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741.
农业流域“汇”型景观结构对径流调控及磷污染物截留作用的研究 总被引:7,自引:3,他引:7
选取天津于桥水库北岸桃花寺流域作为实验流域,进行了流域景观格局对生态水文及磷污染物迁移转化过程影响的野外实验研究.研究结果表明,流域中广泛分布于季节性河流附近的汇型景观结构(石坝、植草水道、植被过滤带、干塘、缓冲区等),通过滞留/缓冲功能,对地表径流的流速及流量具有双重调控作用,延长了养分物质在流域内部的滞留时间,对产生于不同源区的面源污染径流具有截留、吸纳、贮存作用,使径流中泥沙和磷素浓度逐渐得到降低,减少了养分对下游水体的负荷输出.多次降雨径流的监测结果表明,无论在大暴雨下的连续流事件还是在小雨下的间断流事件中,汇型景观结构均能表现出良好的养分持留功能.在2003年6月22日连续径流事件中,地表径流的流速可由系统入口处的37.2 cm·s-1降至系统出口处的11.1 cm·s-1,污染径流体积可削减50.2%,TSS、TP、TDP、DRP的持留率分别可达72.7%,69.3%,59.8%和57.9%.在间断径流事件中,污染径流全部为汇型景观结构所截留,泥沙和磷素的持留率更高.对21场降雨-径流事件的统计分析结果表明,干塘和植被过滤带是本实验流域控制污染物输出较为稳定的两种结构. 相似文献
742.
南水北调中线水源区浮游植物与水质研究 总被引:1,自引:0,他引:1
2003~2005年对南水北调中线水源区水体浮游植物的调查结果表明,该水域共有浮游植物96种及变种,隶属于8门63属,其中种类最多的藻类植物依次是硅藻、绿藻和蓝藻.藻类的细胞密度表现出夏季最高、冬季最低的明显季节变化.运用Margalef和Menkinick多样性指数对该水域的水质进行评价,结果显示,水体为寡污型,基本处于中营养状态.图3表3参14 相似文献
743.
本文对位于亚热带丘岗区畜牧业生态经济亚系统的畜种结构和生态效率进行研究。因地制宜地调整和优化畜种结构,充分合理地利用当地饲料资源,改善饲料营养结构,增强亚系统的总体功能。 相似文献
744.
A variety of animals use olfactory appendages bearing arrays of chemosensory neurons to detect chemical signatures in the water or air around them. This study investigates how particular aspects of the design and behavior of such olfactory appendages on benthic aquatic animals affect the patterns of intercepted chemical signals in a turbulent odor plume. We use virtual olfactory `sensors' and `antennules' (arrays of sensors on olfactory appendages) to interrogate the concentration field from an experimental dataset of a scalar plume developing in a turbulent boundary layer. The aspects of the sensors that we vary are: (1) The spatial and temporal scales over which chemical signals arriving at the receptors of a sensor are averaged (e.g., by subsequent neural processing), and (2) the shape and orientation of a sensor with respect to ambient water flow. Our results indicate that changes in the spatial and temporal resolution of a sensor can dramatically alter its interception of the intermittency and variability of the scalar field in a plume. By comparing stationary antennules with those sweeping through the flow (as during antennule flicking by the spiny lobster, Panulirus argus), we show that flicking alters the frequency content of the scalar signal, and increases the likelihood that the antennule encounters peak events. Flicking also enables a long, slender (i.e., one-dimensional) antennule to intercept two-dimensional scalar patterns. 相似文献
745.
Liselotte Sundström 《Behavioral ecology and sociobiology》1993,33(5):345-354
Summary The genetic population structure and the sociogenetic organization of the red wood ant Formica truncorum were compared in two populations with monogynous colonies and two populations with polygynous colonies. The genetic population structure was analysed by measuring allele frequency differences among local subsets of the main study populations. The analysis of sociogenetic organisation included estimates of nestmate queen and nestmate worker relatedness, effective number of queens, effective number of matings per queen, relatedness among male mates of nestmate queens and relatedness between queens and their male mates. The monogynous populations showed no differentiation between subpopulations, whereas there were significant allele frequency differences among the subpopulations in the polygynous population. Workers, queens and males showed the same genetical population structure. The relatedness among nestmate workers and among nestmate queens was identical in the polygynous societies. In three of the four populations there was a significant heterozygote excess among queens. The queens were related to their male mates in the polygynous population analysed, but not in the monogynous ones. The data suggest limited dispersal and partial intranidal mating in the populations with polygynous colonies and outbreeding in the populations having monogynous colonies. Polyandry was common in both population types; about 50% of the females had mated at least twice. The males contributed unequally to the progeny, one male fathering on average 75% of the offspring with double mating and 45–80% with three or more matings.
Correspondence to: L. Sundström 相似文献
746.
膜-生物反应器混合液性质对膜污染影响的研究进展 总被引:5,自引:0,他引:5
膜-生物反应器作为一种新型的污水处理和回用技术,近年来在基础研究和实际应用领域都得到广泛关注,但是影响其长期稳定运行的膜污染问题却一直没有得到深入研究和解决.混合液特性是影响膜污染控制的重要因素,从混合液理化性质(组成、功能、结构和环境因素)和生物学性质(微生物群落结构、微生物功能特征)2个方面进行介绍,综述了目前关于混合液性质与膜污染关系的研究现状.目前的研究虽然取得一定进展,但在相关性分析、群落特征与膜污染关系、污染层形成机理等方面仍存在许多不足. 相似文献
747.
748.
749.
针对城市产业水污染状况,应用产业结构和工业行业结构优化模型,试图找出城市产业结构调整方法。研究以株洲市为例,根据株洲市产业结构和行业结构特点对模型进行改进和最优化计算。计算结果表明,产业和行业生产用水的调整可以减少废水排放量和实现经济增长。在此基础上,提出了株洲市产业和行业凋整方案,以期实现城市经济发展与环境保护协调发雇。 相似文献
750.
Fangliang He Pierre Legendre Claude Bellehumeur James V. LaFrankie 《Environmental and Ecological Statistics》1994,1(4):265-286
Scale is emerging as one of the critical problems in ecology because our perception of most ecological variables and processes depends upon the scale at which the variables are measured. A conclusion obtained at one scale may not be valid at another scale without sufficient knowledge of the scaling effect, which is also a source of misinterpretation for many ecological problems, such as the design of reserves in conservation biology.This paper attempts to study empirically how scaling may affect the spatial patterns of diversity (tree density, richness and Shannon diversity) that we may perceive in tropical forests, using as a test-case a 50 ha forest plot in Malaysia. The effect of scale on measurements of diversity patterns, the occurrence of rare species, the fractal dimension of diversity patterns, the spatial structure and the nearest-neighbour autocorrelation of diversity are addressed. The response of a variable to scale depends on the way it is measured and the way it is distributed in space.We conclude that, in general, the effect of scaling on measures of biological diversity is non-linear; heterogeneity increases with the size of the sampling units, and fine-scale information is lost at a broad scale. Our results should lead to a better understanding of how ecological variables and processes change over scale. 相似文献