Arctic Ecology and Biogeochemistry Division, National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Vasco-da-gama, 403804, Goa, India.
Department of Biology, United Arab Emirates University (UAEU), Al Ain, Abu Dhabi, UAE.
World J Microbiol Biotechnol. 2022 Jan 6;38(2):28. doi: 10.1007/s11274-021-03210-3.
The permafrost in the polar regions is vital for maintaining the status quo of the earth's climate by limiting greenhouse gas emissions. The present study aims to investigate the seasonal variations and the influence of physicochemical parameters on the bacterial diversity and community structure of active layer permafrost (AL) around Ny-Ålesund, Svalbard. The AL soil samples were collected from four different geographical locations around Ny-Ålesund during the winter and summer seasons. The 16S rDNA amplicon sequencing was carried out to investigate the diversity and distribution profiles of bacterial communities among the collected AL samples. Physico-chemical parameters including soil pH, moisture content, total carbon (TC), total nitrogen (TN), and trace metals concentrations were measured. Bacterial phyla, Proteobacteria (15.4%-26%) and Chloroflexi (9.6%-22.5%) were predominantly distributed across both seasons. In the winter samples, Verrucomicrobiota (14.12%-23.39%) phylum, consisting of genera Chthoniobacter and Opitutus were highly abundant (Lefse, p < 0.05), whereas in summer bacterial genera belonging to Gemmatimonadota (3.3%-13.74%) and Acidobacteriota (18.02%-28.52%) phyla were highly abundant. The bacterial richness and diversity index were not significantly different between the winter and summer seasons. Principal coordinate analysis (PCoA) has revealed a distinct grouping between two seasons (PERMANOVA, p < 0.05). Bacterial community structure was significantly varied between winter and summer seasons, whereas the physico-chemical variable, TN, influenced the community structure. About 37.8% of the total operational taxonomic units (OTUs) were shared between seasons, whereas 25.4% and 36.8% of OTUs were unique to the summer and winter seasons. The present study revealed that the conditions prevailing during winter and summer has shaped bacterial community structure in AL samples albeit the stable diversity and most of the variation was explained by TN, indicating its critical role in oligotrophic permafrost.
极地地区的永久冻土对于限制温室气体排放、维持地球气候现状至关重要。本研究旨在探讨斯瓦尔巴群岛新奥尔松周围活动层永久冻土（AL）的季节性变化以及理化参数对细菌多样性和群落结构的影响。在冬季和夏季，从新奥尔松周围的四个不同地理位置采集 AL 土壤样本。通过 16S rDNA 扩增子测序，研究了采集的 AL 样本中细菌群落的多样性和分布特征。测量了理化参数，包括土壤 pH 值、水分含量、总碳（TC）、总氮（TN）和痕量金属浓度。两个季节都主要分布有细菌门，变形菌门（15.4%-26%）和绿弯菌门（9.6%-22.5%）。在冬季样本中，疣微菌门（14.12%-23.39%），包含 Chthoniobacter 和 Opitutus 属，高度丰富（Lefse，p < 0.05），而在夏季，属于 Gemmatimonadota 门（3.3%-13.74%）和 Acidobacteriota 门（18.02%-28.52%）的细菌属高度丰富。冬季和夏季的细菌丰富度和多样性指数没有显著差异。主坐标分析（PCoA）揭示了两个季节之间的明显分组（PERMANOVA，p < 0.05）。冬季和夏季的细菌群落结构有显著差异，而理化变量 TN 影响了群落结构。两个季节之间共享了约 37.8%的总操作分类单元（OTUs），而夏季和冬季特有的 OTUs 分别占 25.4%和 36.8%。本研究表明，尽管稳定的多样性和大部分变化由 TN 解释，但冬季和夏季的条件塑造了 AL 样本中的细菌群落结构，表明其在贫营养永久冻土中的关键作用。
