材料期刊网

通过构建室内模拟系统,研究了外源氮素恒定输入时沉水植物菹草对氮去除作用的影响.结果表明,(1)系统稳定后植物组对进水中总氮、氨氮和硝氮的去除率分别较无植物对照组提高了14.7％、25.0％和21.6％.(2)实验期间沉积物中可转化态氮含量整体呈下降趋势;与此同时,非转化态氮的含量上升,植物组的上升幅度是对照组的1.9倍.这表明菹草能够降低内源沉积物氮的释放风险.(3)整个实验期间生物脱氮是系统脱氮的主要途径,分别占植物组和对照组氮素输入总量的44.8％和28.7％;植物组微生物脱氮量较对照组增加了0.139 g,植物吸收脱氮量为0.182 g.可见植物吸收和加速微生物脱氮是菹草促进系统脱氮的两个主要途径.

An indoor simulation system was constructed to investigate the effect of a submerged macrophyte,Potamogeton crispus L.(P.crispus),on the removal of exogenous nitrogen from the system at a constant inflow rate of nitrogen.The results showed that when the system was stable,compared with unplanted treatment,the removal efficiencies of total nitrogen,ammonia nitrogen and nitrate nitrogen from the inflow water in the planted treatment increased by 14.7％,25.0％ and 21.6％,respectively.During the experiment,the concentration of transferable nitrogen in the planted treatment decreased in general.At the same time,the concentration of untransferable nitrogen in the planted treatment increased by 1.9 times.This indicates that P.crispus could reduce the risk of endogenous nitrogen release from the sediments.During the experiment,biodenitrification was the main process in removing nitrogen from the system.Nitrogen removed by biodenitrification accounted for 44.8％ and 28.7％ of the total nitrogen input in the planted and unplanted treatments,respectively.The amount of nitrogen removed by microbial denitrification in the planted treatment increased by 0.139 g as compared to the unplanted treatment.The amount of nitrogen removed by plant uptake was 0.182 g.Therefore,it can be concluded that plant uptake and plant-promoted microbial denitrification were the two main processes promoting denitrification in the system by P.crispus.