Shifts in microbial community composition and function in the acidification of a lead/zinc mine tailings

Abstract

SummaryIn an attempt to link the microbial community composition and function in mine tailings to the generation of acid mine drainage, we simultaneously explored the geochemistry and microbiology of six tailings collected from a lead/zinc mine, i.e. primary tailings (T1), slightly acidic tailings (T2), extremely acidic tailings (T3, T4 and T5) and orange-coloured oxidized tailings (T6). Geochemical results showed that the six tailings (from T1 to T6) likely represented sequential stages of the acidification process of the mine tailings. 16S rRNA pyrosequencing revealed a contrasting microbial composition between the six tailings: Proteobacteria-related sequences dominated T1-T3 with relative abundance ranging from 56 to 93%, whereas Ferroplasma-related sequences dominated T4-T6 with relative abundance ranging from 28 to 58%. Furthermore, metagenomic analysis of the microbial communities of T2 and T6 indicated that the genes encoding key enzymes for microbial carbon fixation, nitrogen fixation and sulfur oxidation in T2 were largely from Thiobacillus and Acidithiobacillus, Methylococcus capsulatus, and Thiobacillus denitrificans respectively; while those in T6 were mostly identified in Acidithiobacillus and Leptospirillum, Acidithiobacillus and Leptospirillum, and Acidithiobacillus respectively. The microbial communities in T2 and T6 harboured more genes suggesting diverse metabolic capacities for sulfur oxidation/heavy metal detoxification and tolerating low pH respectively.

Generation of Acid Mine Lakes Associated with Abandoned Coal Mines in Northwest Turkey

“…The presence of bacterial species with closest affiliation to Fe-oxidizer bacteria (Acidithiobacillus spp.) indicates that the microbial oxidation of Fe(II) is a significant biogeochemical process in the sediments of AML 2 as noted in previous studies (e.g., Friedrich et al 2005;Rohwerder and Sand 2007;Ghosh and Dam 2009;Schippers et al 2010;Dopson and Johnson 2012;Chen et al 2013). Insignificant variations in pH, along with observed changes in DO and Fe concentration throughout the water column until a depth of 6 m, also suggest co-occurrences of Fe(II) oxidation and precipitation of Fe(III) minerals buffering pH as reported in various AMLs with pH ranging from 2.59 to 3.79 (Kusel 2003;Peiffer et al 2013;Vithana et al 2015).…”

Microbial Diversity and Community Assembly across Environmental Gradients in Acid Mine Drainage

“…To date, several attempts have been made to investigate the microbial community dynamics related to the acidification process of the mine tailings [14,25,47]. Remarkable shifts in microbial community composition and structure have been found at different oxidation stages, most likely due to the distinct environmental gradients produced during AMD generation [48][49][50]. For example, according to the result of a simulated experiment of oxidative dissolution of pyrite, the most dominant genera were Tumebacillus, Alicyclobacillus, and Ferroplasma at the early, mid, and final stage, respectively [47].…”

“…In many studies, archaea (mostly Ferroplasma spp.) were found to be predominant at the late oxidation stage, which was usually characterized by low pH (<3.0) and a high concentration of metals [47,49,50], revealing their favorable adaptation of harsh environmental conditions and indispensability in such ecosystems [51]. Metagenomic as well as transcriptomic analyses deciphered significant variations in microbial community function [27,52,53].…”

“…For example, previous metagenomics study of tailings acidification showed that the sulfur oxidation was mainly performed by Thiobacillus at the early stage and by Acidithiobacillus at the late stage [50].…”

Exploring the dynamics of bacterial community composition in soil: the pan-bacteriome approach

“…Indeed, environmental changes often affect taxonomic composition and abundance in microbial communities (Allison and Martiny 2008), which may have a strong effect on soil health and plant productivity (Chaparro et al 2012). Several works have been performed inspecting bacterial community variation both in cross sectional (different sites at the same time) and longitudinal studies (the same site studied over time) (Bartram et al 2014;Chen et al 2013;Costello et al 2009;Kuang et al 2012;Logares et al 2013;Pini et al 2012;Smith et al 2012).…”