矾矿区重金属污染土壤对细菌群落特征和生态功能的影响机制研究

Effect mechanism of heavy metal contaminated soil on bacterial community characteristics and ecological function in alum mining area

为了研究重金属长期污染下土壤菌群特征对土壤重金属分布的响应机制,本研究通过区域网格划分选点,取样分析了自唐朝开采的安徽大矾山矿区50个典型特征点位的土壤理化性质和重金属含量,采用潜在生态风险评价法进行土壤综合污染程度分级,并利用Illumina MiSeq高通量测序技术和PICRUSt功能预测探究了不同程度重金属污染水平下土壤细菌群落的多样性及生态功能.结果表明:长期超标的重金属污染显著减少了矿区土壤细菌群落的多样性,抑制了变形菌门(Proteobacteria)等环境敏感菌的生长,但随着区域土壤有机质(OM)、全钾(TK)含量的增加,部分富营养型菌群,如酸杆菌门(Acidobacteriota)获得增殖优势;受污染区优势菌门为变形菌门、酸杆菌门和厚壁菌门(Firmicutes),优势菌属为埃希氏菌属(Escherichia-Shigella)、Terracidiphilus和链球菌属(Streptococcus).Proteobacteria环境适应性强,但在高度污染下生长受限,而Acidobacteriota和Firmicutes对重金属具有一定的耐受能力;RDA分析表明全磷(TP)、TK、pH、砷(As)和镉(Cd)是土壤细菌群落结构的主要驱动因素;土壤细菌群落的核心功能为新陈代谢和遗传信息处理,随着污染加剧,细菌群落的免疫系统、内分泌系统和次级代谢产物合成等途径被激活.该研究可为大矾山废弃矿区土壤重金属污染的修复治理提供理论依据.

In order to study the response mechanism of soil flora characteristics to soil heavy metal distribution under long-term heavy metal pollution,based on regional grid division method,the soil samples were collected and analyzed from 50 typical sites for soil physical and chemical properties,as well as heavy metal contents in Dafanshan mining area of Anhui province,which were mined since Tang Dynasty.The soil comprehensive pollution degree was graded with the potential ecological risk assessment method.The diversity and ecological function of soil bacterial communities under different heavy metal polluted level was investigated with Illumina MiSeq high-throughput sequencing technology and PICRUSt function prediction.The results showed that:the diversity of soil bacterial community was reduced and the growth of environmentally sensitive bacteria was inhibited heavy metal polluted soil over a long period.However,with the increase of soil organic matter(OM)and total potassium(TK)content in local area,some eutrophic bacteria were improved,such as Acidobacteriota.The dominant bacteria in the contaminated areas were Proteobacteria,Acidobacteria and Firmicutes.The dominant bacteria genera are Escherichia-Shigella,Terracidiphilus and Streptococcus.Proteobacteria has strong environmental adaptability,but its growth is also limited with high pollution.Acidobacteriota and Firmicutes have a certain tolerance to heavy metals.RDA analysis showed that total phosphorus(TP),TK,pH,arsenic(As)and cadmium(Cd)were the main driving factors of soil bacterial community structure.The core functions of the soil bacterial community are metabolism and genetic information processing.But with the worsening environmental pollution,the immune system,endocrine system and secondary metabolic product synthesis of the bacterial community were activated.This study can provide theoretical basis for the remediation of heavy metal pollution in the soil of Dafanshan abandoned mining area.