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21.
云南省鹤庆盆地2.78Ma以来的环境演化   总被引:14,自引:3,他引:11  
肖海丰  沈吉  肖霞云 《湖泊科学》2006,18(3):255-260
通过构建于新沂河河漫滩上的表面流人工温地系统处理污染河水的现场中试研究表明,在CODMn和NH4 -N进水浓度分别为11.69-60.00 mg/L和1.37-20.18 mg/L时,种植千屈菜、美人蕉、香蒲、水葱4种不同植物的表面流人工湿地系统,对CODMn的平均去除效率分别为26.44%、40.12%、46.71%、28.23%,对NH4 -N的平均去除效率分别为64.27%、70.49%、66.78%、58.52%,其中香蒲和美人蕉的净化能力较强.4种植物中水葱的耐淹能力最强,在完全淹水达22 d以上时,水葱依然生长良好;千屈菜的耐淹能力最弱,在完全淹水7 d后就开始枯萎,淹水17 d后地上、地下部分全部死亡.  相似文献   
22.
The major hydrological factors in lake-marsh systems are water level (depth), water surface area, and water volume. The key index for determining the lake-marsh pattern is water level, which leads to the variation of lake-marsh patterns under natural hydrological alternations. In addition, the vegetation structure also affects the lake-marsh pattern. With socioeconomic development and climate change, the ‘land use’ and ‘water use’ competitions appear more seriously between a lake-marsh system and its surrounding socioeconomic system, also inside the lake-marsh system. The possible optimal lake-marsh pattern could solve the contradictions mentioned above. As few studies focus on this issue, this study proposed an optimal lake-marsh pattern determination method with eco-hydrological management on relieving the land use and water use competitions. The optimal lake-marsh pattern determination method considers the protection objects (water depth demands), water supply (precipitation, surface water, and groundwater), and water demand (especially evapotranspiration) in the system at annual and monthly scales. Calculation and analysis were performed for the optimal pattern of the Wolonghu Wetlands as an example. The results mainly showed that the lake-marsh pattern of the Wolonghu Wetlands cannot be achieved on meeting both the maximum ecological services values and minimum water shortage amount under present natural condition. With artificial regulation measures, the possible optimal annual lake-marsh patterns can be obtained based on both ecological and hydrological objectives, with the area ratio of lake and marsh in the range of 0.650:0.350 and 0.726:0.274, the corresponding water level of lake body was of 86.85 to 87.0 m. This study could provide references for the Wolonghu Wetlands management, also for similar lake-marsh systems and other ecological systems.  相似文献   
23.
Vegetated wetlands are naturally subjected to changes in their water-level and macrophyte coverage leading to high habitat heterogeneity. The opportunistic ecological strategy of many planktic algae and bacteria makes them suitable for studying adaptive mechanisms to environmental change in wetlands at different temporal and spatial scales. In this study, we assessed the response of microbial aquatic organisms to sudden changes in habitat conditions, resulting from regime shifts involving the presence/absence of a dense floating-macrophyte cover, by means of a 72 h cross-transplant experiment using dialysis bags. Contrasting conditions imposed by the existing regime, such as light availability and dissolved oxygen concentration, accounted for the differences in phytoplankton and picoplankton compositions. Communities newly exposed to improved light and oxygen conditions exhibited a short-term (hours) response of C-strategists algae, such as small flagellated chrysophyceans. The onset of oxygen depletion and light impoverishment favoured the development of anaerobic anoxygenic photosynthetic bacteria (AnAnPB) and low-light adapted S-strategists (thin filamentous oscillatoriales) algae in few days. These results provide in-field evidence that phytoplankton and picoplankton assemblages are highly sensitive to environmental changes in a brief time scale, less than 72 h. Thus, these microbial organisms can act as sentinels to fluctuations in vegetated wetlands, also giving a quick response to sudden changes deriving from anthropogenic practices that impact on wetlands water-level and provoke fluctuations in their floating vegetation cover.  相似文献   
24.
2004年第七届国际湿地会议内容包括综合水资源管理中湿地的作用、环境管理中的湿地科 学、湿地的生物地球化学功能、湿地环境中植物的作用、湿地的保护和管理、湿地恢复和重 建、湿地和全球气候变化、湿地对改进水质的作用、热带湿地的功能和合理利用9部分. 在总结国际湿地会议研讨内容的基础上,通过相关资料的查询与统计,综合分析近年来国际湿地研究的热点领域及对我国湿地研究的启示.  相似文献   
25.
基于C4.5算法的遥感影像分类   总被引:2,自引:2,他引:0  
随着城市化进程的加快,湿地对整个生态系统的可持续发展具有重要的意义。以洪泽湖湿地为研究区,集合TM影像的光谱信息和纹理信息构建空间数据库,获取训练样本,并从训练样本集中获取分类规则;然后利用C4.5算法构建决策树,并基于知识规则推理得到遥感影像分类结果;最后将分类结果与传统的最大似然法进行比较分析。实验表明,基于C4.5算法得到的分类结果的分类总精度为91.9701%,其分类总精度结果明显高于传统的最大似然法的80.0885%;同样,前者的分类结果的Kappa系数为0.900 3,也远远高于最大似然法的0.746 5。  相似文献   
26.
1996-1998年对黄河三角洲湿地鸟类连续进行了3年观察和调查,共观察到和鉴定出湿地鸟类199种,隶属于16目38科。  相似文献   
27.
山东省湿地资源丰富,可分为自然湿地和人工湿地2类,自然湿地包括湖泊、海岸、沼泽、河口湾湿地,人工湿地主要为水稻田、水库、池塘湿地等,湿地面积约为1.71万km^2。该文分析研究了山东省的湿地环境地质问题,并提出了工程措施和非工程措施2种防治措施。  相似文献   
28.
The paper presents the first comprehensive survey of congener profiles (12 congeners) of polybrominated diphenyl ethers (PBDEs) in core sediment samples (<63 microm) covering seven sites in Sundarban mangrove wetland (India). Gas-chromatographic analyses were carried out in GC-Ms/Ms for tri- to hepta- brominated congeners. Results pointed out a non-homogenous contamination of the wetland with summation operator(12) PBDE values ranging from 0.08 to 29.03 ngg(-1), reflecting moderate to low contamination closely in conformity to other Asian aquatic environments. The general order of decreasing congener contribution to the total load was: BDE 47>99>100>154, similar to the distribution pattern worldwide. Although tetrabromodiphenyl ether BDE 47 was found in all samples followed by hexabromodiphenyl ether BDE-154, they were not necessarily the dominant congeners. No uniform temporal trend on PBDE levels was recorded probably due to particular hydrological characteristics of the wetland and/on non-homologous inputs from point sources (untreated municipal wastewater and local industries, electronic wastes from the dump sites, etc.) of these compounds. Because of the propensity of PBDEs to accumulate in various compartments of wildlife and human food webs, evaluation of biological tissues should be undertaken as a high priority.  相似文献   
29.
Groundwater heads and chemical composition were measured at approximately two week intervals during the summer of 1993 along a 1 km transect across the Insh Marshes floodplain mire in Inverness-shire, Scotland. Groundwater heads were generally higher near the valley side slope, with lower pH values and greater dissolved organic carbon, A1 and C1 concentrations. In the centre of the transect, upward groundwater heads were identified and pH, conductivity and concentrations of base cations were much greater. Near the River Spey, pH and base cation concentrations decreased and A1 and C1 concentrations increased. Deep groundwater followed a similar spatial trend but was generally more base-rich than shallow groundwater. These variations reflect the influence of three major water sources with different chemical signatures. Runoff from the valley side slope increased dissolved organic carbon and A1 in the shallow groundwater, the upward flow of groundwater increased the pH and Ca concentration and inundation near the river decreased the base status and increased C1 and A1.  相似文献   
30.
Inland flooding remains one of the greatest threats to the safety of human population in the United States (US). While few large-scale studies exist, the potential role of naturally occurring wetlands in mitigating flood duration and intensity has been widely discussed. This study examines the relationship between wetland alteration and coastal watershed flooding in Texas and Florida over a 12-year period. Specifically, we geo-reference wetland alteration permits required under Section 404 of the US Clean Water Act and correlate the number of granted permits with the degree of flooding measured by stream gauge data. Results indicate that specific types of federal permits exacerbate flooding events in coastal watersheds while controlling for various environmental and socioeconomic characteristics.  相似文献   
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