| Autor: |
Wu X; Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, United States., Chauhan A; Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, United States., Layton AC; Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, United States., Lau Vetter MCY; Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States., Stackhouse BT; Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States., Williams DE; Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, United States., Whyte L; Department of Natural Resource Sciences, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada., Pfiffner SM; Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, United States., Onstott TC; Department of Geosciences, Princeton University, Princeton, New Jersey 08544, United States., Vishnivetskaya TA; Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee 37996, United States. |
| Abstrakt: |
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. |
