Impacts of nanoplastics on life-history traits of marine rotifer (Brachionus plicatilis) are recovered after being transferred to clean seawater.

With the continuous accumulation of nanoplastics (NPs) in the ocean, it becomes urgent to explore their potential effects on filter-feeding zooplankton. This study exposed marine rotifer (Brachionus plicatilis) to 0, 20, 200, and 2000 μg/L of 70-nm polystyrene NPs (PS NPs) for two generations (F0 - F1), followed by two-generation (F2 - F3) culture in clean seawater, to investigate the impacts on life-history traits. The results showed that NPs were ingested by the rotifers within 10 min and reached a maximum level after 12 h of exposure. NPs were also observed in the feces of F0 and F1 generation rotifers and on the surface of F1 generation eggs. The intake of NPs inhibited microalgae ingestion, decreased body volume, delayed the first spawning time, reduced the total number of eggs and offspring of F0 and F1 generation. Moreover, 2000 μg/L NPs postponed the first hatching time of F0 generation eggs by 2.5 h, and the hatching time of F1 generation eggs was delayed by 7.3 h and 6.8 h under 200 and 2000 μg/L NPs exposure. The first spawning time and the first hatching time of rotifers were still significantly prolonged in the F2 generation, but other life-history traits returned to normal. After being cultured in clean seawater for two generations, all these indicators were recovered to the normal level. Overall, this study demonstrates that the life-history traits of marine rotifers could be flexibly changed with/without PS NPs exposure.