Significant Impacts of Both Total Amount and Availability of Heavy Metals on the Functions and Assembly of Soil Microbial Communities in Different Land Use Patterns.

Zhen Zhen,Sibo Wang,Songqiang Deng,Shuwen Luo,Rongchao Yang,Lei Ren,Yueqin Zhang,Lina Zou,Yongtao Li,Yanqiu Liang,Zhong Lin,Dayi Zhang

doi:10.3389/fmicb.2019.02293

Abstract

Land use change alters the accumulation of heavy metals (HMs) in soils and might have significant influence on the assembly and functions of soil microbial community. Although numerous studies have discussed the impacts of either total amounts or availability of metals on soil microbes in land change, there is still limited understanding on which one is more critical. In the present study, soils from three land use types (forest, mining field, and operating factory) located in Shaoguan city (Guangdong Province, China) were collected to investigate the impacts of soil HMs on soil enzyme activities and bacterial community structures. Mining activities remarkably increased the concentrations of HMs in soils, and land use patterns changed soil properties and nutrition level. Soil pH, total and available HMs (Cu, Pb, Zn, and Cd) and organic matters (SOM) were identified as the key influential factors shaping soil ecological functions (soil enzyme activities) and community assembly (bacterial community composition), explained by HMs accumulation and soil acidification caused by human activities. In addition, total amount and availability of some metals (Zn, Pb, Cu, and Cd) showed similar and significant effects on soil bacterial communities. Our findings provide new clues for reassessing the environmental risks of HMs in soils with different land use.

Highlights

Land use change is one of the most important environmental changes affecting the biodiversity and function of ecosystems (Ferreira et al, 2016)
Significant soil acidification was observed in mining fields (MF) and operating factories (OF), whereas forest fields (FF) soils were only slightly acidic with pH ranging from 5.83–6.84
The total amounts of heavy metals (HMs) increased in MF and OF soils, whereas the availability of Cu, Pb and Zn and Cd rose through land use change from FF to MF or OF, potentially correlated with the change in soil properties, e.g., decreases of soil organic matters (SOM), humus, cation exchange capacity (CEC), total nitrogen (TN), and total phosphorus (TP)

Summary

Introduction

Land use change is one of the most important environmental changes affecting the biodiversity and function of ecosystems (Ferreira et al, 2016). Caused by the intensive anthropogenic activities and urbanization, land use change has a significant influence on soil quality (Pielke, 2005; Xia et al, 2011). There are numerous environmental problems accompanying with land use change, and soil contamination by heavy metals (HMs) has become a major one (Huang Y. et al, 2018; Pacwa-Plociniczak et al, 2018). Metal Availability Influences Microbial Community of land use pattern on the accumulation of HMs in soils (Liu et al, 2016; Trujillo-González et al, 2016). HMs accumulation under different types of land use and their detrimental effects on soil quality have attracted increasing attention (Zhao et al, 2007; Jiao et al, 2010; Ren et al, 2015)

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