【摘要】 根据2017年12月—2019年12月和2018年小浪底水库泄洪期间对黄河下游营养盐的月观测和日观测，系统的分析了黄河下游溶解态营养盐浓度、组成和通量变化。结果表明，除DON(溶解有机氮)、DSi(溶解态硅)和DIP(溶解无机磷)外，其他各溶解态营养盐浓度均呈丰水期低、枯水期高的特点。在观测期间，DSi/DIN(溶解态硅/溶解无机氮)比值月变化呈升高趋势，而DIN/DIP和DSi/DIP比值呈降低的趋势，可能与近年来黄河流域生态环境变化有关。水库泄洪期间DIN和DSi浓度升高，主要与水库下泄高浓度营养盐水体和大径流冲刷沿岸土壤导致营养盐释放进黄河水体有关；DIP和DOP(溶解有机磷)浓度降低，主要受到大径流稀释和悬浮颗粒物吸附作用的影响。水库泄洪期间DSi/DIP与DSi/DIN比值增加，而根据水体富营养化潜力指标(ICEP)显示，水库泄洪的年份P-ICEP和N-ICEP均高于非水库泄洪的年份数倍，进一步证明水库泄洪事件会加剧营养盐失衡，潜在影响黄河口及其邻近海域浮游植物群落结构。2018年水库水沙调控期间输送了全年各项营养盐入海通量的13%～25%,在全年营养盐输送通量中扮演重要的角色。更多还原

【Abstract】 Variations of the nutrient concentration, composition and flux were analyzed during the monthly observations and daily analysis in the events of the flood discharge of the Xiaolangdi reservoir in the lower reaches of the Yellow River. Almost all the dissolved nutrients were higher in dry season than in flood season except for dissolved organic nitrogen(DON), dissolved silicon(DSi) and dissolved inorganic phosphorus(DIP) during December 2017 to December 2019. In addition, the variations of monthly DSi and dissolved inorganic nitrogen ratios(DSi/DIN) showed increasing trend while DIN/DIP and DSi/DIP ratios showed decreasing trends, which could be related to the ecological environment changes of the Yellow River Basin in recent years. The increase of DIN and DSi concentrations during the flood discharge of the reservoir could be mainly influenced by the high nutrient concentrations water discharged from the Xiaolangdi reservoir and the erosion of coastal soil by large runoff. While discharge dilution and suspended particles adsorption could be the reasons for the decline of the DIP and DOP during the flood discharge of the reservoir. On the other hand, both the indicator of coastal eutrophication potential(ICEP) of nitrogen(N-ICEP) and phosphorus(P-ICEP) were several times higher in Non-flood discharge of the reservoir year than flood discharge of the reservoir year, which would further result in the imbalance of nutrient compositions and affect phytoplankton community structure in the Yellow River Estuary and its adjacent sea. Nutrient fluxes during the flood discharge periods accounted for 13%～25% of annual nutrient fluxes respectively, which play significant roles in the annual nutrient transport.更多还原