key Laboratory of Marine Resources and Chemistry(No.201105)
文摘A total of 26 isolates were obtained from solar salt ponds of different salinities(100, 150, 200, and 250) in Hangu Saltworks Co. Ltd., Tianjin, China. Phylogenetic analysis of 16 SrRNA gene sequences indicated that five bacteria genera H alomonas, Salinicoccus, Oceanobacillus, Gracibacillus, and Salimicrobium and one archaea genera H alorubrum were present. The genus H alomonas was predominant with eight strains distributed in a salinity range of 100–200, followed by H alorubrum with six strains in salinity 250. Based on the genus and original sampling salinity, eight bacterial and two archaeal isolates were selected for further morphological, physiological, and biochemical characterization. All of the bacterial strains were moderately halophilic with the optimal salinity for growth being either 50 or 100, while two archaeal strains were extremely halophilic with an optimal growth salinity of 200. Additionally, we put forth strain SM.200-5 as a new candidate S alimicrobium species based on the phylogenic analysis of the 16 SrRNA gene sequence and its biochemical characteristics when compared with known related species.
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In Japan, various countermeasures have been taken to improve the water quality of public waters such as rivers and lakes. Though water quality has improved, it is still insufficient. In summer, eutrophication is seen in lakes and inner bays, as well as rivers. As a countermeasure to prevent eutrophication, the removal treatment of nutrient salts such as nitrogen and phosphorus is done, in addition to organic substance elimination in the domestic sewerage system. This report will show the water quality characteristics of rivers and ponds in Japan. It is considered that these investigative results are effective when the water quality improvement of the stabilization ponds where eutrophication occurs are examined in China.
文摘Nowadays, rainwater harvesting (RWH) technology is increasingly adopted as a strategic pathway for reducing poverty in rural drought prone areas for enhancing agricultural productivity and boosting farm income. The aim of this study is to assess the level of adoption and the impacts of RWH ponds on farm income in Ntarama sector of Bugesera District in Eastern Province of Rwanda. Fifteen farm ponds were visited and the level at which households adopted RWH ponds, their impact on farm income and performance in storing water were assessed. Interviews and questionnaires methods were used to farm ponds beneficiaries and the storage capacity of farm ponds was calculated to ensure that they meet irrigation water demand. Then, Microsoft excel was used as a data analysis tool. The results show that 42.5% of households have adopted RWH ponds and the adoption level of RWH ponds fails due to the lack of training about the role and use of RWH ponds before their implementation. Beside this the low level of public involvement during the site selection for ponds associated with social conflicts among water users was observed. However, it is further revealed that the use of RWH ponds positively impacts on agricultural income on 1/4 hectare per year by about 2,325,000 RWF (3100USD). The studied portion of area can bear 222 ponds of 120 m<sup>3</sup> each if all the rain is harvested throughout the year instead of being three ponds. Furthermore, we found that the quantity of rainwater harvested of 328.5 m<sup>3</sup> as a total of the 3 ponds was still too less to meet irrigation water demand. As negative impacts, the RWH technology can cause dangerous effects such as social conflicts, breeding site for mosquitoes, water related diseases, accidents and others with a level of severity of 32%, 24%, 20%, 16% and 8%, respectively. This happens when the RWH ponds are not properly managed.
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.
基金the National Oceanic and Public Research Project(201405003).
文摘By measuring water temperature,salinity,pH,dissolved oxygen,nitrite and ammonia nitrogen,the annual variation regularity of water quality in the aquaculture ponds for sea cucumbers Apostichopus japonicus in Dalian were studied.Results showed that the physicochemical indicators kept changing in the year,and the various ranges of water temperature,salinity,pH,dissolved oxygen,nitrite,and ammonia nitrogen were 6.38-27.27℃,29.20‰-33.78‰,7.86-8.38,5.19-13.36 mg/L,0.0037-0.0090 mg/L and 0.0171-0.0908 mg/L,respectively.Analysis indicated that there was an extremely significant negative correlation between water temperature and dissolved oxygen(P<0.01),an extremely significant positive correlation between water temperature and ammonia nitrogen(P<0.01),a significant negative correlation between salinity and nitrite(P<0.05),a significant negative correlation between dissolved oxygen and nitrite(P<0.05),and an extremely significant negative correlation between dissolved oxygen and ammonia nitrogen(P<0.01)in the aquaculture ponds for sea cucumber in Dalian.Research showed that the water quality of aquaculture ponds kept fluctuating all the time during the tested period,there were complicated and close relationships among physicochemical indicators,and a slight variation of external factors would bring consecutive reactions to different indicators in the water quality of aquaculture ponds.A reference for the production and management of sea cucumbers could be provided from the results.
基金supported by the National Natural Science Foundation of China (Nos. 41506222, 41776205)the Chinese Polar Environment Comprehensive Investigation & Assessment Programmes (Nos. CHINARE 2017-03-04 and 2017-0402)
文摘Climate warming has a significant impact on the sea ice and ecosystem of the Arctic Ocean.Under the increasing numbers of melt ponds in Arctic sea ice,the phytoplankton communities associated with the ice system are changing.During the 7th Chinese National Arctic Research Expedition cruise in summer 2016,photosynthesis pigments and nutrients were analyzed,revealing differences in phytoplankton communities between melt ponds and open water in the central Arctic.Photosynthetic pigment analysis suggested that Fuco(5-91μg m^-3)and Diadino(4-21μg m^-3)were the main pigments in the open water.However,the melt ponds had high concentrations of Viola(7-30μg m^-3),Lut(4-59μg m^-3)and Chl b(11-38μg m^-3),suggesting that green algae dominated phytoplankton communities in the melt ponds.The significant differences in phytoplankton communities between melt ponds and open water might be due to the salinity difference.Moreover,green algae may play a more important role in Arctic sea ice ecosystems with the expected growing number of melt ponds in the central Arctic Ocean.
文摘This paper presents a method for in situ determining sediment oxygen demand (SOD) in cultivation pond. This method based on sediment surface structure, temperature, and other determining conditions like those in shrimp cultivation environments, overcomes defects of old methods and provides more accurate estimation of SOD’s effect on dissolved oxygen in culture waters. Our experiment shows that the sediment surface structure and temperature had important effect on SOD in culture water. Different SOD values were derived from different parts of oxygen consumption curves of sediment, because the curves were not linear. According to the oxygen consumption curves of sediment and saturated DO in culture water, it was thought more suitable to calculate SOD with dissolved oxygen reduction from 5.0 to 2.0 mg/l. This method to determine the SOD of shrimp ponds yielded satisfactory results.
基金Supported by the Ministry of Science and Technological Development,Republic of Serbia,Projects(Nos.451-03-68/2020-14/200178,451-03-68/2020-14/200026)。
文摘Phosphorus overenrichment of shallow ponds prevailing in wetlands leads to their eutrophication causing the collapse of those vulnerable habitats.The potential of phosphorus accumulation by periphyton developed on artificial substrata has been investigated in two shallow ponds(Bara?ka and?iroki Rit)in northwest Serbia and compared to the same ability of plankton and metaphyton.The periphyton substrate carrier has been submerged from May to October.Both continuously(CS)and monthly developed(MS)periphyton were sampled.Autotrophic component of all investigated communities has been qualitatively assessed.Maximum accumulation of only 14.7 mg TP/m^(2) was recorded in three-month exposed periphyton CS.MS exposed from July to August reached maximal 12.7 mg TP/m^(2).Plankton community that was characterized by more diverse and abundantly developed algal component was more effective in phosphorus accumulation(0.7 mg/g dry weight)in comparison with dominantly inorganic and diatom-dominated periphyton in Bara?ka.Unstable conditions caused by recent revitalization(dredging organic matter and mud from pond basin—redigging)as well as rapid desiccation of?iroki Rit disabled making an unambiguous conclusion about the efficiency of phosphorus accumulation among different communities,but suggested slight potential of phosphorus harvesting by metaphyton in this pond.Due to the shorter exposure time that brings the reduced risk of unpredictable changes in the ecosystem,as well as the considerable amount of accumulated phosphorus,large-scale application of one-month exposed periphyton developed on artificial substrates would be more advisable for phosphorus harvesting in nutrient affected shallow ponds.
