Effects of Mercury Contamination on Microbial Diversity of Different Kinds of Soil

Abstract

Soil microorganisms promote the recovery of contaminated soil by influencing the cyclic transformation of various substances. In this study, we investigated the impact of mercury pollution on the structure, composition, and main populations of soil microbial communities using a high-throughput sequencing method and observed that mercury pollution significantly influenced the diversity, structure, and distribution pattern of microbial communities. Furthermore, during mercury pollution, the Shannon and Chao indices decreased for the bacterial communities and increased for the fungal communities. Mercury pollution mainly reduced the relative abundances of Proteobacteria (16.2–30.6%), Actinomycetes (24.7–40.8%), and other dominant bacterial phyla. The relative abundance of Ascomycota decreased by 17.4% and 16.7% in alkaline and neutral soils, respectively, whereas the relative abundance of unclassified_k_Fungi increased by 26.1% and 28.6%, respectively. In acidic soil, Ascomycota increased by 106.3% and unclassified_k_Fungi decreased by 71.2%. The results of redundancy and correlation analyses suggested that soil microbial diversity was significantly correlated with soil properties such as pH, cation exchange capacity, soil organic carbon, and total nitrogen (p < 0.05) under different treatments. Our findings highlight the impact of Hg pollution on soil microbial communities, thereby providing a theoretical foundation for the bioremediation of soil Hg pollution.

A Retrospection on Mercury Contamination, Bioaccumulation, and Toxicity in Diverse Environments: Current Insights and Future Prospects

“…Basidiomycota increased to 1.61 and five times in alkaline and neutral pH, respectively, and decreased by 18% in acidic pH. On the contrary, Ascomycota showed an inverse relationship with pH, with a slight increase in population (5%) under acidic conditions [102].…”

“…Proteobacteria, Actinomycota, Blastomonas, and Acidobacters were dominant in Hg-exposed soil, irrespective of pH. The predominant bacteria, Actinobacter, was found to dominate the post-Hg treatment though it is negatively correlated to Hg [102]. Exposure of 50 mg Hg/kg soil of mercury on agricultural soil significantly decreases pH from 7 to 6 with a decrease in total organic content and macronutrients.…”

Bioremediation of environments contaminated with mercury. Present and perspectives

“…(Hall et al 2020 ; Li et al 2022a ). In turn, Hg affects the composition of bacterial communities, decreasing their diversity (Mariano et al 2020 ; Zheng et al 2022 ; Hu et al 2023 ). Likewise, the natural selection of tolerance to heavy metals can be linked, by a phenomenon of co-selection, to resistance to other compounds such as antibiotics (Robas et al 2021b ; Karnachuk et al 2023 ; Tran et al 2023 ), as well as the horizontal transfer of these resistances (Robas et al 2021b ; Li et al 2022a ; Kothari et al 2023 ).…”

The impact of main Areca Catechu root exudates on soil microbial community structure and function in coffee plantation soils

“…While the addition of AUX, OA, and PA had a beneficial effect on AK, AHN, and pH in the rhizosphere soil of this study, the ensuing increase in nitrogen and pH levels may have exceeded the tolerable range of certain microbial communities, thereby inducing adverse changes in their living environment that inhibited their growth. Specifically, the pronounced alterations in the soil environment could hinder the growth of microbial populations that had adapted to the original living conditions (Zheng et al, 2022). The rise in soil nitrogen content accelerated the loss of rare species and led to a decline in microbial diversity.…”