Wang Jing, Liu Hong-Jie, Lei Yu, Xu Jing, Song Li-Yan, Li Yong
College of Resources and Environment, Southwest University, Chongqing 400715, China.
Environmental Microbiology and Ecology Research Center, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
Huan Jing Ke Xue. 2017 Mar 8;38(3):946-953. doi: 10.13227/j.hjkx.201606202.
Three Gorge Dam Reservoir (TGDR) is a new forming ecosystem and its sediments dynamics remains unknown. Investigation on the nitrification and denitrification dynamics of sediments of TGDR during water collection and release events-anti-seasonal actions-is critical for nitrogen management in TGDR. In this study, we sampled sediments in three locations (upstream, center, and downstream along water flow) of South River, located in a typical small tributary, Nanhe, in TGDR during 2015 water collection and release events to characterize its physiochemical property and determine its nitrification and denitrification rates using acetylene inhabitation method. The results showed that the concentrations of physiochemical parameters of sediments (total carbon, total nitrogen, nitrate, and ammonia) were significantly higher (<0.05) in water collection event than those in water release event, suggesting there were external materials (e. g., soil) entering into TGDR. Furthermore, the nitrification rate of sediments in water collection event[194.06 μmol·(m·h)] was significantly higher than that in water release event[16.52 μmol·(m·h)]. Sediments nitrification rate was positively correlated to the physiochemical parameters. In contract, the denitrification rate of sediments was higher in water release event[647.20 μmol·(m·h)] than that in water collection event[24.04 μmol·(m·h)). Accordingly, the denitrification rate of sediments was negatively correlated to the physiochemical parameters.
三峡大坝水库（TGDR）是一个新形成的生态系统，其沉积物动态尚不清楚。研究三峡大坝水库在蓄水和放水事件（反季节行动）期间沉积物的硝化和反硝化动态，对于三峡大坝水库的氮管理至关重要。在本研究中，我们于2015年蓄水和放水事件期间，在三峡大坝水库典型小支流南河的南河三个位置（沿水流方向的上游、中游和下游）采集沉积物样本，以表征其理化性质，并使用乙炔抑制法测定其硝化和反硝化速率。结果表明，蓄水事件期间沉积物的理化参数（总碳、总氮、硝酸盐和氨）浓度显著高于（<0.05）放水事件期间，这表明有外部物质（如土壤）进入三峡大坝水库。此外，蓄水事件期间沉积物的硝化速率[194.06 μmol·(m·h)]显著高于放水事件期间[16.52 μmol·(m·h)]。沉积物硝化速率与理化参数呈正相关。相反，放水事件期间沉积物的反硝化速率[647.20 μmol·(m·h)]高于蓄水事件期间[24.04 μmol·(m·h)]。因此，沉积物的反硝化速率与理化参数呈负相关。
