东鱼河春季沉积物反硝化脱氮作用与N_2O排放研究  

Denitrification and N_2O Emission in Sediments of Dongyu River in Spring

作　　者：邓焕广[1] 张智博 张菊[1] 刘涛 张怀珍[1] ZHANG Zhibo;ZHANG Ju;LIU Tao;ZHANG Huaizhen(School of Environment and Planning,Liaocheng University,Liaocheng,Shandong 252000)

机构地区：[1]聊城大学环境与规划学院,山东聊城252000

出　　处：《水土保持学报》2019年第1期283-287,共5页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(41401563);山东省自然科学基金项目(ZR2014JL028;ZR2016CL14)

摘　　要：为研究东鱼河春季沉积物的反硝化脱氮作用以及N_2O产生速率,于2017年5月沿东鱼河采集沉积物和表层水样,分别采用乙炔抑制法和培养法分析测定了反硝化作用和N_2O产生速率,利用顶空法提取水样中N_2O结合双层扩散模型法估算水体N_2O的排放通量,并结合水体理化性质探讨了主要影响因素。结果表明:东鱼河春季沉积物反硝化潜势为7 305.8～26 947.7μmol/(m^2·h),但从上游到下游沿程均呈先增高后波动降低的趋势;沉积物反硝化速率为86.6～694.2μmol/(m^2·h),显著低于对应点位的反硝化潜势(P<0.01),且二者的沿程变化规律不一致;反硝化速率仅与沉积物中NH_4^+含量呈显著正相关关系(P<0.05),表明其受沉积物和上覆水理化性质的综合影响,且可能存在硝化—反硝化的耦合作用。沉积物N_2O产生速率在19.8～144.3μmol/(m^2·h);水体表现为大气N_2O的排放源,排放通量为170.9～667.8mol/(m^2·h),显著高于对应点位沉积物N_2O的产生速率(P<0.01),且与上覆水的DO和NO_2^-含量具有显著正相关关系(P<0.05),表明东鱼河在春季除沉积物产生N_2O外,其上覆水中氮转化过程亦是向大气排放N_2O的重要途径之一。In order to study the denitrification and N2O production rate of sediments in the Dongyu River in spring,the sediment and surface water samples were collected along the Dongyu River in May,2017.The acetylene inhibition method and incubation method were applied to determine the denitrification potential,denitrification rate and N2O production rate.The N2O diffusion flux was estimated by using the headspace equilibrium method and two-layered diffusion model.Moreover,the physicochemical properties of sediment and surface water were also analyzed to discuss the main influencing factors by using correlation analysis.The results showed that denitrification potential of the spring sediments in Dongyu River was 7 305.8 ~ 26 947.7 μmol/(m^2·h),but from upstream to downstream,it tended to increase first and then decrease.The denitrification rate of sediment was 86.6 ~ 694.2 μmol/(m^2·h),which was significantly lower than the denitrification potential at the same site (P<0.01),moreover the change of the denitrification rate along the Dongyu River was not in accordance with the change of denitrification potential.The denitrification rate was only significantly positively correlated with the NH4^+ concentration in the sediments (P<0.05),which indicated that the denitrification rate of sediment might be synthetically affected by the physicochemical properties of the sediments and surface water,and also there might be coupling effect of nitrification and denitrification in the water body.The N2O production rate was 19.8 ~ 144.3 μmol/(m^2·h),and the diffusion flux of N2O varied from 170.9 ~ 667.8 μmol/(m^2·h),which indicated that the water body of the Dongyu River was the source of N2O emission to atmosphere.The diffusion flux of N2O was significantly higher than the N2O production rate of the corresponding point (P<0.01),and it was significantly positively correlated with the concentrations of DO and NO2^- in the overlying water (P<0.05),which suggested that besides the N2O produced from the sediment,the transformation

关 键 词：反硝化作用 N2O 沉积物 东鱼河 

分 类 号：X142[环境科学与工程—环境科学] X542