Heavy metal pollution in farmland soils surrounding mining areas in China and the response of soil microbial communities
Ping Wen,
Shi-wei Feng,
Jie-Liang Liang,
Pu Jia,
Bin Liao,
Wen-sheng Shu,
Jin-tian Li,
Xinzhu Yi
Affiliations
Ping Wen
Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, PR China
Shi-wei Feng
Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, PR China
Jie-Liang Liang
Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, PR China
Pu Jia
Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, PR China
Bin Liao
School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, PR China
Wen-sheng Shu
Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, PR China
Jin-tian Li
Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, PR China
Xinzhu Yi
Institute of Ecological Science, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, PR China; Corresponding author.
Mining activities lead to significant heavy metal pollution in nearby farmland soils, affecting the soil's microbial community and functions. To comprehensively investigate the heavy metal contamination in farmland soils caused by mining activities and the impacts on soil microbial communities and functions, we collected 87 soil samples from farmlands near 29 mining sites nationwide, measured levels of cadmium, lead, copper, and zinc. Our findings revealed that 75.8% of the sampled farmlands exhibited varying degrees of heavy metal pollution. Cadmium contamination stood out, being 2.84 to 5.35 times higher compared to other metals. This pollution notably decreased microbial diversity in agricultural soils (P ≤ 0.04), causing a shift from intricate interconnected microbial co-occurrence modules to a higher number of simpler ones, indicating a fragmentation of the microbial interaction network. Additionally, heavy metal contamination led to a 10.9% increase in the importance of the heterogeneous selection process in community assembly. Despite reduced microbial alpha diversity, we observed an increase in the diversity and abundance of metal resistance genes (MRGs) and intensified microbe-MRG interaction. This suggests that microbial communities, even when altered, maintain functionality through enhanced redundancy, which probably facilitates the preservation of microbial activities. We also identified key taxa with intense connectivity in the microbial interaction networks, 58% of which have been recognized in previous studies for their predictive effects on soil health. These findings offer important insights for developing strategies to enhance soil health, such as promoting the presence of ''super-connectors'' in microbial networks for the maintenance of microbial community.
