scholarly journals Microbial adaptation in vertical soil profiles contaminated by an antimony smelting plant

2020 ◽  
Vol 96 (11) ◽  
Author(s):  
Rui Xu ◽  
Xiaoxu Sun ◽  
Hanzhi Lin ◽  
Feng Han ◽  
Enzong Xiao ◽  
...  

ABSTRACT Antimony mining has resulted in considerable pollution to the soil environment. Although studies on antinomy contamination have been conducted, its effects on vertical soil profiles and depth-resolved microbial communities remain unknown. The current study selected three vertical soil profiles (0–2 m) from the world's largest antimony mining area to characterize the depth-resolved soil microbiota and investigate the effects of mining contamination on microbial adaptation. Results demonstrated that contaminated soil profiles showed distinct depth-resolved effects when compared to uncontaminated soil profiles. As soil depth increased, the concentrations of antimony and arsenic gradually declined in the contaminated soil profiles. Acidobacteria, Chloroflexi, Proteobacteria and Thaumarchaeota were the most variable phyla from surface to deep soil. The co-occurrence networks were loosely connected in surface soil, but obviously recovered and were well-connected in deep soil. The metagenomic results indicated that microbial metabolic potential also changed with soil depth. Genes encoding C metabolism pathways were negatively correlated with antimony and arsenic concentrations. Abundances of arsenic-related genes were enriched by severe contamination, but reduced with soil depth. Overall, soil depth-resolved characteristics are often many meters deep and such effects affected the indigenous microbial communities, as well as their metabolic potential due to different contaminants along vertical depths.

2020 ◽  
Author(s):  
Rui Xu ◽  
Xiaoxu Sun ◽  
Feng Han ◽  
Enzong Xiao ◽  
Baoqin Li ◽  
...  

Abstract BackgroundSoil microbes play critical roles in the biogeochemical cycling of antimony (Sb) and arsenic (As), and the effects of Sb and As contamination on soil microbiota have been well documented in surface soils (< 0.2 m). However, their effects in deep soils remain poorly understood. This study determined the depth-resolved effects of Sb and As contamination on the microbial adaptation throughout soil profiles (0–2 m) and compared contaminated soil samples to uncontaminated samples.Methods16S rRNA amplicon sequencing and shotgun metagenomic sequencing were employed to investigate the microbial community and their metabolism traits in soil profiles. Co-occurrence network analysis was used to present the pairwise interactions of microbes.ResultsAs soil depth increased, Acidobacteria (18.8%–44.7% from top to bottom, hereafter), Chloroflexi (8.7%–42.4%), Proteobacteria (11.4%–27.1%), and Thaumarchaeota (0.49%–20.17%) were the most variable phyla from surface to deep soil. A set of co-occurrence networks revealed an obvious changing pattern of microbial interactions as soil depth increased. The networks were loosely connected in the heavily contaminated surface soil but gradually recovered and were well connected in the less contaminated deep soil. Results suggested that individual species became more connected with other patterns to perform syntrophic functions in the less contaminated soil depth. Shotgun metagenomic sequencing results indicated that microbial metabolic potential also changed with soil depth. Genes encoding C metabolism pathways were negatively correlated with Sb and As concentrations. A set of arsenic-related genes was enriched by the high Sb and As contamination but reduced with soil depth. ConclusionsSoil depth-resolved characteristics are often many meters deep and their microbial diversity and community structures obviously change along their vertical soil profiles due to different nutrient contents and biomasses. The significance of this study is that it further reveals how the microbial communities and microbial physiological traits respond to different soil profiles contaminated by high concentrations of Sb and As.


Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 173
Author(s):  
Huiling Guan ◽  
Jiangwen Fan ◽  
Haiyan Zhang ◽  
Warwick Harris

Soil erosion is prevalent in karst areas, but few studies have compared the differences in the drivers for soil microbial communities among karst ecosystems with different soil depths, and most studies have focused on the local scale. To fill this research gap, we investigated the upper 20 cm soil layers of 10 shallow–soil depth (shallow–SDC, total soil depth less than 100 cm) and 11 deep–soil depth communities (deep–SDC, total soil depth more than 100 cm), covering a broad range of vegetation types, soils, and climates. The microbial community characteristics of both the shallow–SDC and deep–SDC soils were tested by phospholipid fatty acid (PLFAs) analysis, and the key drivers of the microbial communities were illustrated by forward selection and variance partitioning analysis. Our findings demonstrated that more abundant soil nutrients supported higher fungal PLFA in shallow–SDC than in deep–SDC (p < 0.05). Furthermore, stronger correlation between the microbial community and the plant–soil system was found in shallow–SDC: the pure plant effect explained the 43.2% of variance in microbial biomass and 57.8% of the variance in the ratio of Gram–positive bacteria to Gram–negative bacteria (G+/G−), and the ratio of fungi to total bacteria (F/B); the pure soil effect accounted for 68.6% variance in the microbial diversity. The ratio of microbial PLFA cyclopropyl to precursors (Cy/Pr) and the ratio of saturated PLFA to monounsaturated PLFA (S/M) as indicators of microbial stress were controlled by pH, but high pH was not conducive to microorganisms in this area. Meanwhile, Cy/Pr in all communities was >0.1, indicating that microorganisms were under environmental stress. Therefore, the further ecological restoration of degraded karst communities is needed to improve their microbial communities.


2019 ◽  
Author(s):  
Tess E. Brewer ◽  
Emma L. Aronson ◽  
Keshav Arogyaswamy ◽  
Sharon A. Billings ◽  
Jon K. Botthoff ◽  
...  

AbstractWhile most bacterial and archaeal taxa living in surface soils remain undescribed, this problem is exacerbated in deeper soils owing to the unique oligotrophic conditions found in the subsurface. Additionally, previous studies of soil microbiomes have focused almost exclusively on surface soils, even though the microbes living in deeper soils also play critical roles in a wide range of biogeochemical processes. We examined soils collected from 20 distinct profiles across the U.S. to characterize the bacterial and archaeal communities that live in subsurface soils and to determine whether there are consistent changes in soil microbial communities with depth across a wide range of soil and environmental conditions. We found that bacterial and archaeal diversity generally decreased with depth, as did the degree of similarity of microbial communities to those found in surface horizons. We observed five phyla that consistently increased in relative abundance with depth across our soil profiles: Chloroflexi, Nitrospirae, Euryarchaeota, and candidate phyla GAL15 and Dormibacteraeota (formerly AD3). Leveraging the unusually high abundance of Dormibacteraeota at depth, we assembled genomes representative of this candidate phylum and identified traits that are likely to be beneficial in low nutrient environments, including the synthesis and storage of carbohydrates, the potential to use carbon monoxide (CO) as a supplemental energy source, and the ability to form spores. Together these attributes likely allow members of the candidate phylum Dormibacteraeota to flourish in deeper soils and provide insight into the survival and growth strategies employed by the microbes that thrive in oligotrophic soil environments.ImportanceSoil profiles are rarely homogeneous. Resource availability and microbial abundances typically decrease with soil depth, but microbes found in deeper horizons are still important components of terrestrial ecosystems. By studying 20 soil profiles across the U.S., we documented consistent changes in soil bacterial and archaeal communities with depth. Deeper soils harbored distinct communities compared to the more commonly studied surface horizons. Most notably, we found that the candidate phylum Dormibacteraeota (formerly AD3) was often dominant in subsurface soils, and we used genomes from uncultivated members of this group to identify why these taxa are able to thrive in such resource-limited environments. Simply digging deeper into soil can reveal a surprising amount of novel microbes with unique adaptations to oligotrophic subsurface conditions.


2021 ◽  
Author(s):  
Ajun Purwanto ◽  
Dony Andrasmoro ◽  
Eviliyanto

Abstract Background: Several mining activities, especially bauxite, have been carried out in several areas in West Kalimantan. The areas most widely carried out bauxite mining are Sanggau and Ketapang districts. Bauxite mining is included in the classification of surface mining or often referred to as open mining. This is characterized by the demolition of the upper layers of soil and taking the results of weathering rocks, namely granite rocks. The demolition of topsoil is done with the clearing of vegetation above. In this condition, the land still has the same morphology when clearing has not been done and the soil has not been much disturbed. But after mining there is a lot of clay, sandstone, topsoil materials, of course, this will have a negative impact on the environment.Result: The results showed that the gradient of the slope has an important role in land conservation. The greater gradient of the slope will automatically increase the surface runoff, so the greater the energy of run-off. The soil depth is shallow on average and has poor deep soil drainage. Soil is easily eroded, so a lot of rocks and gravel are exposed on the surface, plants cannot develop properly. Floods often occur, in areas of alluvial plains with a range of more than 24 hours. The water availability capacity is also very low. Rainwater in the area mostly becomes runoff. The nutrient content in the ex-mining area is also low. Therefore it is necessary to improve efforts by means of reforestation of the former land so that in the future it can be used for certain uses, especially for agriculture, plantations, and forests.Conclusion: Slopes have an important role in land conservation. Slope affects runoff, effective soil depth, erosion rate, plant growth, waterlogging. Nutrient content in ex- Bauxite mining areas is also low.


Author(s):  
Jingjie Hao ◽  
Yen Ning Chai ◽  
Lucas Dantas Lopes ◽  
Raziel A. Ordóñez ◽  
Emily E. Wright ◽  
...  

This study investigated the differences in microbial community abundance, composition and diversity throughout the depth profiles in soils collected from corn and soybean fields in lowa, USA using 16S rRNA amplicon sequencing. The results revealed decreased richness and diversity in microbial communities at increasing soil depth. Soil microbial community composition differed due to crop type only in the top 60 cm and due to location only in the top 90 cm. While the relative abundance of most phyla decreased in deep soils, the relative abundance of the phylum Proteobacteria increased and dominated agricultural soils below the depth of 90 cm. Although soil depth was the most important factor shaping microbial communities, edaphic factors including soil organic matter, soil bulk density and the length of time that deep soils were saturated with water were all significant factors explaining the variation in soil microbial community composition. Soil organic matter showed the highest correlation with the exponential decrease in bacterial abundance with depth. A greater understanding of how soil depth influences the diversity and composition of soil microbial communities is vital for guiding sampling approaches in agricultural soils where plant roots extend beyond the upper soil profile. In the long term a greater knowledge of the influence of depth on microbial communities should contribute to new strategies that enhance the sustainability of soil which is a precious resource for food security. IMPORTANCE Determining how microbial properties change across different soils and within the soil depth profile, will be potentially beneficial to understanding the long-term processes that are involved in the health of agricultural ecosystems. Most literature on soil microbes has been restricted to the easily accessible surface soils. However, deep soils are important in soil formation, carbon sequestration, and in providing nutrients and water for plants. In the most productive agricultural systems in the USA where soybean and corn are grown, crop plant roots extend into the deeper regions of soils (> 100 cm), but little is known about the taxonomic diversity or the factors that shape deep soil microbial communities. The findings reported here highlight the importance of soil depth in shaping microbial communities, provide new information about edaphic factors that influence the deep soil communities and reveal more detailed information on taxa that exist in deep agricultural soils.


2008 ◽  
Vol 74 (5) ◽  
pp. 1620-1633 ◽  
Author(s):  
Colleen M. Hansel ◽  
Scott Fendorf ◽  
Phillip M. Jardine ◽  
Christopher A. Francis

ABSTRACT Spatial heterogeneity in physical, chemical, and biological properties of soils allows for the proliferation of diverse microbial communities. Factors influencing the structuring of microbial communities, including availability of nutrients and water, pH, and soil texture, can vary considerably with soil depth and within soil aggregates. Here we investigated changes in the microbial and functional communities within soil aggregates obtained along a soil profile spanning the surface, vadose zone, and saturated soil environments. The composition and diversity of microbial communities and specific functional groups involved in key pathways in the geochemical cycling of nitrogen, Fe, and sulfur were characterized using a coupled approach involving cultivation-independent analysis of both 16S rRNA (bacterial and archaeal) and functional genes (amoA and dsrAB) as well as cultivation-based analysis of Fe(III)-reducing organisms. Here we found that the microbial communities and putative ammonia-oxidizing and Fe(III)-reducing communities varied greatly along the soil profile, likely reflecting differences in carbon availability, water content, and pH. In particular, the Crenarchaeota 16S rRNA sequences are largely unique to each horizon, sharing a distribution and diversity similar to those of the putative (amoA-based) ammonia-oxidizing archaeal community. Anaerobic microenvironments within soil aggregates also appear to allow for both anaerobic- and aerobic-based metabolisms, further highlighting the complexity and spatial heterogeneity impacting microbial community structure and metabolic potential within soils.


1975 ◽  
Vol 39 (6) ◽  
pp. 1220-1223
Author(s):  
K. M. Holtzclaw ◽  
J. M. Rible ◽  
P. F. Pratt
Keyword(s):  

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 298
Author(s):  
Despoina Konstantinou ◽  
Rafael V. Popin ◽  
David P. Fewer ◽  
Kaarina Sivonen ◽  
Spyros Gkelis

Sponges form symbiotic relationships with diverse and abundant microbial communities. Cyanobacteria are among the most important members of the microbial communities that are associated with sponges. Here, we performed a genus-wide comparative genomic analysis of the newly described marine benthic cyanobacterial genus Leptothoe (Synechococcales). We obtained draft genomes from Le. kymatousa TAU-MAC 1615 and Le. spongobia TAU-MAC 1115, isolated from marine sponges. We identified five additional Leptothoe genomes, host-associated or free-living, using a phylogenomic approach, and the comparison of all genomes showed that the sponge-associated strains display features of a symbiotic lifestyle. Le. kymatousa and Le. spongobia have undergone genome reduction; they harbored considerably fewer genes encoding for (i) cofactors, vitamins, prosthetic groups, pigments, proteins, and amino acid biosynthesis; (ii) DNA repair; (iii) antioxidant enzymes; and (iv) biosynthesis of capsular and extracellular polysaccharides. They have also lost several genes related to chemotaxis and motility. Eukaryotic-like proteins, such as ankyrin repeats, playing important roles in sponge-symbiont interactions, were identified in sponge-associated Leptothoe genomes. The sponge-associated Leptothoe stains harbored biosynthetic gene clusters encoding novel natural products despite genome reduction. Comparisons of the biosynthetic capacities of Leptothoe with chemically rich cyanobacteria revealed that Leptothoe is another promising marine cyanobacterium for the biosynthesis of novel natural products.


2013 ◽  
Vol 10 (7) ◽  
pp. 5115-5124 ◽  
Author(s):  
J. Esperschütz ◽  
C. Zimmermann ◽  
A. Dümig ◽  
G. Welzl ◽  
F. Buegger ◽  
...  

Abstract. In initial ecosystems, concentrations of all macro- and micronutrients can be considered as extremely low. Plant litter therefore strongly influences the development of a degrader's food web and is an important source for C and N input into soil in such ecosystems. In the present study, a 13C litter decomposition field experiment was performed for 30 weeks in initial soils from a post-mining area near the city of Cottbus (Germany). Two of this region's dominant but contrasting pioneering plant species (Lotus corniculatus L. and Calamagrostis epigejos L.) were chosen to investigate the effects of litter quality on the litter decomposing microbial food web in initially nutrient-poor substrates. The results clearly indicate the importance of litter quality, as indicated by its N content, its bioavailability for the degradation process and the development of microbial communities in the detritusphere and soil. The degradation of the L. corniculatus litter, which had a low C / N ratio, was fast and showed pronounced changes in the microbial community structure 1–4 weeks after litter addition. The degradation of the C. epigejos litter material was slow and microbial community changes mainly occurred between 4 and 30 weeks after litter addition to the soil. However, for both litter materials a clear indication of the importance of fungi for the degradation process was observed both in terms of fungal abundance and activity (13C incorporation activity)


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