Effects of nano/microplastics on the growth and reproduction of the microalgae, bacteria, fungi, and Daphnia magna in the microcosms

Over the past 20 years, nano/microplastics have become a prominent environmental concern of the public and scientific community. The difference between model microplastic particles used in the laboratory with the MPs that exist in the environment and the low ecological relevance of the data obtained from single species experiments are two knowledge gaps that must be overcome before a comprehensive ecological risk assessment on MPs can be conducted. Therefore, this study examined the effects of 14 plastic particles and 6 fiber materials on the growth of microorganisms in single species and microcosm exposure experiments. The statistical analysis results of over 300 experimental data revealed that higher concentrations and smaller particle sizes of MPs led to lower growth rates of Chlorella spp. Fibrous MPs inhibited the growth of Chlorella spp. less than fragmented MPs. All the types of MPs inhibited the growth of Euglena which has no cell wall protection. Aerobic Bacillus subtilis were inhibited by MPs more than facultative anaerobic bacteria, and yeast. The existence of PS spheres caused a negative effect on the growth and reproduction of the parental D. magna, which in turn led to a negative effect on the development of the progeny. These findings demonstrated that MPs selectively inhibit or promote the growth of different species in the same habitat, which means that the presence and increase of MPs have the potential to change the species structure in natural ecosystems.