Jin Zan-Fang, Gong Jia-Lin, Shi Yi-Li, Jin Man-Tong, Li Fei-Li
College of Environment, Zhejiang University of Technology, Hangzhou 310032, China.
Huan Jing Ke Xue. 2017 Apr 8;38(4):1423-1430. doi: 10.13227/j.hjkx.201606116.
Identifying nitrate sources and its transformation mechanisms are important for nitrate pollution control in surface water. The columnar core sediment samples in West Lake were taken in different seasons. The transformation of nitrogen at the sediment-water interface was studied using nitrogen and oxygen isotopes, stable isotope analysis in R (SIAR) and acetylene inhibition method in the West Lake, Hangzhou. The results showed that the concentration gradient of both NOand NH existed at the sediment-water interface. NO concentrations decreased from bottom water to pore water and NO was accumulated in sediments. NH concentrations increased from bottom water to pore water and NH was released from sediments. Nitrate sources in bottom water where nitrification exited were sewage (manure), soil nitrogen, chemical fertilizer and precipitation. Sewage (manure) was the major nitrogen contributor (60.8%) in summer. Particularly high δ N values in pore water indicated that there was strong denitrification at the sediment-water interface in West Lake. The average nitrification rate and denitrification rate at the sediment-water interface were 2.85 mmol·(m·d) and 23.51 μmol·(m·d), respectively. The sediment-water interface played a role in nitrogen removal process in aquatic environment. Seasonal and spatial variations of nitrification rates and denitrification rates were found in this study. Temperature and dissolved oxygen were the main influential factors for the transformation of nitrogen at the sediment-water interface in West Lake.
识别硝酸盐来源及其转化机制对于地表水硝酸盐污染控制至关重要。采集了西湖不同季节的柱状岩芯沉积物样本。利用氮和氧同位素、R语言中的稳定同位素分析（SIAR）以及乙炔抑制法，对杭州西湖沉积物 - 水界面的氮转化进行了研究。结果表明，沉积物 - 水界面处NO和NH均存在浓度梯度。NO浓度从底层水到孔隙水降低，且NO在沉积物中积累。NH浓度从底层水到孔隙水升高，且NH从沉积物中释放。存在硝化作用的底层水中硝酸盐来源为污水（粪便）、土壤氮、化肥和降水。夏季污水（粪便）是主要的氮贡献源（60.8%）。孔隙水中特别高的δN值表明西湖沉积物 - 水界面存在强烈的反硝化作用。沉积物 - 水界面处的平均硝化速率和反硝化速率分别为2.85 mmol·(m·d)和23.51 μmol·(m·d)。沉积物 - 水界面在水生环境的氮去除过程中发挥了作用。本研究发现了硝化速率和反硝化速率的季节和空间变化。温度和溶解氧是西湖沉积物 - 水界面氮转化的主要影响因素。
