Microbial Communities of Polymetallic Deposits’ Acidic Ecosystems of Continental Climatic Zone With High Temperature Contrasts

Abstract

Acid mine drainage (AMD) systems are globally widespread and are an important source of metal pollution in riverine and coastal systems. Microbial AMD communities have been extensively studied for their ability to thrive under extremely acidic conditions and for their immense contribution to the dissolution of metal ores. However, little is known on microbial inhabitants of AMD systems subjected to extremely contrasting continental seasonal temperature patterns as opposed to maritime climate zones, experiencing much weaker annual temperature variations. Here, we investigated three types of AMD sites in Eastern Transbaikalia (Russia). In this region, all surface water bodies undergo a deep and long (up to 6 months) freezing, with seasonal temperatures varying between −33 and +24°C, which starkly contrasts the common well-studied AMD environments. We sampled acidic pit lake (Sherlovaya Gora site) located in the area of a polymetallic deposit, acidic drainage water from Bugdaya gold-molybdenum-tungsten deposit and Ulan-Bulak natural acidic spring. These systems showed the abundance of bacteria-derived reads mostly affiliated with Actinobacteria, Acidobacteria, Alpha- and Gammaproteobacteria , chloroplasts, Chloroflexi, Bacteroidetes , and Firmicutes . Furthermore, candidate taxa “ Ca . Saccharibacteria” (previously known as TM7), “ Ca . Parcubacteria” (OD1) and WPS-2 were represented in substantial quantities (10–20%). Heterotrophy and iron redox cycling can be considered as central processes of carbon and energy flow for majority of detected bacterial taxa. Archaea were detected in low numbers, with Terrestrial Miscellaneous Euryarchaeal Group (TMEG), to be most abundant (3%) in acidic spring Ulan-Bulak. Composition of these communities was found to be typical in comparison to other AMD sites; however, certain groups (as Ignavibacteriae ) could be specifically associated with this area. This study provides insight into the microbial diversity patterns in acidic ecosystems formed in areas of polymetallic deposits in extreme continental climate zone with contrasting temperature parameters.

Pollution Intensity of Hazardous Metals, Microbiome and Potential Bacterial-Based Toxic Metal Sequestration of Coal Mine Drainage

“…The AMD water was acidic (pH = 3.1 ± 0.265), and contained characteristic anions that are common to AMD including dissolved sulphides (1.37 ± 0.233 mg/l), sulphates (313.0 ± 15.9 mg/l), carbonate (253.0 ± 22.4 mg/l) and nitrate (86.6 ± 41.0 mg/l) above the allowable limits of WHO. Although the acidic pH of AMD in the present study compares well with those associated with mines in Russia [14], more extreme acidic pH values have been reported in other climes. Negative pH values of -1.56 and -3.6 were observed in AMD from Iberian Pyrite Belt [17] and Richmond Mine at Iron Mountain, USA [18], respectively.…”

“…In conjunction with oligotrophic heterotrophs (such as Acidocella and Thermoplasma), the early microbial colonizers indirectly ameliorate HMs toxicity via syntrophic commensal associations with iron-and sulphuroxidizers [3]. Thus, they utilize organic compounds (cell exudates and lysates) originating from the autotrophic primary producers, thereby essentially "detoxifying" the environment for the later groups of microorganisms [14][15]. Sulphate reducing bacteria (SRB) belonging to the genus Desulfosporosinus and Desul tobacterium and genre of Firmicutes and Actinobacteria have been detected in mine lakes reversing the chemical reactions that formed AMD, attenuating toxic metals/metalloids concentrations by sulphide precipitation, redox reactions, and raising the pH of the acidic water [3,6,10].…”

High Representation of Archaea Across All Depths in Oxic and Low-pH Sediment Layers Underlying an Acidic Stream

“…Firstly, there is still an extremely small number of archaeal taxa cultured from AMD, in comparison to bacteria. Bacterial acidophilic diversity associated with AMD sites is assigned to more than 13 genera belonging to various phyla (Acidobacteria, Actinobacteria, Firmicutes, Nitrospirae, and Proteobacteria) ( Mendez-Garcia et al, 2015 ; Gavrilov et al, 2019 ). However, all cultured archaea from similar AMD environments with validly published names are affiliated with the single order, Thermoplasmatales of the phylum Euryarchaeota (genera Ferroplasma , Acidiplasma , and Cuniculiplasma ) ( Golyshina et al, 2000 , 2009 , 2016b ; Hawkes et al, 2008 ).…”

“…5% within Core 1. The metabolic features of these organisms previously detected in acidic ecosystems, remain unknown ( Gavrilov et al, 2019 ).…”

Prokaryotic communities in the historic silver mine Reiche Zeche

“…Likewise, sequences belonging to the phylum Thaumarchaota in sample BFRZ6b could not be specified further than up to the ammonium oxidizing Candidatus Nitrosotaleaceae (part of minor phyla). The occurrence of this Candidatus family was shown in mine-impacted habitats and is discussed as important group for nitrification in low pH environments (Herbold et al 2017 ; Gavrilov et al 2019 ; Miettinen et al 2021 ).…”