过去2000年湖泊生态系统演化是全球变化研究的重要内容。青藏高原湖泊生态系统脆弱，对气候变化响应敏感。项目选择青藏高原浅水草型湖泊—更尕海为研究对象，采用 AMS C-14、Pb-210和 Cs-137等测年手段建立更尕海沉积岩芯的年代序列，分析岩芯中枝角类、软体动物壳体、硅藻、沉水植物化石组成以及总有机碳和总氮含量变化，重建近2000年湖泊水生动植物群落演化序列，利用多种统计方法阐明生态系统结构、生物多样性等的演变过程。结合湖泊现代水文环境调查结果以及区域已经发表的古气候记录，分析不同时间尺度上湖泊生态系统演化对气候变化的响应机制。项目的开展有助于理解青藏高原浅水草型湖泊生态系统的长期演化模式与机理，为制定湖泊生态系统保护和恢复策略提供科学依据。

The evolutions of lake ecosystems in the past 2000 years have been key scientific issues in recent global changes studies. The lake ecosystems in the Qinghai-Tibetan Plateau are fragile, and are sensitive to climate changes. In this project, we choose a shallow, macrophyte-dominated lake, i.e. Genggahai Lake from the northeastern Qinghai-Tibetan Plateau as our study site. Chronological frame of a core drilled from the lake can be established through multi-dating methods of AMS C-14, Pb-210 and Cs-137. The evolution history of major aquatic flora and fauna communities over the past 2000 years will reconstructed based on analyses of total organic carbon (TOC) content, total nitrogen (TN) content, and biologic macrofossils (including cladocerans, mollusk shells, diatoms and aquatic plant remains). The structure, organization and biodiversity of the lake ecosystem will be clarified by multiple statistical methods. Combining with the results of modern hydrological environment investigations and the published paleoclimate records from this area, the response mechanisms of lake-ecosystem evolutions to climate changes at different time scales will be investigated. This research will play an important role in understanding of the ecosystem evolutions of macrophyte-dominated lakes and the potential forcing mechanisms on Qinghai-Tibetan Plateau, and will contribute to the strategy for the protection and restoration of lake ecosystems.