基于放射性同位素的双龙库区营养盐历史重构

Historical Reconstruction of Nutrient in Sediment of Shuanglong Reservoir Based on Radioisotope

以滇池流域双龙库区为研究靶区,对沉积物柱进行放射性核素、营养盐浓度进行分析,结合定年结果及人类活动历史变化,解析沉积物中营养盐历史演变及其对人类活动的响应。结果表明,210 Pbex活度随深度增加呈现衰减趋势,沉积柱各营养盐总氮、总磷、总有机碳浓度剖面变化趋势均呈现自上而下递减,其浓度的增加与不同时期人类活动密切相关,反映了建库前后人为活动对生态环境演变的影响。根据C/N结果可以推断有机质来源为陆生与内源混合输入。

The sediment samples collected from the Shuanglong Reservoir were analyzed for the concentrations of 210 Pb ex,137 Cs,total organic carbon(TOC),total nitrogen(TN)and total phosphorus(TP).The distribution characteristics with depth and impact factors were discussed.Results showed that the 210 Pb ex concentration decreased with depth.The concentrations of TN,TP and TOC were much higher in the surface layers and decreased with depth.The increase in nutrient concentrations were closely related to the intensive human activities.The results of C/N suggested that endogenous plankton and terrestrial might be the main source of sedimentary OM.