Zigui Ecological Station for Three Gorges Dam Project, State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China.
Zigui Ecological Station for Three Gorges Dam Project, State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China; College of Hydraulic & Environmental Engineering, China Three Gorges University, Yichang 443002, Hubei, China.
J Hazard Mater. 2021 Jun 5;411:125172. doi: 10.1016/j.jhazmat.2021.125172. Epub 2021 Jan 16.
Manganese (Mn) in acidic paddy soil has large potential in emigrating from the soil and pollute adjacent ecosystems. Single microorganisms modulate the biogeochemistry process of Mn via redox reactions, while the roles of microbial aggregates (e.g. periphytic biofilm) in modulating its biogeochemical cycle is poorly constrained. Here we collected a series of periphytic biofilms from acidic paddy fields in China to explore how periphytic biofilm regulates Mn behavior in paddy fields. We found that periphytic biofilms have large Mn accumulation potential: Mn contents in periphytic biofilm ranged from 176 ± 38 to 797 ± 271 mg/kg, which were 1.2-4.5 folds higher than that in the corresponding soils. Field experiments verified the Mn accumulation potential, underlining the biofilms function as natural barriers to intercept Mn emigrating from soil. Extracellular polymeric substances, especially the protein component, mediated adsorption was the main mechanism behind Mn accumulation by periphytic biofilm. Microorganisms in periphytic biofilms in general appeared to have inhibitory effects on Mn accumulation. Climatic conditions and nutrients in floodwater and soil affect the microorganisms, thus indirectly affecting Mn accumulation in periphytic biofilms. This study provides quantitative information on the extent to which microbial aggregates modulate the biogeochemistry of Mn in paddy fields.
在酸性稻田土壤中，锰（Mn）有很大的潜力从土壤中逸出并污染相邻的生态系统。单一微生物通过氧化还原反应调节 Mn 的生物地球化学过程，而微生物聚集体（如周生生物膜）在调节其生物地球化学循环中的作用还受到很大限制。在这里，我们从中国酸性稻田中收集了一系列周生生物膜，以探索周生生物膜如何调节稻田中的 Mn 行为。我们发现周生生物膜具有很大的 Mn 积累潜力：周生生物膜中的 Mn 含量范围为 176±38 至 797±271 mg/kg，比相应土壤中的含量高 1.2-4.5 倍。田间实验验证了 Mn 的积累潜力，突出了生物膜作为拦截土壤中 Mn 逸出的天然屏障的功能。细胞外聚合物物质，特别是蛋白质成分，介导的吸附是周生生物膜积累 Mn 的主要机制。周生生物膜中的微生物总体上似乎对 Mn 积累有抑制作用。洪水和土壤中的气候条件和养分影响微生物，从而间接影响周生生物膜中 Mn 的积累。本研究提供了定量信息，说明微生物聚集体在多大程度上调节了稻田中 Mn 的生物地球化学性质。
