京津冀典型湖泊湿地水体富营养化对CH4和CO2排放的影响及其机制

Lake wetlands play an important role in carbon cycle in the terrestrial ecosystem. The accumulation of carbon, nitrogen and phosphorus will change the process of carbon cycle as eutrophication becoming more and more serious in lake wetlands. Study on the effect of eutrophication on carbon emission as well as its mechanism in lake wetlands is scarce. The present study will be conducted in Baiyang lake, which is a typical eutrophied lake wetland in Beijin-Tianjin-Hebei region. In-situ measurement and laboratory incubation are designed to study the temporal dynamics, patterns and impacting factors of CH4 and CO2 emissions in lake wetlands of different degree of eutrophication. Effect of eutrophication degree on dissolved carbon-rich gases in water，organic carbon decomposition and methane production potential in lake sediments will be determined in lake wetlands. The mechanism of impact of eutrophication on carbon emission in lake wetlands will be ultimately studied. The present study is helpful to understand the carbon cycle process and will theoretically support the carbon emission reduction in eutrophied lake wetlands.

湖泊湿地在陆地生态系统碳循环中发挥着重要的作用。随着水体富营养化日趋严重，大量碳、氮、磷营养物质的累积将改变湖泊湿地生态系统的碳循环过程。目前，关于富营养化对湖泊湿地碳排放的影响及其机制的研究还非常有限。本项目拟选取京津冀地区具有代表性的富营养化湖泊湿地——白洋淀作为研究对象，通过野外原位观测和室内培养试验，研究不同富营养化程度湖泊湿地CH4和CO2季节排放动态、模式及影响因子，揭示不同程度富营养化对湖泊湿地水体溶存含碳气体的影响，明确不同富营养化程度湖泊底泥的有机碳分解及CH4产生潜力，探讨富营养化对湖泊湿地碳排放的影响机制。本研究有助于了解富营养化湖泊湿地碳循环过程，为湖泊湿地碳减排提供理论依据。

湖泊湿地在陆地生态系统碳循环中发挥着重要的作用。随着水体富营养化日趋严重，大量碳、氮、磷营养物质的累积将改变湖泊湿地生态系统的碳循环过程。目前，关于富营养化对湖泊湿地碳排放的影响及其机制的研究还非常有限。本项目拟选取京津冀地区具有代表性的富营养化湖泊湿地——白洋淀作为研究对象，分析富营养化对湖泊湿地CH4和CO2排放的影响。研究结果表明：（1）水体富营养化可能转换了湖泊水体CH4源汇功能；（2）水体富营养化可能加剧了水-气界面CO2通量的排放；（3）湖泊水体中溶存的CH4和CO2浓度表现为随着COD浓度增加而升高，随着TN、NH4+、NO3-、TP浓度增加而降低的趋势。（4）氮营养元素对底泥产甲烷能力的影响要高于磷营养元素以及氮磷交互营养元素。研究结果可以为准确评估湖泊湿地碳收支提供数据支持，为国家碳减排和生态补偿决策提供理论支撑，也为地方管理部门科学进行湖泊湿地富营养化治理提供理论依据。