持续的流域开发导致了云南湖泊面临富营养化、蓝藻爆发等环境问题，也改变了食物网结构与有机碳循环模式。为了评价富营养化过程对湖泊内源有机碳源及其传输路径的影响，拟针对枝角类浮游与底栖碳源开展综合研究，应用碳稳定同位素方法示踪有机碳源信号与沉积物有机质组成的变化。以营养水平不同的四个湖泊为研究对象，对现生枝角类及其主要碳源（如浮游植物、有机碎屑）开展季节与空间调查，识别枝角类的稳定同位素信号对浮游与底栖碳源的指示意义及其时空变化的主控因子。结合现代调查与表层沉积物分析，辨识枝角类壳体同位素信号指示现代过程的可靠性。进一步通过钻孔枝角类壳体与总有机质碳同位素信号的时间序列分析，应用同位素混合模型与多指标记录，甄别近百年来沉积物有机质组成与有机碳来源变化的历史与特征，最终识别高原湖泊营养盐富集影响有机碳传输路径的长期过程与区域模式。本研究可为认识污染湖泊的有机碳循环过程及开展生态修复提供科学依据。

With long-term catchment development, lakes in Yunnan have increasingly experienced nutrient enrichment and cynobacteria blooms, with significant ecological consequences such as changes in food web structure and organic carbon cycling. To uncover the effect of eutrophication on organic carbon sources and trophic pathways, we focus on cladocerans and their planktonic and benthic carbon sources and identify the signals of organic carbon source and the compositional change of sediment organic matters through stable isotope methods. Focusing on four lakes of different trophic state, spatial and seasonal surveys will be conducted on live cladocerans and their main carbon sources (i.e. phytoplankton and macrophytes) in lake waters for quantifying the relative role of benthic and planktonic pathways in driving the change of cladoceran isotope signals and identifying the drivers for their spatio-temporal variations. Through combining modern processes with surface sediment surveys, the reliability and sensitivity of their representation for modern isotope indicators will further be assessed. With time series analysis of the isotopic signals of both cladoceran valves and sediment organic matters, the history and patterns in the compositional changes of sediment organic matters and the pathways of carbon transfer during the last century were identified through the application of isotopic mixing models and multi-proxy sediment analyses. Finally, the regional patterns and processes in the transfer pathways of organic carbon will be evaluated in the context of nutrient enrichment. Therefore, this study will serve as scientific basis for evaluating the processes behind organic carbon cycling and facilitate the ecological restoration for polluted lakes in Yunnan.