Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023, China.
Ecotoxicol Environ Saf. 2022 May 1;236:113475. doi: 10.1016/j.ecoenv.2022.113475. Epub 2022 Mar 29.
Most aquatic ecosystems are at risk of being polluted by new environmental pollutant nanoparticles. As the main food source of zooplankton, the biomass of algae always fluctuates. Cladocerans, an important part of zooplankton, are usually be simultaneously exposed to different abundance of algae and nanoparticles in aquatic environment. To evaluate the combined effects of food abundance and ZnO nanoparticles concentration on the development and early reproductive performance of cladocerans, we exposed Daphnia magna, a common and representative model organism in cladocerans, to the combinations of different abundances of Chlorella pyrenoidosa and different concentrations of ZnO nanoparticles, recorded the key life-history traits, and used multiple models to fit the data. Results showed that high level of ZnO nanoparticles and low abundance Chlorella had an interactively negative effect on the life history of D. magna. When D. magna was exposed to ZnO nanoparticles, some life history traits, such as survival time, body length at maturation, and offspring per female, increased exponentially with the increase of food abundance, and then reached a theoretical maximum value, whereas some other life history traits, such as time to maturation and time to first brood, showed an opposite trend. However, higher Chlorella abundance reduced the negative effect of ZnO nanoparticles on D. magna, but the negative effect could not be eliminated with the increase of food abundance. Below Chlorella 0.30 mg C L, food plays a decisive role, while at or above this threshold, ZnO nanoparticles play a decisive role. Therefore, the effect of different ZnO nanoparticles concentrations can be fully reflected only when food is sufficient, and the negative effects of food shortages may mask the toxic effects of ZnO nanoparticles on D. magna. The findings indicated that the effects of food abundance should be considered in evaluating the realistic impact of pollutants on zooplankton.
大多数水生生态系统都面临着被新型环境污染物纳米颗粒污染的风险。作为浮游动物的主要食物来源，藻类的生物量总是波动的。枝角类，浮游动物的重要组成部分，通常同时暴露于不同丰度的藻类和纳米颗粒在水生环境中。为了评估食物丰度和 ZnO 纳米颗粒浓度对枝角类发育和早期生殖性能的联合影响，我们将一种常见的枝角类模式生物大型溞暴露于不同丰度的蛋白核小球藻和不同浓度的 ZnO 纳米颗粒的组合中，记录关键的生活史特征，并使用多个模型对数据进行拟合。结果表明，高水平的 ZnO 纳米颗粒和低丰度的小球藻对大型溞的生活史有交互的负面影响。当大型溞暴露于 ZnO 纳米颗粒时，一些生活史特征，如存活时间、成熟时的体长和每雌后代数量，随着食物丰度的增加呈指数增长，然后达到理论最大值，而其他一些生活史特征，如成熟时间和第一次产卵时间，呈相反的趋势。然而，较高的小球藻丰度降低了 ZnO 纳米颗粒对大型溞的负面影响，但随着食物丰度的增加，这种负面影响无法消除。在小球藻 0.30mg C L 以下，食物起着决定性的作用，而在这个阈值以上，ZnO 纳米颗粒起着决定性的作用。因此，只有在食物充足的情况下，才能充分反映不同 ZnO 纳米颗粒浓度的影响，而食物短缺的负面影响可能会掩盖 ZnO 纳米颗粒对大型溞的毒性作用。研究结果表明，在评估污染物对浮游动物的实际影响时，应考虑食物丰度的影响。
