基于稳定同位素技术研究陆源有机质向青海湖输入

Terrestrial organic matters are the most important sources of inland lakes (e.g., Qinghai lake), therefore, the environmental changes around the lake exhibit great influnce on the composition and content of the inland lake ecosystem. At present, the environments in Qinghai lake and the surounding areas have deteriorated significantly due to the natural environmental changes and human activities, which has exerted great negative impacts on the ecosystem balance, and sustainable development of nature, society and economy. However, most studies focus on the single influence of environmental changes on either terrestrial or lake ecosystem; not regarding the interaction of them. Therefore, our project plans to take Qinghai lake as an example, focus on the input process of organic matters of terrestrial ecosystem into lake ecosystem, link the two ecosystems with the primary consumers (planktonic copepods and benthos), measure the stable isotopes of carbon, nitrogen of terrestrial and lake ecosystems, illustrate the process and mechanism of terrestrial organic matters to incorporate into the lake system through land-lake food web, trying to clearify the contribution of terrestrial organic matters to Qinghai lake ecosystem. Our project will not only help promote the health evaluation, effective management and integrative utilization of resources of Qinghai lake ecosystem, strengthen the process of protection and restoration of the lake system, but also play a key role in maintaining biodiversity and stability of Qinghai lake ecosystem and the surrounding areas.

湖体周围环境变化直接影响陆源有机质对内陆湖体的补给和输入。目前，受自然环境条件变化和人为活动的综合影响，青海湖地区的生态环境急剧恶化，必将影响陆源有机质向湖体的输入和补给。然而，有关青海湖流域的研究多侧重环境变化对陆地生态系统的影响，而忽视了陆地生态系统对湖体生态系统的作用。本研究以陆地生态系统对湖体生态系统的有机质输入为主线，以湖体初级消费者（浮游桡足类和底栖动物）为纽带，通过对陆源和当前湖体有机质稳定性碳、氮同位素的测定，基于同位素生物地球化学过程和质量平衡原理，揭示陆源有机质参入到湖体营养的过程和动态，阐明湖区环境变化的大背景下陆源有机质对青海湖湖体的输入和贡献。项目实施对维持青海湖生态系统生物多样性及其稳定性起重要的理论指导作用，将有助于促进湖体生态系统的健康评价、有效管理和湖体资源合理利用。

湖体周围环境变化直接影响陆源有机质对内陆湖体的补给和输入。目前，受自然环境条件变化和人为活动的综合影响，青海湖地区的生态环境急剧恶化，必将影响陆源有机质向湖体的输入和补给。本项目以青海湖湖区及主要入湖河流（倒淌河、泉吉河、布哈河、黑马河、沙流河）为研究区域，通过对其湖内颗粒有机质、沉积有机质、浮游动物、水生植物（藻类）、底栖无脊椎动物、裸鲤（含鳅类），湖边土壤、植被和主要食鱼鸟类粪便中碳、氮稳定性同位素组成的测定，依据IsoSource软件分析，初步阐明了青海湖湖区生态系统土壤、植被、颗粒有机质、沉积有机质、浮游动物和植物的稳定性碳氮同位素的组成特征及分馏模式，初步揭示陆源有机质参入到湖体营养的过程和动态，阐明湖区环境变化的大背景下陆源有机质对青海湖湖体的输入和贡献。.项目对湖体营养的有机质输入过程和动态的研究成果，为青海湖湖区生态系统的恢复与重建、生态系统生物多样性的维持和可持续发展以及青海湖裸鲤资源的合理保护和利用提供了基础资料和理论依据，将有助于促进湖体生态系统的健康评价、有效管理和湖体资源合理利用。