Effects and Mechanism of Two Nanoparticles (Titanium Dioxide and Silver) to Moina mongolica Daday (Crustacea, Cladocera)

Abstract

The nearshore and estuary are the main gathering areas of nanoparticles (NPs), and salinity change is a crucial characteristic in these marine areas. Moina mongolica Daday is an important open-ended bait in the nearshore aquaculture environment. Investigating the toxicity mechanism of NPs to M. mongolica under different salinity conditions is crucial to exploring the biological impact of NPs in the nearshore environment. Two typical metal oxide and metal NPs of TiO2 and Ag were used in this study to test the acute, chronic, and reproductive toxicities of M. mongolica (Cladocera) in marine environments of different salinity gradients. The toxic effects and mechanisms of the two NPs on M. mongolica were discussed by ecotoxicology and transcriptional analysis, respectively. A total of 27,274 genes were assembled, and 11,056 genes were successfully compared. Results suggested that TiO2 and Ag NPs showed particle toxicity with oxidation generation and immune emergencies on M. mongolica. Compared with TiO2, Ag NPs showed strong toxicity with reproductive toxicity due to the release of Ag+, resulting in a reduction in reproduction, which is a decrease in the number of offspring and the rm. Critical DEGs involved in carapace showed carapace damage of M. mongolica, due to adhesion and accumulation (approximately 40%–60% of all accumulation) on carapace, which was one of the toxic mechanisms of the two NPs. The salinity factor caused the aggregation of both NPs, and Ag+ release of Ag NPs. The toxicity of TiO2 NPs to M. mongolica increases with salinity, but that of Ag NPs decreases.