流域生物地球化学循环与水文耦合过程及其调控机制

Biogeochemical cycle and its hydrological coupling processes and associative controlling mechanism in a watershed

流域生态系统的水文和生物地球化学循环通过水文通量的物理作用紧密耦合,其时空尺度的物质和能量耦合为流域生物地球化学过程的物质平衡和能量流动提供重要基础。通过研究流域尺度生物地球化学循环—水文耦合过程,将更加深刻揭示水循环驱动下陆地—水生生态系统碳氮循环与人类活动及气候系统的生物学、物理学和化学过程的耦合机制。本文综合阐述了流域生态系统的时间、空间以及时间—空间尺度的生物地球化学循环与水文耦合特征,揭示营养元素循环在时间—空间尺度上的耦合特征,通过大气、陆地、河流、河口和海洋系统形成了一个连续体并由水、气体和气溶胶通量进行物理连接;分析流域营养物质的生物地球化学循环与水文耦合过程随着时空尺度在大气—陆地界面、陆地—河流界面以及河口—海洋界面的耦合变异性;最后通过流域生态化学计量特征及水陆交错带对营养物质输出的调控分析耦合过程的生物学调控机制,以提高对流域景观水平的生态水文、生物地球化学和生态动力学的理解。

Hydrological and biogeochemical cycles process in a watershed ecosystem are closely coupled by the physical function of the hydrological flux, of which the coupling process of the matter and energy in the spatial and temporal scales will provide important basis for matter balance in biogeochemical cycles. These cycles also influence ecosystem productivity and exchanges with the atmosphere and the downstream water bodies. Therefore, the research on biogeochemical cycle and hydrological coupling process in the watershed scale will reveal the coupling mechanism on the carbon-nitrogen coupling cycles between terrestrial and aquatic ecosystem under water cycle driving, and the interaction of human activities and associated biological, physical and chemical processes under climatic change. The aims of this study are to synthetically clarify the biogeochemical and hydrological coupling characteristics in temporal, spatial and spatio-temporal scales within a watershed ecosystem, reveal the coupling of nutrient cycling in spatio-temporal scales within a continuum of atmosphere-land-riversestuaries-marine systems, which are connected by water, gas and aerosol fluxes; disclose the biological regulation mechanism of the biogeochemical and hydrological coupling processes by the change of ecological stoichiometry characteristics within the watershed and the regulation of nutrient input and output by water-land interaction zone, and then finally enhance our understanding of ecohydrological and biogeochemical process and its ecological dynamics at watershed landscape scale.