河口潮滩N2O产生途径的定量辨识与调控机理研究

Production and emission of nitrous oxide (N2O) in estuarine and coastal environments have attracted considerable attentions and been identified as a hot and cutting-edge scientific issue. However, quantitative discrimination and associated influencing mechanisms of N2O generation pathways in these complex ecosystems still remain unclear so far. Extensive intertidal mudflats have developed along the Yangtze estuarine and coastal zone due to the deposition of substantial amounts of suspended sediment from the Yangtze River Basin, which are considered an ideal field laboratory. Therefore, in this study the Yangtze estuarine and intertidal flat is selected as a typical study area. The objectives of this project are (1) to study the spatiotemporal distributions of the main pathways of N2O production in the estuarine and tidal environment with nitrogen and oxygen stable isotopic techniques, (2) to quantitatively discriminate the N2O generations from nitrification, nitrifier denitrification, denitrification and coupled nitrification-denitrification, (3) to reveal the key factors and the microbial mechanisms controlling N2O generation with molecular microbial techniques. This project is of significance to further understanding of N2O generation mechanisms in the estuarine and intertidal ecosystems. Also, it can provide important guidance for controlling N2O production in these environments.

河口滨岸环境中氧化亚氮（N2O）的产生与排放研究是当前广泛关注的热点和前沿科学问题。然而，在河口滨岸这一复杂环境系统内有关N2O来源的定量辨析及调控机理至今尚未被清楚地认识。鉴于此，本项目拟以长江口潮滩作为典型研究区，运用氮氧稳定同位素示踪和现代分子生物学技术，研究河口潮滩环境中N2O主要来源途径的空间变异与时间变化特征，定量辨析硝化、硝化细菌反硝化、反硝化和耦合的硝化-反硝化对河口潮滩N2O产生的贡献，阐明影响河口潮滩N2O来源途径的关键因素，并揭示影响河口潮滩N2O产生的微生物作用机理。通过本项目的开展，不仅可深化对河口潮滩N2O产生机制的理论认识，而且可为调控河口潮滩环境N2O的产生提供重要的科学依据。

有关自然生态系统中N2O的产生及其影响机制研究是当今学界的研究热点和前沿科学问题。作为陆地和海洋生态系统的重要过渡带，河口海岸是氮循环的热区，也是N2O产生的重要场所。近年来，国内外学者对河口海岸环境N2O的排放通量进行了大量研究，但对N2O的主要来源途径缺乏定量化认识。为此，本项目选择长江口潮滩作为典型研究区，运用氮氧稳定同位素和现代分子生物学技术，分析了河口潮滩环境中N2O主要来源途径的空间变异与时间变化特征，定量辨析了硝化、硝化细菌反硝化、反硝化等过程对河口潮滩N2O产生的贡献，阐明了影响河口潮滩N2O来源途径的关键因素，并揭示了影响河口潮滩N2O产生的微生物调控机理。相关研究成果已在Science Advances、Water Research、Journal of Hydrology等国际主流学术期刊上发表学术论文25篇，获批专利2项。上述研究成果深化了对河口海岸环境N2O产生机制的理论认识，同时可为河口滨岸带湿地生态环境的保护与管理、以及N2O产生与排放控制提供重要的科学依据。