眼点拟微球藻和近头状伪蹄型藻对抗生素的生理响应及去除效应

抗生素的广泛使用对水生生态环境造成潜在风险。为探讨水体残留抗生素对藻类的毒性作用，分别以海洋微藻眼点拟微球藻和淡水微藻近头状伪蹄型藻为对象，探讨三种典型抗生素（红霉素、诺氟沙星和磺胺嘧啶）胁迫下藻类的生理响应和去除效应。实验结果显示，三种抗生素中红霉素的毒性较强。高浓度红霉素对两种藻类生长均起到抑制作用，低浓度红霉素暴露则会刺激藻类生长，眼点拟微球藻和近头状伪蹄型藻的72 h半数最大有效浓度（EC₅₀）分别为6.13 mg/L和27.7 μg/L。随着红霉素浓度的增加，两种藻类的光合色素含量显著降低（p < 0.05）。藻体内超氧化物歧化酶和过氧化氢酶活性也表现出低浓度红霉素暴露时显著增强，高浓度时则显著受到抑制的现象（p < 0.05）。实验结果表明所选藻类对诺氟沙星和磺胺嘧啶具有一定的生物去除能力。经144 h暴露后，眼点拟微球藻对诺氟沙星和磺胺嘧啶的去除率分别为57%和78.3%，近头状伪蹄型藻在暴露120 h后对诺氟沙星和磺胺嘧啶的去除率分别为51.2%和8.3%。

Physiology responses of Nannochloropsis oculata and Pseudokirchneriella subcapitata to antibiotic pollution and their removal effects

The widespread use of antibiotics has caused potential risks to aquatic ecological environment.In order to investigate the physiology responses and their removal effects of algae to antibiotic pollution, three kinds of antibiotics erythromycin, norfloxacin and sulfadiazine, seawater algae Nannochloropsis oculata and freshwater Pseudokirchneriella subcapitata, were chosen for the study.Among three antibiotics, erythromycin was the most toxic.Lower concentrations of erythromycin stimulated the growth of algae, but its higher concentrations inhibited the growth of algae.The values of half maximal effective concentration (EC₅₀) at 72 h to Nannochloropsis oculata and Pseudokirchneriella subcapitata were 6.13 mg/L and 27.7 μg/L, respectively.With the increased concentration of erythromycin, the photosynthetic pigments of both algae decreased significantly (p < 0.05).The activities of superoxide dismutase and catalase of two algae were significantly enhanced when erythromycin was at the low concentrations, but with the increased concentrations of erythromycin their activities gradually decreased (p < 0.05).Results indicated that the studied two algae were capable of removing the residual antibiotics to some extents.After 144 h of culture, 57.0% of norfloxacin and 78.3% of sulfadiazine were removed by Nannochloropsis oculata, 51.2% of norfloxacin and 8.3% of sulfadiazine were removed by Pseudokirchneriella subcapitata after 120 h of culture.