河口沉积物孔隙水营养盐分布特征及扩散通量

通过2010年夏季在李村河口潮滩区3个站位的采样分析,研究了孔隙水营养盐的分布特征,并利用Fick第一定律估算了沉积物-水界面间营养盐的扩散通量。结果表明,孔隙水营养盐在不同站位间质量浓度不同,呈现出自河口上游向下游逐渐降低的分布趋势。NH₄⁺-N质量浓度为26.21~53.10 mg/L,是孔隙水中营养盐的主要组分。沉积物中有机物的降解反应主要在还原状态下进行,营养盐质量浓度在垂向上的变化受有机质含量及沉积物氧化还原环境改变的综合影响。除NO₃^--N外其他营养盐均由沉积物向上覆水体扩散,沉积物是底层水体营养盐的重要来源。

Distribution of nutrients in interstitial water and diffusion flux in estuary

The spatial distribution characteristics of nutrients and diffusion fluxes at the sediment-water interface were analyzed in the three sites of the Licun River estuary in the summer of 2010. The results showed that the nutrient contents in interstitial water were different within the investigated sites, which decrease with the distance from the inner Licun River estuary. The concentration of NH₄⁺-N was 26.21-53.10 mg/L, which was the main form of nutrients in interstitial water of sediment. The organic matter decomposition was completed in anaerobic condition. The nutrients concentration profile in sediment interstitial water was influenced by the concentration of organic matter and the oxidation-reduction environment. The diffusion of nutrients in tidal flat area was from pore water into overlying water, except NO₃^--N. The sediment in tidal flats was the important sources for nutrients in bottom water.