白洋淀湿地氮素转化和N2O排放特征研究

通过对华北地区最大的湖泊湿地白洋淀近1年的野外观测,对湿地上覆水、沉积物/土壤中各种形态氮以及反硝化作用产物N2O排放通量的时空变化进行了系统研究。研究结果表明,白洋淀湿地对氮素污染物铵态氮的去除能力较强,平均去除率为77.1%。湿地中氮素的迁移转化过程时空变化明显,夏季是其氮素转化的快速期。湿地是温室气体N2O的排放源,夏季其排放通量最大,占全年排放通量总和的62.1%。其中湖滨带是整个湿地生态系统中氮素转化的活跃区,N2O年内平均排放通量高达109μg·m-2·h-1。由此可见,良好的湖滨带有利于湖泊富营养化的自然恢复。     

外源氮素对人工湿地N2O排放通量影响的研究

氮素通过干湿沉降、地表径流、农业灌溉等途径进入湿地中,导致湿地N2O的产生和排放发生变化,而N2O是一种温室气体,具有较高的温室效应潜力,会对环境造成严重影响。本研究模拟白洋淀芦苇湿地,构建人工模拟湿地系统进行外加氮素试验,用静态暗箱-气相色谱法进行N2O的通量观测,研究外源氮素输入对湿地N2O排放通量的影响。结果表明,外源氮素形态的不同不仅影响湿地系统中环境因子的改变,还会影响氮素进入湿地系统后的迁移转化。硝态氮是湿地N2O产生和排放的主要影响因子,芦苇湿地系统中氮素的反硝化作用强于无植被湿地系统,N2O的排放主要发生在反硝化过程中。     

白洋淀芦苇湿地退化及其保护研究

白洋淀芦苇湿地是华北地区最大的淡水湖泊,近40年来,呈现出明显的退化趋势.对白洋淀芦苇湿地的退化状况、退化原因以及保护白洋淀湿地的重要性进行了分析.最后,提出了以保护白洋淀芦苇湿地的自然资源和生物资源并加强湿地科研工作为主保护内容.     

毛乌素沙地典型湖滨带湿地有机碳、氮素空间分布特征

通过对陕西毛乌素沙地典型湖滨带湿地有机碳和氮素的空间分布特征进行研究,为探讨湿地生态系统如何在沙化环境下发挥其特有的功能提供科学依据。在巴吓采当湖泊湖滨带A~F类型区采集土壤,测定土壤的有机碳、全氮、有机氮、硝态氮和铵态氮等指标。利用方差分析、Spearman相关性分析和主成分分析等方法分析对湖滨带有机碳、氮素空间分布特征进行研究。土壤表层0~10cm的有机碳和全氮含量随水位升高呈增加趋势。除了铵态氮外,有机碳、全氮、有机氮和硝态氮含量垂直分布上随着土壤深度增加呈降低趋势。土壤有机碳、全氮含量分别与全磷、土壤容重、含水率、水位显著相关。铵态氮和全磷、含水率、土壤容重、全氮、有机碳和水位等显著相关。硝态氮与微生物生物量碳、氮的相关系数分别为r=0.637和r=0.617(中度正相关)。有机碳及氮素的含量与土壤粘粒含量相关性不高。主成分分析提取3个主成分,累积贡献率达76.15%。土壤全磷、土壤含水率、土壤容重和水位是影响湖滨带土壤有机碳、氮素空间分布的主要因子。     

关于白洋淀引水的几点体会

白洋淀是华北平原最大的湖泊,位于河北省中部,淀区主要分布在保定市安新县境内,另一部分在沧州地区,涉及任丘、安新、容城、雄县、高阳等市县,是国家重点旅游区和开放区。白洋淀南距石家庄189km,北距北京162km,东距天津155km,水域面积366km~2,是京津冀腹地,素有"华北明珠"之美誉。1.白洋淀现状"华北明珠"白洋淀是华北地区最大淡水湖泊和重要的天然湿地生态系     

基于湖泊完整性的查干湖健康评价

文章从水文水资源、水质状况、水生生物、湖岸带和社会服务功能等5个准则层和16个指标层对2015年的查干湖湖泊健康状况进行评价。结果表明,受人类开发活动影响,查干湖健康评价指数赋分为56分,湖泊处于亚健康状态;农业开发、气候变干、石油开发以及旅游业发展是造成湖泊生境变化的主要因素。提出了湖泊水资源调控、湖滨带修复与管理、水质修复、鱼类资源保护、湿地生态系统恢复等湖泊健康管理措施。     

太湖生态清淤与湖滨湿地带构筑

湖滨湿地带是湖泊水生态系统与陆地生态系统间非常重要的生态过渡带.近年来,太湖各湖区滨岸带底泥被淘蚀,植被生长空间被压缩,出现水生植物面积大幅缩小、生态功能退化等问题,严重影响了湖滨带生态系统功能的发挥.本文对生态清淤与湖滨湿地带构筑相结合设计进行分析,利用生态清淤底泥就近构建湖滨湿地带是一种解决清淤底泥出路的可行途径.     

白洋淀湿地面临的生态问题及可持续发展对策

白洋淀湿地是华北地区最大的淡水湖泊,近年来,生态环境退化现象十分严重,面临着干淀的威胁。现对白洋淀生态环境现状及面临的问题,如水量减少、泥沙淤积、生物多样性减少、污染加重等方面进行了认真的分析研究,为维护白洋淀湿地资源的可持续利用,确保其生态系统的安全,提出了可持续发展的实施方案和具体保护措施。     

引调水工程对调蓄湖泊生态环境的影响分析

引调水工程利用天然湖泊调蓄,将引起调蓄湖泊水文情势、水质发生一定变化,对与湖泊水环境关系密切的水生生物、湖滨植被、湿地鸟类产生影响.以金沙江某提水工程方案比选阶段利用拉市海调蓄方案为例,采用图形叠置法、类比分析法、生态机理法等方法,分析工程运行对拉市海水生生物、湖滨植被、湿地鸟类的影响,为引调水工程对调蓄湖泊的生态环境...     

抚仙湖北岸生态调蓄带工程入湖污染物减排效益核算

抚仙湖属珠江流域西江水系的源头型深水湖泊,湖岸陡峭,岸滩不发育,湖泊生态系统十分脆弱,水质一旦被污染将很难恢复。近年来受流域内人类活动强度持续加剧与全球气候变化的双重驱动影响,抚仙湖水位持续降低、河湖水污染问题日益突出,湖泊水质保护问题迫在眉睫,因此,2017年针对入湖污染负荷占比最大且农田面源污染问题最为突出的抚仙湖北岸片区实施了集截污、调蓄、水质净化、水资源回用、清水置换、湿地补水建设于一体的抚仙湖北岸生态调蓄带工程,并将1179.09亩农田改建为调蓄带湿地。从实施效果来看,调蓄带工程2018—2021年期间减少的TN、TP入湖负荷量分别为245.84 t、28.99 t,调蓄带对抚仙湖北岸片区农田面源负荷削减率均超过81%;从生态调蓄带入湖污染物减排效益贡献大小来看,土地利用方式变化＞湿地水质净化＞湖滨湿地补水＞水资源回用＞清洁水资源置换;从调蓄带入湖污染物减排效益持续提升来看,水资源回用和清洁水资源替换潜力有待进一步挖掘和提升。     

生物预处理技术在嘉兴地区给水厂的应用比较

对嘉兴地区主要给水厂近年来应用立体弹性填料、LT型悬浮球填料、YS型悬浮填料、卵石填料等的生物预处理工艺从填料及配套设施、工艺运行参数、运行效果、成本等方面进行了比较.认为弹性填料生物预处理更适用于低浊(50 NTU以下)、低氨氮(1.5 mg/L以下)原水,LT型悬浮球填料生物预处理适用于低中浊(100 NTU以下)、低中氨氮(2.5 mg/L以下)原水,YS型悬浮填料生物预处理及"SAF"滤池对低浊、中高氨氮(2.5 mg/L以上)原水有较好的适应性.最后探讨了弹性填料存在的短流、积泥,悬浮填料存在的部分填料流化不均匀,富氧的生物工艺单元内水生动物泛滥等问题.     

中国部分河口及其近海水域缺氧现象研究

对长江、珠江等河口及其近海水域缺氧现象与影响因素进行研究,结果表明,主要分布于长江与珠江河口及其邻近海域的缺氧现象,夏季(6—8月)达到最盛,秋冬季消失;长江口的缺氧区域主要位于30.75°N~32°N,122.5°E~123.25°E附近海域,具有南北2个缺氧中心;珠江口缺氧程度相对较轻,缺氧区域主要在广州黄埔区河段至虎门水域和伶仃洋;辽河、钱塘江、海河等河口区域也时而出现零星的缺氧现象;水体缺氧受控于多项环境要素,物理层化作用是缺氧产生的最初诱因之一,陆源污染物的分解则是重要的耗氧负荷;各河口区特征各异,潮汐、洋流、营养盐、叶绿素a等要素对缺氧区的范围、程度和持续时间影响程度不一。     

无资料流域水文预报(PUB计划)研究进展

无资料流域水文预报，简称为PUB(Predictions in Ungaugecl Basins)，从2003年7月开始成为国际水文科学学会新的国际水文十年计划主题．文中首先简述了PUB计划的主要研究内容，然后回顾了国际和国内已有的PUB研究进展，最后展望了对水文学发展有重要意义的几个PUB前沿研究，包括不确定性研究、对水循环各个环节因素的预报和对无资料流域水文过程的预报。     

Changes in urban stream channels in Zimbabwe

Although channel change has been documented downstream of urban areas there have been few previous studies which have focused upon the spatial variation of erosion and upon examples of such channel change in tropical areas. In the Avondale stream basin, which includes part of Harare the capital of Zimbabwe the way in which the channel network has evolved from the extensive dambo system in the period 1891 to 1984 is reconstructed showing that drainage density which was initially between 0.35 and 0.80 km km^?2 has increased to 3.15 km km^?2 including stormwater drains. Characteristics of erosion of the modified urban channels are described and the downstream reaches indicate an average channel widening of 1.7 times involving average rates of bank erosion of 0.33 m per year. Peak discharge is estimated from channel characteristics to be increased to two times former values and it is concluded that channel type and the relationship of channel change to the accommodation of peak discharges requires further research.     

北京某学校雨水利用设计

以北京市某中学为例,介绍一种学校雨水利用的方法。根据校区水量平衡计算结果,对利用校园内汇集的雨水作为冲厕、绿化和景观用水等进行设计;采取相应的技术措施,对雨水径流的污染进行控制,保障所利用雨水的水质达到要求,并采用生态净化的方式,使学校景观水体循环起来。虽然雨水利用工程投资较高,但其社会和环境效益显著。     

水利高性能计算的进展

针对水利信息化对精细模拟与高性能运算提出的愈来愈高的要求,在简单介绍高性能计算的硬件、软件环境及其在水利上的几个应用实例后,着重介绍了并行有限元法、并行边界元法的一些进展以及网格技术的最新进展。指出从网络到网格是高性能计算发展的最新方向,应以网格平台支持、促进水利信息化进程。     

中国内地水库淤积的差异性分析

为了解水库的淤积现状,根据115座具有代表性的中国内地水库淤积资料,对这些水库按类型和区域进行统计分析,结果表明,中小型水库比大型水库淤积严重,不同流域水库淤积的空间差异明显,黄河中下游地区水库淤积比例最大,西南地区水库年均淤积率最大。截止到2003年,根据代表性水库淤积的计算结果推算出中国内地水库的平均淤积比例约为20%,库容年均淤积率为0.76%,相当于每年损失1座库容近42.3亿m3的超大型水库。     

Trends in ecological river engineering in Korea

Ecological river engineering can be defined as the design and implementation of river works and river restoration works for the benefit of human society. It also guarantees the sustainable ecological functions of a river, such as its habitats and self-purification of its water. It is currently in the beginning stages in Korea, utilizing scientific knowledge on the processes of aquatic ecosystem degeneration and a methodology for solving the ecological problems in artificially altered rivers currently under development. The changes in river management and work practices in Korea may be best explained with a chronologically progressing sequence of ‘Natural’, ‘Disaster-prevention’, ‘Occupied’, ‘Park’, and ‘Close-to-nature’ rivers. Since the 1960s, the focus on river management and work has shifted from flood control only, to both flood control and riverine habitat conservation and restoration. Five research topics have been selected for this article, and the progress of each research area is briefly described with a representative picture in each topic. They are as follows: (1) flow resistance due to vegetation, (2) environmental flow, (3) floodplain vegetation modeling, (4) small dam removal, and (5) river restoration. For the future prospects of research on ecological river engineering in Korea, a necessity of further research on floodplain vegetation recruitment and succession, which can explain the so-called ‘white river’ and ‘green river’, is underlined, among others. Finally, two ongoing large research programs on river ecosystem restoration, of which are sponsored by the Government of Korea, are briefly introduced, followed by the introduction of a near-prototype experiment facility recently completed mainly for research on ecological river engineering.     

吉林省2001年汛期降水量趋势预测

本文根据历年6－9月降水量距平值累计曲线和历年6－9月降水量特征值变化，对我省今后汛期全省各地区降水趋势及降水量进行了预测，可供有关部门参考。     

Lake—Wide Seasonal Changes in Limnological Conditions in Lake Michigan in 1976

Data collected on lake-wide cruises in 1976 were used to study seasonal and vertical variations in water temperature, transparency, chlorophyll a, and nutrients in Lake Michigan. Data were analyzed according to subsets corresponding to the northern and southern open lake. Comparisons (t-tests) of data from the open lake indicated that the average water temperature was cooler and average water transparency was greater in the northern lake than in the southern, but with the exception of total phosphorus, average nutrient concentrations did not differ between the northern and southern parts. It was found that physical-chemical characteristics of nearshore and Straits of Mackinac stations differed significantly from open lake stations. Seasonal phytoplankton dynamics in the open lake were related to seasonal and vertical changes in silica and nitrate nitrogen. The spring phytoplankton bloom occurred before the lake was strongly stratified thermally. After thermal stratification was well developed, epilimnetic concentrations of chlorophyll a decreased, probably due to some combination of nutrient limitation and zooplankton grazing, and maximum chlorophyll a concentrations were found below the thermocline. Epilimnetic silica concentrations decreased after thermal stratification and diatoms were replaced in the phytoplankton assemblage by green and blue-green algae in late summer. Total phosphorus averaged only 8 μg/L on a lake-wide basis and thus only small but significant reductions in absolute concentration can be expected from phosphorus control programs. However, over a period of several years, these small reductions in concentration may be difficult to verify from total phosphorus measurements which have relatively large sampling errors and variances.