黄河下游垦利站溶解N_2O浓度和通量的季节变化及其调控因子分析  

Seasonal variation of dissolved nitrous oxide concentration and flux in the downstream Yellow River and their regulating factors

作　　者：王岚[1] 叶旺旺 宋达[1] 侯静[1] 郑文静[1] 张桂玲[1] 

机构地区：[1]中国海洋大学海洋化学理论与工程技术教育部重点实验室,青岛266100

出　　处：《环境科学学报》2016年第6期1917-1927,共11页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金项目(No.41376088);国家重点基础研究发展规划项目(No.2011CB409802);国家自然科学创新研究群体基金项目(No.41221004)~~

摘　　要：于2012年3月至2014年3月每月在黄河下游垦利站采集表层河水,测定其溶解氧化亚氮(N_2O)浓度并估算了其水-气交换通量,并于2012年10月至2013年12月每月对表层河水和沉积物进行了受控培养实验以认识其产生过程.结果表明:黄河下游表层河水中溶解N_2O浓度范围为11.63~27.23 nmol·L^(-1),平均值为(16.29±4.23)nmol·L^(-1).N_2O浓度呈现出较为明显的季节变化,具体表现为冬季和春季高于夏季和秋季,但全年变化幅度不大.溶解N_2O浓度主要受到温度、黄河径流量和溶解无机氮等因素的影响.N_2O饱和度范围为101.1%~343.0%,平均值为190.8%±72.3%,黄河下游N_2O全年处于过饱和状态,是大气N_2O的净源.利用LM86、W92和RC01公式估算出其平均水-气交换通量分别为(10.2±12.3)、(17.3±18.8)、(25.8±26.6)μmol·m-2·d^(-1).初步估算了2012—2013年黄河向河口及其邻近海域输入N_2O的量约为5.8×105mol·a^(-1).培养实验表明:水体和沉积物整体表现为净产生N_2O,其中潜在反硝化速率均明显高于硝化速率,反硝化作用在黄河N_2O的产生过程中有重要作用.水体中的潜在反硝化速率(以N计)的变化范围为(0.18~332.20)nmol·L^(-1)·h^(-1),平均值为(52.74±95.63)nmol·L^(-1)·h^(-1),沉积物中潜在反硝化速率的变化范围为0.37~187.60 nmol·kg^(-1)·h^(-1),平均值为(29.61±56.91)nmol·kg^(-1)·h^(-1).Dissolved nitrous oxide（ N2O） in surface waters of the downstream Yellow River was measured monthly at Kenli Station from March 2012 to March 2014,and sediments and waters were incubated at laboratory monthly from October 2012 to December 2013 to estimate the potential nitrification and denitrification rates. Dissolved N2O concentrations in surface waters ranged from 11. 63 to 27. 63 nmol·L^-1 with an average of（ 16. 29 ± 4. 23）nmol·L^-1,and showed slight seasonal variations with high values in winter and spring. There was good positive correlation between N2O concentrations and the water discharge,while N2O concentrations had negative correlation with temperature. N2O in surface waters were over-saturated at downstream Yellow River all the year round and the saturations ranged from 101.1% to 343.0% with an average of 190.8% ±72.3%. The sea-to-air fluxes of N2O were estimated to be（ 10.2±12.3）,（ 17.3±18.8）,（ 25.8± 26. 6） μmol·m^-2·d^-1 using the LM86,W92 and RC01 relationships,respectively. The average annual input of N2O from the Yellow River to the estuary and its adjacent area was estimated to be 5.8×105mol·a^-1. Potential denitrification rates were significantly higher than potential nitrification rates,indicating that denitrification played a dominant role in the production of N2O. The potential denitrification rates in waters ranged from 0.18 to 332.20 nmol·L^-1·h^-1with an average of（ 52.74±95.63） nmol·L^-1·h^-1,and those in sediments ranged from 0.37 to 187.60 nmol·kg^-1·h^-1with an average of（ 29.61±56.91） nmol·kg^-1·h^-1.

关 键 词：黄河 氧化亚氮 硝化 反硝化 释放 季节变化 

分 类 号：X142[环境科学与工程—环境科学]