土地利用变化下岩溶湿地氮的收支及迁移特征研究

由于人为活动干扰的日益增加，原生湿地退化严重，湿地调节净化功能被削弱，导致一系列的环境问题。本项目拟以包含多种土地利用类型的，已呈富营养化状态的岩溶湿地为研究对象，以探求土地利用方式（及与之相联系的人为氮输入）对湿地的氮营养水平、氮的迁移及收支的影响为目标，通过居民调查、野外观测、实验室培养等手段估算湿地氮的收支情况，并运用NO3-中15N和18O的同位素自然丰度技术结合贝叶斯模型对土壤中的进行源解析，揭示湿地NO3-的迁移特征。同时通过研究水文条件变化对湿地氮的分布、迁移及输出的影响，探讨湿地生态系统中氮的循环特征，综合评价评价湿地的氮营养水平和氮净化能力，深入认识湿地生态系统中氮的循环机理，进一步揭示人为活动对湿地氮循环的影响，并为湿地氮淋溶风险提供科学的判断依据。

Due to increasing anthropogenic disturbance, natural wetlands have been deteriorated greatly. The function of wetland to purify nutrients and pollutants has been weakened. It resulted in a series of environmental problems..In this study, we choose a Karst wetland which contains various land-use covers and has shown symptoms of eutrophication to conduct our study with the aim of exploring the impact of multiple land-use covers (and the related anthropogenic N input) on the nitrogen level, N transport and N input-output budget in the wetland. We plan 1) to carry out multiple research approaches such as investigation, observation and lab incubation to estimate the N input/output budget; 2) to apply the 15N & 18O of NO3- isotope natural abundance technique combining with Bayesian model for source partitioning of NO3- and reveal nitrogen transport characteristics; 3) study the impact of hydrological conditions on N distribution, transport and export. Based on these results, we can evaluate the N level and N removal capacity of the wetland; further reveal the impact of anthropogenic activities on wetland N cycles; provide scientific basis of evaluating the N leaching risk from the wetland.