【作者】 郭长城；

【导师】 喻国华； 王国祥；

【作者基本信息】 南京水利科学研究院 ， 港口、海岸及近海工程， 2007， 博士

【摘要】 生态修复是当今国内外研究的热点问题,修复退化生态系统、改善环境质量的研究与实践已经逐步得到广泛重视。针对江滩湿地生态退化和环境状况特点,研究江滩湿地主要环境因子对湿地植物恢复重建的影响、湿地植物恢复重建后的环境效应等,为江滩湿地的修复、环境质量的改善提供依据。论文主要开展了以下几个方面的研究:(1)通过模拟试验研究了底质水分含量、水位、泥沙淤积、泥沙附着、水体浊度等对湿地植物生长发育的影响。结果表明,①湿地植物萌发与底质水分含量显著正相关。在无淹水基质上,土壤水分含量越低,菖蒲萌发率越低,土壤水分含量10%时,萌发率仅32.5%,幼苗平均高度19.0cm,为饱和水分条件下的1/3。淹水程度对菖蒲萌发影响显著,菖蒲在淹水深度120cm时最终萌发率仅为35%。中度(0.35%TOC)有机质含量可能是沉水植物生长的有利条件。②菹草石芽上淤积的泥沙虽不影响最终萌发率,但延迟萌发时间,对单株平均生物量影响较明显,实验105天,无淤积菹草单株生物量是淤积厚度5.0cm菹草的2.7倍。③泥沙附着可导致沉水植物衰亡,沉水植物在泥沙附着情况下启动应急保护机制,如丙二醛(MDA)含量、过氧化物酶(SOD)活性及超氧化物歧化酶(POD)活性增加,以进行自我保护。④水体浊度不影响菹草石芽萌发,但延迟石芽萌发速率,同时,高浊度明显抑制苦草成株的生长及光合产能效率,对苦草光合系统PSⅡ造成较大损伤,最终影响其恢复重建。(2)在可控条件下构建了由挺水、浮叶及沉水植物组成的镶嵌组合群落,并初步研究其对水体悬浮泥沙及氮磷的去除与净化效果。结果表明:湿地植物通过改变水流动力条件,改变水体泥沙运动规律,同时植物体表还会吸附部分较小粒径组成的悬浮颗粒物,对水体悬浮泥沙有较好的去除作用。挺水、浮叶和沉水植物对水体悬浮泥沙去除效果挺水植物(36.74%)＞浮叶植物(18.38%)＞沉水植物(13.16%)。沉水植物对悬浮泥沙的平均去除率差别不明显,依次为黑藻(14.38%)＞苦草(12.80%)＞金鱼藻(12.33%)。挺水植物对较大粒径组成(25μm-50μm和10μm)的泥沙具有较好的去除作用。沉水植物对较小粒径(2.5μm、7μm和10μm)的泥沙具有较强的吸附效果。在冬春季节,菹草对粒径组成为10μm-25μm的泥沙颗粒影响显著。江滩人工湿地在去除水体悬浮泥沙的同时也去除了水体中大量氮磷元素。江滩人工湿地对挟沙水体中总磷的净化百分率在12小时的停留时间内可达34.8%,比对照28.19%高出6.61%,对水体总氮的去除率为11.9%,比对照组5.3%高出6.6%。菹草对平均泥沙含量83.0 mg/L、平均总磷含量0.053mg/L的水体,在滞留时间24小时条件下,对总磷的净化百分率可达10.83%。(3)论文在实验室通过模拟方法还研究了泥沙与不同形态氮、磷和COD等的耦合特性,粒径组成、pH值、泥沙含量、污染程度、温度、扰动时间等均可影响泥沙对污染物的吸附效果。随污染物或泥沙含量增加,吸附效果明显增强。泥沙粒径组成越细吸附效果相对越好,单位重量的粒径组成为44μm-55μm的泥沙吸附量是125μm-150μm的2倍。酸性条件下吸附效果较碱性条件下明显,pH=1下吸附量达0.85mg/g,pH=13下释放量达0.147mg/g,这可能与泥沙表面有机质及金属离子的组成有关。特定温度25℃下前2个小时的吸附百分率可达53.14%。(4)通过示范研究了人工江滩湿地系统对长江水体悬浮泥沙颗粒物及氮、磷等的去除效应。在实验条件下,挺水植物对平均泥沙含量130.87mg/L的长江水体,去除率达75%,100小时的沉降量达402g/m~2。菱对长江水水体泥沙去除率37.8%,100小时的沉降量达271g/m~2,而去除率为8.1%,沉水植物区沉降量0.0115g/m~2。监测结果初步验证了室内模拟实验的结论,对工程实践具有较强的指导意义。(5)水力负荷及水力停留时间是影响人工湿地系统对挟沙水体悬浮颗粒物及营养元素去除净化的重要因素。室内实验和室外示范研究的结果均表明,适当控制水力负荷可达到较好的悬浮泥沙颗粒物及营养元素的去除效果。更多还原

【Abstract】 Ecological restoration is hotspot of study nowadays inside and outside our country.Study and ways of restoration of degenerated ecosystem and improve environment are applied widely.In allusion to degeneration and environmental characteristic of flood beaches wetland study for influence of main environmental factors to ecological restoration and wetland restoration environmental function et al can provide basis for restoration of flood beaches wetland and environmental improvement.The main points of this doctoral dissertation are listed as follows.1.The influence of soil,water level,sediment deposition and sediment-attaching to growth is studied under simulate condition in laboratory.①There is remarkable relativity between germination and soil water level.The germination ratio is only 32.56%under sustaining drought condition and the ratio is 1/3 of normal condition. The average stature is 19.0cm under sustaining drought condition and the ratio is 1/3 of normal condition.Soil pollute has some influence to highness and chlorophyll content of submerged plants.Middle level pollution of soil is favorable to submerged plants.Water level has some degree influcncc to bourgcon of Acorus calamus Linn.Thc ratio of germination of Acorus calamus Linn.is only 35%under 120cmwater level.②Sedimcnt deposition can delay the germination of bud of Potamogeton crispus.Sediment deposition has no influence to bud of Potamogeton crispus,but has evident influence to biomass of single Potamogeton crispus.The biomass of single Potamogeton crispus（sediment deposition is 0.0cm） is 2.7 times（the biomass is 2.23g/single） of that sediment deposition is 5.0cm.③Sediment-attaching debase the photosynthesis and increase the MDA of Vallisneria spiralis.The structure and function of membrane may be shatter.However sediment-attaching facilitate the producc of superoxide dismutaes（SOD） and Peroxidase（POD） that clear away overfull O^2-.④Feculent water has no influence to bud growth of Potamogeton crispus,but delay the germination of bud of Potamogeton crispus.Photosynthesis have remarkable difference because of feculent and this lead to distinction of growth.Potamogeton crispus has high growth speed in low level feculent water.There are many factors which influence the restoration and construction of ecosystem.Such as DO,T,depth,soil,polluted load,attachment （alga,secretion etc.） and illumination.Pilot study is applied in this dissertation in order to explain how the diaphaneity influence the restoration and construction of submerged plants.2.Decontamination of community composed by hydrophytes（emerging plants, floating-leaved plants and submerged plants） to suspended sediment and TN,TP is studied in the condition of manmade.It indicates that the result is so evident.The mechanism of decontamination is from federal action of several different hydrophytes （emerging plants,floating-leaved plants and submerged plants）.The decontamination ability of hydrophytes to suspended sediment is emerging plants（36.74%）＞floating-leaved（18.38%）＞submerged plants（13.16%） and Hydrilla verticillata （14.38%）＞Vallisneria spiralis（12.80%）＞Ceratophyllum demersum（12.33%） among those submerged plants.Emerging plants have evident impact to sediment of big particle size（such as 25μm-50μm and beyond 10μm） and submerged plants more have evident impact to sediment of little particle size（such as below 2.5μm,7μm and 10μm ）.In winter Potamogeton crispus can improve the diaphaneity of water by reducing concentration of sediment.Potamogeton crispus has important impact on sediment of average particle size and 10μm-25μm.In the same time,decontamination of community composed by hydrophytes（emerging plants,floating-leaved plants and submerged plants） to TN and TP is also studied.Manmade everglade can also reduce TN and TP in the course of reducing sediment.The cleaning presses to TN and TP include three aspects.Manmade everglade can reduce 34.8%of TP in 12 hours HRT and this is higher 6.61 ratio than 28.19%of the CK.To TN the number is 11.9%and this is higher 6.6 ratio than 5.3%of the CK.In winter however the Potamogeton crispus can reduce 10.83%of TP.3.Coupling or adsorption of Yangtze River sediment and different kinds of N and P as well as COD is studied in laboratory.Sediment diameter,pH, concentration of sediment,pollute degree,temperature and surge time may all influence the adsorption.The adsorption became strong when concentration of sediment or contamination increases.At the same time the minute of sediment diameter the more evident for adsorption.The adsorption capacity of sediment which the diameter is 44-55μm is two times of that for the sediment of 125-150μm.The adsorption is more evident under acid condition.The adsorption capacity is 0.85mg/g at pH=1 and the desorption capacity is 0.147mg/g at pH=13 however.The adsorption capacity for two hour is 53.14%under 25℃.4.In order to validate the conclusion of laboratory demonstration research is performed for the removal of sediment and contamination by macrophytes of constructed flood beaches wetland.Under the condition of precontract emerging plants can remove 75%sediment for the Yangtze river water（the concentrate of sediment is 130.87mg/L）,and the sedimentation is 402 g/m² in 100 hours.However, the removal and sedimentation by floating-leaved is 37.8%and 271g/m².The demonstration research is high up in the pictures in some degree and this must has important guidance for ecology restore engineering.5.Hydraulic burthen or HRT is one of the very important factors in the course of reducing to sediment and TN,TP.In order to achieve more evident effect Hydraulic burthen and HRT must be controlled properly.更多还原