【作者】 杨红军；

【导师】 王文华；

【作者基本信息】 上海交通大学 ， 环境工程， 2008， 博士

【摘要】 湖滨带是湖泊水生态系统和陆地生态系统之间的过渡带。在保持物种多样性、拦截陆源污染物质和净化水体、稳定相邻生态系统等方面发挥了积极作用,是湖泊的天然保护屏障。近年来,随着人口的增加和人类活动的加剧,越来越多的湖泊湖滨带受到人类的干扰而严重退化,湖滨带生态功能受到削弱。2003年起,国家太湖863项目在太湖的五里湖开展了一系列生态恢复和重建的研究和实践,本论文对西五里湖的生态重建工程进行了分析,对影响湖滨带生态功能的岸带结构、生物和湿地等多因素进行了深入研究,在此基础上对东五里湖生态恢复和重建规划提出初步方案。论文的主要内容和结果如下:1.从湖滨岸带结构对生态环境影响角度看,由于构造差异,其对湖水理化指标、氮磷循环菌的分布和浮游植物生物量均有显著的影响;岸带对水环境中的营养盐的去除能力为:滩地岸带>碎石岸带>硬质陡岸。夏、秋季节滩地岸带和碎石岸带对氨氮、硝酸盐氮、TN和TP的去除能力达到最高,而冬季由于磷细菌数量相对较高,碎石和滩地岸带也保持了较高的TP去除率;以NH4+、TP和TN为指标,以修正的卡尔森营养指数为基础,提出了不同岸带结构的近岸湖水营养指数(EM),以此表征不同岸带结构对近岸湖水环境的影响,三种岸带结构的指数值大小为硬质陡岸(EMv=1.85)>碎石岸带(EMs=1.76)>滩地岸带(EMw=1.72)。2.湖泊中水生植被的存在,能显著提高湖水中氮循环菌群的分布、降低TN、NH4+-N和NO3--N等营养盐的浓度且改善水质;同时能通过水生植物的生长代谢,影响湖水中藻类的生物量,抑制水华的发生。在生长季节、芦苇植被的生态功能最强,而在冬、春季节,植物浮床和沉水植被也有良好的生态效果。水环境生态指标的变化,可以通过人工基质上的着生生物的生物量及多样性指标反应出来。3.湖滨交错带芦苇湿地土壤渗滤液中N、P营养元素的分布呈现出一定的规律性。表层DON、NO3--N、TN和TP浓度较高,随土壤深度增加而下降,至60cm深度土层附近达到最低值;而NH4+-N在表层含量较低,浓度随土壤深度增加而增加。营养盐的垂直分布受土壤周期性干湿交替及季节变动的影响,与土壤TOC、ORP、温度、植物根系生物量、土壤微生物的分布密切相关。4.受人类活动的影响,五里湖湖滨带土壤重金属大都超过太湖地区重金属背景值,且污染具有同源性。受植物根系的影响,重金属在土壤中植物根区部分含量最低,然后再随深度增加而升高。湿地植物(芦苇和丁香蓼)对Cu、Zn和Pb的富集系数较大,根是主要贮存器官。相比之下,芦苇和丁香蓼对Cd和Cr的富集系数较小,说明总体上湖滨带的植物对这两种重金属元素的吸收能力较低。上述结果对指导太湖湖滨带生态修复,选择合适的湿地植物,控制重金属污染有一定的指导意义。5.湖滨岸带的景观植被具有改善景观和净化陆源污染的作用。净化能力随植物种类变化,对TN、氨氮而言,净化能力为:高羊茅>白三叶>结缕草;对TP,则是高羊茅>结缕草>白三叶;对硝酸盐氮而言是白三叶最好,其次为高羊茅和结缕草。对营养盐的净化随植被带宽度及土壤深度而增强,且缓和的坡度处理能力较强。6.在上述研究的基础上,本文结合东五里湖生态环境状况及无锡市对五里湖地区的整体定位,运用恢复生态学和景观生态学的理论,对东五里湖湖滨带的生态恢复和重建规划提出了设想。本规划实施后,整个东五里湖岸带结构综合指数将从目前的EM=1.84降低到EM=1.78,该指数可以作为湖滨带生态恢复工程实施后定期监测评估指标。更多还原

【Abstract】 Aquatic-terrestrial ecotone (ATE) is an important functional interface zone between the ecosystems of freshwater and terrene, which can provide essential ecosystem services such as lakeshore stabilization, fisheries resources and habitant, food for migratory, aesthetic scenery and recreational opportunities for human populations. It also offers a protection on water body from harmful impacts of terrestrial matter such as nutritive materials and heavy metals. Due to the higher population and more activities from human population more and more ATEs have been deteriorated and the ecological function has been worse, which turns out to be an outstanding challenge for the human life environment. The ecological restoration and reconstruction has been paid more attention to. Since 2003, China has conducted a series of research and practice in Taihu Lake. This thesis focused on the research and assessment on the ecological reconstruction of Wulihu Lake, a part of Taihu Lake. Based on the completed reconstruction in west part of the lake, the influences from the multi-factors, such as the bank structure and biology as well as wetland, were researched. The plan of the ecological reconstruction on east part of Wulihu Lake was designed based on the results above. The research results are followed:1. With impact from the three type’s lakeshore structure of ATE, the physical-chemical indexes, phytoplankton, nitrogen and phosphobacteria in the waters were influenced significantly. On the point of the ability to minimize the nutritive salt, it can be ordered as wetland lakeshore (WL), gravelly lakeshore (GL) and vertical lakeshore (VL). In summer and fall, the ability to minimize the NH4+-N、NO3--N、TN and TP by lakeshore is stronger, while in winter, with relatively high biomass of phosphobacteria, the concentration of TP was also reduced in GL and WL. The ecological lakeshore index which was proposed for the long term monitoring program of the lakeshore ecological condition,was 1.84 in the east Lake Wulihu.2. The results also indicated that, the hydrophytes in the lake can increase the distribution of nitrogen cycle bacteria, decreased the concentration of nutritive salt, such as TN, NH4+-N and NO3--N, improving the water quality and minimize the alga biomass. The ecology function of reed was very strong in growing seasons, while in spring and winter the planted floats and submerged plant have better ecology function. The variety of ecological indexes can be indicated by the biomass and diversity of periphyton.3. There were distribution rules of N, P in the soil percolate of the ATE. The concentration of DON、NO3--N、TN and TP was high in topsoil percolate and it decreased with depth. But the concentration of NH4+-N was the lowest in topsoil percolate and increased with depth. The vertical distribution of nutritive salt was dependant on the humidity and seasons. It was highly correlated with the distribution of TOC, ORP, root biomass and edaphon in soil.4. The study about the heavy metals in wetland and plants indicated that the concentrations of heavy metals decreased with increasing depth in the top 40 cm soil, and then increased slightly with increasing depth. investigation also indicated that the concentrations of Cd, Cr, Pb and Zn exceeded the geochemical background values in Taihu Lake area, and the concentrations of Cd at all depth soil exceeded the Environment quality Standard for Soils of China. Correlation analysis suggested the heavy metals had the same origin. The dominant plants of the wetland were reed and false loosestrife, and the root is the main organ where heavy metals were largely accumulated. The general order was root >rhizome >stem >leaf, whereas in the false loosestrife, leaf was the main organ for Cr accumulation. Both reed and false loosestrife had the highest concentration factor to the Cu.5. The landscape vegetation has the function of ecology as well as the scenic; the research on the simulative overland runoff indicated that the order of the purify ability of TN、NH4+-N was Festuca arundinacea>Trifolium repens > Zoysia japonica; with TP, the order was F.arundinacea>Z.japonica>T.repens, and regarding NO3--N, the order was T. repens>F.arundinacea>Z.japonica. Generally, the strength of purify function increases with higher depth and lower slope.6. Based on the environment status of the lake Wulihu and the basal research of the west lake Wulihu, this thesis made the primary plan for the ecological restoration and reconstruction of the east lake Wulihu. The whole lake zone was divided as ecological protection zone, plants restoration zone, eco-system reconstruction zone and else zone, then the four zones were programmed respectively. With implementation of this project, the water quality of the Lake Wulihu can be improved significantly and the ecological function can be recovered to meet the environment requirement from the Eleventh Five-Year Plan for Environmental Protection. Besides this, it also improves the ecological, economical and general social development harmoniously.更多还原