半潜式波浪能养殖平台与系泊系统的耦合动力分析

以“澎湖号”半潜式波浪能养殖平台为研究对象,开展养殖平台及其系泊系统在浪、流联合作用下水动力性能的研究。基于三维势流理论,应用一阶泰勒展开边界元方法对其频域水动力进行计算,研究不同浪向下平台的运动响应和二阶波浪漂移力。采用间接时域分析方法和异步耦合方法实现平台和系泊系统的时域耦合动力求解,对不同浪流组合工况下平台的时域运动与锚链张力进行分析。研究表明,在南海常规海况中平台稳定性较好,立柱间水动力干扰尤为明显,顺浪时平台所受的二阶波浪漂移力最小。在与系泊系统的耦合作用下,平台的横摇与纵摇运动受入射波浪向的影响较大,入射波波高对顺浪下的平台横摇运动和横浪与斜浪下平台纵摇运动影响明显。     

Establishment of a real-time PCR method for quantification of geosmin-producing Streptomyces spp. in recirculating aquaculture systems

Geosmin and 2-methylisoborneol (MIB) have been associated with off-flavour problems in fish and seafood products, generating a strong negative impact for aquaculture industries. Although most of the producers of geosmin and MIB have been identified as Streptomyces species or cyanobacteria, Streptomyces spp. are thought to be responsible for the synthesis of these compounds in indoor recirculating aquaculture systems (RAS). The detection of genes involved in the synthesis of geosmin and MIB can be a relevant indicator of the beginning of off-flavour events in RAS. Here, we report a real-time polymerase chain reaction (qPCR) protocol targeting geoA sequences that encode a germacradienol synthase involved in geosmin synthesis. New geoA-related sequences were retrieved from eleven geosmin-producing Actinomycete strains, among them two Streptomyces strains isolated from two RAS. Combined with geoA-related sequences available in gene databases, we designed primers and standards suitable for qPCR assays targeting mainly Streptomyces geoA. Using our qPCR protocol, we succeeded in measuring the level of geoA copies in sand filter and biofilters in two RAS. This study is the first to apply qPCR assays to detect and quantify the geosmin synthesis gene (geoA) in RAS. Quantification of geoA in RAS could permit the monitoring of the level of geosmin producers prior to the occurrence of geosmin production. This information will be most valuable for fish producers to manage further development of off-flavour events.     

边坡人工湿地/水生植物塘集成技术处理水产养殖排水

针对上海松江五厍农业园区水产养殖污染问题,提出以边坡人工湿地/水生植物塘集成技术进行处理。集成技术示范工程的实际运行结果表明:该技术对水产养殖污染物的削减行之有效,每年COD、TN、TP的减排强度分别达到896、35.21、0.9 kg/hm2,初步解决了园区水产养殖排水污染问题。同时,水生植物塘中生长的浮萍可以用作水产养殖饲料,符合现代水产养殖的发展趋势。     

Modeling impact of culture facilities on hydrodynamics and solute transport in marine aquaculture waters of North Yellow Sea

An increasing number of marine aquaculture facilities have been placed in shallow bays and open sea, which might significantly affect hydrodynamic and solute transport processes in marine aquaculture waters. In this study, a coupled hydrodynamic and solute transport model was developed with high-resolution schemes in marine aquaculture waters based on depth-averaged shallow water equations. A new expression of drag force was incorporated into the momentum equations to express the resistance of suspended culture cages. The coupled model was used to simulate the effect of suspended structures on tidal currents and the movement of a contaminant cloud in the marine aquaculture of the North Yellow Sea, China. The simulation results showed a low-velocity area appearing inside the aquaculture cage area, with a maximum reduction rate of velocity close to 45% under high-density culture. The results also showed that tidal currents were sensitive to the density of suspended cages, the length of cages, and the drag coefficients of cages. The transport processes of pollutants inside aquaculture facilities were inhibited away from the vicinity of the culture cage area because of the diminished tidal currents. Therefore, the suspended cages significantly affected the transport processes of pollutants in the coastal aquaculture waters. Furthermore, the reduced horizontal velocity significantly decreased the food supply for the aquaculture areas from the surrounding sea.     

长湖纳污能力及水产养殖污染负荷估算

以CODMn、NH3-N、TN、TP作为污染指标,采用湖库均匀混合模型、狄龙模型和合田健模型对长湖纳污能力进行计算,并针对目前长湖水产养殖污染较重的特点,采用排污系数法、污染负荷率法对长湖水产养殖污染负荷进行估算。结果表明:长湖CODMn、NH3-N、TN、TP的纳污能力分别为8 523.15 t/a、1 495.57 t/a、1 932.70 t/a、96.64 t/a,长湖水产养殖所产生的COD、NH3-N、TN、TP污染负荷量分别为3 724.10 t/a、51.98 t/a、279.96 t/a、26.42 t/a。水产养殖对于长湖COD、TP的污染贡献较大是导致长湖有机污染和富营养化的一个重要污染源。     

Methylmercury Concentrations Found in Wild and Farm-raised Paddlefish

ABSTRACT: Paddlefish ( Polyodon spathula ) were collected from 4 sites in Kentucky: the Ohio River, Lake Cumberland, and 2 aquaculture sources (private reservoir and catfish ponds). They were tested for methylmer-cury concentrations in their flesh. Paddlefish from all sources had methylmercury levels below the 1 part per million Food and Drug Administration-mandated action limit for seafood. However, using the U.S. Environmental Protection Agency reference dose for methylmercury, only paddlefish from the Ohio River exceeded the reference dose for unrestricted consumption. Some Ohio River and Lake Cumberland paddlefish had higher-than-average methylmercury concentrations, whereas aquacultured paddlefish had low concentrations of methylm-ercury. There was a direct proportionality between fish age and methylmercury concentration; older paddlefish tended to have higher amounts of methylmercury in their meat.     

Fatty acid composition of the total, neutral and phospholipids of pond-raised Brazilian Piaractus mesopotamicus

Seven sample lots of farmed Piaractus mesopotamicus , fed a set diet, collected at different times during the year were analysed. The total lipids (11 ± 3% fresh weight, muscle) consisted of 94% neutral lipids and 5% phospholipids. Sixty-seven fatty acids and dimethylacetals were detected in the total lipids, the principal acids being 18:1ω9±ω7 (41.0 ± 1.7%), 16:0 (24.2 ± 1.2%), 18.2ω6 (9.1 ω 0.5%), 16:1ω7 (8.9 ± 0.7%), 18:0 (7.7 ± 0.5%) and 14:0 (3.2 ± 0.5%). The neutral lipids exhibited a similar profile. The phospholipids had a higher proportion of polyunsaturated fatty acids, the major components being 18:1ω6 (9.1 ± 0.7%) (17.5 ± 1.8%), 16:0 (16.7 ± 2.0%), 20:4ω6 (11.6 ± 1.3%), 22:6ω3 (11.0 ± 1.3%), 18:2ω6 (9.1 ± 0.7%), 18:0 (8.9 ± 1.1%), 22:5ω (5.8 ± 0.7%). No definite trend was seen in relation to season (water temperature, 7–26°C). The fish samples analysed were poor in ω3 fatty acids, which appeared to reflect the low ω3 fatty acid content of the diet.     

基于EtherNet和Profibus现场总线水产养殖环境控制系统

根据水产养殖的特点,提出了EtherNet和Profibus-DP现场总线技术相结合的水产养殖环境自动化控制系统。介绍了基于工业以太网和Profibus总线通信协议的自动化系统的组成方式和系统配置方案。通过对水产养殖过程溶解氧自动控制领域现状的分析,提出了通过模糊PID控制算法控制养殖池塘的溶解氧含量。系统实际运行表明,方案合理可行,提高了养殖池塘的经济效益。     

对虾养殖水体氨氧化菌的多样性分析与硝化作用的特征

为了研究珠三角地区不同空间分布的对虾养殖水体中氨氧化菌多样性的异同与探究养殖水体中氨氧化菌的硝化作用特征,应用PCR-DGGE技术,结合非加权算术平均法(UPGMA)聚类分析和多维尺度分析(MDS)的方法,对珠三角地区7个对虾养殖场的水样中氨氧化菌的多样性进行对比分析,继而构建了模拟养殖生态系统,评估了系统中微生物的硝化能力和硝化作用特征。结果表明:在养殖水体中,氨氧化古菌的类别明显少于氨氧化细菌,各样品间相似性较低,为41%到80%,没有高相似性的聚类;模拟系统中存在连续完整的亚硝化与硝化作用。     

不同填料强化生态浮床对淡水养殖水体的净化效果

人工填料强化生态浮床是近年来发展起来的一种新兴生态工程修复技术。选取3种不同类型的人工填料与挺水植物组合,分析其对高磷浓度养殖水体和上海市养殖池塘水体的净化效果。结果表明,在高磷浓度(2.36~3.42 mg/L)养殖水体中,人工填料强化生态浮床对TN、TP、COD的平均去除率分别为34.9%,12.2%,26.1%,且3组系统之间差异不明显。在上海市养殖水体平均浓度条件下,3组系统对TN和TP的去除能力为:立体弹性填料强化生态浮床＞组合填料强化生态浮床＞生物绳填料强化生态浮床,立体弹性填料强化生态浮床对TN和TP的去除率分别为83.9%和69.3%;3组系统对COD和NH₄⁺-N的去除率均在70%以上。因此,立体弹性填料强化生态浮床可以考虑应用于上海市淡水养殖池塘水体的生态修复工程。