Comparative Metagenomics of the Active Layer and Permafrost from Low-Carbon Soil in the Canadian High Arctic
Publication Year
2021
Type
Journal Article
Abstract
Approximately 87% of the Arctic consists of low-organic carbon mineral soil, but knowledge of microbial activity in low-carbon permafrost (PF) and active layer soils remains limited. This study investigated the taxonomic composition and genetic potential of microbial communities at contrasting depths of the active layer (5, 35, and 65 cm below surface, bls) and PF (80 cm bls). We showed microbial communities in PF to be taxonomically and functionally different from those in the active layer. 16S rRNA gene sequence analysis revealed higher biodiversity in the active layer than in PF, and biodiversity decreased significantly with depth. The reconstructed 91 metagenome-assembled genomes showed that PF was dominated by heterotrophic, fermenting Bacteroidota using nitrite as their main electron acceptor. Prevalent microbes identified in the active layer belonged to bacterial taxa, gaining energy via aerobic respiration. Gene abundance in metagenomes revealed enrichment of genes encoding the plant-derived polysaccharide degradation and metabolism of nitrate and sulfate in PF, whereas genes encoding methane/ammonia oxidation, cold-shock protein, and two-component systems were generally more abundant in the active layer, particularly at 5 cm bls. The results of this study deepen our understanding of the low-carbon Arctic soil microbiome and improve prediction of the impacts of thawing PF. © 2021 American Chemical Society
Keywords
Biodiversity,
Encoding (symbols),
Microorganisms,
Organic carbon,
permafrost,
RNA,
Signal encoding,
Sulfur compounds,
16S rRNA gene sequence,
Aerobic respiration,
Canadian high arctic,
Microbial activities,
Microbial communities,
Polysaccharide degradation,
Taxonomic composition,
Two component systems,
Genes,
carbon,
cellulose,
cold shock protein,
cytochrome c oxidase,
methane,
nitrate,
nitrite,
organic carbon,
polysaccharide,
RNA 16S,
sulfate,
sulfur,
carbon,
active layer,
biodiversity,
comparative study,
genetic analysis,
genome,
microbial community,
permafrost,
soil microorganism,
archaeal genome,
Article,
bacterial count,
bacterial metabolism,
biodiversity,
Canada,
carbohydrate metabolism,
carbon dioxide fixation,
fermentation,
geochemistry,
metagenome,
metagenomics,
microbial activity,
microbial community,
nitrogen metabolism,
nonhuman,
Oxidation,
permafrost,
pH,
plant cell,
soil chemistry,
soil microflora,
Arctic,
genetics,
metagenomics,
microbiology,
soil,
Bacteria (microorganisms),
Arctic Regions,
Canada,
Carbon,
metagenomics,
permafrost,
RNA,
Ribosomal,
16S,
soil,
Soil Microbiology
Journal
Environmental Science and Technology
Volume
55
Pages
12683-12693