【作者】 卢凤云；

【导师】 季宏兵；

【作者基本信息】 首都师范大学 ， 自然地理学， 2011， 硕士

【摘要】 水体中有机质来源的研究对流域侵蚀状况及水体营养质量的评估具有重要意义。本文选取北京市北部两个重要的水体——潮白河流域和野鸭湖湿地作为研究区域,进行表层沉积物和悬浮物采样,同时采集了研究区内的优势植物和土壤作为端元。测定和分析所有样品中C、N元素含量和稳定同位素(δ13C、δ15N)值,然后使用端元定位法对沉积有机质和悬浮颗粒有机碳来源进行示踪,进一步使用多元混合模型对这些来源的相对贡献进行定量计算。实验结果表明潮白河流域和野鸭湖湿地碳、氮同位素分布范围存在差异,潮白河沉积有机质的δ13C值间于-27.75‰～-21.58‰之间,δ15N值间于1.32‰～6.74‰之间,悬浮物中颗粒有机碳的δ13C值间于-29.34‰～-25.91‰之间,δ15N值间于-0.34‰～6.36‰之间；野鸭湖沉积有机质的δ13C值间于-27.07‰～-23.05‰之间,δ15N值间于0.24‰～7.86‰之间,悬浮物中颗粒有机碳的δ13C值间于-29.76‰～-26.70‰之间,δ15N值间于-1.10‰～7.59‰之间。通过有机质来源的定性和定量分析表明,潮河和白河沉积有机质主要来源为外源土壤有机质,悬浮颗粒有机碳主要来源为内源水生维管束植物,说明短期内表层沉积物更多的来自于物理侵蚀的粗糙产物,而悬浮物沉积下来的量很少,大部分随水流走；密云水库沉积有机质和悬浮颗粒有机碳主要来源均为土壤有机质,表明潮河和白河携带的有机物是密云水库沉积有机质的主要来源,而水库本身有机质的贡献则较少,个别站位沉积物中有数量的C4植物来源,悬浮物中有少量的C3植物来源；野鸭湖沉积有机质和颗粒有机碳主要来源均为水生藻类。潮白河流域沉积有机质来源分析表明,和河北境内相比,北京境内沉积有机质中土壤有机质的贡献减少,水生维管束植物和浮游植物的贡献增加,尤其表现在白河流域,同时也说明沉积有机质来源可以严格反映流域侵蚀状况。对比河流和湖泊中沉积有机质的来源,分析得出河流主要是外源,湖泊主要是内源,主要是因为河水的大量外源输入及相对短暂的水力停留时间,而湖泊处于相对封闭和稳定的水域环境。更多还原

【Abstract】 Source organic matter in water for the assessment of watershed soil erosion and Nutritional-quality has a very important role. The suspended particles、surface sediment、dominant plant and soil were collected in the Upper Reaches of the Chaobai River and Yeyahu wetland in northern Beijing.Elemental Contents (OC/TN) and stable carbon isotopic composition were analyzed and then employed to trace the sources of organic matter. At last, a three-end-Member mixing model was utilized to assess quantitatively contribution of different sources of organic matter in suspended particles and surface sediment.The result indicate that the carbon and nitrogen isotopes in the the suspended particles、surface sediment are different in the Upper Reaches of the Chaobai River and Yeyahu wetland. It was found that the ratio of carbon and nitrogen isotopic were-27.75%o～-21.58%o and 1.32‰～6.74‰in the surface sediments, while they are-29.34‰～-25.91‰and-0.34‰～6.36‰in the suspended particles respectively in the Upper Reaches of the Chaobai River. Furthermore, it was found that the ratio of carbon and nitrogen isotopic were-27.07‰～-23.05%o and 0.24‰～7.86‰in the surface sediments, while they are-29.76‰～-26.70‰and-1.10‰～7.59‰in the suspended particles respectively in the Yeyahu wetland.The analysis of Source organic matter indicated that soil organic matter is a significant contributor to sediment OM, while the vascular aquatic plants to suspended POM in the Chao River and the Bai River. This reveals that sediment is from particles of soil erosion, and suspended particles was washed away by river. Soil organic matter is a significant contributor to sediment OM and suspended POM in the Miyun reservoir, and a source of sedimentary organic matters in the Miyun reservoir is mainly carried by the Chao River and the Bai River, other source is from C4 vegetation growing around Miyun reservoir for individual point station. Aquatic algae is a significant contributor to sediment OM and suspended POM in the yeyahu wetland.Compared with the situation of Hebei province, the contribute of soil organic matters decreased obviously and river plankton vascular aquatic plants increased evidently in Beijing areas, especially in Bai River.This study reveals that the source of organic matter has a close relationship with the situation of soil erosion in the areas. Organic matter in river is mainly from outside source, and organic matter in lake is mainly from inside source.The reason of this difference is that there is vast outside source input and relative short hydraulic power remain time in river, but the environment is Closed and stable in lake.更多还原