This work integrates cultivation studies of Siberian permafrost and analyses of metagenomes from different locations in the Arctic with the aim of obtaining insights into the community of photosynthetic microorganisms in perennially frozen deposits. Cyanobacteria and microalgae have been described in Arctic aquatic and surface soil environments, but their diversity and ability to withstand harsh conditions within the permafrost are still largely unknown. Community structure of photosynthetic organisms in permafrost sediments was explored using Arctic metagenomes available through the MG-RAST. Sequences affiliated with cyanobacteria represented from 0.25 to 3.03% of total sequences, followed by sequences affiliated with Streptophyta (algae and vascular plants) 0.01–0.45% and Chlorophyta (green algae) 0.01–0.1%. Enrichment and cultivation approaches revealed that cyanobacteria and green algae survive in permafrost and they could be revived during prolonged incubation at low light intensity. Among photosynthetic microorganisms isolated from permafrost, the filamentous Oscillatoria-like cyanobacteria and unicellular green algae of the genus Chlorella were dominant. Our findings suggest that permafrost cyanobacteria and green algae are expected to be effective members of the re-assembled community after permafrost thawing and soil collapse.

中文翻译：

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多年冻土对光合微生物群落的见解

这项工作整合了西伯利亚多年冻土的栽培研究以及对来自北极不同地区的元基因组的分析，目的是获得对常年冻结矿床中光合微生物群落的见识。蓝细菌和微藻已在北极水生和表层土壤环境中进行了描述，但它们的多样性和承受多年冻土中恶劣条件的能力仍然未知。利用可通过MG-RAST获得的北极元基因组，探索了多年冻土沉积物中光合生物的群落结构。与蓝细菌有关的序列占总序列的0.25％至3.03％，其次是与链霉菌属（藻类和维管植物）有关的序列0.01％至0.45％和绿藻（绿藻）所占的0.01％至0.1％。富集和培养方法表明，蓝藻和绿藻可以在多年冻土中存活，并且可以在弱光下长时间孵育后恢复。从多年冻土中分离出的光合微生物中，丝状颤样蓝藻和属单细胞绿藻绿藻占主导地位。我们的研究结果表明，多年冻土融化和土壤崩塌后，多年冻土蓝细菌和绿藻有望成为重组社区的有效成员。