Effects of microplastics on microalgae have not been compared from different habitat. To answer this question, three marine microalgae species (Chlorella marined, Nannochloropsis oculate, and Phaeodactylum tricornutum) and two freshwater species (Chlorella vulgaris and Tetradesmus obliquus) were selected and exposed to the environment relevant concentrations of polystyrene microplastics. The results indicated that microplastics have a significant concentration effect on the growth of microalgae. The attachment of microalgae to microplastics surface and the aggregation of microalgae with each other were observed. Under exposure of microplastics, the photosynthesis of microalgae was inhibited while the antioxidant system was activated, indicating that microplastics had a negative impact on microalgae. At the end of exposure, the oxidative stress status caused by microplastics in marine microalgae were alleviated, but the antioxidant system of freshwater microalgae was still at high levels, indicating a stress response. In addition, integrated biomarker response (IBR) indicated that the effects of microplastics on freshwater microalgae were severer than marine microalgae, which might relate to their differences in removing reactive oxygen species (ROS) effectively and membrane structure. Our study provides a reliable data for understanding the complex effects of microplastics on microalgae, and especially for comparing the differential effects of microplastics among different microalgae.

尚未比较不同栖息地的微塑料对微藻的影响。为了回答这个问题，三种海洋微藻类（Chlorella marined、Nannochloropsis oculate和Phaeodactylum tricornutum）和两种淡水物种（Chlorella vulgaris和Tetradesmus obliquus) 被选择并暴露于环境相关浓度的聚苯乙烯微塑料。结果表明，微塑料对微藻的生长具有显着的浓度效应。观察到微藻附着在微塑料表面和微藻相互聚集。在微塑料暴露下，微藻的光合作用受到抑制，抗氧化系统被激活，表明微塑料对微藻产生了负面影响。暴露结束时，海洋微藻因微塑料引起的氧化应激状态有所缓解，但淡水微藻的抗氧化系统仍处于高水平，表明存在应激反应。此外，综合生物标志物反应（IBR）表明，微塑料对淡水微藻的影响比海洋微藻严重，这可能与它们在有效去除活性氧（ROS）和膜结构方面的差异有关。我们的研究为理解微塑料对微藻的复杂影响，特别是比较微塑料对不同微藻的差异效应提供了可靠的数据。