黄渤海海水中叶绿素a的分布特征及其环境影响因素

摘要

基于2013年夏、秋季和2014年春季黄渤海海域调查数据,分析了该海域叶绿素a的含量、分布特征及其环境影响因素(温度、盐度、pH 值、溶解无机氮、硅酸盐、磷酸盐).结果表明:2013年夏、秋季和2014年春季,黄渤海海水中叶绿素 a 含量范围分别是0.918~9.287,1.477~6.435,1.837~5.966 μg/L,平均浓度分别为3.527 ,3.467,3.524 μg/L;夏季和春季叶绿素a含量略高,秋季叶绿素a含量最低且变化范围较小;渤海海域叶绿素 a 分布具有明显区域特征,其分布基本呈近岸高、中部海域低的分布趋势;将水质参数作为自变量输入支持向量机(SVM)中,GA-SVM算法拟合效果(R2>0.9)和精确度(MSE<0.01)较好,不同水质参数对海水叶绿素a含量的影响相对重要性具有季节差异,夏季,对海水叶绿素a含量影响最重要是磷酸盐和温度;秋季,对于海水叶绿素a含量影响最重要是硅酸盐和盐度;春季,对于海水叶绿素 a 含量影响最重要的是盐度和溶解无机氮.所有调查季节,对于海水叶绿素 a 含量影响最重要的是盐度和磷酸盐 .综合参数影响重要性,表明陆源输入是黄渤海海域叶绿素a含量的最重要影响因素.%The distribution characteristics of chlorophyll-a (Chl-a) and the related environmental factors (T, S, pH, DIN, SiO3 2--Si, PO4 3--P) were examined for seawater samples obtained from the Yellow Sea (YS) and the Bohai Sea (BS) in the summer of 2013, the autumn of 2013 and the spring of 2014. The results showed that Chl-a concentration ranged 0.918~9.28μg/L in the summer of 2013 with an average of 3.527μg/L, 1.837~5.966μg/L in the autumn of 2013 with an average of 3.524μg/L and 1.477~6.435μg/L in the spring of 2014 with an average of 3.467μg/L; Chl-a spatial distribution showed a decreasing trend from inshore area to offshore area; The GA-SVM model was used to investigate the Chl-a response relationship with the above environmental factors and the results confirmed the good performance (R 2>0.9, MSE<0.01). The influence of parameters on the distribution of Chl-a had a significant seasonal variation. The two most significant variables to the distribution of Chl-a were PO4 3--P and T in summer, SiO3 2--Si and S in autumn, S and PO4 3--P in spring and S and PO4 3--P in all three seasons which demonstrated that the terrestrial input were most tightly related to the distribution of Chl-a in the BS and the YS.