Knowledge Resource Center for Ecological Environment in Arid Area
| 额济纳三角洲河岸带胡杨和柽柳水分来源划分研究 | |
| 其他题名 | The study of water sources dividing of Populus euphratica and Tamarix ramosissima in the riparian zones in Ejina Delta, the lower reaches of Heihe River Basin, China |
| 李亚飞 | |
| 出版年 | 2017 |
| 学位类型 | 硕士 |
| 导师 | 于静洁 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 额济纳三角洲位于我国第二大内陆河黑河的下游，是我国西北地区的重要生态屏障。该区降水稀少，蒸发强烈，植被主要分布在河岸带及尾闾湖岸。自2000年黑河下游实施生态输水工程以来，额济纳三角洲的河道流量、河道过水时间、地下水埋深、河水补给土壤水和地下水等一系列水文过程均发生了显著的变化，额济纳绿洲尤其是河岸带植被得到不同程度恢复。但黑河下游额济纳三角洲的生态用水与黑河中上游日益增长的社会经济用水产生矛盾，急需通过提高水资源利用效率和实现水资源的优化配置，解决水资源短缺问题。而额济纳三角洲植物水分来源的研究，可为生态用水提供直接证据，因此成为干旱区生态水文研究的热点之一。 为研究黑河下游额济纳三角洲河岸带胡杨与柽柳的水分来源及其时空变化规律，本研究考虑水源条件差异等，在额济纳东、西河沿岸选取8处样点，开展土壤质地剖面调查、植被调查和水文调查，于2015年的植物生长期7~9月及2016年6~9月，分别采集各样点处胡杨和柽柳木质部样品、分层土壤样品以及河岸带和非河岸带地下水样品；在2015年6月~2016年9月采集该地区降水、河水样品；经低温真空抽提获取土壤和植物木质部水分样品，与降水、河水和地下水一起，经过滤后利用液态水同位素分析仪测试，获取各样品的δ2H、δ18O数据序列，并用光污染校正曲线对植物木质部水分样品的δ2H、δ18O结果进行光污染校正；基于植物木质部水分的δ2H、δ18O与土壤水的δ2H、δ18O，利用氧同位素直接比较法确定植物主要吸水层位；土壤水氢氧同位素相对地区大气降水线的差值lc-excess用于判断植物主要吸水层位是否受蒸发影响；利用IsoSource线性混合模型定量各层土壤对植物水分的贡献率，以及各补给水源对各层土壤的贡献率，进而得到各补给水源对植物水分的贡献率。主要结论如下： (1) 额济纳三角洲河岸带胡杨和柽柳的主要吸水层位平均为100cm埋深至饱和土壤层的范围，但吸水层位存在显著的空间差异，河水漫溢使植物吸水层位上边界变浅，较粗的上层土壤质地使得植物吸水层位上边界变深，吸水层位的下边界主要受地下水位波动的影响。 (2) 利用“lc-excess”在土壤剖面的分布特征，将土壤剖面划分为lc-excess剧烈变化的蒸发渗透带(EP, Evaporation penetration)和lc-excess稳定在0值附近的优先补给带(PR, Prefenrential recharge)；胡杨和柽柳主要吸水层位在优先补给带PR范围内，该层位氢氧同位素受蒸发影响较小，未对补给水源贡献率定量造成干扰。 (3)该地区降水入渗的深度在0~40cm范围内，胡杨和柽柳几乎不利用该范围内的土壤水，因此降水因水量少且入渗深度浅，对胡杨和柽柳的贡献率可忽略；河水和地下水对胡杨贡献率分别为68%和32%，对柽柳的贡献率分别为35%和65%，且河水对胡杨和柽柳贡献率在输水期增大，地下水贡献率在非输水期增大。河水对胡杨和柽柳的贡献率在东河沿岸略高于西河沿岸；河水贡献率在河流上、中、下游略有差异，但空间差异并不显著。 (4)河岸带地下水与河水交互作用强烈使得二者的δ18O值较为接近，给基于氢氧同位素的植物水分来源定量带来干扰，有待通过提高采样代表性和测试精度以及优化模型等实现精准定量。 |
| 英文摘要 | Ejina Delta locates in the lower reaches of Heihe River, the second largest inland river in China. It is one of the important ecological barriers in Northwestern China. With low precipitation and strong evaporation in this region, the local vegetation mainly distributes in the riparian zones of rivers and tail-end lakes. Since 2000, with the implement of the project of environmental flow controls in the lower reaches of Heihe River, great changes have taken place for the local hydrological processes (e.g., streamflow, river discharge period, groundwater level depth, the reacharge of river water to soil moisture and groundwater). The local hydrological variations promoted the vegetation restoration in the oasis areas, especially in the riparian zones. University, the ecological water usage conflicted with the increasing social and economic water demand in the up and middle reaches of Heihe River. It became urgent to take action to improve water use efficiency and optimize water resource allocation. Since plant water use can provide the information of ecological water usage, it has been one of the hot topics in the field of eco-hydrological research in arid regions. The aim of this study was to quantify and analyze the spatial and temporal variations of the water sources of Populus euphratica and Tamarix ramosissima in the riparian zones of Ejina Delta, the lower reaches of Heihe River. Considering the hydrological variations, eight sampling sites were chosed along the East and West Rivers in Ejina. The soil textural profile, the vegetation distribution and hydrological condition at the sites were investigated before sampling. The samples of storeyed soil and plant xylem were taken monthly during the growth season of July to September in 2015 and June to September in 2016 at eight sites. The groundwater samles in the riparian and non-riparian zones were taken synchronously. The local rainwater, river water and groundwater were taken during the period of June, 2015 to September, 2016. The water samples of soil and plant xylem were extracted under the cryogenic vacuum condition. All the water samples were filtrated and then analyzed with Liquid Water Isotope Analyzer to obtain the δ2H and δ18O values. The δ2H and δ18O values of plant xylem water were revised with spectral interference correction curves. The δ18O values of soil moxiture were compared with the δ18O values of plant xylem water, to obtain the main depth of plant water uptake. The “lc-excess” (Line-conditioned excess), which represents the differences of δ2H and δ18O values between soil moisture and local meteorological water line (LMWL), was used for judging whether the plant water uptake zones was affected by evaporation. The linear-mixed model called “IsoSource” was used to quantify the contributions of different soil layers to plant water uptake, and the contributions of recharge water resources to different soil layers, so as to calculate the contributions of recharge water resources to plant water uptake. Main findings of this study are as follows: (1) The water uptake zones of Populus euphratica and Tamarix ramosissima were in the ranges from the average depth of 100 cm to the saturated zones, but the plant water uptake zones spatial varied. The upper boundary of plant water uptake zones was shallowed by river overflow, but deepened by rough texture of top-soil. Whereas, the lower boundary of plant water uptake zones was mainly affected by groundwater level variation. (2) According to the “lc-excess” curve of a specific soil textural profile, the soil layers was divided into the evaporation penetration zones (samplified as EP zones,), the lc-excess values of which sharply changed, and the preferential recharge zones (simplified as PR zones), the lc-excess values of which were relatively constant. The species of Populus euphratica and Tamarix ramosissima mainly absorbed water from the PR zones, where the soil moisture was less affected by evaporation, and thus had less effect on quantifying the contributions of recharge water resources. (3) The local rainfall maximally infiltrated into the depth of 40 cm, which was beyond the water uptake zones of Populus euphratica and Tamarix ramosissima, and thus the donation of rainwater to the two species could be ignored because of its less water amount and shallow infiltration depth. Populus euphratica utilized 68% of river water and 32% of groundwater respectively, while Tamarix ramosissima consumed 35% of river water and 65% of groundwater. During the discharge period of the environmental flow controls, the contributions of river water increased but the contributions of groundwater decreased; whereas, during the non-discharge period, the situations were reversed. The spatial differences of the contributions of river water and groundwater were not significant at the eight sampling sites, though contributions of river water were higher along the East River than that along the West River, and varied from the upper to the lower reaches of the East and West Rivers. (4) Affected by the exchange between river water and groundwater in the riparian zones, the δ18O values of river water and riparian groundwater were close to each other, which made it less accurate to quantify plant water source with hydrogen and oxygen stable isotopic analysis. The accurate quantifying of plant water source has to be improved through improving sampling representativeness and measuring accuracy, as well as optimizing modeling. |
| 中文关键词 | 荒漠河岸带 ; 植物水分来源 ; 氢氧稳定同位素 ; 黑河下游 ; 生态输水工程 |
| 英文关键词 | The desert riparian zone plant water source stable hydrogen and oxygen isotope the lower reaches of Heihe River environmental flow controls |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 环境科学 |
| 来源机构 | 中国科学院地理科学与资源研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287858 |
| 推荐引用方式 GB/T 7714 | 李亚飞. 额济纳三角洲河岸带胡杨和柽柳水分来源划分研究[D]. 中国科学院大学,2017. |
| 条目包含的文件 | 条目无相关文件。 | |||||
| 个性服务 |
| 推荐该条目 |
| 保存到收藏夹 |
| 导出为Endnote文件 |
| 谷歌学术 |
| 谷歌学术中相似的文章 |
| [李亚飞]的文章 |
| 百度学术 |
| 百度学术中相似的文章 |
| [李亚飞]的文章 |
| 必应学术 |
| 必应学术中相似的文章 |
| [李亚飞]的文章 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
