芦苇型水陆交错带湿地根孔及根际环境对氮素去除的影响及其机理研究

Nitrogen is one of the key factors of eutrophication in wetland. Studies had showed that the reed root channels at land/inland water ecotones have the abilities of transferring water, oxygen and solute, promoting the nitrification and degradation of nitrogen in the rhizosphere by forming biofilm with rhizosphere microorganisms. However, the nitrogen-removing effect and its mechanism of root channels and rhizosphere environment at reed-dominated land/inland water ecotones were not clear. Therefore, the project is planned to analyze the transformation characteristics of applied nitrogen and soil nitrification/denitrification microorganisms quantity and community structure in order to investigate the effect and mechanism of reed root channels and its rhizosphere environment in the transfer and transformation of applied nitrogen with application of stable nitrogen isotope trace technique and modern molecular biotechnology by using rhizobox simulation and field fixed-point measurement methods, which would provide theoretic basis and technical instructions for the control of agricultural non-point source pollution.

氮素是湿地富营养化的关键因子之一。水陆交错带芦苇根孔具有优先运输水分、氧气和溶质的性能，与根际微生物一起形成根孔生物膜，促进氮素在根际的硝化和降解，但根孔与根系形成的根际环境对氮素去除的作用机制和相关机理尚未明确。本项目拟选取河北白洋淀水陆交错带芦苇湿地为研究基地，采用实验室根箱模拟和野外定点监测手段，利用氮稳定同位素示踪和现代分子生物学技术，分析外源氮素在水陆交错带芦苇根际转化特征和土壤硝化/反硝化微生物数量与种群结构，揭示芦苇根孔及其根际特殊环境存在对外源氮素迁移转化的影响和微生物学机理，为农业非点源污染的治理提供理论依据和技术指导。