巢湖流域河流沉积物N_2O释放对水体溶存N_2O贡献研究  

N_2O Flux Across Sediments-water Interface and Its Contribution to Dissolved N_2O in the Chao Lake Tributaries,China

作　　者：杨丽标[1,2] 王芳[1] 晏维金[1] 

机构地区：[1]中国科学院地理科学与资源研究所,北京100101 [2]中国环境科学研究院河流与海岸带环境创新基地,北京100012

出　　处：《农业环境科学学报》2013年第4期771-777,共7页Journal of Agro-Environment Science

基　　金：国家自然科学基金"河流溶存N2O及其在水气界面的交换过程"(20777073);国家自然科学基金"河流沉积物对水体溶存N2O贡献及其不同反硝化过程N2O产生速率研究"(41203080)

摘　　要：2010年11月在巢湖支流丰乐河与杭埠河采用现场培养和实测方法研究了沉积物N2O释放对水体(水柱)溶存N2O的影响,并采用NO-3削减法估算了沉积物的反硝化速率。研究结果表明,丰乐河与杭埠河N2O平均溶存浓度分别为0.26±0.10(SD)μgN-N2O·L-1和0.18±0.04(SD)μgN-N2O·L-1,饱和度分别为186%和151%,表明两条河流为大气N2O的潜在释放源。丰乐河与杭埠河沉积物-水界面N2O平均释放通量分别为0.39±0.44、0.15±0.16μgN-N2O·m-2·h-1,由此可分别贡献水体中约89%和45%的溶存N2O。对河流沉积物的反硝化速率估算结果表明,丰乐河与杭埠河沉积物反硝化速率分别为0.12±0.07、0.10±0.05mgN·m-2·h-1,与已有的沉积物反硝化速率报道相比较低。An in situ incubation and measurement was conducted in November 2010 in Fengle River and Hangbu River, two major tributaries of Chao Lake, to investigate the impact of sediment on dissolved N20 in water column and the denitrification rate of sediments. Results showed that Fengle River and Hangbu River were both supersaturated with N20 with a mean concentration of 0.26±0.10μg N-N2O·L-1 （ 186 in percent saturation ）and 0.18±0.04 （SD）（ 151 in percent saturation ） μg N-N20· L-1, respectively. This suggested the studied rivers were po- tential sources of atmospheric N20. The mean N20 flux across sediment-water interface was 0.39±0.44（ SD ） μg N-N20·m-2·h-1 in Fengle River and 0.15±0.16（ SD ） μg N-N20·m-2·h-t in Hangbu River. It was estimated that about 89% of the dissolved N20 in Fengle River and 45% of the dissolved N20 in Hangbu River was contributed by river sediments. Denitrification rate in sediments was estimated through the re- duction of nitrate over incubation time. The mean denitrification rate in sediments was 0.12±0.07 mg N·m-2·h-1 in Fengle River and 0.10± 0.05 mg Nm-2· h-1 in Hangbu River, which is relatively low than values previously reported for different aquatic ecosystems.

关 键 词：沉积物 溶存N2O 释放通量 反硝化速率 

分 类 号：X511[环境科学与工程—环境工程]