2001—2011年黄河口营养盐变化及入海通量估算

Nutrients Variations and Fluxes Estimation in the Yellow River Estuary from 2001 to 2011

为更好地认识黄河向渤海的营养盐输送情况及其对渤海生态环境的影响,根据文献资料和实验室监测数据,讨论了黄河口淡水端4a间的营养盐浓度月际变化,并用月均浓度占年均浓度比例的方法对2001—2011年营养盐入海通量进行了估算。结果表明:黄河口DIN的月平均浓度变化范围为222.6～403.8μmol/L,NO3--N占DIN的比例约为94.3%,5月份浓度约为8月份的1.8倍。NH4+-N枯水期浓度约为丰水期的10倍。NO2--N浓度变化范围较大,约有1/4的月份超过7.14μmol/L。PO34--P普遍处于0.80μmol/L以下,秋、冬季高于春、夏季。SiO23--Si的月浓度基本在年均浓度上下浮动。2001—2011年黄河口DIN的年平均通量约为6.51×104 t/a,其中NO3--N约为5.76×104 t/a,NH4+-N约为0.80×104t/a,NO2--N约为0.108×104 t/a。PO34--P的年入海通量约为211.4t/a,SiO23--Si约为5.79×104 t/a。2005年以来DIN通量的下降幅度大于同期径流量的下降幅度,说明黄河向渤海输送的营养盐浓度呈现降低趋势。

To better understand the transport of nutrients of Yellow River and the ecological impact on the Bohai Sea, based on the literature cited and measured data, the monthly variations of nutrients con- centrations were discussed. The fluxes of nutrients of 2001-2011 were estimated by the scale factors be- tween monthly concentration and mean annual concentration. The result showed that the monthly average concentration of DIN was 222. 6-403.8 ffmol/L and the ratio of NO^--N to DIN was 94.3~//00. The concen- tration in May was 1.8 times of that in August. The concentration of NH＋-N in dry season was ten times of wet period. The concentrations of NO2--N varied greatly and about a quarter of monthly concentrations were more than 7. 14 ffmol/L. The concentrations of PO43---P was generally lower than 0. 80 ffmol/L and the concentrations in fall and winter were higher than that in spring and summer. The monthly concentra- tion of SiO32--Si fluctuated in the range of annual average concentration. The mean annual flux of DIN in the Yellow River Estuary from 2001 to 2011 was 6.51 104t/a, with the flux of NO32-N was 5.76 104t/a, NH＋-N was 0. 80 104t/a and NO;-N was 0. 108 104t/a. The flux of POa4--P was 211.4 t/a and SiO3- -Si was 5.79 104t/a. The decline in flux of DIN was more than the decrease in runoff since 2005. The nutrients input showed a downtrend from the Yellow River to the Bohai Sea.