莲藕面积对藕鳖共生田浮游植物群落结构的影响

为了确定藕鳖种养模式中莲藕的最适种植面积,采用生物多样性研究方法,开展4种莲藕种植面积百分比（A型-10%、B型-30%、C型-50%和D型-70%）藕鳖种养水体中浮游植物群落结构特征与多样性比较研究。研究结果表明,C型藻类48属75种,平均密度和频度分别为151442个/L和69.89%;以绿藻（小球藻、栅藻等）为绝对优势种类,绿藻种类平均数极明显高于A型、B型(>LSR_0.01),明显高于D型(>LSR_0.05);C型浮游植物Shannon-Wiener多样性指数H、Pielou均匀度指数E和Simpson优势度指数D均最高,平均值分别为2.188、0.949和0.841。因此,种植50%莲藕的C型水体中浮游植物群落复杂程度高,生物多样性高,水体更稳定。     

苏北不同地区藕虾种养模式浮游生物群落结构特征分析

藕虾种养是将莲藕种植和小龙虾养殖有机结合的一种生态种养模式,但小龙虾属于杂食性水产动物,因留塘虾的存在和养殖环境的不确定性,养殖户投料量难以精准确定。为改进藕虾种养策略并为藕虾种养参数提供理论依据,研究了苏北不同地区藕虾种养模式水体浮游生物群落结构特征。通过对泰州兴化、扬州宝应、淮安金湖、盐城盐都、徐州睢宁、宿迁中扬6个地区藕虾种养模式的水体理化指标和浮游生物种类与数量分析,并应用多样性指数法对养殖水体环境状况进行了生物学评价。扬州宝应地区共鉴定出浮游植物26属29种,平均密度和生物量分别为1.6×10⁶个/L和1.21 mg/L,绿藻门的密度最大。扬州宝应地区浮游植物Shannon-Wiener多样性指数、Simpson优势度指数和Pielou均匀度指数均高于其他5个地区,浮游生物群落结构及生物多样性复杂,水体环境状况更为稳定。苏北6个地区藕虾种养水体浮游生物群落结构存在一定差异,且扬州宝应地区的藕虾塘水体环境状况相对较好。     

河道拦网养鳖技术

1.河道拦网养鳖的好处河道拦网养鳖是利用河道流水良好的水体环境,通过人工拦围圈养鳖的新技术,其好处是不占用土地,无需水电成本,又因河道是野生环境,养出的鳖售价较高,具     

藕田套养小龙虾生态种养技术

<正>近几年,我们在藕田试验套养小龙虾复合种养模式,取得了显著的生态效益和经济效益。实践证明,充分利用种藕田块的水体空间套养小龙虾,藕田中的水草、生物饵料可作为小龙虾的天然饲料,既起到了为藕田生态除草的作用,又提高了藕田的利用率,小龙虾的排泄物还为藕田增加了有机肥料,实现了良性循环。现将这一实用技术介绍如下:一、藕田条件与田间工程建设1.藕田条件。选择地势低洼,保水性能好,光照充足,土壤pH值6~7,田地平坦的地块,每片藕田面积     

藕田养殖小龙虾增收技术要诀

<正>我国藕田资源丰富,但单纯种藕利用率不高,产出效益不明显。如果在藕田养殖小龙虾实行综合种养,就可以充分利用藕田的水体和生物资源,提高单位面积产出,实现比较理想的综合种养效益。但要想达到藕虾双丰收,必须掌握以下增收技术要诀:一、抓好藕田改造,确保满足种藕养虾环境需要藕田养虾,必须保证藕虾互利共生,和谐相处,这就对藕田选址、改造等工作提出了一定要求。     

中国稻鳖共作技术研究进展与展望

近年来,中国稻鳖共作技术发展迅速,国内学者对这一技术进行了大量的理论研究和应用实践。对于技术理论的研究,主要涉及稻鳖共作对稻田病虫草害的影响、对稻田土壤环境及微生物群落的影响、对水稻产量及稻米品质的影响,并取得了大量研究成果。从技术应用角度来说,不同地区的不同学者均开展了大量实践工作,明确了技术规范,部分地区形成了技术规程。部分学者还开展了“稻-鳖-鱼-鸭”“、稻-鳖-鱼”等进一步的创新工作。在总结现有研究的基础上,本研究在4个方面对该项研究进行了展望,分别是稻鳖共作关键技术的创新、对鳖品质质量的研究、专业化人才的培养、地区的标准化和产业化发展。     

莲藕田出现僵藕怎么办?

正僵藕是近年来藕莲主产区新出现的一种病态表现。发病率不断上升,发生程度日趋严重,已导致部分地区大幅度减产,甚至失收。连作4~6年以上的僵藕田,发病严重;而未种过莲藕的田块,发病很轻。用轻度僵化的藕作种,种植后会加快僵化程度,而用正常藕作种,一般不发生僵化现象。大量施用化肥,特别是碳酸氢铵、尿素等,造成藕田有机质含量逐年下降,理化性质变劣,莲藕僵化程度也逐年加重。1.发病症状地上、地下部分各器官均比正常植株明显小,藕身表皮出     

库湾网箱养鳖新技术

利用各种有效水体养殖特种名贵水产品,已成为我国农村致富奔小康的新途径,其中利用库湾网箱养鳖有以下优点：一是节省土地和水资源;二是生长快,一般养殖100天,能够增重500克以上;三是疾病少,除了放养初期较易感染真菌性疾病外,其他疾病基本不发生,鳖成活率可达97%以上;四是鳖的品质优,体色自然,售价可达到200元/千克以上,经济效益明显。现把库湾网箱养殖商品鳖的新技术介绍如下,供有条件的地区参考应用。     

藕田养殖商品河蟹关键技术

藕田养殖河蟹是利用同一块水田,既种植莲藕,又进行河蟹养殖的一种综合生产方式.它充分利用藕田的自然环境条件,同时又辅以人为措施,从而较好地实现了莲藕与河蟹的互利共生,提高了藕田的产出力和经济效益.藕田养殖河蟹是一种典型的生态渔业生产方式,具有较大的推广价值和发展前景.     

藕田生态混养黄鳝泥鳅

<正>江苏省滨海县莲藕种植户为提高藕田的综合效益,将黄蟮和泥鳅混养于藕田中,2012-2015年共推广黄鳝、泥鳅混养莲藕田面积达2200亩,平均每亩净产莲藕3000千克、黄鳝600千克、泥鳅500千克,平均每亩增收36 000元,取得了显著的生态效益、经济效益和社会效益。这种种养结合的生态农业模式,既增加了黄鳝、泥鳅的养殖收入,又改善了藕田的生态环境,使莲藕种植年限延长,病虫害减少,其产量、质量都有明显提高。     

分区池塘中浮游生物的分析研究

为了净化水质,改善底层鱼类的生长繁殖环境。本试验采用分区池塘的养殖模式,并对分区池塘与普通池塘中的浮游生物进行了比较研究。结果显示：关于浮游动物,就种类而言,1、2号池塘中的浮游动物有42种,隶属于4门;3、4号池塘中的浮游动物有43种,隶属于4门。4口池塘间没有明显的差异,均是原生动物和轮虫的种类数居多;其次是枝角类、桡足类最少;就密度和生物量而言,4口池塘差异显著,其中2号池塘（传统池塘）浮游动物的数量和生物量最多,3号池塘（分区池塘）浮游动物的数量和生物量最少。关于浮游植物,就种类数而言,4口池塘没有明显的区别,4口池塘中的浮游植物均有43种,隶属于7门。优势度排序为：绿藻门>硅藻门>蓝藻门>其他。其中,黄藻门、隐藻门、甲藻门、裸藻门占据的比例相当,均为2.0%;就其密度和生物量而言,4口池塘间存在显著性的差异,不同的采样日期内,均是2号池塘中的浮游植物的丰度和生物量最高,最低是3号池塘。结果表明：分区池塘中的浮游生物量明显小于传统池塘,比较适合于喜水质清瘦的鱼类养殖。     

Intercropping maize and wheat with conservation agriculture principles improves water harvesting and reduces carbon emissions in dry areas

In arid and populated areas or countries, water shortage and heavy carbon emissions are threatening agricultural sustainability with food security severely, and becoming a major issue. It is unclear whether improved farming systems can be developed to tackle those issues through a sustainable agriculture. Here three farming practices that have proven to be essential and successful, which were: (a) crop intensification through strip intercropping, (b) water harvesting through conservation tillage; and (c) carbon sequestration through improved crop residue management options, were integrated in one cropping system. We hypothesize that the integrated system allows the increase of crop yields with improved water use efficiency, while reducing carbon emissions from farming. The hypothesis was tested in field experiments at Hexi Corridor (37°96′N, 102°64′E) in northwest China. We found that the integrated system increased soil moisture (mm) by 7.4% before sowing, 10.3% during the wheat–maize co-growth period, 8.3% after wheat harvest, and 9.2% after maize harvest, compared to the conventional sole cropping systems. The wheat/maize intercrops increased net primary production by 68% and net ecosystem production by 72%; and when combined with straw mulching on the soil surface, it decreased carbon emissions by 16%, compared to the monoculture maize without mulch. The wheat/maize intercrops used more water but increased grain yields by 142% over the monoculture wheat and by 23% over the monoculture maize, thus, enhancing water use efficiency by an average of 26%. We conclude that integrating strip intercropping, conservation tillage as well as straw mulching in one cropping system can significantly boost crop yields, improve the use efficiency of the limited water resources in arid areas, while, lowering the carbon emissions from farming. The integrated system may be considered in the development of strategies for alleviating food security issues currently experienced in the environment-damaged and water-shortage areas.     

Stability of a nonlinear red tide dynamic model in a polluted environment

We develop a nonlinear red tide dynamic model to study the effect on a system of two harmful phytoplankton and zooplankton and of a toxicant emitted into the environment from external sources and a toxin excreted by phytoplankton. We use modern nonlinear dynamics to discuss stability and bifurcation, and obtain the thresholds of persistence and extinction for each species. Numerical simulations are used to validate the theoretical results. The results show that a sequence of Hopf bifurcations occur at the interior equilibrium as the delay increases or the growth rates increase.     

Phytoplankton Community Succession of Typical Surface Water in North China

To provide consultation for algae removal, an investigation on phytoplankton community in Yinluan raw water was conducted during February to October 2006.It was shown that there were 68 species of phytoplankton in Yinluan raw water, which belonged to 7 phylum and 43 genera.And the structure of the species and concentration of phytoplankton varied seasonally.Chlorophyta was dominant in spring and autumn with low phytoplankton concentration.in while summer, Microcystis flos aquae was dominant with high phytoplankton concentration, and Microcystis flos aquae's multiplying sharply lead Shannon index to decline.The correlation analysis indicated that water temperature was the key role in variation of phytoplankton community.     

嘉陵江合川段浮游生物及其与环境因子的关系

为了研究嘉陵江合川段浮游生物群落结构及其与环境因子的关系,2018年春季及夏季对该江段浮游生物和环境因子进行了调查分析。共鉴定出浮游植物6门87种,以硅藻门和绿藻门为主;浮游动物4类38种,以轮虫和枝角类为主;浮游植物密度为8.71×10⁴~98.95×10⁴ 个/L,浮游动物密度为23.9~417.4个/L,夏季浮游生物密度总体高于春季;根据地表水营养状态指数(TLI)分析显示,研究水域处于中-富营养状态,春季富营养程度高于夏季。温度、pH、叶绿素a均对浮游植物和浮游动物产生影响,COD_Mn仅对浮游植物产生影响,且呈显著相关(P<0.05)。     

鲥鯸淀秋季浮游植物群落与水环境相关性分析

为充分了解鲥鯸淀浮游植物群落结构及其与环境因子之间的关系,采用物种相似性指数、均匀度指数、多样性指数等指标分析2018年秋季鲥鯸淀浮游植物的群落结构特征。结果表明：鲥鯸淀检出绿藻(Chlorophyta)、硅藻(Bacillariophyta)、蓝藻(Cyanophyta)、裸藻(Euglenophyta)、隐藻(Cryptophyta)、甲藻(Pyrrophyta)6门99种,浮游植物的数量在3.68×10⁷~8.22×10⁷ cells/L,生物量在18.96~200.9 mg/L;各采样点相似性指数变化在0.26~0.52,介于轻度相似和中度相似,相似性较低;优势度分析显示值在0.07~0.31,该水域浮游植物优势度较低,种类较多;多样性和均匀度分析结果分别在4.05~4.82与0.7~0.85,表明该地区秋季浮游植物群落结构较稳定;水体综合营养状态指数值（TLI值）表明该地区处于轻度富营养与中度富营养状态之间,相关性分析结果显示以氮、磷为主的环境因子影响着浮游植物群落结构的变化。鲥鯸淀秋季水体呈中度富营养状态,浮游植物群落结构较稳定,氮、磷为主的营养元素对浮游植物群落结构的变化有较大的影响。     

Population Structure and Diversity of Plankton in the Wetland of Qilihai in Tianjin

The population structure and diversity of plankton in the wetland of Qilihai in Tianjin was investigated in May, July and September, 2012 by fi eld investigation and sampling examination. The results showed that there were 44 species of phytoplankton belonged to 6 phyla, including 11 species of Cyanophyta, 18 species of Chlorophyta, 8 species of Bacillariophyta, 4 species of Euglenophyta, 1 species of Pyrrophyta and 2 species of Cryptophyta. There were 13 genus and 22 species of zooplankton, among which 4 genus and 4 species belonged to Cladocera; 2 genus and 2 species belonged to Copepoda; 7 genus and 16 species belonged to Rotifera. The investigation results of density and biomass of plankton in May, July and September showed that the density and biomass of phytoplankton was shown as September>July>May, and that of zooplanktonic was shown as May>September>July. In addition, the diversity of phytoplankton and zooplanktonic were evaluated using Shannon-Wiener index, and the results demonstrated that the phytoplankton species were rich in May, July and September, while the zooplanktonic species were poor in May and general in July and September. There were explicit relationships between the diversity characteristics of plankton and nutrient pollution which caused water eutrophication, and the extent of water eutrophication in the different months was also shown as May>July>September.     

Utilisation of rural wastes for algal biomass production with Scenedesmus Acutus and Spirulina Platensis in India

A technology for the production of the green alga, Scenedesmus acutus, and blue-green alga, Spirulina platensis, in clean water has been developed at our Institute to suit Indian conditions. Experience gained on algal production technology in India indicates the scope for applying this at the rural level for use in the production of animal feed. Spirulina is the most promising alga in view of its amenability to low level technology. Nutrient input to the cultures is one of the expensive steps. It is shown that agricultural and domestic wastes can be effectively recycled for algal biomass production by replacing, at least partly, the nutrient inputs. Urine and bonemeal reduce the inputs of nitrate, calcium and phosphate salts into the culture medium. Sheep's blood has a growth promoting effect on algal cultures and a good potential for application. Carbon dioxide enriched air—‘aerobic biogas’—produced by composting cow dung, can be used as a carbon source for algal cultivation. Several experiments carried out in India indicate the possibility of developing an integrated algal production system in rural areas by means of which wastes can be effectively recycled. The use of algae in poultry and fish feeds is a distinct possibility for the future.     

Modelling the dynamics of the North Sea's Mesozooplankton

A simple biomass-only zooplankton submodel is presented, describing the dynamics of copepods and carnivorous zooplankton in the North Sea. This submodel together with the other process-oriented submodels (viz. phytoplankton dynamics, the microbial food web, benthic processes, fish dynamics and large-scale advective transport) forms a spatially resolved simulation model of the North Sea ecosystem, the European Regional Seas Ecosystem Model (ERSEM). A large set of field measurements of zooplankton abundance has been assembled against which to compare the ERSEM's performance. These data are not only internally consistent, but have also gathered at the large spatial scales appropriate to the ERSEM. In addition to the spatially resolved, monthly estimates of zooplankton abundance, several instantaneous, in situ estimates of the carbon fluxes between different components of the planktonic web in the northern North Sea are presented. Simulated dynamics are in good agreement with the data only during the mid-summer to mid-winter period. During the latter part of the winter and throughout the spring period zooplankton abundance is underpredicted and the simulated zooplankton growth rate is overpredicted during spring. The excessive decline of mesozooplankton biomass during winter may be caused by failing to capture many of the behavioural/physiological changes which zooplankton manifest during winter. It is suggested that the excessive spring growth is a consequence of a. a failure to properly distinguish between somatic and population growth, b. an inadequate representation of the small scale processes which influence feeding success, and c. an excessive spring phytoplankton bloom. The large phytoplankton bloom is, in part at least, a consequence of the excessively low simulated standing crop of omnivorous zooplankton in spring.