Variation in microbial community structure correlates with heavy-metal contamination in soils decades after mining ceased

Abstract

Microorganisms play vital roles in Earth's biogeochemical cycles. Identifying disturbances in microbial communities due to anthropogenic contamination can provide insights into the health of ecosystems. Picher, Oklahoma, was the site of large-scale mining operations for Pb, Zn, and other heavy metals until the mid-1950s, operating within the Tri-State Mining District (TSMD) of Missouri, Kansas and Oklahoma. Although mining ceased decades ago, high concentrations of heavy metals (>1000 ppm) remain in area soil and water systems. Previously, we mapped metal concentrations on samples collected from mine tailings in Picher and along cardinal-direction transects within an 8.05-km radius of the town. To elucidate changes in microbial community structure due to regional metal contamination, 16S rRNA gene sequences and qPCR calculations of total Bacteria and Archaea were analyzed against these metal concentrations. Bacteria were negatively and significantly correlated with Pb, Cd, Zn, and Mg; however, Archaea was only significantly and positively correlated with pH. Illumina sequencing of 16S rRNA genes showed significant differences in microbial communities of chat and west transect samples. Comparison of soil chemistrywith community structure indicated that Al, Pb, Cd, and Zn significantly impacted community composition and distribution of individual OTUs. Mapping the distribution of heavy-metal contamination and microbial communities in these soils represents the first step in understanding effects of long-term, heavy-metal contamination at a basic trophic level.

Spatial Distribution of Toxic Metal(loid)s and Microbial Community Analysis in Soil Vertical Profile at an Abandoned Nonferrous Metal Smelting Site

“…As reflected by Figure 4 b, however, Pielou’s evenness index was slightly higher in top soil (1–3 m) than in subsoil (4–10 m). As shown in Table S2 , the diversity indexes were impacted by soil properties and the contents of metal(loid)s, indicating environmental conditions, such as pH, TK, CEC, ORP, and Bio-Cu ( p < 0.05), impacted the soil microbial evenness through limiting the survival of certain microorganisms [ 27 , 28 ]; while, soil microbes adapt to higher metal(loid)s pollution in top soil by changing microbial communities, rather than changing their evenness [ 29 ]. Moreover, Shannon’s diversity index and Simpson’s index of diversity exhibited a decreasing trend from 1 m to 10 m of soil depth, which might be ascribed to the decrease in evenness with increase in depth, as shown in Figure 4 c,d.…”

Microbial community response to environmental changes in a technosol historically contaminated by the burning of chemical ammunitions

“…The 15 most abundant bacterial OTUs included a high proportion of genera usually found in polluted or extremely acidic mining environments. The main genus, Sphingomonas, comprises some heterotrophic species commonly found on contaminated sites, including sites polluted by metals (Beattie et al, 2018). They are able to degrade aromatic compounds (Fredrickson et al, 1995 ;Zylstra and Kim, 1997) and carry functional genes, such as the ars genes, linked to As resistance (Macur et al, 2001 ;Escalante et al, 2009) and the aioA genes linked to As oxidation (Kinegam et al, 2008).…”

Ecology of industrial pollution in China

“…They are more sensitive to environmental stresses than macroorganisms in the soil ecosystem and will be more likely to be affected by industrial pollutants (Chu 2018). Such industrial activities as mining can affect the soil microbial community structure (Beattie et al 2018). Based on the analysis of soil microbial phospholipid fatty acids (PLFA), abundance of the community composition and activities of fungal and bacteria fell 5-35% and 8-32%, respectively, under the influence of heavy metals, which consequently had an adverse impact on the soil microbial carbon immobilization (Xu et al 2019).…”