Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39.382
Filtrar
1.
J Hazard Mater ; 421: 126790, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34358973

RESUMO

Acid mine drainage (AMD) system represents one of the most unfavorable habitats for microorganisms due to its low pH and high concentrations of metals. Compared to bacteria and fungi, our understanding regarding the response of soil protozoa to such extremely acidic environments remains limited. This study characterized the structures of protozoan communities inhabiting a terrace heavily contaminated by AMD. The sharp environmental gradient of this terrace was generated by annual flooding from an AMD lake located below, which provided a natural setting to unravel the environment-protozoa interactions. Previously unrecognized protozoa, such as Apicomplexa and Euglenozoa, dominated the extremely acidic soils, rather than the commonly recognized members (e.g., Ciliophora and Cercozoa). pH was the most important factor regulating the abundance of protozoan taxa. Metagenomic analysis of protozoan metabolic potential showed that many functional genes encoding for the alleviation of acid stress and various metabolic pathways were enriched, which may facilitate the survival and adaptation of protozoa to acidic environments. In addition, numerous co-occurrences between protozoa and bacterial or fungal taxa were observed, suggesting shared environmental preferences or potential bio-interactions among them. Future studies are required to confirm the ecological roles of these previously unrecognized protozoa as being important soil microorganisms.


Assuntos
Mineração , Solo , Ácidos , Bactérias , Microbiologia do Solo
2.
J Environ Manage ; 301: 113916, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34634723

RESUMO

The mineralization of soil organic matter (SOM) is closely related to the emission of greenhouse gas into atmosphere and the stability of organic carbon in soil. The influence of minerals on SOM mineralization in the specific soil received very few attentions. The influence characteristics and potential mechanisms of oxides on the mineralization of SOM in the paddy soil were observed in this study by incubating soil with the addition (dosage: 10 g kg-1) of prepared gibbsite, goethite, ferrihydrite or birnessite for 60 days. A sequence control treatment (753 mg CO2-C kg-1) > goethite treatment (656 mg CO2-C kg-1) ≈ gibbsite treatment (649 mg CO2-C kg-1) > birnessite treatment (529 mg CO2-C kg-1) > ferrihydrite treatment (441 mg CO2-C kg -1) was found in the cumulative amount of released CO2 in 60 days of incubation. Oxides especially ferrihydrite significantly decreased the content of dissolved organic matter (DOM) but tended to increase the content of microbial biomass carbon (MBC). The molecular structure of DOM in the paddy soil was simplified by gibbsite, ferrihydrite and birnessite after the incubation. Oxides especially birnessite and ferrihydrite reduced soil pH and the content of soil available N but increased soil redox potential (Eh). All examined oxides especially Fe oxides enhanced soil bacterial abundance but only birnessite significantly affected bacterial composition at phyla level. The stimulation on the immobilization and/or microbial assimilation of labile organic carbon, the modulation on soil basic properties (available N, pH, Eh), and the decrease of the relative abundance of some decomposing bacteria phyla such as Actinobacteria were the potential pathways of oxides in decreasing SOM mineralization.


Assuntos
Alumínio , Solo , Carbono , Ferro , Manganês , Óxidos , Microbiologia do Solo
3.
Sci Total Environ ; 803: 150006, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34487902

RESUMO

Soil contamination with trace metal(loid) elements (TME) is a global concern. This has focused interest on TME-tolerant plants, some of which can hyperaccumulate extraordinary amounts of TME into above-ground tissues, for potential treatment of these soils. However, intra-species variability in TME hyperaccumulation is not yet sufficiently understood to fully harness this potential. Particularly, little is known about the rhizosphere microbial communities associated with hyperaccumulating plants and whether or not they facilitate TME uptake. The aim of this study is to characterize the diversity and structure of Arabidopsis halleri rhizosphere-influenced and background (i.e., non-Arabidopsis) soil microbial communities in four plant populations with contrasting Zn and Cd hyperaccumulation traits, two each from contaminated and uncontaminated sites. Microbial community properties were assessed along with geographic location, climate, abiotic soil properties, and plant parameters to explain variation in Zn and Cd hyperaccumulation. Site type (TME-contaminated vs. uncontaminated) and location explained 44% of bacterial/archaeal and 28% of fungal community variability. A linear discriminant effect size (LEfSe) analysis identified a greater number of taxa defining rhizosphere microbial communities than associated background soils. Further, in TME-contaminated soils, the number of rhizosphere-defining taxa was 6-fold greater than in the background soils. In contrast, the corresponding ratio for uncontaminated sites, was 3 and 1.6 for bacteria/archaea and fungi, respectively. The variables analyzed explained 71% and 76% of the variance in Zn and Cd hyperaccumulation, respectively; however, each hyperaccumulation pattern was associated with different variables. A. halleri rhizosphere fungal richness and diversity associated most strongly with Zn hyperaccumulation, whereas soil Cd and Zn bioavailability had the strongest associations with Cd hyperaccumulation. Our results indicate strong associations between A. halleri TME hyperaccumulation and rhizosphere microbial community properties, a finding that needs to be further explored to optimize phytoremediation technology that is based on hyperaccumulation.


Assuntos
Arabidopsis , Microbiota , Poluentes do Solo , Biodegradação Ambiental , Cádmio , Rizosfera , Solo , Microbiologia do Solo , Poluentes do Solo/análise , Zinco
4.
J Hazard Mater ; 422: 126793, 2022 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-34399213

RESUMO

The use of biosolids as fertilizers in agriculture can lead to the exposure of soil biota to sulfidised silver nanoparticles (Ag2S NPs), generated during the wastewater treatment procedures. Considering the crucial role of microorganisms on soil functions, we aimed to study the effects of 10 mg kg-1 soil of Ag2S NPs or AgNO3 on the soil microbiome, using an indoor mesocosm. After 28 days of exposure, Ag2S NPs induced a significant change in the soil microbiome structure, at class, genera and OTU levels. For instance, a significantly higher abundance of Chitinophagia, known for its lignocellulose-degrading activity, was observed in Ag2S NPs-treated soil toward the control. Nevertheless, stronger effects were observed in AgNO3-treated soil, over time, due to its higher silver dissolution rate in porewater. Additionally, only the AgNO3-treated soil stimulates the abundance of ammonia-oxidizing (AOB; amoA gene) and nitrite-oxidizing (NOB; nxrB gene) bacteria, which are involved in the nitrification process. Distinct variants of amoA and nxrB genes emerged in silver-treated soils, suggesting a potential succession of AOB and NOB with different degree of silver-tolerance. Our study highlights the latter effects of Ag2S NPs on the soil microbiome composition, while AgNO3 exerted a stronger effect in both composition and functional parameters.


Assuntos
Nanopartículas Metálicas , Microbiota , Amônia , Archaea , Íons , Nanopartículas Metálicas/toxicidade , Nitrificação , Oxirredução , Prata/análise , Prata/toxicidade , Compostos de Prata , Solo , Microbiologia do Solo
5.
Chemosphere ; 286(Pt 2): 131709, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34340117

RESUMO

Phenanthrene (PHE) is frequently detected in worldwide soils. But it is still not clear that how the microbial community succession happens and the nitrogen-cycling processes alter during PHE degradation. In this study, the temporal changes of soil microbial community composition and nitrogen-cycling processes during the biodegradation of PHE (12 µg g-1) were explored. The results showed that the biodegradation of PHE followed the second-order kinetics with a half-life of 7 days. QPCR results demonstrated that the bacteria numbers increased by 67.1%-194.7% with PHE degradation, whereas, no significant change was observed in fungi numbers. Thus, high-throughput sequencing based on 16 S rRNA was conducted and showed that the abundances of Methylotenera, Comamonadaceae, and Nocardioides involved in PHE degradation and denitrification were significantly increased, while those of nitrogen-metabolism-related genera such as Nitrososphaeraceae, Nitrospira, Gemmatimonadacea were decreased in PHE-treated soil. Co-occurrence network analysis suggested that more complex interrelations were constructed, and Proteobacteria instead of Acidobacteriota formed intimate associations with other microbes in responding to PHE exposure. Additionally, the abundances of nifH and narG were significantly up-regulated in PHE-treated soil, while that of amoA especially AOAamoA was down-regulated. Finally, correlation analysis found several potential microbes (Methylotenera, Comamonadaceae, and Agromyces) that could couple PHE degradation and nitrogen transformation. This study confirmed that PHE could alter microbial community structure, change the native bacterial network, and disturb nitrogen-cycling processes.


Assuntos
Microbiota , Fenantrenos , Nitrogênio , Ciclo do Nitrogênio , Solo , Microbiologia do Solo
6.
Chemosphere ; 286(Pt 2): 131567, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34343920

RESUMO

Soil bacterial community (SBC) and fertility are pivotal for the evaluation of phytoremediation performance. Although affected by earthworms (E) and arbuscular mycorrhizal fungi (AMF), little is known about the impacts of the E-AMF interaction on the variation of SBC and fertility in cadmium (Cd)-spiked soil. We elucidated these impacts in rhizosphere soil of Solanum nigrum L. Loss of nutrient availability, and SBC diversity was observed in Cd-polluted soil. AMF increased available phosphorous (AP), whereas E increased available potassium (AK). In soils with 60 and 120 mg/kg Cd, the contents of AK, AP, and soil organic matter (SOM) increased by 7.0-19.7%, 23.7-25.5%, and 11.5-17.4%, respectively; and the residual Cd after remediation decreased by 7.9-8.5% in soils treated with EAM compared to untreated soil. EAM-treated soil had higher alpha diversity estimators compared to uninoculated soil. The predominant bacterial phyla were Proteobacteria and Bacteroidetes, accounting for 72.5-84.0%. Redundancy analysis showed that total carbon (TC), SOM, pH, and C/N ratio were key factors determining SBC at the phylum level, explaining 26.9, 24.1, 15.1, and 14.8% of the total variance, respectively. These results suggested that EAM affected SBC composition by altering SOM, TC, and C/N ratio. The E-AMF cooperation ameliorates soil nutrients, SBC diversity, and composition, facilitating phytoextraction processes.


Assuntos
Microbiota , Micorrizas , Oligoquetos , Poluentes do Solo , Animais , Cádmio/análise , Fertilidade , Fungos , Raízes de Plantas/química , Solo , Microbiologia do Solo , Poluentes do Solo/análise
7.
Chemosphere ; 286(Pt 2): 131750, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34352537

RESUMO

The remediation effects of hydrogen peroxide (H2O2) oxidation and surfactant-leaching alone or in combination on three typical oilfield sludges were studied. The removal efficiency of total petroleum hydrocarbons (TPHs) of Jidong, Liaohe and Jiangsu oil sludges by hydrogen peroxide oxidation alone was very poor (6.5, 6.8, and 3.4 %, respectively) but increased significantly (p < 0.05), especially of long-chain hydrocarbons, by combining the use of H2O2 with surfactants (80.0, 79.8 and 82.2 %, respectively). Oxidation combined with leaching may impair microbial activity and organic manure was therefore added to the treated sludges for biostimulation and the composition and function of the microbial community were studied. The addition of manure rapidly restored sludge microbial activity and significantly increased the relative abundance of some salt-tolerant and alkali-tolerant petroleum-degrading bacteria such as Corynebacterium, Pseudomonas, Dietzia and Jeotgalicoccus. Moreover, the relative abundance of two classic petroleum-degrading enzyme genes, alkane 1-monooxygenase and catechol 1, 2-dioxygenase, increased significantly.


Assuntos
Microbiota , Petróleo , Poluentes do Solo , Biodegradação Ambiental , Hidrocarbonetos , Peróxido de Hidrogênio , Petróleo/análise , Esgotos , Microbiologia do Solo , Poluentes do Solo/análise , Tensoativos
8.
Chemosphere ; 286(Pt 2): 131693, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34358886

RESUMO

Based on the sustainable development practice-zero growth in chemical fertilizer application, this article used bagasse organic fertilizer and rice husk derived biochar to investigate the response of soil bacterial community in apple orchard. Aimed at realize the soil quality improvement and biomass resource recovery to contribute agricultural and environmental sustainability. The co-trophic Proteobacteria was predominant in all the treatments (29-36 %) and enriched in non-nitrifying Alphaproteobacteria (9-11 %) and ammonia oxidant Betaproteobacteria (8-10 %), especially richest in bagasse fertilizer combine biochar treated soil. In addition, bacterial community variation was assessed by alpha and beta diversity, four treatments dispersed distribution and richer abundance observed in combined apply bagasse fertilizer and biochar treatment (3909.22 observed-species) than single application (3729.88 and 3646.58 observed-species). Biochar as microbial carrier combined organic fertilizer were established synergistic interaction and favorable to organic matter availability during sustainable agriculture. Finally, integrated biochar-bagasse fertilizer was richer than single organic or biochar fertilization in improving soil bacterial diversity, notably by promoting the metabolism of copiotrophic bacteria, nutrient cycling, plant growth and disease inhibit-related bacteria.


Assuntos
Fertilizantes , Malus , Agricultura , Bactérias/genética , Celulose , Carvão Vegetal , Fertilizantes/análise , Solo , Microbiologia do Solo
9.
Chemosphere ; 286(Pt 2): 131663, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34371357

RESUMO

In this study, an immobilization method for forming and keeping dominant petroleum degradation bacteria was successfully developed by immobilizing Pseudomonas, Acinetobacter, and Sphingobacterium genus bacteria on wheat bran biochar pyrolyzed at 300, 500, and 700 °C. The removal efficiency indicated that the highest TPHs (total petroleum hydrocarbons) removal rate of BC500-4 B (biochar pyrolyzed at 500 °C with four kinds of petroleum bacteria) was 58.31%, which was higher than that of BC500 (36.91%) and 4 B (43.98%) used alone. The soil properties revealed that the application of biochar increased the content of organic matter, available phosphorus, and available potassium, but decreased pH and ammonium nitrogen content in soil. Bacterial community analysis suggested that the formation of dominant degrading community represented by Acinetobacter played key roles in TPHs removal. The removal rate of alkanes was similar to that of TPHs. Besides, biochar and immobilized material can also mediate greenhouse gas emission while removing petroleum, biochar used alone and immobilized all could improve CO2 emission, but decrease N2O emission and had no significant impact on CH4 emission. Furthermore, it was the first time to found the addition of Acinetobacter genus bacteria can accelerate the process of forming a dominant degrading community in wheat bran biochar consortium. This study focused on controlling greenhouse gas emission which provides a wider application of combining biochar and bacteria in petroleum soil remediation.


Assuntos
Gases de Efeito Estufa , Petróleo , Poluentes do Solo , Álcalis , Bactérias , Biodegradação Ambiental , Carvão Vegetal , Fibras na Dieta , Gases de Efeito Estufa/análise , Hidrocarbonetos , Petróleo/análise , Solo , Microbiologia do Solo , Poluentes do Solo/análise
10.
Chemosphere ; 286(Pt 3): 131800, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34399258

RESUMO

Chemical fertilizers are used in modern agricultural practice to increase plant output. They possess anthropogenic compounds which are hazardous, result in poor soil quality, poor crop nutrition and pollutes the water table. Currently, food crops that lack in micro-nutrients (Zn, silicates and Se) can be enriched with micronutrients by use of fertilizers. Eco-friendly bio-fertilizers have been proved to provide a known population of microorganisms that create a mutual benefit to the plants & the rhizosphere soil. Nanomaterials are often used in plant fertilizer formulation, allowing for controlled release and targeted delivery of beneficial nanoscale components, as well as to boost plant production and reduce environmental pollutants. In the present study we identified a multipotent micronutrient solubilizing bacterium (MSB) - Pseudomonas gessardi and Pseudomonas azotoformans as a bio-fertiliser. Comparative study of the formulated MSB, with nanocomposite prepared with the soya chunks as natural carrier material and chemically synthesized cerium oxide was performed on the growth of fenugreek for its effectiveness. The SEM images of nanocomposite showed the non-uniform distribution of CeO2 in bio-inoculant with an average size of 25.24 nm. The current study deals with increase in the shoot and root length of the fenugreek plant with only 75 ppm of CeO2 in nanocomposite, thereby preventing bioaccumulation of Ce in soil. This work gives a potential use of CeO2 nanocomposite with MSB bio-inoculants which could be applied to soil deficient with the micronutrients that can enhance the crop yield.


Assuntos
Fertilizantes , Nanocompostos , Produtos Agrícolas , Fertilizantes/análise , Micronutrientes , Nutrientes , Pseudomonas , Solo , Microbiologia do Solo
11.
Chemosphere ; 286(Pt 2): 131752, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34426136

RESUMO

Over recent decades, hydrocarbon concentrations have been augmented in soil and water, mainly derived from accidents or operations that input crude oil and petroleum into the environment. Different techniques for remediation have been proposed and used to mitigate oil contamination. Among the available environmental recovery approaches, bioremediation stands out since these hydrocarbon compounds can be used as growth substrates for microorganisms. In turn, microorganisms can play an important role with significant contributions to the stabilization of impacted areas. In this review, we present the current knowledge about responses from natural microbial communities (using DNA barcoding, multiomics, and functional gene markers) and bioremediation experiments (microcosm and mesocosm) conducted in the presence of petroleum and chemical dispersants in different samples, including soil, sediment, and water. Additionally, we present metabolic mechanisms for aerobic/anaerobic hydrocarbon degradation and alternative pathways, as well as a summary of studies showing functional genes and other mechanisms involved in petroleum biodegradation processes.


Assuntos
Microbiota , Poluição por Petróleo , Petróleo , Poluentes do Solo , Biodegradação Ambiental , Hidrocarbonetos , Poluição por Petróleo/análise , Microbiologia do Solo , Poluentes do Solo/análise
12.
Sci Total Environ ; 803: 150030, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34525688

RESUMO

Biological soil crusts (BSCs), known as ecological engineers, play an important role in soil organic carbon (SOC) sequestration in dryland ecosystems. Although numerous individual studies had been conducted, the global patterns of the changes in SOC concentration following BSCs establishment remain unclear. In this study, we performed a comprehensive meta-analysis of 184 independent observations at 47 sites to quantify the responses of SOC and other soil variables to BSCs establishment and identify the underlying mechanisms. Our results showed that BSCs generally increased SOC by 70.9% compared to the controls (uncrusted soil), and the positive effects of BSCs on SOC in deserts (120.3%) were stronger than those in grasslands (32.7%). Mosses and lichens had a stronger positive effect on SOC than algae crusts (67.5%, 82.8%, and 58.2% respectively). Mixed crusts accumulated more SOC (181.6%) than single (moss, lichen and algae) crusts. The presence of BSCs considerably increased total nitrogen (TN) (+80.7%), total phosphorus (TP) (+20.3%), available N (+62.7%), and available P (+14.3%). Significant relationships were observed among the effect size of SOC and climate and soil N and P in both desert and grassland. The random forest analysis showed that TN could be considered as a determinant of the concentration of SOC, followed by climate (P < 0.01). Our study shows that the capacity of the BSCs to fix and store C could be regulated by soil N and P dynamics, indicating a major finding opening new ways to promote soil recovery and formation. Our findings highlight the remarkable contribution of mixed crusts to soil C pools; this contribution needs to be incorporated into regional and global models to predict the effects of human disturbance on drylands worldwide and for assessing the soil C budget.


Assuntos
Cianobactérias , Solo , Carbono , Sequestro de Carbono , China , Clima Desértico , Ecossistema , Humanos , Nitrogênio , Microbiologia do Solo
13.
Sci Total Environ ; 802: 149671, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34454147

RESUMO

The usage of reclaimed wastewater (RWW) for irrigation of agricultural soils is increasingly being acknowledged for reducing water consumption by promoting reuse of treated wastewater, and for the delivery of extant nutrients in the soil. The downside is that RWW may be a vector for contamination of soils with contaminants of emerging concern (CECs), if left uncontrolled. Its usage is anticipated to alter the soil properties, consequently also the soil microbial community. In the present study, soil microcosms were set to monitor how short periods (up to fourteen days) of RWW irrigation influence the soil ecosystem, namely its physicochemical properties, functioning, and colonising microbiota (differentiating fungi from bacteria). Two scenarios were studied: clean soil and soil contaminated (spiked) with 9 CECs, at conditions that limit any abiotic decay processes, monitoring along time fluctuations in the taxonomic and functional microbiota diversity. As shortly as fourteen days, the irrigation of either soil with RWW did not significantly (p > 0.05) alter its physicochemical properties and scarcely impacted the bioremediation processes of the CECs that showed decay levels ranging from 24% to 100%. Bacillus spp. dominance was enhanced along time in all the soil microcosms (reaching over 70% of the total abundance on the 7th day) but the RWW help to preserve, to some extent, high bacterial diversity. Besides, irrigation with RWW acted as a buffer of the soil mycobiota, limiting alterations in its composition caused either along time (to a minor degree) or due to contamination with CECs (to a great degree). This includes limiting the rise of Rhizopus sp. relative abundance. Collectively, our data support the utility of short-term periods of RWW irrigation for preserving the soil microbial diversity and functioning, especially when fungi are considered.


Assuntos
Microbiota , Águas Residuárias , Irrigação Agrícola , Solo , Microbiologia do Solo , Águas Residuárias/análise
14.
Sci Total Environ ; 802: 149843, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34455279

RESUMO

Losses of microbial diversity in degraded ecosystems still have obscure consequences, especially when considering the interaction between arbuscular mycorrhizal fungi (AMF) and soil bacteria. This study investigates the effect of decreasing microbial biomass on mycorrhizal attributes and soil quality indicators. The dilution-to-extinction approach was applied in microcosms to search for associations among bacterial diversity, mycorrhizal attributes, and soil quality indicators. The experiment was conducted with four soil treatments (undiluted control 100 = D0, 10-3 = D3, 10-6 = D6, and 10-9 = D9) from a short-term (two years = 2Y) and a long-term (15 years = 15Y) coal mine revegetation area. Microcosms were inoculated with 300 spores of Acaulospora colombiana, Gigaspora albida, and Claroideoglomus etunicatum with millet as the host plant. Results included the total number of AMF spores, mycorrhizal colonization, soil aggregation, glomalin, fluorescein diacetate hydrolysis (FDA), basal soil respiration, microbial biomass, and soil bacterial microbiome. Larger differences were observed between areas than between dilution treatments within the sampling area. Attributes that presented differences in the dilutions compared to D0 2Y samples were mycorrhizal colonization (D0 = 85% and D9 = 43.3%), FDA (D0 = 77.2% and D9 = 55.5%), extractable glomalin-related soil protein (D0 = 0.09 and D9 = 0.11) and bacterial diversity (D0 = 7.3 and D6 = 5.3). D0 15Y samples presented differences in microbial biomass nitrogen (D0: 232.0) and bacterial diversity (D0: 7.9, D9: 5.6) compared to the dilutions. Bacterial microbiome present in the D0 samples formed distinct clusters as to other samples and correlated with soil aggregation and basal respiration attributes. Results suggest that AMF inoculation and dilution-to-extinction did not affect soil quality indicators preeminently, but the bacterial community is affected and can influence the process of environmental revegetation. A long-term revegetation period is substantial to improve quality indicators and establish the diversity of microorganisms and consequently revegetation in areas impacted by coal mining.


Assuntos
Minas de Carvão , Microbiota , Micorrizas , Biomassa , Fungos , Raízes de Plantas , Indicadores de Qualidade em Assistência à Saúde , Solo , Microbiologia do Solo
15.
Sci Total Environ ; 802: 149835, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34461468

RESUMO

Soil carbon supplementation is known to stimulate plant growth by improving soil fertility and plant nutrient uptake. However, the underlying process and chemical mechanism that could explain the interrelationship between soil carbon supplementation, soil micro-ecology, and the growth and quality of plant remain unclear. In this study, we investigated the influence and mechanism of soil carbon supplementation on the bacterial community, chemical cycling, mineral nutrition absorption, growth and properties of tobacco leaves. The soil carbon supplementation increased amino acid, carbohydrates, chemical energy metabolism, and bacterial richness in the soil. This led to increased content of sugar (23.75%), starch (13.25%), and chlorophyll (10.56%) in tobacco leaves. Linear discriminant analysis revealed 49 key phylotypes and significant increment of some of the Plant Growth-Promoting Rhizobacteria (PGPR) genera (Bacillus, Novosphingobium, Pseudomonas, Sphingomonas) in the rhizosphere, which can influence the tobacco growth. Partial Least Squares Path Modeling (PLS-PM) showed that soil carbon supplementation positively affected the sugar and starch contents in tobacco leaves by possibly altering the photosynthesis pathway towards increasing the aroma of the leaves, thus contributing to enhanced tobacco flavor. These findings are useful for understanding the influence of soil carbon supplementation on bacterial community for improving the yields and quality of tobacco in industrial plantation.


Assuntos
Carbono , Solo , Suplementos Nutricionais , Raízes de Plantas , Rizosfera , Microbiologia do Solo , Amido , Açúcares , Tabaco
16.
Sci Total Environ ; 802: 149899, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34464792

RESUMO

A mass of tailings left by mineral exploitation have caused serious environmental pollution. Although many studies have shown that soil microorganisms have the potential to remediate environmental pollution, the interaction mechanism between microorganisms and the surrounding environment of tailings is still unclear. In this study, 15 samples around pyrite mine tailing were collected to explore the ecological effects of environmental factors on bacterial community. The results showed that most of the samples were acidic and contaminated by multiple metals. Cadmium (Cd), copper (Cu), nickel (Ni) migrated and accumulated to into downstream farmlands while chromium (Cr) was the opposite. Proteobacteria, Chloroflex and Actinobacteria were the dominant phyla. Soil pH, total phosphorus (TP), total nitrogen (TN), available potassium (AK), available phosphorus (AP), the bacteria abundance and diversity all gradually increased with the increase of the distance from the tailing. Invertase, acid phosphatase, total organic carbon (TOC), pH, TP and Cr were the main influencing factors to cause the variation of bacterial community. This work could help us to further understand the changes in soil microbial communities around pollution sources.


Assuntos
Metais Pesados , Poluentes do Solo , China , Monitoramento Ambiental , Poluição Ambiental , Metais Pesados/análise , Solo , Microbiologia do Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
17.
Sci Total Environ ; 802: 149657, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34464797

RESUMO

The decomposition of organic matter mediated by soil enzymes is the key process that transports carbon from the soil into the atmosphere. To better understand the effect of global warming on organic matter decomposition, we evaluated the temperature sensitivity (Q10) of invertase (EC3.2.1.26), ß-glucosidase (EC3.2.1.21), urease (EC3.1.1.5), acid phosphatase (EC3.1.3.2), and arylsulfatase (EC3.1.6.1) activities in red soil from the subtropical region and black soil from the mid-temperate region at 5, 15, 25, 35, and 45 °C. Further, the in-situ stoichiometry of the products released by enzymes was modelled. All of the enzyme activities in the tested soils increased with the increasing temperature (1.1-8.9 fold per 10 °C), indicating an enhanced degradation of the organic substrate with warming. In the lower temperature range (5-25 °C), Q10 of the enzyme activities in the red soil evaluated in terms of total enzyme activity index were more prominent than that in black soil (1.53 and 3.46 vs 1.16 and 3.19). Changes in the in-situ stoichiometry of enzyme products with warming indicated that, in colder months (Jan. to Apr. and Oct. to Dec.), the microbial nutrient demand in the red soil exhibited the following order, N > P > S > C. While in the black soil, it suggested that there is increasing microbial demand for only N and S. In the warmer months (May to Sep.), the microbial nutrient demands in the two soils were opposite to the colder months. The results suggested differential changes in microbial nutrient limitation with warming, which has significant implications for the carbon stocks management in farmlands under the changing global climate.


Assuntos
Microbiologia do Solo , Solo , Carbono , Fazendas , Aquecimento Global , Nutrientes
18.
Sci Total Environ ; 804: 150148, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34520919

RESUMO

Root exudates play essential roles in shaping root-associated microbial communities in plant-soil systems. However, knowledge regarding the influence of root exudates on soil communities, particularly concerning their assembly processes and species coexistence patterns, remains limited. In this study, we performed a 20-month pot experiment using a nitrogen (N) addition gradient (0, 2.5, 5, 7.5, 10, and 15 g N m-2 yr-1), amplicon sequencing, and metabolomics to investigate the effect of short-term N addition on the assembly process and species coexistence of fungal communities, as well as their association with root exudates in the rhizosphere and bulk soils around Bothriochloa ischaemum. The results demonstrated that short-term N addition led to distinct differences in the diversity, composition, assembly process, and co-occurrence networks of fungal communities in the rhizosphere and bulk soils. The diversity of fungal communities in the rhizosphere soil increased with the rate of N input and peaked at N10 treatment; this could be correlated with the increased abundance in long-chain organic acids (LCOAs). However, above the threshold N rate of 10 g N m-2 yr-1, diversity decreased probably because of the high N-induced inhibitory effect on root exudates (i.e., LCOAs). N addition increased the relative abundance of Sordariomycetes in the rhizosphere and decreased the relative abundance of Mortierellomycetes in the bulk soil, while enhancing the abundance of pathotrophs in both bulk and rhizosphere soils. The rhizosphere fungal community was dominated by a stochastic process at a low N input (N0 and N2.5) and by deterministic processes at a high N input (N10 and N15), which is opposite to the trends in the bulk soil. These fungal assembly processes determine the coexistence of fungal species; deterministic processes lead to less interconnected networks in rhizosphere soils that harbor a more complex network than the bulk soil. Associations between the assembly process and species coexistence in the rhizosphere of B. ischaemum were closely related to the changes in root exudates, such as amino acids, short-chain organic acids, and phenols, which were stimulated by N addition. Collectively, our study emphasizes the key roles of root exudates in the establishment of fungal communities in the plant-soil system and furthers our understanding of plant-microbe interactions.


Assuntos
Micobioma , Rizosfera , Exsudatos e Transudatos , Fungos , Raízes de Plantas , Solo , Microbiologia do Solo
19.
Sci Total Environ ; 804: 149994, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34798714

RESUMO

Most ecosystem functions attributed to earthworms are mediated by their internal microbiomes, and these are sensitive to disturbances in the external environment. However, few studies have focused on the response of the earthworm gut microbiome to soil chronosequence. Here, we used 16S rRNA high-throughput sequencing and high-throughput quantitative PCR to investigate the variations in bacterial communities and functional gene abundance in earthworm (Lumbricina sp.) guts and upland soils under 700 years of cultivation. Our results indicated that 700 years of upland cultivation significantly shaped bacterial communities and increased functional traits of microbes in earthworm guts, which were more sensitive to cultivation age compared to the surrounding soils. The earthworm gut bacterial community changed rapidly over the first 300 years of cultivation and then changed slowly in the following centuries. Along with the cultivation age, we also observed that the earthworm gut microbiota was successive towards a copiotrophic strategy (e.g., Xanthobacteraceae, Nocardioidaceae, Hyphomicrobiaceae, and Bacillaceae) and higher potential functions (e.g., ureC, nirS, nosZ, phoD, and pqqC). Furthermore, canonical correspondence analysis further revealed that soil pH, C:N ratio, soil organic carbon, and total nitrogen were key abiotic drivers shaping earthworm gut bacterial communities. Taken together, this study reveals the succession of bacterial communities and potential functions in earthworm guts within 700 years of upland cultivation, which may provide a broader space for us to rationally exploit and utilize the interactions between soil and earthworm gut microbiotas to benefit the soil nutrient cycling process.


Assuntos
Microbioma Gastrointestinal , Microbiota , Oligoquetos , Animais , Carbono , RNA Ribossômico 16S/genética , Solo , Microbiologia do Solo
20.
Sci Total Environ ; 804: 150032, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34798716

RESUMO

Mountainous alpine ecosystems are sensitive to global change, where soil nutrient content would potentially vary under current climate change background, and thus possibly influence the activity of nitrifiers and denitrifiers, as well as N2O emissions. However, within mountainous alpine ecosystems, the potential variation of soil nutrients under current global change and the consequence to N2O emission from nitrification and denitrification are still unclarified, hampering a comprehensive understanding of the feedback mechanisms between the nitrogen cycle and climate change. In order to fill this knowledge gap, we selected alpine grasslands at three different elevations and investigated the distribution and environmental drivers of nitrifiers and denitrifiers. The results showed that the lowest elevation site tended to have higher total phosphorus (TP) accumulation within the topsoil. The abundance of functional groups, emission of CO2 and N2O, and the N2O/CO2 ratio showed a decreasing trend along elevation. TP was the greatest influence on denitrifier composition (nosZ/narG and nirS/nirK ratios) and considerably influenced nitrifier composition (AOA/AOB ratio), and was significantly correlated to the N2O/CO2 ratio. In microcosms of soils from the highest elevation site, TP addition decreased the ratios of nosZ/narG, nirS/nirK, and AOA/AOB, and increased N2O/CO2 ratio and N2O emission, thus contributing to positive climate change feedback. This study indicates the potential for change within the nitrifier and denitrifier communities under current climate change, and highlights the role TP plays in governing nitrification and denitrification in mountainous alpine ecosystems.


Assuntos
Fósforo , Solo , Mudança Climática , Desnitrificação , Ecossistema , Retroalimentação , Pradaria , Óxido Nitroso/análise , Microbiologia do Solo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA