Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China; Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, USA.
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
Sci Total Environ. 2023 Jan 20;857(Pt 1):159314. doi: 10.1016/j.scitotenv.2022.159314. Epub 2022 Oct 8.
Thermal remediation is one of the most common approaches of removing organic pollutants in the retired contamination sites. However, little is known about the performance of bacterial community characteristics after in situ thermal remediation. In this study, the ecological response and spatial distributional characteristics of microorganisms and polycyclic aromatic hydrocarbons (PAHs) were investigated using a high throughput sequencing method in a retired coal gas plant site after in situ thermal remediation in Nanjing, China. Combination of Venn, clustering-correlation heatmap and two - factor correlation network analysis revealed that, microbial communities were obviously affected and classified by soil depths, temperature, and contamination level, respectively. The common and endemic microorganisms of each group were identified. The relative abundances of Thermaerobacter, Calditerricola, Brevibacillus, Ralstonia and Rhodococcus (aerobic bacteria) gradually declined with the increase of soil depth, while those of Bacillus, Fictibacillus, Paenibacillus, Rheinheimera presented opposite tendency. Some thermophilic degradation bacteria of PAHs, including Thermaerobacter, Calditerricola, Bacillus, Rhodococcus, unclassified_p__Firmicutes, Arthrobacter and Deinococcus, were identified and increased in the abundance at heavily polluted sites. Additionally, Proteobacteria, Bacteroidota, Deinococcota, Chloroflexi, Acidobacteriota, and Actinobacteriota showed negative response to the increase of soil depth, temperature and pollution level, while Firmicutes presented a positive response. This implied that Firmicutes has better stress resistance and adaptability to thermal remediation condition. The key environmental factors affecting microorganism composition and distribution were Temperature, Total nitrogen, Oxidation-Reduction Potential, Organic matters, and PAHs concentrations, which explains the dominant driving mechanism of soil depth, temperature, and contamination level on microbial characteristics in thermal remediation site. Our study could contribute to a better understanding of the resilience and adaptation mechanisms of microbial community at the contaminated site after the in situ thermal remediation.
热修复是去除退役污染场地中有机污染物的最常用方法之一。然而，原位热修复后微生物群落特征的表现仍知之甚少。本研究采用高通量测序方法，在中国南京某退役煤气厂原位热修复后，研究了微生物和多环芳烃（PAHs）的生态响应和空间分布特征。Venn、聚类相关热图和双因素相关网络分析组合表明，微生物群落分别受土壤深度、温度和污染水平的明显影响和分类。确定了每个组的常见和特有微生物。随着土壤深度的增加，好氧菌Thermaerobacter、Calditerricola、Brevibacillus、Ralstonia 和 Rhodococcus 的相对丰度逐渐降低，而 Bacillus、Fictibacillus、Paenibacillus 和 Rheinheimera 的相对丰度则呈现相反的趋势。一些嗜热降解 PAHs 的细菌，包括 Thermaerobacter、Calditerricola、Bacillus、Rhodococcus、未分类的_p__Firmicutes、Arthrobacter 和 Deinococcus，在重度污染区的丰度增加。此外，Proteobacteria、Bacteroidota、Deinococcota、Chloroflexi、Acidobacteriota 和 Actinobacteriota 对土壤深度、温度和污染水平的增加表现出负响应，而 Firmicutes 则表现出正响应。这表明Firmicutes对热修复条件具有更好的抗应激能力和适应性。影响微生物组成和分布的关键环境因素是温度、总氮、氧化还原电位、有机物和 PAHs 浓度，这解释了土壤深度、温度和污染水平对热修复区微生物特征的主要驱动机制。本研究有助于更好地理解原位热修复后污染场地微生物群落的恢复力和适应机制。
