室内工厂化养殖犬齿牙鲆的生长特性     

李秉钧  王波  张桂军 《海洋水产研究》2007,28(5):30-35

对室内工厂化养殖的犬齿牙鲆生长特性进行了研究。结果表明,其生长旺盛期在2龄,日生长最快达5.52g/d,第1年平均为1.65g/d,第2年平均为2.34g/d,第3年平均为1.3g/d,第4年平均为0.75g/d。养殖1周年其平均体重可达600g左右,两周年达1500g;其全长和体重的关系为W=0.0076TL3.1785(R2=0.9765),全长与体高和标准体长的关系分别为TL=2.5685BD-0.6594(R2=0.9823),TL=1.1957SL-0.1724(R2=0.9922)  相似文献   

3种工业废水对牙鲆胚胎的毒性效应   总被引：4，自引：1，他引：4       下载免费PDF全文

曲克明  陈民山  马绍赛  辛福言 《中国水产科学》2003,10(2):155-159

通过室内实验，研究了印染废水、电镀废水、农药废水3种工业废水及其混合物(等体积混合)对牙鲆胚胎的毒性效应。印染废水的主要有毒物为苯胺(20mg/L)和苯酚(24mg/L)，电镀废水主要有毒物为锌(1970mg/L)、铜(9mg/L)和铅(7．5mg/L)；农药废水及混合物主要有毒物为久效磷和亚磷酸盐。实验表明，这4种类型废水对牙鲆胚胎发育孵化有显著影响的最低体积分数分别为0．5％、0．15％、0．25％和0．25％；对牙Gf胚胎起始半数致死浓度(95％可信限，体积分数)分别为3．38％(2．29％—3．87％)、0．81％(0．71％—0．92％)、1．57％(1．37％—1．82％)和1．48％(1．24％—1，76％)。以牙鲆胚胎起始半数致死浓度(体积分数)为指标，这几种工业废水的毒性顺序为电镀废水＞农药废水＞印染废水。  相似文献   

浅析北京园博会园中园设计--以岭南园、江苏园、北京园为例     

周泱 《广东园林》2014,(1):46-49

文章介绍了北京园博会的总体情况,并图文并茂地分析北京园博会三个主要的园中园--岭南园、江苏园、北京园的空间布局、地域特色、设计亮点与不足。通过总结这三个园中园的异同,进一步探讨了北京园博会园中园的设计特色与不足。  相似文献   

Outdoor phytoplankton continuous culture in a marine fish–phytoplankton–bivalve integrated system: combined effects of dilution rate and ambient conditions on growth rate, biomass and nutrient cycling     

Sbastien Lefebvre  Ian Probert  Christel Lefranois  Jrme Hussenot 《Aquaculture (Amsterdam, Netherlands)》2004,240(1-4):211-231

Natural phytoplankton populations were cultured in outdoor continuous cultures using fish-farm effluents as the source of nutrients. The dilution rate was assumed to be the integrating factor of phytoplankton growth and biomass development (flux and stock). In this context, the combined effects of (i) dilution rates of the outdoor culture and (ii) ambient conditions were tested on phytoplankton growth, biomass and cycling of the major nutrient elements (C, N and P). Experiments were carried out in outdoor polyester tanks (0.7 m deep), homogenised by gentle aeration. Si/P ratio was balanced at around 5 in the inflow in order to induce diatom domination while maintaining high N and P assimilation by phytoplankton. Nutrient cycling was assessed through analyses of the different forms of particulate and dissolved nutrients in the inflow and the outflow. Culture dilution rates determined the longevity of the culture and the assimilation efficiency of nutrients. Dissolved phosphorus was the most limiting nutrient. The optimal dilution rate was approximately 0.5 day⁻¹ at 10 °C and 1.5 day⁻¹ at 20 °C with a mean diatom biomass of 9 μM P. Under these conditions, 80% of the dissolved nutrients provided to the tanks were transformed, a production of 8 g C m⁻² day⁻¹ and an assimilation rate of 0.3 g P m⁻² day⁻¹ were recorded. Assimilation by diatoms was the major pathway of nutrient cycling. During the experiment, a bottom sediment developed progressively and this also played an important role in denitrifying the excess dissolved nitrogen in the fish-farm effluent. However, the results showed that diatom biomass can collapse and we hypothesize that this was the consequence of an increase in cellular sinking rates due to cell aggregation under nutrient or light stress. Modelling approaches are needed in future research in order to determine optimal dilution rates taking into account phytoplankton growth rates, nutrient inputs and ambient conditions (e.g. light and temperature).  相似文献   

Treatment of shrimp farm effluent with omnivorous finfish and artificial substrates   总被引：1，自引：0，他引：1  

Dirk Erler  Peter Pollard  Peter Duncan  & Wayne Knibb 《Aquaculture Research》2004,35(9):816-827

Long‐term environmental sustainability and community acceptance of the shrimp farming industry in Australia requires on‐going development of efficient cost‐effective effluent treatment options. In this study, we aimed to evaluate the effectiveness of a shrimp farm treatment system containing finfish and vertical artificial substrates (VAS). This was achieved by (1) quantifying the individual and collective effects of grey mullet (Mugil cephalus L.) and VASs on water and sediment quality, and (2) comparing the retention of N in treatment systems with and without the presence of finfish (M. cephalus and the siganid Siganus nebulosus (Quoy & Gaimard)), where light was selectively removed. Artificial substrates were found to significantly improve the settlement of particulate material, regardless of the presence of finfish. Mullet actively resuspended settled solids and reduced the production of nitrate when artificial substrates were absent. However, appreciable nitrification was observed when mullet were present together with artificial substrates. The total quantity of N retained by the mullet was found to be 1.8– 2.4% of the incoming pond effluent N. It was estimated that only 21% of the pond effluent N was available for mullet consumption. When S. nebulosus was added, total finfish N retention increased from 1.8% to 3.9%, N retention by mullet also improved (78±16 to 132±21‐mg N day^?1 before and after siganid addition respectively). Presence of filamentous macroalgae (Enteromorpha spp.) was found to improve the removal of N from pond effluent relative to treatments where light was excluded. Denitrification was also a significant sink for N (up to 24% N removed). Despite the absence of algal productivity and greater availability of nitrate, denitrification was not higher in treatments where light was excluded. Mullet were found to have no effect on the rates of denitrification but significantly reduced macroalgal growth on the surface of the water. When mullet were absent, excessive macroalgal growth led to reduced dissolved oxygen concentrations and nitrification. This study concludes that the culture of mullet alone in shrimp farm effluent treatment systems does not result in significant retention of N but can contribute to the control of macroalgal biomass. To improve N retention and removal, further work should focus on polyculturing a range of species and also on improving denitrification.  相似文献   

The efficiency and condition of oysters and macroalgae used as biological filters of shrimp pond effluent   总被引：3，自引：0，他引：3  

A B Jones  N P Preston  & W C Dennison 《Aquaculture Research》2002,33(1):1-19

Current shrimp pond management practices generally result in elevated concentrations of nutrients, suspended solids, bacteria and phytoplankton compared with the influent water. Concerns about adverse environmental impacts caused by discharging pond effluent directly into adjacent waterways have prompted the search for cost‐effective methods of effluent treatment. One potential method of effluent treatment is the use of ponds or raceways stocked with plants or animals that act as natural biofilters by removing waste nutrients. In addition to improving effluent water quality prior to discharge, the use of natural biofilters provides a method for capturing otherwise wasted nutrients. This study examined the potential of the native oyster, Saccostrea commercialis (Iredale and Roughley) and macroalgae, Gracilaria edulis (Gmelin) Silva to improve effluent water quality from a commercial Penaeus japonicus (Bate) shrimp farm. A system of raceways was constructed to permit recirculation of the effluent through the oysters to maximize the filtration of bacteria, phytoplankton and total suspended solids. A series of experiments was conducted to test the ability of oysters and macroalgae to improve effluent water quality in a flow‐through system compared with a recirculating system. In the flow‐through system, oysters reduced the concentration of bacteria to 35% of the initial concentration, chlorophyll a to 39%, total particulates (2.28–35.2 µm) to 29%, total nitrogen to 66% and total phosphorus to 56%. Under the recirculating flow regime, the ability of the oysters to improve water quality was significantly enhanced. After four circuits, total bacterial numbers were reduced to 12%, chlorophyll a to 4%, and total suspended solids to 16%. Efforts to increase biofiltration by adding additional layers of oyster trays and macroalgae‐filled mesh bags resulted in fouling of the lower layers causing the death of oysters and senescence of macroalgae. Supplementary laboratory experiments were designed to examine the effects of high effluent concentrations of suspended particulates on the growth and condition of oysters and macroalgae. The results demonstrated that high concentrations of particulates inhibited growth and reduced the condition of oysters and macroalgae. Allowing the effluent to settle before biofiltration improved growth and reduced signs of stress in the oysters and macroalgae. A settling time of 6 h reduced particulates to a level that prevented fouling of the oysters and macroalgae.  相似文献   

海水工厂化养鱼水处理系统工程的研究——工艺流程、综合气浮、接触氧化池   总被引：6，自引：1，他引：6  

宋德敬  薛正锐  陈庆生  王秉心 《海洋水产研究》2002,23(2):49-52

对海水工厂化养殖牙鲆、大菱鲆的循环水处理系统工程进行了研究，对循环水系统各环节的设备性能及水质指标进行了测试和研究，确定了工艺流程及系统设施设备，对水处理系统各单元分别进行了设计计算。为我国海水工厂化养殖走向产业化打下了良好的基础。  相似文献   

城市工业用地性质变更过程的土壤环境影响预评价     

朱小曼  黄晔  毕爱民  展漫军 《安徽农学通报》2014,(19):52-54

城市化进程的加快,推动了城市规划及产业布局的调整,原有工业用地性质变更的地块越来越多,因土壤污染原因造成规划项目选址矛盾的问题日渐显现。为避免招拍挂取得的土地无法直接开发利用,防止矛盾纠纷及经济损失,维护各方权益,应在土地出让前进行土壤环境影响预评价。该文在分析城市工业用地土壤污染成因的基础上,选择南京某关停企业原址用地,对其土壤进行采样与污染因子的监测。根据监测结果评价地块再次开发利用的可行性,说明土地出让前进行土壤环境预评价的作用。  相似文献   

工业等级烟叶质量的主成分分析和聚类分析评价     

王玉胜  扈强  梁荣  左安建  李旭华  金保锋  叶为民 《安徽农业科学》2014,(27):9518-9519,9543

[目的]对不同工业等级的烟叶进行初步质量评价.[方法]选取总糖、施木克值、糖碱比、香气量、香气质、杂气、刺激性、成熟度、身份、油分10个烟叶质量指标,以SPSS软件为工具,运用主成分分析法和Q型聚类分析对韶关市始兴县14个不同工业等级标准的烟叶质量进行评价.[结果]分析表明,按累积贡献率≥85％的标准,筛选出化学成分因子、感官质量因子、烟气成分因子共3个主成分,其对变异的累积贡献率达95.04％.不同等级的烤烟烟叶的综合评价得分差异明显,其中MO1、CF1、MF23个等级烟叶质量得分高于其他等级烟叶,而XO2、XF2、XO3 3个等级烟叶质量得分则低于其他等级烟叶.聚类分析结果表明,14个不同等级样品分为3类,其中第1类有CF2、MO2、CO1、MO3、MF2、MF3、CO2、ML2;第2类有MO1、MF1、CF1,第3类有XF2、XO3、XF3.[结论]研究可为工业等级烟叶质量评价提供参考.  相似文献   

从缺口理论看流域补偿     

袁舟航  吴迪  罗凌  姜雪梅 《山东林业科技》2014,(2):25-27

两缺口模型是20世纪60年代由美国经济学家H·B钱纳里等提出的,用以分析发展中国家投资大于储蓄和进口大于出口的一种经济模型。通过从产业结构的角度对流域补偿进行分析,可以找到流域补偿侧重。欠发达地区对发达地区进行提供生态服务,发达地区对欠发达地区提发展机会,资本的合理流动与利用可以取得"两缺口"模式的优势,取得良好的社会经济效益。  相似文献