黄河小浪底水库水沙调控对其下游氮迁移转化及通量的影响OA
Impacts of the water-sediment regulation scheme at Xiaolangdi Reservoir on nitrogen mi-gration,transformation,and flux in the lower Yellow River
为了解小浪底水沙调控对黄河下游氮迁移转化及通量的影响,本文于2023年水沙调控、调水、调沙前后共6次采集黄河下游近库口花园口站和入海口利津站表层水样,分析了流量、悬浮泥沙、总氮(TN)以及水相和悬浮相中硝态氮(NO3--N)、氨氮(NH3-N)和硝酸盐氮氧同位素(815N-NO3-和δ18O-NO3-).结果表明:调水阶段,花园口和利津站流量分别最高升至4560和3690 m3/s,TN浓度因清水下泄而降低,水相中NO3--N浓度升高,悬浮相中NO3--N含量降低,同时水相中 818O-NO3-值降低,悬浮相中NH3-N含量则表现为先升高后降低的变化特征.大量清水冲刷下,外源氮进入水体过程中发生了矿化和硝化作用,引起水相中NO3--N浓度升高,同时扰动河道底部泥沙再悬浮,携带NH3-N进入水体.随着调水的进行,悬浮泥沙中NH3-N被释放进入水相.调沙阶段花园口站和利津站流量先升后降,峰值分别达到4010和3480 m3/s,最后回落至591和726 m3/s.泥沙浓度较调水阶段显著升高,最高分别升至53.3和31.6g/L.同时,TN、水相和悬浮相中NO3--N、NH3-N浓度均明显降低,且利津站较花园口站NO3--N浓度降低更显著.相较于调水阶段,调沙阶段悬浮泥沙δ15N-NO3-明显升高,且沿水流方向悬浮相中815N-NO3-明显增加,NO3--N浓度显著降低,说明水沙调控期间氮在迁移入海过程中耦合了硝化—反硝化作用.基于利津站TN通量计算,调水后期入海TN通量最高(1867 t/d),其次为调沙前期(1724 t/d)及调水前期(1102 t/d).研究结果可为黄河下游水沙变化与氮输出变化的关系研究提供科学依据.
To investigate the impacts of the Xiaolangdi Reservoir's regulated water and sediment releases on nitrogen migration,transformation,and flux to the sea in the lower Yellow River,surface water samples were collected six times in 2023 from two hydrological stations—Huayuankou(HYK)near the reservoir outlet and Lijin(LJ)near the river mouth—covering the periods be-fore,during,and after the water-sediment regulation event.Measured parameters included river discharge,suspended sediment con-centration(SSC),total nitrogen(TN),and dissolved and particulate nitrate nitrogen(NO3--N),ammonium nitrogen(NH3-N)con-centrations,and nitrate isotopic composition(δ15N-NO3-and δ18O-NO3-).During the water regulation stage,discharges at HYK and LJ increased to maxima of 4560 and 3690 m3/s,respectively.TN concentration decreased due to the release of clear water,while dissolved NO3--N increased and particulate NO3--N decreased.Concurrently,818O-NO3-values declined in the dissolved phase,and particulate NH3-N concentration exhibited an initial rise followed by a decline.These patterns suggest that the large discharge flushed external nitrogen into the river,stimulating mineralization and nitrification that raised dissolved NO3--N levels.Concurrently,sediment resuspension caused by the scouring flow released NH3-N into the water column,with further mobilization of NH3-N from suspended particles as regulation progressed.During the sediment regulation stage,discharges at HYK and LJ first peaked at 4010 and 3480 m3/s,then fell to 591 and 726 m3/s,respectively,while SSC increased markedly to maxima of 53.3 and 31.6 g/L.Concentrations of TN,NO3--N,and NH3-N in both dissolved and particulate phases decreased significantly from the pre-to post-sediment regulation period,with a more pronounced reduction in NO3--N at LJ than at HYK.Compared to the water regulation stage,particulate δ15N-NO3-increased during sediment regulation,and its values rose along the flow path alongside de-creasing particulate NO3--N concentrations,indicating the coupling of nitrification and denitrification.Based on TN flux estimates at LJ,the flux to the sea was highest during the post-water regulation stage(1867 t/d),followed by the pre-sediment(1724 t/d)and pre-water regulation stages(1102 t/d).These findings provide a scientific basis for understanding how water-sediment regula-tion influences nitrogen cycling and export in the lower Yellow River.
李艳利;高凯洋;任世航
河南理工大学资源环境学院,焦作 454000河南理工大学资源环境学院,焦作 454000河南理工大学资源环境学院,焦作 454000
水沙调控氮稳定同位素耦合硝化—反硝化作用黄河下游水浪底水库
Water and sediment regulationnitrogenstable isotopescoupled nitrification-denitrificationlower Yellow RiverXiaolangdi Reservoir
《湖泊科学》 2026 (3)
1021-1032,12
水资源与水电工程科学国家重点实验室开放基金项目(2022SWG01)资助.
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