象山港海域N、P污染特征及潜在性富营养化程度评价

Characteristics polluted by nitrogen and phosphorus and potential eutrophication assessment in Xiangshan Harbor

根据2002年4～9月份象山港海域表层海水N、P营养盐监测基础资料,分析探讨了象山港海域在赤潮多发期N、P污染的时空变化特征,并利用潜在性富营养化评价模式,对整个象山港海域水质富营养化程度进行了评价.结果表明:在赤潮多发期,象山港海域水质N、P污染严重,表层海水DIN指标数倍于Ⅳ类海水最大允许值,明显呈现高N、低P的污染特征;由于受港湾季节性生态环境的演变和陆源径流的影响,象山港海域N、P污染存在明显的空间分异和时间变化特征,NO2-N含量也会因硝化细菌活动的加剧而增加;潜在性富营养化评价结果表明:在赤潮多发期,整个象山港海域由于P的限制,总体上处于潜在性富营养化阶段.

On the base of the monitoring data of nitrogen（N） and phosphorus（P） nutrient at surface seawater from Apr. to Sep. 2002 in Xiangshan Harbor, the characteristics on spatio-temporal variations of N and P pollution in Xiangshan Harbor was analyzed and discussed in periods during which the red tide occurs frequently. By mean of the potential eutrophication assessment model, the eutrophication grade in Xiangshan Harbor was assessed. The results shown that the water quality in Xiangshan Harbor was seriously polluted by nitrogen and phosphorus, and the red tide occurs frequently. The characteristics on spatial-temporal variations of nitrogen and phosphorus pollution were observed obviously, NOz-N at surface seawater was increased with nitrifying bacteria. The results of the potential eutrophication assessment showed that in period of high frequency of the red tide, the water quality in the whole of Xiangshan Harbor was at the stage of potential eutrophication because hmit of phosphorus.