东海赤潮高发区COD和石油烃分布特征及其与赤潮发生关系的初步研究

Distributions of COD and petroleum hydrocarbons and their relationships with occurrence of red tide in East China Sea

根据 2 0 0 2年 4月 2 5日～ 5月 2日对东海赤潮高发区化学耗氧量 (COD)、石油烃等项目的现场调查 ,探讨了该海区COD、石油烃以及富营养化指数 (EI)的分布特征 .结果表明 ,COD和富营养化指数 (EI)均表现为近岸高、外海低 ,沿离岸方向呈逐渐降低的趋势 .此外 ,赤潮发生与上述各项因素关系的初步研究表明 ,COD和海水富营养化程度高 ,是调查海区赤潮发生的必要条件 .在合适的温盐和光照条件下 ,当海水EI和COD浓度分别处在 2 .5～ 15和 0 .8～ 1.4mg·L-1范围内可导致赤潮发生 .

Based on the data of COD and petroleum hydrocarbons collected in the cruise from April 25 to May 2, 2002 in intensive red tide occurrence areas in East China Sea, the distribution of COD,and petroleum hydrocarbons and the eutrophication index(EI) were analyzed. The results showed that the EI and COD value were both high in coastal water, and decreased gradually away from shore. After the preliminary study on the relationships between correlative factors and occurrence of red tide, it was found that high EI and COD were necessary. There would be great chances for the red tide to break out under conditions that the EI was between 2.5 and 15 and COD concentration was between 0.8 to 1.4 mg·L -1 in seawater, along with the favorable temperature and salinity.