ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Terrestrial Microbiology
This article is part of the Research TopicMicrobial Interactions with Metals/Minerals: From Environmental Aspects to ApplicationsView all 6 articles
Mercury contamination alters soil microbial communities and functional traits in farmland soils of a mining region, south-western China
Provisionally accepted
- Tongren University, Tongren, China
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To determine the status of soil mercury (Hg) contamination and to understand soil microbial community structure and function and their relationships with environmental factors in farmland surrounding mercury mining regions, we analysed the soil physicochemical properties, Hg pollution indices, and bacterial community structure and function of samples from farmland surrounding a mercury mining region (Chuandong town, CD, Huaqiao town, DP, Bahuang town, BG, and Shuangjiang town, LT) in Tong Ren, south-western China. The interactions among soil environmental factors and bacterial community structure and function were determined using correlation analysis and redundancy analysis. The results revealed that CD and LT soils were categorized by “light” Hg contamination, whereas DP and BG soils exhibited “moderate” Hg contamination. The potential ecological risk was “moderate” for CD soils, “considerable” for BG and LT soils, and “high” for DP soils. Long-term Hg contamination significantly increased soil bacterial community diversity and decreased bacterial community richness. Bacterial communities underwent adaptive restructuring, with Acidobacteria (16.90% relative abundance) dominating the acidic, high-Hg soils at the DP site and Proteobacteria (29.71% relative abundance) thriving in nutrient-rich conditions at the LT site. Key metal-resistant genera (Rokubacteriales, Gaiella) emerged as potential biomarkers of contamination. PICRUSt2 analysis revealed maintained metabolism potential under Hg stress, with carbohydrate metabolism and amino acid metabolism pathways collectively accounting for 26.43% of all predicted functions. Redundancy analysis identified soil pH, THg, and Gaiella were the key the factors driving the soil bacterial community function, with their independent contributions contributions to the variance being 72.83%, 84.64%, and 81.97%, respectively. These findings provide a mechanistic understanding of microbial resilience in Hg-contaminated ecosystems and identify critical leverage points for remediation strategies targeting both metal toxicity and the functional restoration of agricultural soils.
Keywords: Adaptation mechanism, community structure, functional metabolic traits, Mercury mine, soil bacteria
Received: 09 Oct 2025; Accepted: 02 Dec 2025.
Copyright: © 2025 Chen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Fen Chen
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