东鱼河春季沉积物反硝化脱氮作用与N_2O排放研究
|
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 N_2O 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 N_2O production rate.The N_2O 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 7 305.8～26 947.7μmol/(m~2·h),but from upstream to downstream,it tended to increase first and then decrease.The denitrification rate of sediment was 86.6～694.2μmol/(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 NH_4~+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 N_2O production rate was 19.8～144.3μmol/(m~2·h),and the diffusion flux of N_2O varied from 170.9～667.8μmol/(m~2·h),which indicated that the water body of the Dongyu River was the source of N_2O emission to atmosphere.The diffusion flux of N_2O was significantly higher than the N_2O production rate of the corresponding point(P<0.01),and it was significantly positively correlated with the concentrations of DO and NO_2~-in the overlying water(P<0.05),which suggested that besides the N_2O produced from the sediment,the transformation of nitrogen in the overlying water was also an important pathway to discharge N_2O to atmosphere from the Dongyu River in spring.
In order to study the denitrification and N_2O 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 N_2O production rate.The N_2O 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 7 305.8～26 947.7μmol/(m~2·h),but from upstream to downstream,it tended to increase first and then decrease.The denitrification rate of sediment was 86.6～694.2μmol/(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 NH_4~+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 N_2O production rate was 19.8～144.3μmol/(m~2·h),and the diffusion flux of N_2O varied from 170.9～667.8μmol/(m~2·h),which indicated that the water body of the Dongyu River was the source of N_2O emission to atmosphere.The diffusion flux of N_2O was significantly higher than the N_2O production rate of the corresponding point(P<0.01),and it was significantly positively correlated with the concentrations of DO and NO_2~-in the overlying water(P<0.05),which suggested that besides the N_2O produced from the sediment,the transformation of nitrogen in the overlying water was also an important pathway to discharge N_2O to atmosphere from the Dongyu River in spring.
引文
[1] Audet J,Wallin M B,Kyllmar K,et al.Nitrous oxide emissions from streams in a Swedish agricultural catchment[J].Agriculture,Ecosystems&Environment,2017,236:295-303.
[2] Burgos M,Ortega T,Forja J,et al.Temporal and spatial variation of N2O production from estuarine and marine shallow systems of Cadiz Bay(SW,Spain)[J].Science of the Total Environment,2017,607/608:141-151.
[3] Liu L,Wang D,Deng H,et al.The capability of estuarine sediments to remove nitrogen:Implications for drinking water resource in Yangtze Estuary[J].Environmental Science and Pollution Research,2014,43(2):745-752.
[4]谭永洁,王东启,周立旻,等.河流氧化亚氮产生和排放研究综述[J].地球与环境,2015,43(1):123-132.
[5]舒凤月,刘玉配,赵颖,等.南四湖水体氮、磷营养盐时空分布特征及营养状态评价[J].环境科学,2012,33(11):3748-3752.
[6]李爽,张祖陆,孙媛媛.基于SWAT模型的南四湖流域非点源氮磷污染模拟[J].湖泊科学,2013,25(2):236-242.
[7]《水和废水监测分析方法》编委会.水和废水监测分析方法[M].4版.北京:中国环境科学出版社,2002:243-281.
[8]韩舞鹰,容荣贵,黄西能.海水化学要素调查手册[M].北京:海洋出版社,1986:127-136.
[9]全国农业技术推广服务中心.土壤分析技术规范[M].2版.北京:中国农业出版社.2006:36-40,73-75.
[10]张羽,秦晓波,廖育林,等.亚热带农业小流域水系N2O扩散通量及其影响因素[J].农业工程学报,2016,32(7):215-223.
[11] Lin H,Dai M,Kao S J,et al.Spatiotemporal variability of nitrous oxide in a large eutrophic estuarine system:The Pearl River Estuary,China[J].Marine Chemistry,2016,182:14-24.
[12]刘荣芳,张林海,林啸,等.闽江口短叶茳芏湿地土壤反硝化潜力[J].生态学杂志,2013,32(11):2865-2870.
[13]刘庆,魏建兵,吴志峰,等.广州市流溪河河岸带土壤反硝化作用的多尺度影响因子[J].中国环境科学,2015,35(10):3069-3077.
[14]李飞跃,杨绒,遆超普,等.秦淮河流域句容水库农业流域水体沉积物的反硝化作用[J].环境科学学报,2009,29(4):854-860.
[15]方婧,曹文志,苏彩霞.南方丘陵地区竹林河岸系统的氮矿化、反硝化作用研究[J].环境科学学报,2011,31(12):2822-2829.
[16] Wang X J,Jia M S,Zhang H,et al.Quantifying N2O emissions and production pathways from fresh waste during the initial stage of disposal to a landfill[J].Waste Management,2017,63:3-10.
[17] Ma L,Tong W,Chen H,et al.Quantification of N2O and NO emissions from a small-scale pond-ditch circulation system for rural polluted water treatment[J].Science of the Total Environment,2018,619:946-956.
[18] Tseng H C,Chen C T A,Borges A V,et al.Distributions and sea-to-air fluxes of nitrous oxide in the South China Sea and the West Philippines Sea[J].Deep Sea Research Part I Oceanographic Research Papers,2016,115:131-144.
[19]吴红宝,吕成文,李玉娥,等.脱甲河农业流域土壤沉积物氮素时空分布与N2O释放[J].环境科学学报,2017,37(4):1539-1546.
[20] Wang D,Tan Y,Yu Z,et al.Nitrous oxide production in river sediment of highly urbanized area and the effects of water quality[J].Wetlands,2015,35(6):1213-1223.
[2] Burgos M,Ortega T,Forja J,et al.Temporal and spatial variation of N2O production from estuarine and marine shallow systems of Cadiz Bay(SW,Spain)[J].Science of the Total Environment,2017,607/608:141-151.
[3] Liu L,Wang D,Deng H,et al.The capability of estuarine sediments to remove nitrogen:Implications for drinking water resource in Yangtze Estuary[J].Environmental Science and Pollution Research,2014,43(2):745-752.
[4]谭永洁,王东启,周立旻,等.河流氧化亚氮产生和排放研究综述[J].地球与环境,2015,43(1):123-132.
[5]舒凤月,刘玉配,赵颖,等.南四湖水体氮、磷营养盐时空分布特征及营养状态评价[J].环境科学,2012,33(11):3748-3752.
[6]李爽,张祖陆,孙媛媛.基于SWAT模型的南四湖流域非点源氮磷污染模拟[J].湖泊科学,2013,25(2):236-242.
[7]《水和废水监测分析方法》编委会.水和废水监测分析方法[M].4版.北京:中国环境科学出版社,2002:243-281.
[8]韩舞鹰,容荣贵,黄西能.海水化学要素调查手册[M].北京:海洋出版社,1986:127-136.
[9]全国农业技术推广服务中心.土壤分析技术规范[M].2版.北京:中国农业出版社.2006:36-40,73-75.
[10]张羽,秦晓波,廖育林,等.亚热带农业小流域水系N2O扩散通量及其影响因素[J].农业工程学报,2016,32(7):215-223.
[11] Lin H,Dai M,Kao S J,et al.Spatiotemporal variability of nitrous oxide in a large eutrophic estuarine system:The Pearl River Estuary,China[J].Marine Chemistry,2016,182:14-24.
[12]刘荣芳,张林海,林啸,等.闽江口短叶茳芏湿地土壤反硝化潜力[J].生态学杂志,2013,32(11):2865-2870.
[13]刘庆,魏建兵,吴志峰,等.广州市流溪河河岸带土壤反硝化作用的多尺度影响因子[J].中国环境科学,2015,35(10):3069-3077.
[14]李飞跃,杨绒,遆超普,等.秦淮河流域句容水库农业流域水体沉积物的反硝化作用[J].环境科学学报,2009,29(4):854-860.
[15]方婧,曹文志,苏彩霞.南方丘陵地区竹林河岸系统的氮矿化、反硝化作用研究[J].环境科学学报,2011,31(12):2822-2829.
[16] Wang X J,Jia M S,Zhang H,et al.Quantifying N2O emissions and production pathways from fresh waste during the initial stage of disposal to a landfill[J].Waste Management,2017,63:3-10.
[17] Ma L,Tong W,Chen H,et al.Quantification of N2O and NO emissions from a small-scale pond-ditch circulation system for rural polluted water treatment[J].Science of the Total Environment,2018,619:946-956.
[18] Tseng H C,Chen C T A,Borges A V,et al.Distributions and sea-to-air fluxes of nitrous oxide in the South China Sea and the West Philippines Sea[J].Deep Sea Research Part I Oceanographic Research Papers,2016,115:131-144.
[19]吴红宝,吕成文,李玉娥,等.脱甲河农业流域土壤沉积物氮素时空分布与N2O释放[J].环境科学学报,2017,37(4):1539-1546.
[20] Wang D,Tan Y,Yu Z,et al.Nitrous oxide production in river sediment of highly urbanized area and the effects of water quality[J].Wetlands,2015,35(6):1213-1223.