National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Headland Sada, Vasco da Gama, Goa, 403804, India.
School of Earth, Ocean and Atmospheric Sciences, Goa University, Taleigao Plateau Goa, 403206, India.
Antonie Van Leeuwenhoek. 2021 Sep;114(9):1339-1360. doi: 10.1007/s10482-021-01604-9. Epub 2021 Jun 20.
Sedimentary environments in the Arctic are known to harbor diverse microbial communities playing a crucial role in the remineralization of organic matter and associated biogeochemical cycles. In this study, we used a combination of culture-dependent and culture-independent approaches to understanding the bacterial community composition associated with the sediments of a terrestrial versus fjord system in the Svalbard Arctic. Community-level metabolic profiling and growth response of retrieved bacterial isolates towards different carbon substrates at varying temperatures were also studied to assess the metabolic response of communities and isolates in the system. Bacterial species belonging to Cryobacterium and Psychrobacter dominated the terrestrial and fjord sediment retrievable fraction. Amplicon sequencing analysis revealed higher bacterial diversity in the terrestrial sediments (Shannon index; 8.135 and 7.935) as compared to the fjord sediments (4.5-5.37). Phylum Proteobacteria and Bacteroidetes dominated both terrestrial and fjord sediments. Phylum Verrucomicrobia and Cyanobacteria were abundant in terrestrial sediments while Epsilonbacteraeota and Fusobacteriia dominated the fjord sediments. Significant differences were observed in the carbon substrate utilization profiles between the terrestrial and fjord sediments at both 4 °C and 20 °C incubations (p < 0.005). Utilization of N-acetyl-D-glucosamine, D-mannitol and Tween-80 by the sediment communities and bacterial isolates from both systems, irrespective of their temperature incubations implies the affinity of bacteria for such substrates as energy sources and for their survival in cold environments. Our results suggest the ability of sediment bacterial communities to adjust their substrate utilization profiles according to condition changes in the ecosystems and are found to be less influenced by their phylogenetic relatedness.
已知北极的沉积环境中蕴藏着多种多样的微生物群落，这些微生物在有机质的再矿化和相关生物地球化学循环中起着至关重要的作用。在这项研究中，我们采用了培养依赖和非培养依赖的方法相结合，来了解与斯瓦尔巴群岛北极地区陆地和峡湾系统沉积物相关的细菌群落组成。我们还研究了从沉积物中回收的细菌分离物对不同碳底物的代谢特征和在不同温度下的生长反应，以评估该系统中群落和分离物的代谢反应。属于 Cryobacterium 和 Psychrobacter 的细菌物种在陆地和峡湾沉积物中占主导地位。扩增子测序分析显示，陆地沉积物的细菌多样性较高（Shannon 指数分别为 8.135 和 7.935），而峡湾沉积物的细菌多样性较低（4.5-5.37）。门 Proteobacteria 和 Bacteroidetes 在陆地和峡湾沉积物中均占主导地位。门 Verrucomicrobia 和 Cyanobacteria 在陆地沉积物中丰度较高，而门 Epsilonbacteraeota 和 Fusobacteriia 在峡湾沉积物中占主导地位。在 4°C 和 20°C 孵育条件下，陆地和峡湾沉积物的碳底物利用谱存在显著差异（p<0.005）。无论是在 4°C 还是 20°C 的培养温度下，来自两个系统的沉积物群落和细菌分离物都利用了 N-乙酰-D-葡萄糖胺、D-甘露醇和 Tween-80，这表明细菌对这些作为能源的底物具有亲和力，并且能够在寒冷的环境中生存。我们的研究结果表明，沉积细菌群落能够根据生态系统条件的变化调整其底物利用谱，并且发现它们受亲缘关系的影响较小。
