胶州湾海水-沉积物界面氮、磷、铁的地球化学特征

对胶州湾底层水溶解氧、总氮、总磷、溶解无机氮、活性磷酸盐、铁及孔隙水中溶解无机氮、磷酸盐、铁和沉积物粒度、有机碳进行了分析。结果显示除铵氮外,孔隙水浓度明显高于底层水中浓度,其中硝酸氮、亚硝酸氮、活性磷酸盐、铁在孔隙水中的浓度分别为在底层水中浓度的17.8、9.3、12.5、7.7倍,暗示孔隙水中的物质可能向上覆水体扩散。在横向上,底层水及孔隙水中硝酸氮、亚硝酸氮、铵氮、活性磷酸盐都呈东岸高西岸低的分布规律,在西南部出现低值。Fe在底层水及孔隙水中的分布规律为东低西高,然而在沉积物中则与此正好相反。氮、磷、铁主要补给源有河流输入、工业生活污染排放、海洋生物自身分解以及孔隙水的释放。影响氮、磷、铁分布的主要因素为物源、河流输入及水动力条件,同时受到沉积物粒度的制约。相关分析显示,溶解氧、有机碳、铁对水体中磷及氮的分布具有某种制约作用。

GEOCHEMISTRY OF NITROGEN,PHOSPHORUS AND IRON AT THE WATER-SEDIMENT INTERFACE IN JIAOZHOU BAY

Concentrations of DO,TN,TP,DIN,PO_(4)-P,and Fe in bottom water,DIN,PO_(4)-P and Fe in interstitial water and grain size and organic carbon in surface sediments of the Jiaozhou Bay are analyzed.With the exception of NH_4-N,the interstitial water shows NO_3-N concentration 17.8 times,NO_(2)-N 9.3 times,PO_(4)-P 12.5 times,and Fe 7.7 times higher than the counterparts of the bottom water.The authors conclude that there is a trend of element releasing from interstitial water into the overlying bottom water.Laterally,concentrations of NO_(3)-N,NO_(2)-N,NH_(4)-N,and PO_(4)-P in both the interstitial and bottom water as well as Fe in the sediments in the east of the Jiaozhou Bay are higher than those in the west,while the distribution of Fe in both the interstitial and bottom water seems opposed.The results suggest that N,P,and Fe contents in bottom water are mainly controlled by the proximity to the estuary of the east Jiaozhou Bay due to the industrial and agricultural waste discharge and decomposition of marine organism,while the diffusion of the above elements from the interstitial water into the overlying bottom water is significant,and hydrodynamical factor and grain size of sediments should marginally affect the distributions of N,P,and Fe.Moreover,correlation analysis indicates that concentrations of N and P in both bottom and interstitial water are correlated with DO in bottom water,and with organic carbon and Fe in sediments respectively.