洞庭湖区典型沟塘反硝化脱氮能力及其影响因素  

Denitrification capacity and its influencing factors in typical ditches and ponds in the Dongting Lake area,China

作　　者：龙广丽 严星 夏永秋[2] 刘鑫 文炯 彭芝 荣湘民[1] LONG Guangli;YAN Xing;XIA Yongqiu;LIU Xin;WEN Jiong;PENG Zhi;RONG Xiangmin(College of Resources and Environment,Hunan Agricultural University,Changsha 410128,China;Nanjing Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;Yueyang Academy of Agricultural Sciences,Yueyang 414000,China)

机构地区：[1]湖南农业大学资源环境学院,长沙410128 [2]中国科学院南京土壤研究所,南京210008 [3]岳阳市农业科学研究院,湖南岳阳414000

出　　处：《农业环境科学学报》2023年第4期842-851,共10页Journal of Agro-Environment Science

基　　金：国家自然科学基金联合基金项目(U19A2050)。

摘　　要：为探究洞庭湖区典型沟塘反硝化脱氮规律,本研究于2020年9月至2021年8月,采集洞庭湖流域不同类型沟塘上覆水样及表层柱状沉积物,通过近似原位的培养方法并结合膜进样质谱法测定了不同沟塘的反硝化速率。结果表明:沟塘反硝化速率存在显著的时空异质性,反硝化速率范围为22.10~238.02μmol·m^(–2)·h^(–1),均值为91.12μmol·m^(–2)·h^(–1),春、夏季节的反硝化速率大于秋、冬季节。不同类型的沟塘反硝化速率也存在显著差异,表现为农沟>支沟>池塘>干沟,有植被沟渠>无植被沟渠。偏最小二乘回归分析(PLSR)表明,水体中硝态氮(NO_(3)^(-)-N)浓度和溶解性有机碳(DOC)浓度及沉积物中DOC含量均会对反硝化速率产生显著影响(P<0.05),其中水体NO_(3)^(-)-N浓度是反硝化作用的最主要限制因素。研究表明,研究区沟塘湿地可去除33.44%的水体氮负荷,从而大幅减少了向下游水域输入的氮污染风险,这对于缓解洞庭湖流域面源污染有重要作用。To investigate the denitrification pattern of denitrification in typical ditches and ponds in Dongting Lake area,based on a nearin situ incubation method combined with membrane inlet mass spectrometry,this study investigated the patterns of denitrification rates in ditches and ponds wetlands in the Dongting Lake basin and the influencing factors in the overlying water and sediments from September 2020 to August 2021.The results showed that there was significant spatial and temporal heterogeneity in denitrification rates in the ditches and ponds of Dongting Lake.Denitrification rates ranged from 22.10μmol·m^(–2)·h^(–1)to 238.02μmol·m^(–2)·h^(–1),with a mean value of 91.12μmol·m^(–2)·h^(–1).The denitrification rates in spring and summer were higher than those in autumn and winter.The types of ditches and ponds also showed significant differences in denitrification rates,with the highest rate in agricultural ditches,followed by branch ditches,ponds,main ditches,vegetated ditches,and non-vegetated ditches.Partial least squares regression(PLSR)analysis showed that nitrate nitrogen(NO_(3)^(-)-N)concentration,dissolved organic carbon(DOC)in the water column,and sediment DOC significantly affected denitrification rates(P<0.05),with nitrate nitrogen concentration the most significant limiting factor for denitrification.The ditch and pond wetlands can remove 33.44%of nitrogen load in the study region,significantly reducing nitrogen input to downstream waters,thereby playing an important role in mitigating non-point source pollution in the Dongting Lake watershed.

关 键 词：反硝化速率 沟塘 脱氮能力 面源污染 

分 类 号：X52[环境科学与工程—环境工程]