中文摘要：

为了探求内蒙古呼伦湖上覆水体和沉积物间隙水之间溶质运移机制，对呼伦湖的1个沉积物柱芯的间隙水、3个湖泊水体以及湖周边7个地下水体中的氯离子（Cl-），氢、氧稳定同位素（δD和δ18O）分别进行分析测试，并利用其示踪性对沉积物中溶质运移特征进行研究.结果显示，δD、δ18O和Cl-浓度在不同水体中的分布具有相似的分布规律，整体上从底部沉积物到上部湖水浓度分布呈现逐渐递减的抛物线趋势，在间隙水中最大值位于所取沉积物柱芯的最深处，Cl-浓度为306 mg/L，δD和δ18O分别为-58‰和-5.9‰；最小值位于沉积物柱芯上层，并与上覆水体中的值相似，Cl-浓度为159 mg/L，δD和δ18O分别为-66‰和-7.3‰.为了明确沉积物柱芯中间隙水的高浓度Cl-和偏正δD、δ18O的来源，比较不同水体的δ18O-δD关系点分布，表明含有偏正值的δD、δ18O和高浓度Cl-的间隙水与上覆湖水关系密切，可能是由于低水位时期湖水与间隙水相互发生扩散作用而产生的结果.一维对流扩散迁移模型证实扩散作用是控制着沉积物间隙水中溶质浓度在垂向上分布的主要机制，同时湖水水位的变化会影响沉积物间隙水与上覆水体的扩散过程，特别是在水位上升期，富集在沉积物中的溶质可能成为湖水的重要物质来源，影响上覆水体的水质.因此，对于封闭湖泊水位的控制和管理不仅在维持湖泊水量方面有着直接的作用，同时在稳定湖泊水质条件上也有着重要的意义.

英文摘要：

To get a better understanding of the solutes transport between overlying lake water and sediment pore water, several water samples from sediment core, lake, wells around the lake were sampled, stable isotopes （oxygen-18, deuterium） and chloride were analyzed and used as tracers to identify the mechanism of solutes transportation through the sediment in Lake Hulun, China. The results showed that the distribution of chloride has the same characters with isotopic compositions in sediment pore water. The highest values （306 mg/L for Cl-, -58‰ for δD, -5.9‰ for δ18O, respectively） in pore water located in the bottom of the core, however, the lowest values （159 mg/L for Cl-, -66‰ for δD, -7.3‰ for δ18O, respectively） exist at top of the core and similar with that in overlying lake water. The well waters have the lower values （18 mg/L to 79 mg/L for Cl-, -13.3‰ to -11.4‰ and -101‰ to -87‰ for δ18O and δD）. Such difference between well water and pore water may illustrate that pore water in this shallow core was not affected by underlying groundwater, the high concentration of chloride and more positive isotopic compositions in pore water only result from surface water evaporation. Furthermore, combined with field data of historic chloride concentration of lake water, pore water with high concentration of chloride and more positive isotopic compositions is likely from the lake water during period of the lowest water level. The diffusive model results suggest the variations of chloride concentration with time in pore water reflect the transport mechanism in this study. In the period of 1941 to 1999, lake was in high and stable water level, and the chloride was equilibrium between sediment pore water and overlying water. In the period of 2000 to 2012, more concentrated chloride migrated from high chloride concentration in overlying lake water to the pore water due to evaporation and decreased river discharge. After 2012, high concentration in pore water was eliminated by lake water with