PDF(Pubmed)
Abstract：
The rapid warming of the Arctic is threatening the demise of its glaciers and their associated ecosystems. Therefore, there is an urgent need to explore and understand the diversity of genomes resident within glacial ecosystems endangered by human-induced climate change. In this study we use genome-resolved metagenomics to explore the taxonomic and functional diversity of different habitats within glacier-occupied catchments. Comparing different habitats within such catchments offers a natural experiment for understanding the effects of changing habitat extent or even loss upon Arctic microbiota. Through binning and annotation of metagenome-assembled genomes (MAGs) we describe the spatial differences in taxon distribution and their implications for glacier-associated biogeochemical cycling. Multiple taxa associated with carbon cycling included organisms with the potential for carbon monoxide oxidation. Meanwhile, nitrogen fixation was mediated by a single taxon, although diverse taxa contribute to other nitrogen conversions. Genes for sulphur oxidation were prevalent within MAGs implying the potential capacity for sulphur cycling. Finally, we focused on cyanobacterial MAGs, and those within cryoconite, a biodiverse microbe-mineral granular aggregate responsible for darkening glacier surfaces. Although the metagenome-assembled genome of Phormidesmis priestleyi, the cyanobacterium responsible for forming Arctic cryoconite was represented with high coverage, evidence for the biosynthesis of multiple vitamins and co-factors was absent from its MAG. Our results indicate the potential for cross-feeding to sustain P. priestleyi within granular cryoconite. Taken together, genome-resolved metagenomics reveals the vulnerability of glacier-associated microbiota to the deletion of glacial habitats through the rapid warming of the Arctic.
摘要：
北极的迅速变暖正威胁着其冰川及其相关生态系统的消亡。因此,迫切需要探索和了解受人为气候变化威胁的冰川生态系统中基因组的多样性。在这项研究中，我们使用基因组解析的宏基因组学来探索冰川占据的流域内不同栖息地的分类学和功能多样性。比较此类流域内的不同栖息地提供了一个自然实验，可以了解栖息地范围变化甚至丧失对北极微生物群的影响。通过分类和注释宏基因组组装的基因组（MAG），我们描述了分类单元分布的空间差异及其对冰川相关的生物地球化学循环的影响。与碳循环相关的多个类群包括具有一氧化碳氧化潜力的生物。同时,固氮是由单个分类单元介导的，尽管不同的分类单元有助于其他氮转化。MAG中普遍存在硫氧化基因，这意味着硫循环的潜在能力。最后,我们专注于蓝藻MAG，还有那些在冰冻岩里面的，一种生物多样性的微生物-矿物颗粒聚集体，负责使冰川表面变暗。尽管Phormidesmispriestleyi的宏基因组组装基因组，负责形成北极冰冻岩的蓝细菌具有高覆盖率，其MAG中没有多种维生素和辅因子生物合成的证据。我们的结果表明，交叉摄食可能会在粒状低温球岩中维持P.priestleyi。一起来看,基因组解析宏基因组学揭示了冰川相关微生物群通过北极快速变暖对冰川栖息地缺失的脆弱性。
