School of Environmental and Geographical Sciences, Shanghai Normal University, Shanghai 200234, China; Key Laboratory of Environment Remediation and Ecological Health, Zhejiang University, Ministry of Education, Hangzhou 310058, China; Yangtze River Delta Urban Wetland Ecosystem National Field Scientific Observation and Research Station, Shanghai 201722, China.
School of Environmental and Geographical Sciences, Shanghai Normal University, Shanghai 200234, China.
J Hazard Mater. 2024 Sep 5;476:134930. doi: 10.1016/j.jhazmat.2024.134930. Epub 2024 Jun 18.
Microorganisms can colonize to the surface of microplastics (MPs) to form biofilms, termed "plastisphere", which could significantly change their physiochemical properties and ecological roles. However, the biofilm characteristics and the deep mechanisms (interaction, assembly, and biogeochemical cycles) underlying plastisphere in wetlands currently lack a comprehensive perspective. In this study, in situ biofilm formation experiments were performed in a park with different types of wetlands to examine the plastisphere by extrinsic addition of PVC MPs in summer and winter, respectively. Results from the spectroscopic and microscopic analyses revealed that biofilms attached to the MPs in constructed forest wetlands contained the most abundant biomass and extracellular polymeric substances. Meanwhile, data from the high-throughput sequencing showed lower diversity in plastisphere compared with soil bacterial communities. Network analysis suggested a simple and unstable co-occurrence pattern in plastisphere, and the null model indicated increased deterministic process of heterogeneous selection for its community assembly. Based on the quantification of biogeochemical cycling genes by high-throughput qPCR, the relative abundances of genes involving in carbon degradation, carbon fixation, and denitrification were significantly higher in plastisphere than those of soil communities. This study greatly enhanced our understanding of biofilm formation and ecological effects of MPs in freshwater wetlands.
微生物可以在微塑料（MPs）表面定殖形成生物膜，称为“塑料体”，这可能显著改变它们的物理化学性质和生态作用。然而，湿地中塑料体的生物膜特征和深层机制（相互作用、组装和生物地球化学循环）目前缺乏全面的认识。在这项研究中，分别在夏季和冬季通过外在添加聚氯乙烯 MPs 到具有不同类型湿地的公园中进行原位生物膜形成实验，以研究塑料体。光谱和显微镜分析的结果表明，在人工林湿地的 MPs 上附着的生物膜含有最丰富的生物量和细胞外聚合物。同时，高通量测序的数据显示，与土壤细菌群落相比，塑料体中的生物多样性较低。网络分析表明，在塑料体中存在一种简单而不稳定的共现模式，而零模型表明，其群落组装的异质选择的确定性过程增加。通过高通量 qPCR 对生物地球化学循环基因进行定量，发现参与碳降解、碳固定和反硝化的基因的相对丰度在塑料体中明显高于土壤群落。这项研究极大地提高了我们对淡水湿地中生物膜形成和 MPs 生态效应的认识。
