流沙湾溶解氧的分布特征及其相关因素的探讨

2008年2月、5月、8月和11月四个航次对流沙湾海水中溶解氧进行详细的调查和研究,同时分别测试其温度、盐度、TOC、COD、叶绿素a等水质指标,通过统计分析,得出流沙湾DO的分布特征,并针对DO与其相关因素之间的关系进行探讨。结果表明:在整个调查海域内,秋冬季溶解氧呈现由外湾向内湾,由南向北逐渐递增的分布趋势;春季溶解氧则呈现由外湾向内湾逐渐递减的分布趋势,站位之间变化幅度较大(4.49～7.71mg/L);夏季内湾和外湾海水中溶解氧的含量较为平均,各站位之间变化幅度较小(5.93～6.99mg/L)。表层海水溶解氧平均含量(6.60mg/L)稍高于底层海水(6.33mg/L)。秋冬季溶解氧的平均含量(7.40mg/L、7.85mg/L)普遍高于春夏(6.26mg/L、6.46mg/L)两个季度,站位7底在四个季度中溶解氧均处于低值区。随着水温升高,氧的溶解度降低,随着盐度升高,溶解氧含量也有下降趋势,冬季和春季的线性关系较为显著。DO和COD随季节变化的规律一致,与TOC的季节变化规律相反。溶解氧与叶绿素a在冬季呈现极显著正相关。春季次之,夏秋两季两者之间不存在相关性。

Distribution Characteristics of Dissolved Oxygen and Correlating Factors Analysis in Liusha Bay

Detailed survey on dissolved oxygen(DO)in water was done in February,May,August and November 2008 in Liusha Bay,with analysis of correlation between DO and temperature,salinity,TOC,COD and chlorophyll a.Results showed that DO increased gradually form outside to inside of the Bay and from south to north in winter and autumn.In spring,DO decreased gradually from outside to inside of the Bay,with larger changes of 4.49～7.71mg/L among the stations.In summer,the content of DO was of evenness in outside and inside of the Bay,with smaller changes of 5.93～6.99mg/L among the stations.The concentration of DO was higher in surface water of 6.60mg/L than in bottom water of 6.33mg/L.The content of DO was higher in winter and autumn of 7.40mg/L and 7.85mg/L than in spring and summer in common.With increasing temperature and salinity,DO concentration decreased.There was a linear correlation between DO and temperature,salinity in winter and spring respectively.DO revealed the consistent seasonal change with COD,but contrary to TOC.DO in the winter was significantly positive correlated with chlorophyll a,followed in spring.However,no correlation was found between summer and autumn.