中文摘要：

基于环境放射性核素210Pbex和137Cs计年法确定抚仙湖北部、中部和南部3个沉积物柱芯的沉积年代,分析了各柱芯近150年的营养盐（TOC、TN和TP）浓度和粒度的垂向分布特征及其相关关系。结果表明,抚仙湖沉积物柱芯TOC浓度整体由稳定、下降转向缓慢增长,TN浓度整体呈小幅度波动趋势,TP浓度垂向分布较为复杂,整体上呈先下降后上升的趋势,这些变化特征与流域历史时期不同程度的自然演化和人类活动密切相关。抚仙湖沉积物中CN自北向南逐渐升高,表明抚仙湖沉积物中有机质来源由湖泊内部菌藻类逐渐过渡至地表陆生植物的贡献。抚仙湖不同湖区沉积物粒度垂向分布均较为紊乱,其大小表现为中部〉北部〉南部,该现象可能与周边入湖河流的密度、长度及产沙量等有关。抚仙湖沉积物中营养盐浓度和粒度的相关性研究表明,TOC浓度与粒径32~63μm呈显著正相关,与4~8μm呈显著负相关;TN浓度与各粒级之间无任何相关性存在,TP浓度则与粒径〈2μm呈显著正相关。

英文摘要：

Based on the results of radionuclides （^210pbex and ^137Cs） dating of three sediment cores respectively from northern, central and southern parts of Lake Fuxian, vertical distribution and correlation of nutrients （TOC, TN and TP） and grain sizes in the past 150 years were analyzed. The results showed that the TOC concentration varied from stable and slow states to rising in sediment cores. The vertical distribution of TN concentration showed a slight fluctuation characteristic. The variation trend of TP concentration was relatively complex, with the overall trend of dropping firstly and rising later. These variation characteristics were closely related to different levels of natural evolution and human activities in past periods. The C/N ratio in the sediment cores had the rising trend from north to south, indicating that the origin of organic matter in the sediments from Lake Fuxian gradually transited from bacteria and algae within the lake to the land plants. The vertical distribution of grain sizes in sediment cores was disordered, and the size order was central 〉 northern 〉 southern, which may be related to the density, length and sediment yield of rivers in the lake catchment. The correlation analysis of nutrients and grain sizes demonstrated that the size in range of 32-63 p,m was significantly positively correlated with TOC concentration, while the size in range of 4-8 μm was significantly negatively correlated with TOC concentration. No correlation was found between TN concentration and grain sizes, and the size of below 2μm was significantly positively correlated with TP concentration.