Chemolithoautotropic Diazotrophy Dominates the Nitrogen Fixation Process in Mine Tailings

Abstract

Nutrient deficiency, especially bio-available nitrogen deficiency, often impedes the bioremediation efforts of mining generated tailings. Biological nitrogen fixation is a critical process necessary for the initial nitrogen buildup in tailings. Current knowledge regarding the diazotrophs that inhabit tailings is still in its infancy. Therefore, in this study, a comprehensive investigation combining geochemical characterization, sequence analyses, molecular techniques, and activity measurements was conducted to characterize the diazotrophic community residing in tailing environments. Significant differences between tailings and their adjacent soils in prokaryotic and diazotrophic communities were detected. Meanwhile, strong and significant correlations between the absolute abundance of the nitrogen fixation (nif H), carbon fixation (cbbL), sulfur oxidation (soxB), and arsenite oxidation (aioA) genes were observed in the tailings but not in the soils. The reconstructed nif-containing metagenome-assembled genomes (MAGs) suggest that the carbon fixation and sulfur oxidation pathways were important for potential diazotrophs inhabiting the tailings. Activity measurements further confirmed that diazotrophs inhabiting tailings preferentially use inorganic electron donors (e.g., elemental sulfur) compared to organic electron donors (e.g., sucrose), while diazotrophs inhabiting soils preferred organic carbon sources. Collectively, these findings suggest that chemolithoautotrophic diazotrophs may play essential roles in acquiring nutrients and facilitating ecological succession in tailings.

Effects of long-term discharge of acid mine drainage from abandoned coal mines on soil microorganisms: microbial community structure, interaction patterns, and metabolic functions

“…In our study, four top OTUs were related to Ferrovum myxofaciens, including OTU833 (9.76%), OTU839 (4.27%), OTU796 (0.76%), and OTU450 (0.71%), with a total relative abundance of up to 15.50%, indicating the presence of considerable amounts of autotrophic bacteria with iron oxidation and nitrogen xation abilities in contaminated soil. This can be attributed to a survival strategy of bacteria in a strongly acidic and oligonitrogenous environment, which provides carbon and nitrogen sources for cell survival through autotrophic carbon xation and carbon sequestration(Sun et al 2020b). OTU835 and OTU322 were identi ed to be similar to Acidithiobacillus ferrooxidans, an acidophilic chemolithoautotrophic bacterium that can grow by oxidizing Fe(II) and reducing sulfur compounds(Jin et al 2020).…”

Highly Contaminated Marine Sediments Can Host Rare Bacterial Taxa Potentially Useful for Bioremediation

“…To gain a deeper insight on the rare portion of the gammaproteobacterial diversity, we conducted a higher-level taxonomic resolution analysis, which indicated that a total of eight gammaproteobacterial families were actually not rare locally (i.e., >1% contribution in at least one site), including Cycloclasticaceae, Halieaceae, KI89A clade, Nitrincolaceae, Rhodocyclaceae, Thioalkalispiraceae, Thiotrichaceae, and UBA10353 marine group (Figure 4B). All of these families include members recently reported to be particularly abundant in naturally-rich and/or contaminated environments that display high concentrations of HMs and/or hydrocarbons (Gołębiewski et al, 2014;Singleton et al, 2015;Yang et al, 2016Yang et al, , 2020Suzuki et al, 2019;Bergo et al, 2020;Noirungsee et al, 2020;Sun et al, 2020).…”

Multiple role of diazotrophs in coupling nitrogen and iron biogeochemical processes through vertical soil profiles of different paddy soil types

“…Besides, a higher proportion of aerobes were noted in diazotrophic community of Fe-accumuli soils as comparing with that in Hapli-type soils ( Figure S12), which might be linked with the NH 4 + -N storage in anaerobic paddy soils of Fe-type soil with weak N 2 xing ability. The phylogenetic a liation and formation mechanism of the presence of these aerobic diazotrophs will be further explored combined with omics and N 2 xation activity analysis (acetylene reduction assay and 15 N-isotope techniques) [23,24] .…”

“…4B). Sulfur reducing and oxidizing microorganisms have been reported to act as active N 2 xers in ecosystems, such as in sul dic sediment [23,55,56] . The obligate anaerobe, Desulfobacca belonging to Syntrophaceae, has been identi ed as major acetate-degrading SRB and common N 2 xers in paddy soil [24,57] .…”

“…~50-70 Tg N year − 1 to agricultural systems) [19,20] . As the key driver for global nitrogen (N) dynamics, diazotrophs also participate other major biogeochemical cycles directly or indirectly, such as for carbon sequestration, iron (Fe) and sulfur (S) cycling [19,[21][22][23] . The abundance, composition and N 2 -xing capacity of diazotrophs varied greatly across soil types, while only studied in the plough layer (0-15 cm), which processes are determined by soil properties, climate and geographical distance [3,24] .…”