香溪河沉积物-水界面的营养盐交换特征

为研究香溪河库湾沉积物-水界面的营养盐交换特征，于2016年6月采集香溪河库湾上覆水和沉积物间隙水样品，分析不同形态氮、磷的空间分布特征并进行相关性分析，计算沉积物-水界面氮、磷的释放通量.结果表明:香溪河库湾上覆水和沉积物间隙水中ρ（TP）的变化范围分别为0.484~0.927和0.511~2.220 mg/L，ρ（TN）的变化范围分别为0.739~4.302和3.571~14.011 mg/L；上覆水和沉积物间隙水中氮、磷质量浓度在沿程和垂向上具有一定的变化规律，上游区域沉积物间隙水中氮、磷质量浓度大于下游区域，沉积物间隙水中氮、磷质量浓度明显大于上覆水；香溪河沉积物总体上表现为PO₄3--P和NH₄+-N的"源"，中下游区域沉积物表现为NO₃--N的"源"，而中上游区域表现为NO₃--N的"汇"；PO₄3--P的释放通量范围为0.129~0.339 mg/（m2·d），NH₄+-N的释放通量范围为0.213~1.415 mg/（m2·d），NO₃--N的释放通量范围为-1.109~3.446 mg/（m2·d）.研究显示，上覆水的环境条件对于沉积物-水界面营养盐交换存在一定的影响，但影响程度各有不同. 

Characteristics of Nutrient Exchange at the Sediment-Water Interface in Xiangxi Bay

Overlying and sediment interstitial water samples from Xiangxi Bay were collected in June 2016 to study the nutrient exchange between sediment and water interfaces. The spatial distribution of nitrogen and phosphorus in the sediment was investigated, and correlation analysis between them was conducted. The results showed that the phosphorus concentration in the overlying water and sediment interstitial water of Xiangxi Bay ranged from 0.484 to 0.927 mg/L and 0.511 to 2.220 mg/L, respectively, and the nitrogen concentration ranged from 0.739 to 4.302 mg/L and 3.571 to 14.011 mg/L. The nitrogen and phosphorus concentrations in the overlying and interstitial water of the sediments had a certain variation along the stream and vertically. The interstitial water nitrogen and phosphorus concentrations in the upstream area were higher than those in the downstream area. The interstitial water nitrogen and phosphorus concentrations in the sediment were significantly larger than those in the overlying water. Xiangxi Bay sediment acts as a source of PO₄3--P and NH₄+-N; however, for NO₃--N it is a source in the middle and lower reaches and a sink in the upstream region. The diffusive flux of PO₄3--P ranged from 0.129 to 0.339 mg/(m2·d); the diffusive flux of NH₄+-N ranged from 0.213 to 1.415 mg/(m2·d); and the diffusive flux of NO₃--N ranged from -1.109 to 3.446 mg/(m2·d). The environmental conditions of the overlying water have some influence on the nutrient exchange of the sediment-water interface, but the degree of influence is different.