三峡库区典型消落带优势草本植物氮磷淹水释放特征
文献类型：学位论文
| 作者 | 王建超 |
| 学位类别 | 硕士 |
| 答辩日期 | 2011-05-27 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 朱波 |
| 关键词 | 三峡库区 消落带 淹水 植被 氮磷释放 |
| 其他题名 | Characteristics of Nitrogen and Phosphorus Release Under Inundation from the Dominant Herbaceous Plants in the Typical Water-Level Fluctuation Zone of the Three Gorges Reservoir Area |
| 学位专业 | 环境工程 |
| 中文摘要 | 水库消落带是水生生态系统与陆地生态系统的衔接过渡地带，对水库水体营养盐具有源和汇的双重作用。消落带淹水后植被腐烂分解导致大量氮、磷释放进入水体，可能成为水库富营养化的重要污染源。三峡水库消落带面积达349km2，而针对消落带植物养分淹水释放的研究还缺乏实质性进展，因此，研究三峡库区消落带植物淹水后氮、磷养分释放特征是三峡水库营养源解析的重要内容，对三峡水库蓄水后环境效应评价及水环境保护具有重要意义。本研究借鉴陆地生态系统凋落物分解研究方法，通过室外室内实验研究了三峡库区消落带植物淹水后的分解过程和氮、磷养分释放特征，初步查明了三峡水库蓄水后消落带植被的分解情况和氮(N)、磷(P)养分的释放机制和通量，弥补了消落带植被生态重建风险评估的不足，对三峡库区营养盐源解析和库区水环境评价提供了基础数据。 1. 三峡库区消落带经过多次淹水，陆生植被反应明显，物种多样性急剧降低。自然恢复植被类型主要为一年生草本植物。地上生物量、植被盖度和物种多样性沿水位高程梯度呈先增加后减小的抛物线状分布特征。消落带下部地上生物量和物种多样性与中上部存在显著差异。 2. 消落带草本植物初始基质的碳、氮含量差异显著，磷含量彼此相近。消落带植物的淹水分解过程具有明显的阶段性，初期分解较快，后期逐渐减缓。Olson指数衰减方程能够较好的描述消落带优势草本植物的分解失重动态。 3. 消落带植物的淹水浸泡会造成水体色度的加深、pH升高和Eh降低。消落带植物淹水后存在氮磷养分的释放，氨态氮和总氮释放过程浓度变化呈抛物线状，总磷释放过程呈对数曲线状。不同植物的氮磷养分释放过程、释放量、释放速率均存在显著差异。氮磷养分的释放峰值时间总氮(TN)＝总磷(TP)＜氨态氮(AN)，养分释放量和释放速率均是总氮＞总磷＞氨态氮。 4. 三峡库区消落带草本植物淹水完全腐烂分解后的污染负荷为：总氮125.2kg/hm2，总磷21.0kg/hm2。消落带植被淹水分解后释放出的氮磷养分已成为三峡水库营养物质的重要来源和影响水库水环境安全的重要因素。 5. 几种消落带优势草本植物淹水后的分解系数与其初始基质碳含量、C/N、C/P呈负相关，与氮含量、磷含量、N/P呈正相关。 6. 不同pH值对消落带草本植物的氮磷养分释放过程和释放量有影响。酸碱性条件促进了消落带植物淹水分解后总氮(TN)、氨态氮(AN)和总磷(TP)的释放。不同pH值条件下消落带植物的氮磷释放峰值时间酸性＞碱性＞中性。 |
| 英文摘要 | Water-level fluctuation zone was the ecotone of aquatic ecosystems and terrestrial ecosystems. It has a dual role of sources and sinks about nitrogen and phosphorus of reservoir. Vegetation decomposing after flooding will lead to a large number of nitrogen and phosphorus released into the water, which is more likely to be an important source of pollution in eutrophication. However, the domestic current study also has not yet concerned this area. The Three Gorges Reservoir area is huge with a total area of 349km2, then the research of nitrogen and phosphorus release from plants in water-level fluctuation zone is the important content of nutrient sources analysis, which has a great significance for eutrophication research and control of the Three Gorges Reservoir. This study through simulated experiment indoors and decomposition experiment outdoors, borrowing ideas from forest ecosystem and grassland ecosystem litter decomposition research methods. To make sure the decomposition rates and the characteristic of nitrogen and phosphorus release of plants, also the main influence factors under natural conditions in water-level fluctuation zone. 1.Most of the land plants in water-level fluctuation zone are sensitive to waterlogged environment after repeated flooding of the Three Gorges Reservoir, species diversity decreased significantly. Natural restoration of vegetation is mainly annual herb and along with water-level elevation gradients showed a layered distribution. Species diversity, the biomass and coverage along with water-level zone first increased and then decreased, showed a single-peak pattern. There has a significant differences on species diversity, the biomass and coverage between the lower and the upper part of water-level fluctuation zone. 2.Vegetation in water-level fluctuation zone has a significant difference on initial carbon content and nitrogen content, but the initial phosphorus content is similar to one another. Vegetation decomposite rapidly in the initial first month. Olson exponential equation can be used to describe weight loss in process of the decomposition of vegetation in water-level fluctuation zone. 3.Waterlogged vegetation can cause the deepening of water color, the higher of water pH and the lower of Eh. There has the release of nitrogen and phosphorus from vegetation in water-level fluctuation zone after flooding. The release process of total nitrogen(TN) and ammonia nitrogen(AN) showed a parabolic curve, but the process of total phosphorus(TP) release showed a logarithmic curve. There has a significant differences among the process of nitrogen and phosphorus release of plants, the amount and the rate of nitrogen and phosphorus release is also. The peak time of nitrogen and phosphorus release is TN=TP＜AN, the amount and the rate of release is TN＞TP＞AN. 4.The pollution loads of nitrogen and phosphorus from decomposition of the unit area vegetation in water-level fluctuation zone of the Three Gorges Reservoir are 125.2kg/hm2 and 21.0kg/hm2. The nitrogen and phosphorus released from vegetation decomposition after flooding in water-level fluctuation zone has became an importance nutrient source. 5.The decomposition coefficient of plants in water-level fluctuation zone is significantly negatively correlated with the initial carbon content, C/N and C/P, positively correlated with nitrogen content, P content, N/P. 6. Different pH have some effects on the process and amount of nitrogen and phosphorus release, and which have inconsistent impact on different plants. Acidic and alkalescent conditions promote the release of TN, AN andTP. The peak time of nitrogen and phosphorus release from vegetation under different pH conditions is acidic＞alkalescent＞neutral. |
| 语种 | 中文 |
| 公开日期 | 2013-01-25 |
| 源URL | [http://192.168.143.20:8080/handle/131551/4844]  |
| 专题 | 成都山地灾害与环境研究所_山地表生过程与生态调控重点实验室 |
| 推荐引用方式 GB/T 7714 | 王建超. 三峡库区典型消落带优势草本植物氮磷淹水释放特征[D]. 北京. 中国科学院研究生院. 2011. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
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