研究揭示滨海潮滩地下环境氮循环调控机制

Coastal tidal flats are a key ecological link connecting land and sea. The hydrological processes in the interface are violent, material exchange and microbial metabolism are frequent. They are hot spots for nitrogen biogeochemical cycles in coastal areas. Submarine groundwater discharge is an important channel for the transport of land-based nutrients to the offshore. Its transport flux and component characteristics directly regulate the eutrophication process of offshore water bodies and the health and stability of the ecosystem.

Recently, a research team from the Yantai Coastal Zone Institute of the Chinese Academy of Sciences used a combination of high-resolution groundwater spatial monitoring and numerical simulation to systematically reveal how tide-driven groundwater flow regulates the migration and transformation process of dissolved inorganic nitrogen (DIN) and its export mechanism to the offshore, and improved the refined mechanism of nitrogen cycle in coastal tidal flats.

研究团队选取山东半岛四十里湾砂质潮滩为研究区，开展了高分辨率野外监测与数值模拟研究。结果表明，潮汐驱动的潮滩地下水循环呈现显著的空间结构特征，潮间带可划分为高速排泄区、中等交换循环区和深层低速循环区三个典型水动力分区。不同分区内氧供应、营养盐底物输送和反应时间的差异，实现了硝化、反硝化、厌氧氨氧化及硝酸异化还原成铵等氮转化途径在空间上的功能分工。

Research has confirmed that the output flux of nearshore DIN is not solely determined by the intensity of groundwater discharge, but is the comprehensive result of the coordinated regulation of groundwater physical transport and internal nitrogen transformation processes. During the migration process of terrestrial nitrogen within the tidal flats, significant morphological transformations and flux changes have occurred. Coastal tidal flats are not simple nutrient transport channels, but active reaction interfaces with highly regulated capabilities.

研究建立了“潮汐驱动水动力过程—水动力分区—氮转化路径—近海输出通量”之间的机制链条，深化了对滨海潮滩地下环境氮循环调控机制的系统认识，为全球变化背景下滨海生态系统营养盐输入与富营养化风险评估提供了科学依据。

相关研究成果发表在《水文学杂志》（Journal of Hydrology)superior. The research work was supported by the National Natural Science Foundation of China,Taishan Scholars Young Experts Program of Shandong Province等的支持。

Paper link 

潮汐地下水驱动氮循环及界面输出机制示意图