微绿球藻的研究进展   总被引：1，自引：0，他引：1  

余颖  陈必链 《海洋通报》2005,24(6):75-81

微绿球藻富含EPA,被认为是一种很有潜力的EPA来源,引起人们广泛的研究兴趣.本文介绍了国内外近年来微绿球藻生长条件及脂肪酸积累调控、生理学特性、规模培养、藻种诱变及作为饵料的应用等方面的研究进展.微绿球藻喜强光,适温范围较广,对pH适应性较强.营养盐、植物生长调节剂、消毒剂、敌草隆和UV等均对藻的生长和EPA合成有影响.微绿球藻的一系列色素如叶绿素a、玉米黄质、角黄素和虾青素等都有较高的含量,可作为商业上的色素来源.采用室内及室外平板式光生物反应器、垂直式平板生物反应器等规模培养微绿球藻获得成功.  相似文献   

Decomposition of Phytoplankton in Seawater. Part I: Kinetic Analysis of the Effect of Organic Matter Concentration     

Minoru Fujii  Shinichiro Murashige  Yuka Ohnishi  Atushi Yuzawa  Hitoshi Miyasaka  Yoshimi Suzuki  Hiroshi Komiyama 《Journal of Oceanography》2002,58(3):438-443

Decomposition experiments were conducted on cultured phytoplankton (Skeletonema costatum) in seawater containing decomposer and consumer of size less than 500 μm. We determined the decomposition rates of bulk particulate organic matter (POM), the ratio of labile to semi-refractory fractions in the POM, and the POM carbon/ nitrogen (C/N) ratio during decomposition. To identify the kinetic mechanisms involved in the reactions of different order (e.g., first- and second-order), we studied the sensitivity of reaction rates to the initial concentration of POM, ranging from 2.4 to 71 mg-C L⁻¹. The results showed that decomposition consists of two first-order reactions: decomposition of labile and of semi-refractory particulate organic carbon (POC). The decomposition rate constants found for labile (0.13 day⁻¹ at 20°C), and semi-refractory POC (0.008 day⁻¹ at 20°C), and the carbon weight ratio of semi-refractory POC (13% at 20°C), were insensitive to the initial organic matter concentration. The time-dependence of the C/N ratio was also independent of this initial concentration. The decomposition rate constants and the content of semi-refractory POC did not change, regardless of the absence or presence of 25–500 μm organisms in natural seawater. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

花鲈亲鱼人工培育与催产技术研究   总被引：1，自引：0，他引：1  

张美昭  高天翔  阮树会  庄虔增  曲永琪 《中国海洋大学学报(自然科学版)》2001,31(2):195-200

作者研究了花鲈人工培育及促熟催产中的技术措施。采用海捕的天然苗种 ,逐年筛选、精心培育 ,共获得 4～ 6龄的成熟亲鱼 50尾。在外源激素 HCG(70 0～ 150 0 IU/ kg)及 LHRH- A3(2～5μg/ kg)的作用下 (雄鱼减半 ) ,共人工采卵 156 0× 10 4粒 ,卵的平均上浮率为 6 1% ,平均受精率为78% ,平均孵化率为 85.7%。  相似文献   

方斑东风螺人工育苗试验   总被引：9，自引：0，他引：9  

梁飞龙  毛勇  余祥勇  刘洪军 《海洋湖沼通报》2005,(1):79-85

2003年3月31日至8月31日，在水温25．0～30．0℃，盐度28．3～35．1，pH8．1～8．5时，在广东省湛江雷州市进行了方斑东风螺人工育苗试验，培育出壳高6～10mm幼螺300多万只。结果表明。投喂新鲜海鱼、蟹类、虾类，短时间阴干、流水刺激或流水培育可以诱导方斑东风螺亲螺交配产卵；幼虫培育密度以2．0～2．5万个／m^3为宜，幼虫培育期间投喂多种天然混合饵料，可以提高幼虫成活率，缩短幼虫浮游时间，提前变态；及时投放附着砂，有利于幼虫顺利变态；壳高5～10mm幼螺培育密度保持在1500个／m^2左右，每10～15d清洗一次附着砂，可加速幼螺的生长，提高幼螺成活率，有效防止病害的发生。  相似文献   

池塘主养团头鲂鱼种高产技术试验     

栾伯荣  乔福洲 《海洋湖沼通报》1994,(3):60-68

试验了主养团头鲂的合理放养密度；配养品种的最佳选择及放养比数；优质配合颗粒饲料；驯化投饵；水质调控等高产技术。试验结果：１９．５９亩水面，总净产鱼种１３１３０．０ｋｇ，平均亩净产鱼种６７０．０４ｋｇ，其中团头鲂亩净产３９７．５０ｋｇ，平均尾重３３．９７克，亩纯收入３３５０．６６元，投入产出比为１：２．３３。  相似文献   

济南西部地区不同类型污染源作用下土壤各类元素含量特征及选择性种植浅析          下载免费PDF全文

于晓静  成世才  白新飞 《山东国土资源》2016,32(11)

通过分析研究区不同类型污染源条件下各类土壤元素含量的顺序,认为重金属在各类污染源土壤剖面中含量的顺序主要为:垃圾堆放污染类污水排放污染类禽畜粪便污染类;水溶性相对较强的K+,Mg2+,Na+,Cl-,SO2-4等离子,受污水排放类污染的影响明显,含量顺序为:污水排放污染类禽畜粪便污染类垃圾堆放污染类;NO-3在土壤中含量的顺序为:禽畜粪便污染类污水排放污染类垃圾堆放污染类;土壤主要常量养分在土壤中含量的顺序为:污水排放污染类垃圾堆放污染类禽畜粪便污染类。选择性种植的观点认为,在土壤肥力充足但重金属元素富集的土地,选择对该重金属元素富集较少的蔬菜(瓜果)进行种植,一方面充分利用了土壤肥力,另一方面较好地规避了重金属对作物的污染。  相似文献   

Assessing the sustainability factors of traditional olive groves on Lesvos Island,Greece (Sustainability and traditional cultivation)     

Christina Giourga  Angeliki Loumou  Iris Tsevreni  Assimina Vergou 《GeoJournal》2008,73(2):149-159

In Europe the process of agricultural engagement or disengagement is attributed to the economic factor and mainly on the level of alternative employment source development. It is the relational quality of economic, social and environmental factors that determine sustainability of agricultural holdings and, hence, households. In regions of poor agricultural structures and of many employment opportunities as well as in regions suffering from agricultural depression, households exhibit stronger tendencies towards agricultural disengagement. Remarkably in southern Europe a stable agricultural engagement and not disengagement is observed, even though in recent years there are limited possibilities of alternative income sources and prevailing agricultural depression. This article highlights the factors which lead households to stable engagement with agriculture in a region of southern Europe, the island of Lesvos. The island is characterised by traditional olive grove mono-culture, poor agricultural structures and limited employment opportunities. The investigation of the economic, social and environmental farm household characteristics concluded that in regions where poor agricultural infrastructure and lack of employment prevail, all three factors of sustainability contribute to stability and/or low agricultural disengagement. Among these, the economic factor is the most sensitive and hence highly influential. The social factor is highlighted as a quality and consistent factor due to the respect for tradition. The environmental factor, finally, is characterised by mild cultivation practices, contributing to environment conservation.  相似文献   

Impacts of – and farmers’ adaptation to – land allocation policies in the north central uplands of Vietnam     

Rikke Folving Ginzburg  Thomas Theis Nielsen 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2018,118(1):36-55

A series of policies on land tenure have been implemented in Vietnam following the doi moi restructuring. This study assesses the impacts of these policies, the extent to which they have had intended effects and coping strategies adopted by farmers. Data were collected in five upland villages in Nghe An Province, North Central Vietnam. The intended effects of the land allocation policies were poverty alleviation, intensification of agriculture, agricultural modernization and forest protection. The policies implemented to achieve these goals include changes in land allocation, purportedly to increase land tenure security. However, the policies have been implemented in a very uneven manner and the effects differ widely due to differences in the local contexts in which they have been implemented. In general, farmers perceive the impacts of policies as adverse and have attempted to cope with their impact in a variety of ways. The paper argues that land allocation policies have: (1) decreased the amount of land available, (2) not improved land tenure security and (3) had a limited impact on farming practices. The differences between the five villages are great, demonstrating the very different results produced by national policies depending on the specific implementation modality and the local context.  相似文献   

浅议测绘新职工入职培训     

刘博  张波 《测绘与空间地理信息》2016,(3):220-221

日益激烈的国际竞争,归根到底是人才的竞争。测绘地理信息作为战略性新兴产业在国防安全、基础测绘、应急保障中的作用日益提升,大量的毕业生作为新的血液为测绘事业增添了新的活力。如何做好新职工入职培训,是搭建人才培养梯队,优化人才成长环境,是快速成才的关键。本文通过系统分析新职工入职培训现状,提出了面向用人单位-培训人员-新职工的三层入职培训模型,以健康成长、快速成才为目的,构建了多层次入职培训模型,优化了人才培养模式,应对地理信息应用对人才需求的挑战。  相似文献   

The erodibility of upland soils and the design of preafforestation drainage networks in the United Kingdom     

Paul A. Carling  Mark S. Glaister  Tim P. Flintham 《水文研究》1997,11(15):1963-1980

Hydraulic thresholds for erosion of fourteen upland mineral and organic soils were determined in a hydraulic flume. These soils are from areas to be afforested in the United Kingdom. Some of the group are erosion resistant but others are susceptible to erosion once denuded of vegetation; for example, by preafforestation ploughing. These threshold data were required to calibrate a hydraulic model for effective design of preafforestation drainage networks on a variety of soils. However, simple field measures of soil properties indicative of erosion potential would be of value to the forestry industry for management purposes. Consequently, hydraulic threshold data were related by linear regression methods to basic soil properties, including organic content, grain size, bulk density, compression strength and penetration resistance. The investigation concluded that four peat soils are not eroded by clear water velocities up to 5·7 m s⁻¹, although a mineral bedload might induce erosion at lesser current speeds. Penetration resistance is a good field indicator of the degree of humification of the peat soils. Although selected physical parameters contribute resistance to water erosion, an increased organic content is pre-eminent in reducing erosion susceptibility in both organic and mineral soils. Although compressive strength was not indicative of soil erodibility, field measurements of penetration resistance on a variety of soils could be related to hydraulic thresholds of erosion; albeit through the construction of discriminant functions interpolated by eye. Consequently, organic content (laboratory) or penetration resistance (field) might form the basis of classifying upland soils in terms of erodibility. Mineral soils differ widely in terms of their erodibility, so that subject to further consideration, the use of ploughing for forestry cultivation might be appropriate in wider circumstances than presently recommended by the Forests and Water Guidelines. Ploughing should be acceptable on deep peat providing the underlying mineral soil is not exposed in the bottom of the furrow, and furrows are not led from mineral soils on to deep peat. © 1997 John Wiley & Sons, Ltd.  相似文献