象山港河鲀养殖区沉积物—海水界面N、P营养盐的扩散通量

Nitrogen and phosphorus fluxes in seawater-sediment in Xiangshan Bay

2008年1月、5月和7月3次对象山港河鲀网箱养殖区海底沉积物进行了底质表层间隙水和上覆水营养盐(NH4-N,NO2-N,NO3-N,PO4-P)的分析,并使用Fick第一定律对该港湾沉积物——海水界面N、P营养盐的扩散通量进行了估算。研究结果表明,养殖区沉积物间隙水中N、P营养盐含量显著高于非养殖区,上覆水和沉积物间隙水中的N从1月份NH4-N为主逐渐转变到7月份以NO3-N为主。养殖区上覆水中NH4-N最高浓度为234.66μmol/L,NO3-N最高浓度为79.25μmol/L。养殖区上覆水中N、P营养盐的含量均严重超标。N、P营养盐的扩散通量估算结果显示:随着养殖高峰期的到来,沉积物—海水界面N、P营养盐的扩散方向由从沉积物向上覆水扩散逐渐转向从上覆水向沉积物扩散;养殖区扩散通量值相对于非养殖区显著扩大化;NH4-N通量变化最大,从1月份最高700.41μmol/(m2.d)降低到7月份27.87μmol/(m2.d)。海水养殖对沉积物中N、P营养盐扩散通量影响显著。

The concentrations of NH4-N,NO2-N,NO3-N and PO4-P in overlying and interstitial waters of sediments in net-cage mari-culture areas of Xiangshan Bay were measured in 3 cruises from Jan to Jul in 2008.The diffuse fluxes of dissolved inorganic N,P in the sediments were estimated by Fick’s first law.The result of investigation showed that the contents of inorganic N,P in interstitial water in the culture areas were hardly higher than non-culture areas.It was also obtained that the main nitrogen salt was turning from NH4-N to NO3-N in overlying and interstitial waters of sediments.The highest NH4-N was 234.66 μmol/L in the water.The highest NO3-N was 79.25 μmol/L in the water.In mari-culture areas,both of nitrogen and phosphorus content in the overlying waters were severely beyond the standards.The result of Diffuse fluxes indicate that the diffuse aspect of inorganic N,P was turned from upward to downward by the mari-culture fastigium coming,and the culture areas’ diffuse fluxes observably enlarger than non-culture areas’.The largest changes was NH4-N diffuse fluxes,which was reducing from 700.41 μmol/（m^2·d） in Jan to 27.87 μmol/（m^2·d） in Jul.