长期放射性环境下微生物群落多样性变化

针对某铀尾渣库，通过深层垂直钻井方式采集了多个点位不同深度的铀尾渣样品，基于Illumina Miseq高通量测序技术研究了库区微生物群落的三维空间分布，阐释了长期放射性环境下微生物群落的多样性变化和环境因子的相关关系.结果表明，铀尾渣样品间的理化性质差异显著，放射性环境显著降低了微生物多样性水平，但仍存在优势菌群（丰度>5%），在门水平上依次为变形菌门（Proteobacteria）、厚壁菌门（Firmicutes）、放线菌门（Actinobacteria）和拟杆菌门（Bacteroidetes），而属水平上节杆菌属（Arthrobacter）和酸杆菌属Gp16表现出较强的耐放射性能力.微生物群落RDA冗余分析显示放射性核素²¹⁰Po、²¹⁰Pb、U，金属元素Mn、Ca以及pH值、SO₄^2-等多种环境因子均对铀尾渣中微生物群落分布影响较大.本研究结果揭示了长期放射性核素环境下的微生物群落演替规律，为发掘潜在生物修复菌种提供理论基础.

Variation of microbial community diversity with long-term exposure of radionuclides in dry uranium tailings pond

Uranium tailings were collected using the deep drilling engineering and were subsequently high-throughput sequencing on Illumina Miseq platform to characterize the microbial community in the dry uranium tailings pond, aiming at comprehensively revealing the three-dimensional spatial distribution of microbial community in the reservoir area and the correlation between the diversity of microbial community and environmental factors with long-term uranium exposure. Results showed a significant variation of the physical and chemical properties among the collected uranium tailings (P<0.05). Moreover, the diversity of microbial community in uranium tailings was declined in the radioactive environment. In the microbial community, the dominant bacterial taxa in uranium tailings at phylum level belonged to Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes. Genus Arthrobacter and Gp16 were tolerant of the radioactivity of uranium tailings. Redundancy analysis indicated that environmental factors including radionuclides U, ²¹⁰Po, ²¹⁰Pb, metals Mn Ca and pH, SO₄^2-were the main drivers shifting the changes of microbial community in uranium tailings at different depths. The results revealed the succession pattern of microbial community with long-term exposure of radionuclides, providing a scientific value for further exploring potential bioremediation strains.