Impact of Heavy Metal Pollution on Ammonia Oxidizers in Soils in the Vicinity of a Tailings Dam, Baotou, China

Abstract

Soil heavy metal pollution has received increasing attention due to their toxicity to soil microorganisms. We have analyzed the effects of heavy metal pollution on ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in soils in the vicinity of a tailings dam of Baotou region, China. Results showed that AOB were dominated with Nitrosomonas-like clusters, while AOA was dominated by group1.1b (Nitrososphaera cluster). Single Cd and Cr contents, as well as compound heavy metal pollution levels, had a significant negative impact on soil potential nitrification rate and both diversities of AOA and AOB. No clear relationship was found between any single heavy metal and abundance of AOA or AOB. But compound pollution could significantly decrease AOA abundance. The results indicated that heavy metal pollution had an obviously deleterious effect on the abundance, diversity, activity and composition of ammonia oxidizers in natural soils.

Ecological Risks of Heavy Metals and Microbiome Taxonomic Profile of a Freshwater Stream Receiving Wastewater of Textile Industry

“…It can, therefore, be adduced that members of Thaumarchaeota were sensitive to HMs and chemicals contained in the TWW that were consistently released into L2. This observation agrees with the conclusions of Liu et al (2018) and Guo et al (2019) but negates the suggestion of He and colleagues (2018) that there may be HM-resistant Thaumarchaeota organisms in metal polluted freshwater. In agreement with the findings of Guo and colleagues (2019), Bathyarchaeota remained abundant in both pristine L1 and TWW-impacted L2, only that the relative abundance became reduced in the TWW-impacted L2 ecosystem, possibly due to the toxic HMs/metalloids in the TWW, and some members might exhibit resistance to HMs/ metalloids.…”

Distribution of ammonia oxidizers and their role in N2O emissions in the reservoir riparian zone

“…The majority (98.77%) of AOA sequences are affiliated to Group I.1b, with high homology to arable soils [31] and coastal alkaline soils [32]. Nitrososphaera were the major AOA populations, as OTU39 was high homology with Nitrososphaera viennensis [33], OTU10 was high homology with Nitrososphaera gargensis [34], and OTU38 and OTU42 were high homologies with Candidatus Nitrososphaera [35]. The phylogenetic tree (Figure 5) showed that AOB OTUs were divided into seven clusters: Cluster 4, Cluster 1, Cluster 3a, Cluster 3a.1, Cluster 3a.2, and Cluster 3b belong to the Nitrosospira group of the phylum β ‐Amastigotes, and Cluster 7 belongs to the Nitrosomonas group of the phylum β ‐Amastigotes.…”

Combined effects of Bacillus sp. M6 strain and Sedum alfredii on rhizosphere community and bioremediation of cadmium polluted soils

“…This AOB increase might be due to the introduction of exogenous microbial agents, increasing soil mineralization. The active carbon and nitrogen improved by mineralization can promote amoA AOB growth ( Liu et al, 2018 ), whereas amoA AOA plays a role in the soil environment with low nitrogen content. Also, more bacterial activity was found in low contaminated soil than with high contamination because of the growth restrictions by high Cd concentration manifesting as the inhibition of cell growth and cell detoxification mechanism (i.e., intracellular efflux of Cd +2 ).…”

“…This AOB increase might be due to the introduction of exogenous microbial agents, increasing soil mineralization. The active carbon and nitrogen improved by mineralization can promote amoA AOB growth (Liu et al, 2018), whereas amoA AOA plays a role in the soil environment with low nitrogen content. Also, more bacterial activity was found in low contaminated soil than with high 10.3389/fpls.2022.913787…”

“…Similarly, Khan et al (2010) confirmed a decrease in microbial enzyme urea amidohydrolase and acid phosphatase activities by up to 33.0% after 2 weeks of soil incubation with 5 mg Cd kg –1 . Another study by Liu et al (2018) showed that Cd decreases amoA gene abundance in the soils, reducing ammonium oxidation. Like nitrifiers, the denitrifying bacterial community was also sensitive to Cd, significantly impacting the denitrifier community structure ( Afzal et al, 2019 ).…”