东海赤潮高发区沉积物中营养盐再生速率的研究

Nutrients regeneration speed of sediment in harmful algae blooms(HAB) area of East China Sea

2 0 0 1年 5月和 2 0 0 2年 5月在东海赤潮高发区的 4个站位 (E4、E5、DB6、DC10 )对沉积物表面分别充氮气和空气进行培养 ,研究沉积物 水界面营养盐交换通量在不同条件下的变化规律 ,以及该海域沉积物中营养盐的再生对水体中营养盐的贡献 .结果表明 ,各溶解态营养盐在还原条件下的迁移较为活跃 .在距离陆地较近的海域 ,营养盐一般由水向沉积物中扩散 ,且距陆地越近 ,交换通量越大 ;而在上升流区 ,营养盐多由沉积物中向水中扩散 .东海赤潮高发区沉积物是SiO3 2 -的源 ,对初级生产力的贡献占 6 % .同时 ,东海赤潮高发区沉积物是氮、磷营养盐蓄积库 .该海域沉积物每年从水体中吸附的DIN、PO43 -分别占长江输入的 5 .9%、6 7% ,沉积物 水界面对水体中SiO3 2 -的贡献占 7.8% .

The fluxes of dissolved nutrients at sediment-water interface were investigated at 4 stations in the HAB area of East China Sea in May 2001 and May 2002. The benthic fluxes of nutrients were determined by incubating the sediment core samples with bottom seawater bubbled with air or nitrogen. The transfer of nutrients was more active under anoxic condition. The fluxes of dissolved nutrients were generally high at the stations close to the coast. The sediment was the source of SiO 3 2-, which accounted for 6% of primary production. For DIN and PO 4 3-, the sediment was the sink. DIN and PO 4 3- adsorbed by sediment accounted for 5.9% and 67% of the riverine DIN and PO 4 3- inputs, respectively, and the inputs of SiO 3 2- accounted for 7.8%.