四种溢油分散剂对青岛大扁藻和小新月菱形藻细胞密度和叶绿素含量的影响

Effects of four dispersants on cell density and chlorophyll contents of Platymonas helgolandica var. tsingtaoensis and Nitzschia closterium f. minutissima

研究了4种溢油分散剂对青岛大扁藻(Platymonas helgolandica var.tsingtaoensis)和小新月菱形藻(Nitzschia closterium f.minutissima)细胞密度和叶绿素含量的影响。实验结果表明:DL、GZ、WP和GM 4种溢油分散剂对青岛大扁藻生长的96 h EC50值分别是0.0722、0.1852、0.1889和0.7198 g·L^(–1);对小新月菱形藻的96 h EC_(50)值分别是0.0511、0.2592、0.2939和0.5816 g·L^(–1)。对青岛大扁藻的96 h EC50-chl-a为0.0433、0.1325、0.1517和0.5121 g·L^(–1),96 h EC_(50)-chl-b为0.0503、0.1719、0.1212和0.3091 g·L^(–1);对小新月菱形藻的96 h EC_(50)-chl-a为0.0425、0.1365、0.1470和0.4215 g·L^(–1)。随溢油分散剂浓度的增加,2种微藻的细胞密度和叶绿素含量显著下降,呈现显著的剂量—效应关系。根据半数抑制浓度值,4种溢油分散剂的毒性大小为DL>GZ>WP>GM。与细胞密度相比,2种微藻的叶绿素含量对4种溢油分散剂更敏感,更适于作为评判溢油分散剂毒性大小的指标。

Effects of four dispersants on cell density and chlorophyll contents of Platymonas helgolandica var. tsingtaoensis and Nitzschia closterium f. minutissima were studied under laboratory conditions. The results showed that the 96 h ECs0 values of four dispersants （DL, GZ, WP and GM） to cell density of P helgolandica var. tsingtaoensis and N. closterium f. minutissima were 0.0722, 0.1852, 0.1889 and 0.7198 g·L-l and 0.0511, 0.2592, 0.2939 and 0.5816 g·L-l, respectively. In addition, the 96 h EC50-chl values of the four dispersants to chlorophyll-a and chlorophyll-b contents of P helgolandica var. tsingtaoensis were 0.0433, 0.1325, 0.1517 and 0.5121 g·L-1 and 0.0503, 0.1719, 0.1212 and 0.3091 g·L-1, respectively. Meanwhile the respective 96 h EC50_chl values to chlorophyll-a content of N. closterium f. minutissima were 0.0425, 0.1365, 0.1470 and 0.4215 g.L 1. According to our data, the cell density and chlorophyll contents of the 2 marine microalgal species decreased obviously with increasing concentrations of dispersants, indicating a significant dose-effect relationship. According to these values of 96 h EC50 and 96 h EC50_chl, DL showed the highest toxicity followed by GZ, WP and GM. Considering the chlorophyll contents were more sensitive to four dispersants than the cell density, the 96 h EC50-chl value was more suitable to be an evaluating index for the toxicity of dispersants to marine microalgae.