The adverse effects of microplastics (MPs) on have been extensively studied; however, their population-level effects are relatively unknown. This study investigated the effect of polyethylene MP fragments (33.90 ± 17.44 μm) and benzophenone-3 (BP-3), which is a widely used plastic additive (2.91 ± 0.02% w/w), on population dynamics in a 34-day microcosm experiment. In the growth phase, neither MP nor MP/BP-3 fragments changed the population size of compared with the control. However, MP/BP-3 fragments significantly reduced ( < 0.05) the population biomass compared to that of the control, whereas MP fragments did not induce a significant reduction. The MP/BP-3 group had a significantly higher ( < 0.05) neonate proportion than that in the control and MP groups. MP/BP-3 fragments upregulated and downregulated , and , altering gene expression in the ecdysone signaling pathway linked to growth and development. These findings suggested that BP-3 in MP/BP-3 fragments may disrupt neonatal growth, thereby decreasing population biomass. In the decline phase, MP fragments significantly decreased ( < 0.05) the population size and biomass of compared with the control and MP/BP-3 fragments. This study highlights the importance of plastic additives in the population-level ecotoxicity of MPs.

中文翻译：

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二苯甲酮-3 添加剂在聚乙烯微塑料对大型溞种群动态影响中的作用

微塑料 (MP) 对人体的不利影响已得到广泛研究；然而，它们对人口水平的影响相对未知。本研究调查了聚乙烯 MP 碎片 (33.90 ± 17.44 μm) 和二苯甲酮-3 (BP-3)（一种广泛使用的塑料添加剂 (2.91 ± 0.02% w/w））对 34 天人口动态的影响微观实验。在生长阶段，与对照相比，MP和MP/BP-3片段均未改变群体大小。然而，与对照相比，MP/BP-3 片段显着降低了种群生物量（< 0.05），而 MP 片段并未引起显着降低。 MP/BP-3组的新生儿比例显着高于对照组和MP组（<0.05）。 MP/BP-3 片段上调和下调，并且改变与生长和发育相关的蜕皮激素信号通路中的基因表达。这些发现表明 MP/BP-3 片段中的 BP-3 可能会破坏新生儿生长，从而降低种群生物量。在衰退阶段，与对照和MP/BP-3片段相比，MP片段的种群规模和生物量显着下降(<0.05)。这项研究强调了塑料添加剂在 MP 的群体生态毒性中的重要性。