宁波南沙港养殖水域沉积物-水界面氮磷营养盐的扩散通量

Diffusion Fluxes of Dissolved Inorganic Nitrogen and Phosphorus Across Sediment-water Interface in Nansha Aquaculture Area,China

在2007年1月—2007年11月分4个航次对宁波南沙港养殖水域上覆水和表层沉积物间隙水中的溶解无机氮(DIN)和活性磷酸盐(PO34--P)浓度进行了现场调查,并应用Fick第一定理对该养殖水域沉积物-水界面DIN和PO34--P的扩散通量进行了估算。结果表明,南沙港养殖水域上覆水中NH4+-N、NO3--N、NO2--N和PO34--P的浓度变化范围分别为1.07～11.73、0.01～121.43、0.06～3.79μmol·L-1和0.42～4.16μmol·L-1;间隙水中NH4+-N、NO3--N、NO2--N和PO34--P浓度年变化范围分别为24.00～219.51、4.02～1250.41、0.45～8.70μmol·L-1和3.41～41.87μmol·L-1;DIN和PO34--P的扩散通量平均值分别为1520.73μmol·m-2·d-1和22.33μmol·m-2·d-1,扩散方向总体表现为从沉积物向上覆水扩散,每年向养殖系统中输入的DIN和PO34--P量分别约为9.87t和0.32t,表明沉积物是南沙港养殖水域水体氮磷营养盐,尤其是DIN的重要的输入源。

Based on 4 cruises of field investigation from January 2007 to November 2007,concentrations of NH4^＋-N,NO3^--N,NO2^--N and PO4^3--P in overlying and interstitial waters of sediments in Nansha aquaculture area were analyzed. Moreover,diffusion fluxes of dissolved inorganic nitrogen and phosphorus across sediment-water interface were estimated according to Fick＇s first law. Results showed that,the concentration variation range of NH4^＋-N,NO3^--N,NO2^--N and PO4^3--P in overlying water were 1.07～11.73 μmol·L^-1,0.01～121.43 μmol·L^-1,0.06～3.79 μmol·L^-1,0.42～4.16 μmol·L^-1,respectively; the concentration variation range of NH4^＋-N,NO3^--N,NO2^--N and PO4^3--P in interstitial water were 24.00～219.51 μmol·L^-1,4.02～1 250.41 μmol·L^-1,0.45～8.70 μmol·L^-1 and 3.41～41.87 μmol·L^-1,respectively. The average diffusion rate of dissolved inorganic nitrogen（DIN） and PO4^3--P across sediment-water interface were 1 520.73 μmol·m^-2·d^-1 and 22.33 μmol·m^-2·d^-1. The annual fluxes of DIN and PO4^3--P from sediment to water were about 9.87 t and 0.32 t,which indicate the sediment is a major output source of nutrient to the water,especially for nitrogen.