Chen Zhu-hong, Chen Neng-wang, Wu Yin-qi, Mo Qiong-li, Zhou Xing-peng, Lu Ting, Tian Yun
Huan Jing Ke Xue. 2014 Sep;35(9):3325-35.
The key processes and fluxes of nutrients (N and P) and gaseous N (N2 and N2O) across the sediment-water interface in a river reservoir (Xipi) of the Jiulong River watershed in southeast China were studied. Intact core sediment incubation of nutrients exchange, in-situ observation and lab incubation of excess dissolved N2 and N2O (products of nitrification, denitrification and Anammox), and determination of physiochemical and microbe parameters were carried out in 2013 for three representative sites along the lacustrine zone of the reservoir. Results showed that ammonium and phosphate were generally released from sediment to overlying water [with averaged fluxes of N (479.8 ± 675.4) mg. (m2. d)-1 and P (4. 56 ± 0.54) mg. (m2 d) -1] , while nitrate and nitrite diffused into the sediment. Flood events in the wet season could introduce a large amount of particulate organic matter that would be trapped by the dam reservoir, resulting in the high release fluxes of ammonium and phosphate observed in the following low-flow season. No clear spatial variation of sediment nutrient release was found in the lacustrine zone of the reservoir. Gaseous N release was dominated by excess dissolved N2 (98% of total), and the N2 flux from sediment was (15.8 ± 12. 5) mg (m2. d) -1. There was a longitudinal and vertical variation of excess dissolved N2, reflecting the combined results of denitrification and Anammox occurring in anoxic sediment and fluvial transport. Nitrification mainly occurred in the lower lacustrine zone, and the enrichment of N2O was likely regulated by the ratio of ammonium to DIN in water.
对中国东南部九龙江流域一座河流水库（西陂）沉积物 - 水界面营养物质（氮和磷）和气态氮（N₂和N₂O）的关键过程及通量进行了研究。2013年，在水库湖相带的三个代表性位点开展了完整岩芯沉积物营养物质交换的培养、过量溶解N₂和N₂O（硝化、反硝化和厌氧氨氧化产物）的原位观测与实验室培养，以及理化和微生物参数的测定。结果表明，铵和磷酸盐通常从沉积物释放到上覆水中[氮的平均通量为(479.8 ± 675.4) mg·(m²·d)⁻¹，磷的平均通量为(4.56 ± 0.54) mg·(m²·d)⁻¹]，而硝酸盐和亚硝酸盐扩散到沉积物中。雨季的洪水事件会引入大量颗粒有机物，这些有机物会被大坝水库截留，导致在随后的低流量季节观测到铵和磷酸盐的高释放通量。在水库湖相带未发现沉积物营养物质释放的明显空间变化。气态氮释放以过量溶解N₂为主（占总量的98%），沉积物的N₂通量为(15.8 ± 12.5) mg·(m²·d)⁻¹。过量溶解N₂存在纵向和垂直变化，反映了缺氧沉积物中反硝化和厌氧氨氧化以及河流输运的综合结果。硝化作用主要发生在湖相带下部，N₂O的富集可能受水中铵与溶解性无机氮比例的调节。
