State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Hazard Mater. 2022 Aug 5;435:129055. doi: 10.1016/j.jhazmat.2022.129055. Epub 2022 May 4.
Soil microbial communities are critical for maintaining terrestrial ecosystems and fundamental ecological processes. Mercury (Hg) is a heavy metal that is toxic to microorganisms, but its effects on microbial community assembly and ecosystem multifunctionality in rice paddy ecosystems remain largely unknown. In the current study, we analyzed the microbial community structure and ecosystem multifunctionality of paddy soils across a Hg contamination gradient. The results demonstrated that Hg contamination significantly altered the microbial community structure. The microbial communities were predominantly driven by deterministic selection rather than stochastic processes. The random forest model and variation partition analysis demonstrated that the Hg level was the most important predictor of microbial profiles. Ecosystem multifunctionality decreased across the Hg concentration gradient, and multifunctionality was significantly correlated with soil biodiversity, suggesting that Hg-induced reductions in soil biodiversity led to reduced ecosystem services. A structural equation model showed that Hg contamination directly and indirectly affected ecosystem multifunctionality. The present work broadens our knowledge of the assembly of the microbiome in rice paddies across a Hg contamination gradient and highlights the significance of soil biodiversity in regulating ecosystem functions, especially in Hg-polluted rice paddies.
土壤微生物群落对于维持陆地生态系统和基本生态过程至关重要。汞（Hg）是一种对微生物有毒的重金属，但它对水稻田生态系统中微生物群落组装和生态系统多功能性的影响在很大程度上仍不清楚。在本研究中，我们分析了 Hg 污染梯度下稻田土壤的微生物群落结构和生态系统多功能性。结果表明，Hg 污染显著改变了微生物群落结构。微生物群落主要受确定性选择而不是随机过程驱动。随机森林模型和变异分解分析表明，Hg 水平是微生物分布的最重要预测因子。随着 Hg 浓度梯度的增加，生态系统多功能性降低，多功能性与土壤生物多样性显著相关，表明 Hg 引起的土壤生物多样性减少导致生态系统服务减少。结构方程模型表明，Hg 污染直接和间接影响生态系统多功能性。本研究拓宽了我们对 Hg 污染梯度下水稻田微生物组组装的认识，并强调了土壤生物多样性在调节生态系统功能（尤其是在 Hg 污染的稻田中）方面的重要性。
