Liu Lin, Wang Dongqi, Deng Huanguang, Li Yangjie, Chang Siqi, Wu Zhanlei, Yu Lin, Hu Yujie, Yu Zhongjie, Chen Zhenlou
School of Resources and Environmental Science, East China Normal University, Shanghai, 200241, China.
Environ Sci Pollut Res Int. 2014 Sep;21(18):10890-9. doi: 10.1007/s11356-014-2914-8. Epub 2014 Apr 27.
Water in the Yangtze Estuary is fresh most of the year because of the large discharge of Yangtze River. The Qingcaosha Reservoir built on the Changxing Island in the Yangtze Estuary is an estuarine reservoir for drinking water. Denitrification rate in the top 10 cm sediment of the intertidal marshes and bare mudflat of Yangtze Estuarine islands was measured by the acetylene inhibition method. Annual denitrification rate in the top 10 cm of sediment was 23.1 μmol m(-2) h(-1) in marshes (ranged from 7.5 to 42.1 μmol m(-2) h(-1)) and 15.1 μmol m(-2) h(-1) at the mudflat (ranged from 6.6 to 26.5 μmol m(-2) h(-1)). Annual average denitrification rate is higher at mashes than at mudflat, but without a significant difference (p = 0.084, paired t test.). Taking into account the vegetation and water area of the reservoir, a total 1.42 × 10(8) g N could be converted into nitrogen gas (N2) annually by the sediment, which is 97.7 % of the dissolved inorganic nitrogen input through precipitation. Denitrification in reservoir sediment can control the bioavailable nitrogen level of the water body. At the Yangtze estuary, denitrification primarily took place in the top 4 cm of sediment, and there was no significant spatial or temporal variation of denitrification during the year at the marshes and mudflat, which led to no single factor determining the denitrification process but the combined effects of the environmental factors, hydrologic condition, and wetland vegetation.
由于长江的大量径流，长江河口的水一年中大部分时间都是淡水。建于长江河口长兴岛上的青草沙水库是一座河口饮用水水库。采用乙炔抑制法测定了长江河口岛屿潮间带湿地和光滩表层10厘米沉积物中的反硝化速率。湿地沉积物表层10厘米的年反硝化速率为23.1 μmol m(-2) h(-1)（范围为7.5至42.1 μmol m(-2) h(-1)），光滩为15.1 μmol m(-2) h(-1)（范围为6.6至26.5 μmol m(-2) h(-1)）。湿地的年平均反硝化速率高于光滩，但差异不显著（配对t检验，p = 0.084）。考虑到水库的植被和水域面积，沉积物每年可将总计1.42×10(8) g的氮转化为氮气（N2），占通过降水输入的溶解无机氮的97.7%。水库沉积物中的反硝化作用可以控制水体中生物可利用氮的水平。在长江河口，反硝化主要发生在沉积物表层4厘米内，湿地和光滩的反硝化作用在一年中没有明显的空间或时间变化，这表明没有单一因素决定反硝化过程，而是环境因素、水文条件和湿地植被的综合作用。
