省级农村经济区划研究--以河南省为例

文章在探讨农村经济区划理论的基础上制定了区划原则体系,将河南全省划为7个农村经济区域,并根据各区的资源条件和现状特点,对其发展方向和重点进行了简单评述,从而为分区指导和发展河南的农村经济提供了可靠依据.     

虾池生态系能流结构分析

阐述虾池生态系的能流结构,将虾池生态系分为两个亚系统：浮游亚系统与底栖亚系统,在浮游亚系统中有３个功能群,底栖亚系统中有５个功能群。系统的能量来源为人工投饵和太阳光。研究分析两个亚系统中各个生物状态变量的公式表达及其在系统中的功能,阐明了能量在系统中的流动方向和公式表达。浮游亚系统与底栖亚系统通过ＰＯＣ的沉降过程以及营养盐在沉积物中的生物地化循环再生后,经由水／底界面进入水体而耦合。     

Analysis of primary production in the Seto Inland Sea, Japan, using a simple ecosystem model

A simple model of lower trophic level ecosystem has been created to analyze possible environmental control of primary production in eight sub-areas of the Seto Inland Sea. The primary production rates observed by Hashimotoet al. (1997a) in these sub-areas are well reproduced by the model, including horizontal processes such as horizontal transport of nutrients and vertical processes such as vertical mixing, light intensity and sinking of particulate matter. Without taking account of horizontal processes the model also successfully reproduces the observed primary production rates in some areas, but if fails to reproduce those in the others. This shows that the relative importance of the horizontal transport on the primary production differs are by area. Two time scales,T _z andT _H, are introduced to explain this difference.T _z is a vertical cycling time of material, which is defined as the time during which the stock of the material in the water column is utilized for primary production;T _H is the horizontal transit time of the material. The relative importance of the horizontal process is well explained by theT _H/T _z ratio; that is, the horizontal transport process is important in the areas where this ratio is small. Further the possible mechanisms of nutrient supply for the primary production in each sub-area are investigated using this model.     

Organochlorine Pesticide Residues in Soils and Sediments of the Herbert and Burdekin River Regions, North Queensland – Implications for Contamination of the Great Barrier Reef

Organochlorine pesticides were widely used in the Australian sugarcane industry from the early 1950s until the late 1980s. Erosion of sugarcane soils and subsequent transport of sediment bound contaminants in river run-off to the Great Barrier Reef lagoon is a growing concern as the cane industry continues to expand. Organochlorine pesticide residues can be used as tracers to examine the worst-case scenario of the spatial extent to which currently used, though less persistent, organic agricultural pesticides might extend. The coastal alluvial flood-plains of the Herbert and Burdekin Rivers in North Queensland have sugarcane growing as the major coastal land-use. Sediment cores and surface sediment samples were collected from near-shore coastal regions of the Herbert and Burdekin Rivers. In addition, soil samples from cane-fields in the two catchments were collected. Analyses of the marine surface sediment samples and three sediment cores revealed the absence of detectable concentrations of organochlorine pesticides (<5 pg/g). However, easily detectable concentrations were found in the sugarcane soil samples (0.01–45 ng/g).     

海洋围隔生态系中环境因子对长牡蛎的生态效应

本研究应用海洋围隔实验技术探索围隔生态系中环境因子对长牡蛎的生态效应。研究结果表明：牡蛎养殖密度与牡蛎体重增长呈负相关;养殖水体的Ｎ、Ｐ平均浓度分别达到２６．４和２．５μｍｏｌ／ｄｍ＾３的水平时牡蛎生物较佳;服物浓度过高会导致牡蛎死     

海洋生态系统动力学研究的相关网上资源

分４部分介绍互联网上与海洋生态系统动力学研究有关的信息资源、主要网址及其主要内容：（１）海洋生态系统模拟研究;（２）海洋科学研究组织和国际研究计划;（３）网上新闻讨论组;（４）海洋生态杂志。     

胶州湾北部水层生态动力学模型与模拟 Ⅱ.胶州湾北部水层生态动力学的模拟研究

利用建立起的浅海水层生态动力学箱式模型,模拟了胶州湾北部１９９５年的浮游植物、浮游动物、无机氮、无机磷、溶解氧以及ＤＯＣ和ＰＯＣ年变化特征。结果是合理的。通过模型参数敏感性实验分析,揭示了该模型系统的一些动力学特征     

伊乐藻-草鱼圈养人工复合生态系统建设的研究

十多年来,在长江中下游浅水湖泊,特别是城郊湖泊,围栏圈养草食性鱼类发展迅速,产量大幅度提高,经济效益明显增长。养鱼过程中,由于大量投喂商品饲料和过量利用湖泊水草资源,加之湖滨人口不断增加等多种原因,导致不少草型湖泊水生植被退化,水草消失,加速了湖泊富营养化进程,湖泊整体功能下降。 伊乐藻是1986年从国外引种东太湖的高等沉水植物,已在东太湖归化,并被广大渔民用作草食性养殖鱼类的饲料。本研究是充分利用伊乐藻的生物学和生态学特性,以及易种植、生物量大、可利用程度高等特点,研究了在浅水湖泊人工种植、采收时间和刈割方法,提高其单位面积产量;测定了草鱼对伊乐藻的消化吸收和饲料系数;研究了伊乐藻在水生态系统中的功能等,从而在浅水湖泊中设计和建设伊乐藻—草鱼圈养人工复合生态系统。即以种植伊乐藻为中心,并以它作为草食性鱼类饲料和在水界物质循环的中介,在湖泊大系统内建立的草—鱼平衡系统,以提高湖泊养鱼产量和其他水产品产量,改善渔业水质和优化湖泊生态环境为主要目的。     

武汉东湖主要湖区的藻类与营养型评价

对东湖９个湖区藻类的群落结构、生长潜力、初级生产力和营养状况进行了比较研究。结果表明,９个湖区藻类的种类组成无明显差异,绿藻为主,蓝藻和硅藻次之;藻类的生长潜力和初级生产力各湖区差异较大,均以茶港湾重污染区最高和牛巢湖最低。根据各项指标综合分析,９个湖区水质优劣的顺序是：牛巢湖、汤林湖、后湖、郭郑湖、菱角湖、筲箕湖、庙湖、喻家湖和茶港湾重污染区。对东湖的大水面郭郑湖４０年来藻类的有关参数进行比较发     

白洋淀浮游植物群落及其与环境因子的典范对应分析

在对湖泊生态系统健康评价研究的基础上,提出用营养状态-综合指数法（TSI-CI）对西湖进行生态系统健康评价．首先选用Chl．a、SD、TP和TN四个指标用相关加权指数法进行营养状态评价,再选择物化和生物指标无量纲化处理后计算综合指数进行综合评价．结果表明：西湖生态系统健康状况与营养状态水平的变化趋势是一致的,1—3月健康状况相对较好,7-9月相对较差．该结果客观反映了西湖的实际情况,为西湖水质管理提供科学依据。