Succession of Microbial Communities in Waste Soils of an Iron Mine in Eastern China

Qin Zhang,Weiao Mao,Pengfei Wei,Hongyi Li,Chunbo Hao,Joseph Frazer Banda,Hailiang Dong,Linqiang Ma

doi:10.3390/microorganisms9122463

Qin Zhang, Weiao Mao + Show 6 more

Open Access

https://doi.org/10.3390/microorganisms9122463

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Abstract

The reclamation of mine dump is largely centered on the role played by microorganisms. However, the succession of microbial community structure and function in ecological restoration of the mine soils is still poorly understood. In this study, soil samples with different stacking time were collected from the dump of an iron mine in China and the physicochemical characteristics and microbial communities of these samples were comparatively investigated. The results showed that the fresh bare samples had the lowest pH, highest ion concentration, and were the most deficient in nutrients while the acidity and ion concentration of old bare samples decreased significantly, and the nutritional conditions improved remarkably. Vegetated samples had the weakest acidity, lowest ion concentration, and the highest nutrient concentration. In the fresh mine soils, the iron/sulfur-oxidizers such as Acidiferrobacter and Sulfobacillus were dominant, resulting in the strongest acidity. Bacteria from genera Acidibacter, Metallibacterium, and phyla Cyanobacteria, WPS-2 were abundant in the old bare samples, which contributed to the pH increase and TOC accumulation respectively. Acidobacteriota predominated in the vegetated samples and promoted nutrient enrichment and plant growth significantly. The microbial diversity and evenness of the three types of soils increased gradually, with more complex microbial networks, suggesting that the microbial community became more mature with time and microorganisms co-evolved with the mine soils.

Highlights

Large-scale opencast metal mining activities can cause great degradation to ecosystems [1], this modern mining technology is an efficient and cost-effective mode for the exploitation of mineral resources
Sulfur-containing minerals (e.g., pyrite (FeS2 )), which are very common in mining wastes, can be oxidized and generate acid mine drainage (AMD) in a humid area, which usually has extremely low pH and elevated concentrations of metals as well as metalloids, posing a severe threat to our ecosystem [4]
Sampling Site Description and Sample Collection opportunity to study the processes of microbial community succession in mine soils

Summary

Introduction

Large-scale opencast metal mining activities can cause great degradation to ecosystems [1], this modern mining technology is an efficient and cost-effective mode for the exploitation of mineral resources. Sulfur-containing minerals (e.g., pyrite (FeS2 )), which are very common in mining wastes, can be oxidized and generate acid mine drainage (AMD) in a humid area, which usually has extremely low pH and elevated concentrations of metals as well as metalloids, posing a severe threat to our ecosystem [4]. The reclamation of the mine dump is largely centered on the role played by microorganisms. Their ecological functions in the soils are immense as they act as biofertilizers

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Conclusion