调水调沙对黄河下游营养盐变化规律的影响

Effect of the First Water-sediment Regulation on the Variations of Dissolved Inorganic Nutrients' Concentrations and Fluxes in the Lower Main Channel of the Yellow River

根据黄河首次调水调沙期间（2002年7月）和2002年在黄河利津站对营养盐的月际观测结果,系统分析了2002年黄河首次调水调沙期间黄河利津站和全年溶解无机态营养盐的变化,讨论了营养盐与水情要素之间的相互关系,计算了调水调沙期间及全年营养盐入海通量,并和历史资料作了比较.结果表明,调水调沙期间NO3^--N、NO2^--N、NH4^＋-N浓度的变化范围分别为169.3-273.2、0.08-0.84、1.39-5.04μmol·dm^-3,平均浓度分别为218.6、0.16、2.27μmol·dm^-3;PO43--P、SiO32--Si浓度的变化范围为0.36-0.56、161.4-195.8μmol·dm^-3,平均浓度分别为0.48、166.7μmol·dm^-3.在调水调沙期间,NO3--N浓度与水量无显著相关性,PO4^3--P浓度与水沙均无显著相关性,而SiO3^2--Si浓度与沙量呈显著正相关.与历史资料相比,调水调沙对黄河下游溶解态无机营养盐浓度在全年的变化规律并无明显影响.但黄河首次调水调沙短短不到一个月的时间,所输送的营养盐通量便占到当年输送通量的一半左右.调水调沙对营养盐输送通量在年内的分配产生重大影响,使得黄河营养盐向河口的输送非常集中．

The variations and fluxes of dissolved inorganic nutrients were studied, based on continuously monitored data in the lower main channel of Yellow River （Lijin） during the period of water-sediment regulation in July 2002. Concentrations rang from 169.3 to 273.2 μmol·dm^-3 for NO3^- -N, 0.08 to 0.84μmol·dm^-3 for NO2^- -N, 1.39 to 5.04 μmol·dm^-3 for NH4^＋ -N, with average of 218.6, 0.16, 2.27μmol·dm^-3, respectively. Concentrations rang from 0.36 to 0.56 μmol·dm^-3 for PO4^3- -P, 161.4 to 195.8 μmol·dm^-3 for SiO3^2- -Si, with average of 0.48, 166.7 μmol·dm^-3, respectively. No significant relationship was found between nitrate, phosphate and water discharge during the period of water-sediment regulation, while silicate correlated well with suspended sediment discharge. Water-sediment regulation has no significant effect on the variation of dissolved inorganic nutrients concentrations during 2002 to 2003. But the fluxes proportion of dissolved inorganic nutrients during water-sediment regulation to the whole year is about 50% .