Biochemical and molecular characterization of microbial communities from a metal contaminated and reclaimed region.
Notice bibliographique
Résumé
Metal contamination in the Greater Sudbury Region (GSR) resulted in severe environmental degradation. Soil liming and tree planting have been the main approaches to restoring the damaged ecosystem. The specific objective of the present study was to assess the effects of soil metal contamination and liming on 1) microbial biomass and abundance, 2) bacterial and fungal diversity, and 3) enzymatic activities and soil respiration. Phospholipid fatty acid (PLFA) analysis and 454 pyrosequencing were used to address these research objectives. Total biomasses for bacteria, arbuscular fungi (AM fungi), other fungi and eukaryotes were significantly lower in metal contaminated compared to uncontaminated reference areas. Analysis of bacterial communities revealed Chao1 index values of 232 and 273 for metal contaminated and reference soils, respectively. For fungi, the Chao index values were 23 for metal contaminated and 45 for reference sites. There was a significant increase of total microbial biomass in limed sites (342.15 ng/g) compared to unlimed areas (149.89 ng/g). Chao1 estimates followed the same trend. But the total number of OTUs (Operational Taxonomic Units) in limed (463 OTUs) and unlimed (473 OTUs) soil samples for bacteria were similar. For fungi, OTUs were 96 and 81 for limed and unlimed soil samples, respectively. Bacterial and fungal groups that were specific to either limed or unlimed sites were identified. Bradyrhizobiaceae family with 12 genera including the nitrogen fixing Bradirhizobium genus was more abundant in limed sites compared to unlimed areas. For fungi, Ascomycota was the most predominant phylum in unlimed soils (46.00%) while Basidiomycota phylum represented 85.74% of all fungi in the limed areas. Detailed analysis of the data showed that although soil liming increases significantly the amount of microbial biomass, the level of species diversity remained statistically unchanged. Soil respiration rates were higher in limed soils (65 ppm) compared to unlimed soils (35 ppm). They were significantly lower in metal contaminated sites (55 ppm) compared to reference sites (90 ppm). β-glucosidase (BG), cellobiohydrolase (CBH), β-N-acetylglucosaminidase (NAGase), aryl sulfatase (AS), acid phosphatase (AP), alkaline phosphatase (AlP), glycine aminopeptidase (GAP), and leucine aminopeptidase (LAP) activites were significantly higher in limed compared to unlimed sites. Metal contamination significantly reduced the activities of these enzymes with the exception of LAP. An opposite trend was observed for peroxidase (PER) enzyme activity that was higher in unlimed and metal contaminated sites compared to limed and reference areas.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».