几种植物对潜流型湖滨湿地中氮磷的处理效果比较

湖滨带是连接湖泊水域生态系统与陆地生态系统的一个功能过渡区,是湖泊的最后一道保护屏障。在河流的入湖口建造湖滨湿地,可有效净化入湖水中携带的部分有机污染物、营养盐等。湿地净化污染物的机理极为复杂,其中植被起着重要的作用。选择适当的植物是构建湿地系统的关键。以云南省抚仙湖北岸的湖滨湿地——马料河潜流型湿地为研究对象,探讨了美人蕉(Cannaindica),菖蒲(AcoruscalamusLinn),伞竹(Cyperusalternifolius),香蒲(Typhaelatifolia)四种不同植被系统的潜流型湖滨湿地去除污水中营养盐的效果,为抚仙湖湖滨带人工湿地的合理优化选择植物提供一定的依据。结果表明,四种植被系统的潜流湿地对总氮和总磷均有一定的去除效果。但是由于湿地长期运行而疏于管理,植物没有定期收割翻新,四种植物的氮磷去除率差别不太大,去除效果均不太佳。其中,美人蕉对总氮和总磷的去除效果较好,其去除率分别是30.4%,19.13%,其次为香蒲和伞竹,效果较差的是菖蒲。并且实验表明,暴雨对四种植物湿地氮的去除效果有很大的影响。连续几天的暴雨情况下,四种植物系统氮的去除率都很低。     

淀山湖上覆水与沉积物孔隙水中重金属的分布特征

研究了淀山湖上覆水和沉积物孔隙水中Pb ,Cd,Cr,Cu ,Fe和Mn的浓度及Eh 分布 ,分析了孔隙水中重金属的扩散通量 .结果表明 ,淀山湖中重金属的浓度由高到低依次为 :Mn >Fe >Cr,Cu ,Pb >Cd ;Fe和Mn在孔隙水中的浓度远远大于它们在上覆水中的浓度 ,表层沉积物孔隙水中Pb ,Cd ,Cr,Cu的浓度稍大于它们在上覆水中的浓度 ;沉积物中的重金属可能按照浓度梯度经孔隙水从沉积物向上覆水中扩散而最终影响上覆水的水质     

Wave Enhancement of Diffusivities within Surficial Sediments

The enhancement of solute diffusivities within coastal surficial sediments as a result of wave action is examined. Fluctuating pressure gradients associated with passing waves cause interstitial water motions leading to enhanced diffusivities through the mechanism of shear dispersion. Wave amplification of diffusivities is likely to be greatest for waves of period 10 s, in shallow water, over a bottom of coarse grain. Diffusivity enhancement of hundreds of times molecular diffusivity is achievable. The mechanism is distinct from, but complements, the mechanism of rotational dispersion which has been previously described. Other mechanisms that enhance solute transport within surficial sediments rely on the interaction between wave-driven or steady flow over bottom obstructions such as biogenic structures or sand ripples. It is suggested that while the resulting advective flows may dominate solute transport within the top few 10 s of centimeters of the sediment column, shear dispersion may be more important deeper within the sediment. In any event, in contrast to these other mechanisms, shear dispersion is operative even when the seabed is flat. Application of the theory to sediments of the South Atlantic Bight would suggest that shear dispersion is capable of explaining a major part of the interstitial transport inferred from measurements.     

星湖沉积物特性研究

以肇庆星湖为研究对象，研究了其沉积物的各种特性。研究表明：(1)星湖沉积物的矿相(晶体物)主要为石英、伊利石、长石、绿泥石等；(2)沉积物中的TP、TN含量，基本随湖水交换和季节变化而变化，与交换量有着简单反比关系，其TP的含量在0．03％～0．06％之间，TN在0．19％～0．28％之间，内负荷较为严重；(3)沉积物的沉降存在很大的不均衡性；(4)沉积物营养物的释放受环境因子影响，其中溶解氧对N、P的释放都有较大的影响，温度对P的影响较N多一些，而保持水体中性，则有利于水体的稳定。     

WIND GENERATED WAVES IN LAKE OKEECHOBEE1

ABSTRACT: The study of wind generated waves is important because waves affect sediment resuspension in lakes. Measurements of wind velocity and wave elevation were made at three different stations in Lake Okeechobee. Significant wave heights were computed using a direct count from the recorded data, and verified by the root-mean-square value approach. The correlation between wind stress and significant wave height also was analyzed. The data revealed a strong correlation. In addition to field measurements, a Boussinesq-type wind-wave model was developed to simulate wind-generated, long-propagating waves. This model included the effects of wind stress and bottom viscous dissipation. Wave elevation and velocity field were evaluated numerically. A six-day simulation using 1996 wind data was conducted. Simulated significant wave heights were found to agree reasonably well with measured values. A predictive wind-wave model provides information about wind generated waves, which is used to compute bottom shear stresses required for sediment resuspension studies.     

抚仙湖北岸入湖径流中总氮变化趋势分析

抚仙湖现有污染主要来自北岸。通过抚仙湖3条入湖河流中总氮负荷量进行调查，对抚仙湖入湖河流中总氮负荷量进行了分析评价，结果表明：3条入湖河流总氮为劣V类水质，是影响抚仙湖水质的主要因素。为湖泊总量控制与治理提供科学依据。     

复合型人工湿地对抚仙湖入湖河道污水中氮的去除

在抚仙湖北岸构建复合型人工湿地污水处理系统,对窑泥沟入湖河道污水中氮的去除效果进行了试验研究,结果表明,系统水力负荷年平均为37mm/d,氮负荷年平均为3.315g/m2·d,对污水中NOx、NH+4、TON和TN去除率年平均分别为62.7%、53.8%、62.4%和57.5%.     

浅析洪湖水生资源的开发与生态保护

洪湖的环境保护不仅对洪湖生物资源的开发利用，而且对洪湖地区的生态农业建设都起着重要作用。通过对洪湖的污染现状分析与防治对策研究，探索建设内陆淡水湖泊生态农业的途径。     

农田土壤中的磷向水体释放的风险评价

通过对比土壤的固磷能力和磷素水平可以评估不同类型土壤中的磷向水体释放的风险。研究表明，磷吸持指数（SI）可以作为土壤最大吸磷量的替代指标来表征土壤的固磷能力。在太湖地区，影响水土界面磷素迁移能力的主要因素是土壤有效磷水平和土壤固磷能力。SI值30左右为一临界值，SI大于此值的土壤对于施磷具有较大的缓冲能力，而SI低于此值的土壤对施磷非常敏感，磷流失风险将随施磷量的增加而呈直线上升趋势。     

藏北高原自然资源的利用与保护

藏北高原面积约60万km²,海拔在4500m以上,为青藏高原的主体。其气候寒冷干燥,人迹稀少,以高寒草原为主的生态系统基本保存完好,其天然草地辽阔,各类可利用草地面积占土地总面积53％,为西藏最大牧区,适宜发展地毯毛羊--藏绵羊。这里栖居着许多青藏高原特有的国家一、二类保护动物及有一定经济价值动物资源。高原上湖泊众多,湖泊面积占全国湖泊总面积的1/4以上。其中许多盐湖盛产有工业开采价值的食盐、天然碱及硼、锂、钾等重要稀有元素,为我国主要矿盐产地和远景开发区。目前因草地生态脆弱和利用不当,已有4％草地退化,沙地面积扩大,野生动物栖居范围也趋缩小;少数盐矿产地环境有所污染,盐湖资源浪费较大。所以适度利用天然草地、保护野生动物和综合开发盐湖资源,防止自然生态环境的恶化乃是开发藏北高原生物矿产资源的重要战略措施。