Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, Nanjing 210023, China.
School of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China.
Sci Total Environ. 2021 Aug 20;783:147154. doi: 10.1016/j.scitotenv.2021.147154. Epub 2021 Apr 17.
The water bodies are greatly influenced by chemical contamination and global increasing temperature. As an emerging pollutant, microplastics are widely distributed in the freshwater environment, raising concerns regarding their potential toxicity to organisms. Especially for zooplankton filter feeders, many of microplastics are in similar size as their food. Individually, both microplastics and temperature have profound effects on zooplankton populations and their function in ecosystems. However, the strength and direction of their interactive effects are still not clear. Here, we performed a comprehensive biotoxicity assessment providing empirical evidence that the temperature played a key role in shaping the sensitivity of the zooplankter, Daphnia magna, against microplastic toxicity. We found that exposure to microplastics generally caused negative effects on Daphnia individual fitness, such as increased lethality, declined fecundity and reduced population growth rate. This microplastic toxicity was more prominent at 30 °C than at 20 °C, and was rather minor at 15 °C. Moreover, the warming accelerated the ingestion of microplastics, and triggered abnormal ultrastructure of intestinal epithelial cells. In addition, the expression profiling of candidate genes revealed oxidative damage, fecundity impairment and energy retardation by microplastics were amplified with increasing temperature, which may contribute to the enhancement of microplastic toxicity under warming. Given that high temperature fluctuations are becoming more common and difficult to predict, the interactive effects of microplastics and climate warming on Daphnia population dynamics and biomass production may become increasingly aggravated in nature. Collectively, extrapolation for environmental risk assessment studies conducted under different temperature contexts may broaden our knowledge microplastic toxicity on aquatic organism fitness.
水体受到化学污染和全球气温升高的极大影响。作为一种新兴污染物，微塑料广泛分布于淡水环境中，其对生物的潜在毒性引发了人们的关注。对于滤食性浮游动物，特别是微塑料的很多种类与它们的食物大小相似。单独来看，微塑料和温度都对浮游动物种群及其在生态系统中的功能有深远的影响。然而，它们的交互作用的强度和方向仍不清楚。在这里，我们进行了一项综合的生物毒性评估，提供了经验证据表明，温度在塑造浮游动物——大型溞对微塑料毒性的敏感性方面起着关键作用。我们发现，暴露于微塑料通常会对大型溞个体的适应性产生负面影响，例如致死率增加、繁殖力下降和种群增长率降低。这种微塑料毒性在 30°C 时比在 20°C 时更为明显，而在 15°C 时则相当轻微。此外，变暖加速了微塑料的摄入，并引发了肠道上皮细胞的异常超微结构。此外，候选基因的表达谱揭示了微塑料引起的氧化损伤、繁殖力受损和能量减缓，随着温度的升高而加剧，这可能是微塑料毒性在变暖条件下增强的原因。鉴于高温波动变得更加普遍且难以预测，微塑料和气候变暖对大型溞种群动态和生物量产生的交互作用可能在自然界中变得更加严重。总的来说，在不同温度背景下进行的环境风险评估研究的外推可能会拓宽我们对微塑料毒性对水生生物适应性的认识。
