“…Beaver ponds overall contained similar levels of saprotrophic fungi to tundra lakes and streams, though the saprotrophic genera Mortierella and Ascobolus displayed heightened relative abundances in beaver ponds. Mortierella have been shown to be carry out plant growth promotion and cellulose decomposition (Ozimek & Hanaka, 2021) and Ascobolus abundance was correlated with OM, N, and P availability in bauxite residues (Dong et al., 2021). Unlike other water‐inundated permafrost settings (Schütte et al., 2019), the damming of rivers by beavers may favor plant:fungi mutualistic interactions, based on the high relative abundance of ectomycorrhizae in beaver ponds.…”
In recent decades the habitat of North American beaver (Castor canadensis) has expanded from boreal forests into Arctic tundra ecosystems. Beaver ponds in Arctic watersheds are known to alter stream biogeochemistry, which is likely coupled with changes in the activity and composition of microbial communities inhabiting beaver pond sediments. We investigated bacterial, archaeal, and fungal communities in beaver pond sediments along tundra streams in northwestern Alaska (AK), USA and compared them to those of tundra lakes and streams in north‐central Alaska that are unimpacted by beavers. β‐glucosidase activity assays indicated higher cellulose degradation potential in beaver ponds than in unimpacted streams and lakes within a watershed absent of beavers. Beta diversity analyses showed that dominant lineages of bacteria and archaea in beaver ponds differed from those in tundra lakes and streams, but dominant fungal lineages did not differ between these sample types. Beaver pond sediments displayed lower relative abundances of Crenarchaeota and Euryarchaeota archaea and of bacteria from typically anaerobic taxonomic groups, suggesting differences in rates of fermentative organic matter (OM) breakdown, syntrophy, and methane generation. Beaver ponds also displayed low relative abundances of Chytridiomycota (putative non‐symbiotic) fungi and high relative abundances of ectomycorrhizal (plant symbionts) Basidiomycota fungi, suggesting differences in the occurrence of plant and fungi mutualistic interactions. Beaver ponds also featured microbes with taxonomic identities typically associated with the cycling of nitrogen and sulfur compounds in higher relative abundances than tundra lakes and streams. These findings help clarify the microbiological implications of beavers expanding into high latitude regions.
“…Beaver ponds overall contained similar levels of saprotrophic fungi to tundra lakes and streams, though the saprotrophic genera Mortierella and Ascobolus displayed heightened relative abundances in beaver ponds. Mortierella have been shown to be carry out plant growth promotion and cellulose decomposition (Ozimek & Hanaka, 2021) and Ascobolus abundance was correlated with OM, N, and P availability in bauxite residues (Dong et al., 2021). Unlike other water‐inundated permafrost settings (Schütte et al., 2019), the damming of rivers by beavers may favor plant:fungi mutualistic interactions, based on the high relative abundance of ectomycorrhizae in beaver ponds.…”
In recent decades the habitat of North American beaver (Castor canadensis) has expanded from boreal forests into Arctic tundra ecosystems. Beaver ponds in Arctic watersheds are known to alter stream biogeochemistry, which is likely coupled with changes in the activity and composition of microbial communities inhabiting beaver pond sediments. We investigated bacterial, archaeal, and fungal communities in beaver pond sediments along tundra streams in northwestern Alaska (AK), USA and compared them to those of tundra lakes and streams in north‐central Alaska that are unimpacted by beavers. β‐glucosidase activity assays indicated higher cellulose degradation potential in beaver ponds than in unimpacted streams and lakes within a watershed absent of beavers. Beta diversity analyses showed that dominant lineages of bacteria and archaea in beaver ponds differed from those in tundra lakes and streams, but dominant fungal lineages did not differ between these sample types. Beaver pond sediments displayed lower relative abundances of Crenarchaeota and Euryarchaeota archaea and of bacteria from typically anaerobic taxonomic groups, suggesting differences in rates of fermentative organic matter (OM) breakdown, syntrophy, and methane generation. Beaver ponds also displayed low relative abundances of Chytridiomycota (putative non‐symbiotic) fungi and high relative abundances of ectomycorrhizal (plant symbionts) Basidiomycota fungi, suggesting differences in the occurrence of plant and fungi mutualistic interactions. Beaver ponds also featured microbes with taxonomic identities typically associated with the cycling of nitrogen and sulfur compounds in higher relative abundances than tundra lakes and streams. These findings help clarify the microbiological implications of beavers expanding into high latitude regions.
“…In the present study, in contrast to the CK treatment, a significant increase was also found in microbial functional activities (Table 1) and communities' richness and diversity for the organic amendment treatments, especially after 180 days incubation (Table 2). Moreover, with the organic amendment, some reported pioneer organisms, such as the halophilic alkalophilic bacteria Ascomycota, Basidiomycota, Actinomycota, Proteobacteria, and Bacillus (Liu et al, 2014;Dong et al, 2021), decreased over incubation, and the appearance of some acidogenic organisms, such as Pseudomonas, Acidobacteria_unclassified, and Acremonium (Schmalenberger et al, 2013), compared to the CK treatments. Villar et al (2004) found that the polysaccharide secreted by microorganisms and the winding effect of fungal hyphae made soil particles better aggregate.…”
Section: Discussionmentioning
confidence: 99%
“…This is beneficial to regulate the alkalinity and salinity, increase the agglomeration of micro-particles, and lastly promote the rehabilitation of bauxite residue (Xue et al, 2019f;Ke et al, 2021). Previous studies have shown that the assembly and succession of fungal flora in rehabilitated bauxite residue were also driven by the improvement of texture structure and fertility and the decrease of alkalinity of bauxite residue matrix (Dong et al, 2021). Nevertheless, there is still necessary to give more investigation on the comprehensive improvement of organic amendment on the aggregate formation and microbial community restoration in bauxite residue.…”
Introduction: Understanding organic amendment and the agglomeration of bauxite residue particles is vital to soil amelioration of bauxite residues. In this study, a pot culture experiment was conducted to illustrate the aggregation of organic amendment on bauxite residues particles and its improvement mechanism. The single organic amendment and its combination with soil inoculum were conducted to explore the aggregation effect of organic matter on bauxite residue particles, and its correlations with microbial rehabilitation.Methods: The dry- and wet-sieving method were used to obtain different sizes of aggregates. The concentrations of soil organic carbon and iron and aluminum (Fe/Al) oxides in the forms extractable by DCB (Fed/Ald) and oxalate (Fe0/Al0) were measured. Microbial rehabilitation after 180 days incubation was determined with the methods of Biolog Ecoplate™ and the high-throughput sequencing.Results and Discussion: The results showed that over 180 days incubation, the alkalinity of bauxite residues was significantly decreased with the organic amendment based on the value of pH, EC and ESP (down to 9.26, 0.61 m/cm and 55.5%, respectively, in HS3). Secondly, organic amendment significantly promoted microbial community establishment and ecological function recovery. Moreover, the MWD value of aggregates also increased to 0.73 mm from the initial 0.32 mm, companied with the increase of the Fe/Al oxidizes. The further Pearson relationship analysis and the characterization of EPMA and SEM indicated that the organic matter and Fe/Al oxides played important roles in cementing fine bauxite residues particles and increasing aggregates stability, while this aggregation process was accelerated by the establishment of microbial ecology in bauxite residues. Therefore, organic amendment was more implication in soil amelioration of bauxite residues other than the directive modifications on alkalinity.
“…The adsorption of vermiculite enhanced the mass transfer effect and increased the biodegradation rate. Moreover, adding vermiculite/fly ash mixtures increased significantly the number of fungi species, carbohydrate utilization by microorganisms and enzyme activity levels (Dong et al , 2021). Fig.…”
Section: Clay Minerals Regulate the Structure And Function Of Soilmentioning
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