Ecological stoichiometry of nitrogen and phosphorus is an important indicator to characterize the nitrogen and phosphorus trophic status in aquatic ecosystems. The study of the spatio-temporal patterns of nitrogen and...Ecological stoichiometry of nitrogen and phosphorus is an important indicator to characterize the nitrogen and phosphorus trophic status in aquatic ecosystems. The study of the spatio-temporal patterns of nitrogen and phosphorus stoichiometry is beneficial to the nitrogen and phosphorus pollution management in pond ecosystems. In this study, 18 groups (36 in total) of typical cascade ponds were selected as long-term observations to investigate the spatial distribution patterns of nitrogen and phosphorus component ratios (ratio of total nitrogen to phosphorus: TN:TP, ratio of dissolved nitrogen to phosphorus: TDN:TDP, ratio of particulate nitrogen to phosphorus: PN:PP) in water bodies in the tropical agricultural watershed of Jinjing. The results showed that the average values of TN:TP and TDN:TDP in the upstream ponds were 26.4 and 53.4, respectively, and were more than those in the downstream (22.95 and 48.1, respectively). In contrast, the PN:PP (13.78) in the upstream was significantly lower than that of the downstream (30.39). Furthermore, the factors of rainfall, agricultural land use and fish farming influenced the spatio-temporal variability of the N:P ratios. The ratios of TN:TP and TDN:TDP were higher in the wet season and lower in the dry season. Agricultural land use and fish farming reduced the ratios of the above three nitrogen and phosphorus components in cascade ponds in the study area. Our results show that strengthening agricultural land pollution control and aquaculture management could help to improve water quality of pond ecosystems in the study area.展开更多
It is not understood well that how the effects of land use and fish farming on the contents of alkali metals (Ca<sup>2+</sup>, Mg<sup>2+</sup>, K<sup>+</sup> and Na<sup>+</...It is not understood well that how the effects of land use and fish farming on the contents of alkali metals (Ca<sup>2+</sup>, Mg<sup>2+</sup>, K<sup>+</sup> and Na<sup>+</sup>) in small water bodies of pond and reservoir ecosystems at the watershed scale. In this study, the concentrations of Ca<sup>2+</sup>, Mg<sup>2+</sup>, K<sup>+</sup> and Na<sup>+</sup> in water bodies were measured for 103 ponds and reservoirs used as fish farming or surrounded by different agricultural land use types in the subtropical hilly watershed of Jinjing (105 km<sup>2</sup>), China. The two important environmental factors of fishing farming and agricultural land use influenced the spatial variation the contents of alkali metals. The ponds and reservoirs in residential area had significantly higher concentrations of Ca<sup>2+</sup> and Na<sup>+</sup> than those with other land use types, reflecting the influence of domestic wastewater. Compared with those of natural ponds with non-fish farming, no significant increase of alkali metal contents occurred in fish farming ponds, due to the regular cleaning of ponds by farmers. However, the effect of fish culture on alkali metal contents was still supported indirectly by the fact that the alkali metal contents significantly correlated with nitrate contents in fish farming ponds and but high related with that of DIP in natural ponds. The suitability assessment for irrigation on the pond water indicated that almost all of ponds were suitable for irrigation except some ponds surrounded by residential area and tea plantation. Generally, our results demonstrated that fish farming and agricultural land use affected the contents of alkali metals in ponds and reservoirs. The agricultural water irrigation would be with caution from the ponds with tea plantation and residential area in the subtropical hilly watershed.展开更多
There are some bad impacts from a critical land such as flood in rainy season and dryness in dry season. Long dryness could cause shortage of water for human consumption, industry and agriculture. Prevention has been ...There are some bad impacts from a critical land such as flood in rainy season and dryness in dry season. Long dryness could cause shortage of water for human consumption, industry and agriculture. Prevention has been made to avoid the both bad impacts by building hydraulic structures like reservoirs and ponds in order to reduce the peak flow during the rainy season and to store the water for use during the dry season. However, they gradually become full of sediment. This will make them work insufficiently and will cause high maintenance cost. Moreover, wells in agriculture field used as retention also suffer dryness to make crop failure. This study aims to develop a model of pond for conservation of land and water in non irrigated land. Community participation is crucial in order to solve the flood and dryness problems. The community, especially the farmers will participate actively in the implementation and maintenance of the model. There are benefits in using the pond model such as: (1) to control sediment transport to the rivers, reservoir or other hydraulic structures; (2) to reduce flood rate; (3) to increase ground water recharge; (4) to contain water for agriculture and (5) to control the fertility of land. The cost of making a unit of model (sedrainpond) of 1.5 m diameter and 1.5 meter depth is relatively cheap between $10 to $20 (US), and the maintenance is done by the farmers. When the pond model becomes functional, besides containing water in the rainy season, the water can be used to sustain water for agriculture in the dry season to avoid any crop failure. When the pond becomes dry, the farmers can harvest the suspended load sediment such as clay or silt to spread onto their land to keep its fertility.展开更多
The establishment of water circulation aquaculture system realized the hi- erarchical use of nitrogen, phosphorus and other eutrophic substances in aquaculture wastewater and the recirculation use of water resource. H...The establishment of water circulation aquaculture system realized the hi- erarchical use of nitrogen, phosphorus and other eutrophic substances in aquaculture wastewater and the recirculation use of water resource. However, no research has been reported on the detailed calculation of the relationship between the area of aquaculture pond and purification pond. In this study, referring to the absorption ability of aquatic plants to pollutants in aquaculture wastewater and pollutant generation and discharge coefficient in aquaculture pond, based on the general rules of water quality management in freshwater aquaculture system, a calculation mode was es- tablished to investigate the relationship between the area of aquaculture pond and purification pond in freshwater recirculation aquaculture system, which was feasible to explain related cases and would provide theoretical basis to reduce the economic costs in the construction of water circulation aquaculture system and realize the bal- ance between the ecological benefits and the economic benefits.展开更多
This article discusses the perception of ecosystem services for French and Brazilian pond fish farming. Its aim is to study the extent to which the industry and its stakeholders are aware of the existence of such serv...This article discusses the perception of ecosystem services for French and Brazilian pond fish farming. Its aim is to study the extent to which the industry and its stakeholders are aware of the existence of such services in order to be able to prioritize them with respect to social well-being. This identification phase is seldom discussed. It requires that survey questionnaires be designed so as to improve understanding of these perceptions. The surveys undertaken combined both open questions where the interviewees expressed their perceptions spontaneously and closed questions where they were invited to rank a pre-established list of the relevant services. These surveys involved 133 fish farmers and 93 stakeholders. The results show that perceptions differ by question type, and confirm the significance of the questionnaire design and the importance of combining several kinds of approach.展开更多
The approximate general composition and the fatty acid profile of Nile tilapia fed Azolla-diets in ponds were studied for 90 days. Six isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ·g>sup>-1) diets wer...The approximate general composition and the fatty acid profile of Nile tilapia fed Azolla-diets in ponds were studied for 90 days. Six isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ·g>sup>-1) diets were formulated to contain 0% (A0), 10% (A10), 20% (A>sub>20), 30% (A30), 40% (A40) and 50% (A50) of Azolla meal (AM), as partial fish meal (FM) substitutes. Diet A0 without AM served as a control. Fish growth decreased as AM level exceeded 20% in diets (P 0.05). Crude lipid was significantly lower in fish fed A50 and significant differences were also found in crude ash (P 20, A30 and A50. High level of the fern reduces growth without negatively affecting fatty acid in fish. Fish PUFA, especially the (n - 3) fatty acids, are affected positively, even when fed 50% AM, which is good for the quality of the fish produced in regard to the benefits for the health of consumers.展开更多
A seven-month research evaluated the management effect on the water quality and sediment of seven fish ponds. Water and sediment were collected at nine sample sites: seven in the fish ponds;one in inlet water and anot...A seven-month research evaluated the management effect on the water quality and sediment of seven fish ponds. Water and sediment were collected at nine sample sites: seven in the fish ponds;one in inlet water and another in the fish farm’s effluent. The soil samples were analyzed for macro- and micro-nutrients and the water samples were analyzed for physical and chemical parameters. Management and local climate conditions affected nutrient seasonality in the sediment and featured high concentrations of Al, Ca, Cu, K, Mg, C, Na, Zn and OM at the effluent with low pH, ranging between 4.4 and 6.5. Sudden decrease of DO (less than 3 mg/L) during the rainy season, with a 180 mmrainfall, and a TSS increase (approximately 10 mg/L) were reported. Use of organic manure in fish pond V6 caused higher rates of ammonia (over 1 mg/L). Due to the sediment’s acid pH (less than 4.8) and Al at 0.92 mg/L at the effluent, great care was required in the fish farm. Maintenance and procedures management in the fish farm under analysis should be given more attention since high levels of Al, Fe and acid pH and low levels of potassium and phosphorus in the sediment may produce unfavorable conditions in the water column, and may ultimately have an impact on fish.展开更多
Water and energy are closely linked natural resources - the transportation, treatment, and distribution of water depends on low-cost energy; while power generation requires large volumes of water. Seawater desalinatio...Water and energy are closely linked natural resources - the transportation, treatment, and distribution of water depends on low-cost energy; while power generation requires large volumes of water. Seawater desalination is a mature technology for increasing freshwater supply, but it is essentially a trade of energy for freshwater and is not a viable solution for regions where both water and energy are in short supply. This paper discusses the development and application of a renewable-energy-driven reverse osmosis (RO) system for water desalination and the treatment and reuse of aquaculture wastewater. The system consists of (1) a wind-driven pumping subsystem, (2) a pressure-driven RO membrane desalination subsystem, and (3) a solar-driven feedback control module. The results of the pilot experiments indicated that the system, operated under wind speeds of 3 m s-~ or higher, can be used for brackish water desalination by reducing the salinity of feedwater with total dissolved solids (TDS) of over 3 000 mg L-1 to product water or permeate with a TDS of 200 mg L-~ or less. Results of the pilot experiments also indicated that the system can remove up to 97% of the nitrogenous wastes from the fish pond effluent and can recover and reuse up to 56% of the freshwater supply for fish pond operation.展开更多
Rice-fish co-culture has gained increasing attention to remediate the negative environmental impacts induced by intensive aquaculture. However, the effect of rice-fish co-culture on oxygen depletion has rarely been in...Rice-fish co-culture has gained increasing attention to remediate the negative environmental impacts induced by intensive aquaculture. However, the effect of rice-fish co-culture on oxygen depletion has rarely been investigated. We constructed a rice-fish co-culture system in yellow catfish(Pelteobagrus fulvidraco) and freshwater shrimp(Macrobrachium nipponense) ponds using a new high-stalk rice variety, and conducted a field experiment to investigate the effect of rice-fish co-culture on water parameters and oxygen consumption. The results showed that rice-fish co-culture reduced the nutrients(total nitrogen, ammonia-N, total phosphorous and potassium) and the dissolved oxygen content in fish and shrimp ponds. However, they showed similar seasonal change of dissolved oxygen in the water of fish and shrimp ponds. Rice-fish co-culture reduced the total amount of oxygen consumption and optimized the oxygen consumption structure in pond. The respiration rates in water and sediment were significantly reduced by 66.1% and 31.7% in the catfish pond, and 64.4% and 38.7% in the shrimp pond, respectively, by additional rice cultivation. Rice-fish co-culture decreased the proportions of respiration in sediment and water, and increased the proportion of fish respiration. These results suggest that rice-fish co-culture is an efficient way to reduce hypoxia in intensive culture pond.展开更多
This research deals with an evaluation of the sink of greenhouse gas CO2 in a eutrophic area of the Venetian lagoon where fish is farmed ("Valle da pesca"). Following CDM UNFCCC (Clean Development Mechanism Unite...This research deals with an evaluation of the sink of greenhouse gas CO2 in a eutrophic area of the Venetian lagoon where fish is farmed ("Valle da pesca"). Following CDM UNFCCC (Clean Development Mechanism United Nations Framework Convention on Climate Change) criteria, this can be considered relevant to the international standard for the voluntary evaluation of carbon credits on the basis of Annex a of Kyoto Protocol. To identify the "Valle da pesca" brackish lagoon properties regulating the carbon dioxide (CO2), a survey has been performed during three seasons in one year and in four different locations. These places are located in the Italian Venetian Lagoon and in the Grado Lagoon in North Italy, Europe. To identify the CO2 sink capacity, a special index is calculated. The CO2 concentrations and sink are regulated by the balance of autotrophic and heterotrophic activities, and the sediment anoxic denitrification and macro algae are crucial tank of CO2 in the valley shallow waters. The ponds potential-CO2 yield of 80-124 kg/m2 per year and the value are related and proportional to the correct human environmental control (water flux control).展开更多
Poultry production clusters (PPC) in Nong Khai raise layer chickens in the poultry houses constructed over fish ponds. Layer farmers use chicken manure to feed their fish. However, unbalance between chicken raising an...Poultry production clusters (PPC) in Nong Khai raise layer chickens in the poultry houses constructed over fish ponds. Layer farmers use chicken manure to feed their fish. However, unbalance between chicken raising and the size of fish pond or number of fish results in low water quality, which affects fish production and the community’s public water resource. In this field study, data was collected from layer farms in three poultry production clusters in Nong Khai province in the northeast of Thailand (a total of 90 farms) between April and August 2013. Data collected consisted of observations of dissolved oxygen (DO) values of water in the fish ponds, the number of egg-laying chickens raised above the fish ponds, the number of fish and size of the fish ponds. When all of these four observations were analyzed, mathematical equations for calculating the number of chickens raised, the number of fish per one rai (1600 m2), and the size of pond suitable for the number of chickens and fish were obtained as follows: 1) number of fish/rai = 5796 + 1097(size of pond) (R2 = 0.71), 2) number of chicken/rai = 513 + 223(size of pond) (R2 = 0.48) and 3) size of pond =-0.328474 + 0.000262(Fish) + 0.00117(Chicken) (R2 = 0.40). When pond = desired pond size, fish = number of fish to be raised and chicken = number of chickens to be raised.展开更多
This study was conducted to determine the contamination data of some heavy metals in 10 fish tissue samples of two different fish species---common carp and Northern pike from four different fish ponds and to compare t...This study was conducted to determine the contamination data of some heavy metals in 10 fish tissue samples of two different fish species---common carp and Northern pike from four different fish ponds and to compare the level of contamination and the differences in the concentration of these elements between these two fish species and between compared fish ponds. In various fish ponds, metal concentrations in the carp muscle tissue varied depending on the metal type. Between compared fish ponds, there were significant differences (P 〈 0.01) in the concentration in muscle carp tissue, except for cadmium. Metal concentrations in the pike muscle tissue also varied among fish ponds, depending on the type of metal. In all compared cases, there were significant differences between metal concentration in pike muscle tissue (P 〈 0.01). Lead and cadmium concentration in pike muscle tissue were significantly higher (P 〈 0.01, P 〈 0.05, respectively), and mercury and arsenic concentration were significantly lower (P 〈 0.01) than concentration of this heavy metals in carp muscle tissue in all comapered fish ponds. The results obtained in this study indicate variation in a range of examined metal concentration in muscle tissue, which seems to be typical for the Serbian fish ponds, but is lower than those in rivers with considerable anthropogenic impact.展开更多
The treatise by Olbrycht Strumieński is chronologically the first book in Poland, and the second in Europe, describinglevelling instruments. A few years after Strumieński’s death, the text was published by Stanisła...The treatise by Olbrycht Strumieński is chronologically the first book in Poland, and the second in Europe, describinglevelling instruments. A few years after Strumieński’s death, the text was published by Stanisław Stroynowski. Until the 19th century,only three Polish-language treatises addressed the problems of levelling. Strumieński described the technique of building andmanaging fish ponds in Moravia, Bohemia and Poland. The presented surveying instruments and measuring methods are sufficientfor the design and construction of a pond that can survive for over 300 years. Strumieński also presented the principles of freshwateraquaculture. Poland, along with Bohemia, Moravia and Hungary, was an exporter of freshwater fish to Western Europe from the 16thto the mid-18th century.展开更多
The Hula Valley was drained in 1957. The land use was modified from natural wetland and old shallow lake ecosystems to agricultural development. About half of the drained land area was utilized for aquaculture. Popula...The Hula Valley was drained in 1957. The land use was modified from natural wetland and old shallow lake ecosystems to agricultural development. About half of the drained land area was utilized for aquaculture. Population size was enhanced and the diary was developed intensively resulting in the enhancement of domestic and husbandry sewage production that increased as well. The natural intact Hula Valley-Lake Kinneret ecosystem was heavily anthropogenically interrupted: The Hula was drained and Kinneret became a national source for domestic water supply. Some aspects of the environmental and water quality protection policy of the system are presented. The causation and operational management implications for the reduction of Nitrogen and Phosphorus migration from the Hula Valley are discussed. Drastic (81%) restriction of aquaculture accompanied by sewage totally removed achieved a reasonable improvement in pollution control which was also supported by the Hula Project. The implications of anthropogenic intervention in the process of environmental management design are presented.展开更多
文摘Ecological stoichiometry of nitrogen and phosphorus is an important indicator to characterize the nitrogen and phosphorus trophic status in aquatic ecosystems. The study of the spatio-temporal patterns of nitrogen and phosphorus stoichiometry is beneficial to the nitrogen and phosphorus pollution management in pond ecosystems. In this study, 18 groups (36 in total) of typical cascade ponds were selected as long-term observations to investigate the spatial distribution patterns of nitrogen and phosphorus component ratios (ratio of total nitrogen to phosphorus: TN:TP, ratio of dissolved nitrogen to phosphorus: TDN:TDP, ratio of particulate nitrogen to phosphorus: PN:PP) in water bodies in the tropical agricultural watershed of Jinjing. The results showed that the average values of TN:TP and TDN:TDP in the upstream ponds were 26.4 and 53.4, respectively, and were more than those in the downstream (22.95 and 48.1, respectively). In contrast, the PN:PP (13.78) in the upstream was significantly lower than that of the downstream (30.39). Furthermore, the factors of rainfall, agricultural land use and fish farming influenced the spatio-temporal variability of the N:P ratios. The ratios of TN:TP and TDN:TDP were higher in the wet season and lower in the dry season. Agricultural land use and fish farming reduced the ratios of the above three nitrogen and phosphorus components in cascade ponds in the study area. Our results show that strengthening agricultural land pollution control and aquaculture management could help to improve water quality of pond ecosystems in the study area.
文摘It is not understood well that how the effects of land use and fish farming on the contents of alkali metals (Ca<sup>2+</sup>, Mg<sup>2+</sup>, K<sup>+</sup> and Na<sup>+</sup>) in small water bodies of pond and reservoir ecosystems at the watershed scale. In this study, the concentrations of Ca<sup>2+</sup>, Mg<sup>2+</sup>, K<sup>+</sup> and Na<sup>+</sup> in water bodies were measured for 103 ponds and reservoirs used as fish farming or surrounded by different agricultural land use types in the subtropical hilly watershed of Jinjing (105 km<sup>2</sup>), China. The two important environmental factors of fishing farming and agricultural land use influenced the spatial variation the contents of alkali metals. The ponds and reservoirs in residential area had significantly higher concentrations of Ca<sup>2+</sup> and Na<sup>+</sup> than those with other land use types, reflecting the influence of domestic wastewater. Compared with those of natural ponds with non-fish farming, no significant increase of alkali metal contents occurred in fish farming ponds, due to the regular cleaning of ponds by farmers. However, the effect of fish culture on alkali metal contents was still supported indirectly by the fact that the alkali metal contents significantly correlated with nitrate contents in fish farming ponds and but high related with that of DIP in natural ponds. The suitability assessment for irrigation on the pond water indicated that almost all of ponds were suitable for irrigation except some ponds surrounded by residential area and tea plantation. Generally, our results demonstrated that fish farming and agricultural land use affected the contents of alkali metals in ponds and reservoirs. The agricultural water irrigation would be with caution from the ponds with tea plantation and residential area in the subtropical hilly watershed.
文摘There are some bad impacts from a critical land such as flood in rainy season and dryness in dry season. Long dryness could cause shortage of water for human consumption, industry and agriculture. Prevention has been made to avoid the both bad impacts by building hydraulic structures like reservoirs and ponds in order to reduce the peak flow during the rainy season and to store the water for use during the dry season. However, they gradually become full of sediment. This will make them work insufficiently and will cause high maintenance cost. Moreover, wells in agriculture field used as retention also suffer dryness to make crop failure. This study aims to develop a model of pond for conservation of land and water in non irrigated land. Community participation is crucial in order to solve the flood and dryness problems. The community, especially the farmers will participate actively in the implementation and maintenance of the model. There are benefits in using the pond model such as: (1) to control sediment transport to the rivers, reservoir or other hydraulic structures; (2) to reduce flood rate; (3) to increase ground water recharge; (4) to contain water for agriculture and (5) to control the fertility of land. The cost of making a unit of model (sedrainpond) of 1.5 m diameter and 1.5 meter depth is relatively cheap between $10 to $20 (US), and the maintenance is done by the farmers. When the pond model becomes functional, besides containing water in the rainy season, the water can be used to sustain water for agriculture in the dry season to avoid any crop failure. When the pond becomes dry, the farmers can harvest the suspended load sediment such as clay or silt to spread onto their land to keep its fertility.
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.
文摘This article discusses the perception of ecosystem services for French and Brazilian pond fish farming. Its aim is to study the extent to which the industry and its stakeholders are aware of the existence of such services in order to be able to prioritize them with respect to social well-being. This identification phase is seldom discussed. It requires that survey questionnaires be designed so as to improve understanding of these perceptions. The surveys undertaken combined both open questions where the interviewees expressed their perceptions spontaneously and closed questions where they were invited to rank a pre-established list of the relevant services. These surveys involved 133 fish farmers and 93 stakeholders. The results show that perceptions differ by question type, and confirm the significance of the questionnaire design and the importance of combining several kinds of approach.
文摘The approximate general composition and the fatty acid profile of Nile tilapia fed Azolla-diets in ponds were studied for 90 days. Six isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ·g>sup>-1) diets were formulated to contain 0% (A0), 10% (A10), 20% (A>sub>20), 30% (A30), 40% (A40) and 50% (A50) of Azolla meal (AM), as partial fish meal (FM) substitutes. Diet A0 without AM served as a control. Fish growth decreased as AM level exceeded 20% in diets (P 0.05). Crude lipid was significantly lower in fish fed A50 and significant differences were also found in crude ash (P 20, A30 and A50. High level of the fern reduces growth without negatively affecting fatty acid in fish. Fish PUFA, especially the (n - 3) fatty acids, are affected positively, even when fed 50% AM, which is good for the quality of the fish produced in regard to the benefits for the health of consumers.
文摘A seven-month research evaluated the management effect on the water quality and sediment of seven fish ponds. Water and sediment were collected at nine sample sites: seven in the fish ponds;one in inlet water and another in the fish farm’s effluent. The soil samples were analyzed for macro- and micro-nutrients and the water samples were analyzed for physical and chemical parameters. Management and local climate conditions affected nutrient seasonality in the sediment and featured high concentrations of Al, Ca, Cu, K, Mg, C, Na, Zn and OM at the effluent with low pH, ranging between 4.4 and 6.5. Sudden decrease of DO (less than 3 mg/L) during the rainy season, with a 180 mmrainfall, and a TSS increase (approximately 10 mg/L) were reported. Use of organic manure in fish pond V6 caused higher rates of ammonia (over 1 mg/L). Due to the sediment’s acid pH (less than 4.8) and Al at 0.92 mg/L at the effluent, great care was required in the fish farm. Maintenance and procedures management in the fish farm under analysis should be given more attention since high levels of Al, Fe and acid pH and low levels of potassium and phosphorus in the sediment may produce unfavorable conditions in the water column, and may ultimately have an impact on fish.
基金supported in part by the U.S.Department of the Interior Bureau of Reclamation(USBR)through a research grant(04-FG-81-1062)
文摘Water and energy are closely linked natural resources - the transportation, treatment, and distribution of water depends on low-cost energy; while power generation requires large volumes of water. Seawater desalination is a mature technology for increasing freshwater supply, but it is essentially a trade of energy for freshwater and is not a viable solution for regions where both water and energy are in short supply. This paper discusses the development and application of a renewable-energy-driven reverse osmosis (RO) system for water desalination and the treatment and reuse of aquaculture wastewater. The system consists of (1) a wind-driven pumping subsystem, (2) a pressure-driven RO membrane desalination subsystem, and (3) a solar-driven feedback control module. The results of the pilot experiments indicated that the system, operated under wind speeds of 3 m s-~ or higher, can be used for brackish water desalination by reducing the salinity of feedwater with total dissolved solids (TDS) of over 3 000 mg L-1 to product water or permeate with a TDS of 200 mg L-~ or less. Results of the pilot experiments also indicated that the system can remove up to 97% of the nitrogenous wastes from the fish pond effluent and can recover and reuse up to 56% of the freshwater supply for fish pond operation.
基金supported by the Natural Science Foundation of China(Grant No.31400379)Natural Science Foundation of Zhejiang Province of China(Grant No.LY15C030002)Innovation Program of Chinese Academy of Agricultural Sciences
文摘Rice-fish co-culture has gained increasing attention to remediate the negative environmental impacts induced by intensive aquaculture. However, the effect of rice-fish co-culture on oxygen depletion has rarely been investigated. We constructed a rice-fish co-culture system in yellow catfish(Pelteobagrus fulvidraco) and freshwater shrimp(Macrobrachium nipponense) ponds using a new high-stalk rice variety, and conducted a field experiment to investigate the effect of rice-fish co-culture on water parameters and oxygen consumption. The results showed that rice-fish co-culture reduced the nutrients(total nitrogen, ammonia-N, total phosphorous and potassium) and the dissolved oxygen content in fish and shrimp ponds. However, they showed similar seasonal change of dissolved oxygen in the water of fish and shrimp ponds. Rice-fish co-culture reduced the total amount of oxygen consumption and optimized the oxygen consumption structure in pond. The respiration rates in water and sediment were significantly reduced by 66.1% and 31.7% in the catfish pond, and 64.4% and 38.7% in the shrimp pond, respectively, by additional rice cultivation. Rice-fish co-culture decreased the proportions of respiration in sediment and water, and increased the proportion of fish respiration. These results suggest that rice-fish co-culture is an efficient way to reduce hypoxia in intensive culture pond.
文摘This research deals with an evaluation of the sink of greenhouse gas CO2 in a eutrophic area of the Venetian lagoon where fish is farmed ("Valle da pesca"). Following CDM UNFCCC (Clean Development Mechanism United Nations Framework Convention on Climate Change) criteria, this can be considered relevant to the international standard for the voluntary evaluation of carbon credits on the basis of Annex a of Kyoto Protocol. To identify the "Valle da pesca" brackish lagoon properties regulating the carbon dioxide (CO2), a survey has been performed during three seasons in one year and in four different locations. These places are located in the Italian Venetian Lagoon and in the Grado Lagoon in North Italy, Europe. To identify the CO2 sink capacity, a special index is calculated. The CO2 concentrations and sink are regulated by the balance of autotrophic and heterotrophic activities, and the sediment anoxic denitrification and macro algae are crucial tank of CO2 in the valley shallow waters. The ponds potential-CO2 yield of 80-124 kg/m2 per year and the value are related and proportional to the correct human environmental control (water flux control).
文摘Poultry production clusters (PPC) in Nong Khai raise layer chickens in the poultry houses constructed over fish ponds. Layer farmers use chicken manure to feed their fish. However, unbalance between chicken raising and the size of fish pond or number of fish results in low water quality, which affects fish production and the community’s public water resource. In this field study, data was collected from layer farms in three poultry production clusters in Nong Khai province in the northeast of Thailand (a total of 90 farms) between April and August 2013. Data collected consisted of observations of dissolved oxygen (DO) values of water in the fish ponds, the number of egg-laying chickens raised above the fish ponds, the number of fish and size of the fish ponds. When all of these four observations were analyzed, mathematical equations for calculating the number of chickens raised, the number of fish per one rai (1600 m2), and the size of pond suitable for the number of chickens and fish were obtained as follows: 1) number of fish/rai = 5796 + 1097(size of pond) (R2 = 0.71), 2) number of chicken/rai = 513 + 223(size of pond) (R2 = 0.48) and 3) size of pond =-0.328474 + 0.000262(Fish) + 0.00117(Chicken) (R2 = 0.40). When pond = desired pond size, fish = number of fish to be raised and chicken = number of chickens to be raised.
文摘This study was conducted to determine the contamination data of some heavy metals in 10 fish tissue samples of two different fish species---common carp and Northern pike from four different fish ponds and to compare the level of contamination and the differences in the concentration of these elements between these two fish species and between compared fish ponds. In various fish ponds, metal concentrations in the carp muscle tissue varied depending on the metal type. Between compared fish ponds, there were significant differences (P 〈 0.01) in the concentration in muscle carp tissue, except for cadmium. Metal concentrations in the pike muscle tissue also varied among fish ponds, depending on the type of metal. In all compared cases, there were significant differences between metal concentration in pike muscle tissue (P 〈 0.01). Lead and cadmium concentration in pike muscle tissue were significantly higher (P 〈 0.01, P 〈 0.05, respectively), and mercury and arsenic concentration were significantly lower (P 〈 0.01) than concentration of this heavy metals in carp muscle tissue in all comapered fish ponds. The results obtained in this study indicate variation in a range of examined metal concentration in muscle tissue, which seems to be typical for the Serbian fish ponds, but is lower than those in rivers with considerable anthropogenic impact.
文摘The treatise by Olbrycht Strumieński is chronologically the first book in Poland, and the second in Europe, describinglevelling instruments. A few years after Strumieński’s death, the text was published by Stanisław Stroynowski. Until the 19th century,only three Polish-language treatises addressed the problems of levelling. Strumieński described the technique of building andmanaging fish ponds in Moravia, Bohemia and Poland. The presented surveying instruments and measuring methods are sufficientfor the design and construction of a pond that can survive for over 300 years. Strumieński also presented the principles of freshwateraquaculture. Poland, along with Bohemia, Moravia and Hungary, was an exporter of freshwater fish to Western Europe from the 16thto the mid-18th century.
文摘The Hula Valley was drained in 1957. The land use was modified from natural wetland and old shallow lake ecosystems to agricultural development. About half of the drained land area was utilized for aquaculture. Population size was enhanced and the diary was developed intensively resulting in the enhancement of domestic and husbandry sewage production that increased as well. The natural intact Hula Valley-Lake Kinneret ecosystem was heavily anthropogenically interrupted: The Hula was drained and Kinneret became a national source for domestic water supply. Some aspects of the environmental and water quality protection policy of the system are presented. The causation and operational management implications for the reduction of Nitrogen and Phosphorus migration from the Hula Valley are discussed. Drastic (81%) restriction of aquaculture accompanied by sewage totally removed achieved a reasonable improvement in pollution control which was also supported by the Hula Project. The implications of anthropogenic intervention in the process of environmental management design are presented.