Miao Lingzhan, Guo Song, Wu Jun, Adyel Tanveer M, Liu Zhilin, Liu Songqi, Hou Jun
Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Xikang Road 1st, Nanjing 210098, People's Republic of China.
Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, DK-1958 Frederiksberg C, Denmark.
J Hazard Mater. 2022 Feb 5;423(Pt B):127117. doi: 10.1016/j.jhazmat.2021.127117. Epub 2021 Sep 6.
There is an increasing concern regarding the potential effects of nanoplastics (NPs) on freshwater ecosystems. Considering the functional values of biofilms in freshwater, knowledge on whether and to what extent NPs can influence the ecosystem processes of biofilms were still limited. Herein, the freshwater biofilms cultured in lab were exposed to 100 nm polystyrene NPs (PS-NPs) of different dosages (1 and 10 mg/L) for 14 days. Confocal laser scanning microscope observation indicated that biofilms were dominated by filamentous, and spiral algae species and the intensity of extracellular polymeric substances increased under PS-NPs exposure. GeoChip 5.0 analysis revealed that PS-NPs exposure triggered a significant increase in functional genes α diversity (p < 0.05) and altered biofilms' functional structure. Furthermore, the abundance of genes involved in the total carbon and nitrogen cycling were increased under PS-NPs exposure. The abundance of nitrogen fixation genes experienced the most pronounced increase (24.4%) under 1 mg/L PS-NPs treatment, consistent with the increase of ammonium in overlying water. Whereas antibiotic resistance genes and those related to photosynthetic pigments production were suppressed. These results provided direct evidence for PS-NPs' effects on the biofilm functions in terms of biogeochemical cycling, improving our understanding of the potentials of NPs on freshwater ecosystems.
纳米塑料（NPs）对淡水生态系统的潜在影响日益受到关注。鉴于生物膜在淡水中的功能价值，关于NPs是否以及在何种程度上会影响生物膜的生态系统过程的知识仍然有限。在此，将实验室培养的淡水生物膜暴露于不同剂量（1和10 mg/L）的100 nm聚苯乙烯纳米塑料（PS-NPs）中14天。共聚焦激光扫描显微镜观察表明，生物膜以丝状和螺旋藻类为主，在PS-NPs暴露下细胞外聚合物的强度增加。GeoChip 5.0分析显示，PS-NPs暴露导致功能基因α多样性显著增加（p < 0.05）并改变了生物膜的功能结构。此外，在PS-NPs暴露下，参与总碳和氮循环的基因丰度增加。在1 mg/L PS-NPs处理下，固氮基因的丰度增加最为显著（24.4%），这与上覆水中铵的增加一致。而抗生素抗性基因和与光合色素产生相关的基因则受到抑制。这些结果为PS-NPs在生物地球化学循环方面对生物膜功能的影响提供了直接证据，增进了我们对NPs对淡水生态系统潜在影响的理解。
