钦州湾夏季营养盐的分布特征及富营养化评价

摘要

Based on the data from the field survey in Qinzhou Bay, Guangxi, at the south of China, in August of 2009, the distribution characteristics of nutrients and their causes were analyzed. The results showed that the average levels of NO2-N, NO3-N, NH3-N, PO4-P and SiO3-Si in the surface seawater were 0.05, 0.46, 0,09, 0.007 and 1.54 mg/L, respectively. A trend of the nutrients declining from the upper bay to the outside bay was found, suggesting that the land runoff was the major controlling factor in summer. The correlation analysis showed that the physical mixing of seawater was the first major factor influencing nutrient distribution in the bay, and the biological and chemical factors were the second influencing factors. The seawater quality of the bay was analyzed by using pollution index A and eutrophication index NQI. The results suggested that there was moderate pollution and eutrophication state in the whole survey area, and inorganic nitrogen was the main pollution factor.%2009年8月对钦州湾海域的现场调查资料,分析了钦州湾表层海水中营养盐的分布特征及其成因结果表明:该湾亚硝酸盐(NO2-N),硝酸盐(NO3-N),铵盐(NH3-N),无机磷(PO4-P)和活性硅(SiO3-Si)平均含量分别为0.05 mg/L,0.46 mg/L,0.09 mg/L,0.007 mg/L和1.54 mg/L.在空间分布上,各营养盐含量均呈现出由湾内向湾外逐渐递减的变化趋势,体现出夏季陆地径流的主导控制作用.相关性分析表明,陆源水的物理混合过程是影响诸营养盐含量的主要因素,生物、化学作用次之.通过污染指数A及营养状态质量指数NQI的分析,整个海湾水质处于中度污染程度和富营养化状态,以无机氮为主要污染因子.