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1.
Sci Total Environ ; 792: 148363, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34465051

RESUMO

The alpine meadow in the Qinghai-Tibet Plateau has been seriously degraded due to human activities and climate change in recent decades. Understanding the changes of the soil microbial community in response to the degradation process helps reveal the mechanism underlying the degradation process of alpine meadows. We surveyed and analyzed changes of the vegetation, soil physicochemical properties, and soil microbial community in three degradation levels, namely, non-degradation (ND), moderate degradation (MD), and severe degradation (SD), of the alpine meadows in the northeastern Qinghai-Tibet Plateau. We found that as the level of degradation increased, plant cover, plant density (PD), above-ground biomass (AGB), plant Shannon-Wiener index (PS), soil water content (SWC), soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP), and available potassium (AK) decreased significantly, while the soil pH increased from 7.20 to 8.57. Alpine meadow degradation significantly changed the composition of soil bacterial and fungal communities but had no significant impact on the diversity of the microbial communities. Functional predictions indicated that meadow degradation increased the relative abundances of aerobic_chemoheterotrophy, undefined_saprotroph, and plant_pathogen, likely increasing the risk of plant diseases. Redundancy analysis revealed that in ND, the soil microbial community was mainly regulated by PS, PH, PD, SWC, and soil pH. In MD, the soil microbial community was regulated by the soil's available nutrients and SOC. In SD, the soil microbial community was not only regulated by the soil's available nutrients but also influenced by plant characteristics. These results indicate that during alpine meadow degradation, while the changes in the plants and soil environmental factors both affect the composition of the soil microbial community, the influence of soil factors is greater. The soil's available nutrients are the main driving factors regulating the change in the soil microbial community's composition alongside degradation levels.


Assuntos
Microbiota , Solo , Carbono/análise , Pradaria , Humanos , Nutrientes , Microbiologia do Solo , Tibet
2.
Inorg Chem ; 59(10): 6747-6754, 2020 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-32250607

RESUMO

We report the synthesis, characterization, and solution self-assembly of plenary Nb6P2W12-based transition-metal substituted polyoxometalate, which is obtained by simply adding transition metals (Co2+) into aqueous solution containing cluster [(NbO2)6P2W12O56]12-, which is obtained by an in situ synthetic method. The incorporation of Co2+ ions significantly affects the crystal structure, resulting in the formation of a 1D chain-like crystal and the first example of a niobotungstate-based cobalt derivative cluster. The behavior and stability of this cluster in solution are confirmed by time-resolved static light scattering, dynamic light scattering, small-angle X-ray scattering, and electrospray mass spectrometry studies.

3.
Dalton Trans ; 49(13): 4078-4083, 2020 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-32134066

RESUMO

Recently, we demonstrated that the in situ formation of a building block is an attractive synthesis strategy for creating novel clusters with controllable structures. Herein, we present the design and synthesis of the first tantaloselenite polyoxoanion [Se4(TaO2)6(OH)4O17]4- (1) and a series of lanthanide derivatives (RE3+ = Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+). In total, we report seven clusters that vary in both composition and structure but which share the same {Se4(TaO2)6} building block. The compounds are fully characterized by single-crystal X-ray diffraction, IR spectra, TG, and PXRD and their decolorization properties for RhB have also been investigated. Compound 1 exhibits good photocatalytic activity for the decolorization of RhB while the introduction of lanthanide into the framework can also maintain this activity.

4.
J Hazard Mater ; 389: 121834, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-31843407

RESUMO

Environmental problems caused by the large-scale use of chemical pesticides are becoming more and more serious, and the removal of chemical pesticides from the ecological environment by microbial degradation has attracted wide attention. In this study, using enrichment screening with seven chemical pesticides as the sole carbon source, a mixed microbial culture (PCS-1) was obtained from the continuous cropping of strawberry fields. The microbial community composition, degradation ability, and detoxification effect of PCS-1 was determined for the seven pesticides. Inoculation with PCS-1 showed significant degradation of and tolerance to the seven pesticides. Microbial community composition analysis indicated that Pseudomonas, Enterobacter, Aspergillus, and Rhodotorula were the dominant genera for the degradation of the seven pesticides by PCS-1. The concentration of the seven pesticides was 10 mg L-1 in hydroponic and soil culture experiments. The fresh weight, plant height, and root length of PCS-1-inoculated alfalfa (Medicago sativa) significantly increased compared with those of non-PCS-1-inoculated M. sativa. PCS-1 not only effectively degraded the residual content of the seven pesticides in water and soil but also reduced the pesticide residues in the roots, stems, and leaves of M. sativa. This study shows that PCS-1 may be important in environmental remediation involving the seven pesticides.


Assuntos
Poluentes Ambientais/análise , Medicago sativa/efeitos dos fármacos , Microbiota/efeitos dos fármacos , Praguicidas/análise , Microbiologia do Solo , Poluentes do Solo/análise , Aspergillus/efeitos dos fármacos , Aspergillus/crescimento & desenvolvimento , Biodegradação Ambiental , Enterobacter/efeitos dos fármacos , Enterobacter/crescimento & desenvolvimento , Poluentes Ambientais/toxicidade , Medicago sativa/crescimento & desenvolvimento , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/toxicidade , Praguicidas/toxicidade , Pseudomonas/efeitos dos fármacos , Pseudomonas/crescimento & desenvolvimento , Rhodotorula/efeitos dos fármacos , Rhodotorula/crescimento & desenvolvimento , Poluentes do Solo/toxicidade
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