Rhizosphere Processes Group, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland.
Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland.
Microb Genom. 2024 Oct;10(10). doi: 10.1099/mgen.0.001301.
Climate warming has led to glacier retreat worldwide. Studies on the taxonomy and functions of glacier microbiomes help us better predict their response to glacier melting. Here, we used shotgun metagenomic sequencing to study the microbial functional potential in different cryospheric habitats, i.e. surface snow, supraglacial and subglacial sediments, subglacial ice, proglacial stream water and recently deglaciated soils. The functional gene structure varied greatly among habitats, especially for snow, which differed significantly from all other habitats. Differential abundance analysis revealed that genes related to stress responses (e.g. chaperones) were enriched in ice habitat, supporting the fact that glaciers are a harsh environment for microbes. The microbial metabolic capabilities related to carbon and nitrogen cycling vary among cryospheric habitats. Genes related to auxiliary activities were overrepresented in the subglacial sediment, suggesting a higher genetic potential for the degradation of recalcitrant carbon (e.g., lignin). As for nitrogen cycling, genes related to nitrogen fixation were more abundant in barren proglacial soils, possibly due to the presence of Cyanobacteriota in this habitat. Our results deepen our understanding of microbial processes in glacial ecosystems, which are vulnerable to ongoing global warming, and they have implications for downstream ecosystems.
气候变暖导致了全球范围内的冰川退缩。对冰川微生物组的分类学和功能研究有助于我们更好地预测它们对冰川融化的反应。在这里，我们使用高通量宏基因组测序来研究不同冰雪栖息地（即地表雪、冰上和冰下沉积物、冰下冰、冰川前缘溪流水和最近融化的土壤）中的微生物功能潜力。功能基因结构在栖息地之间差异很大，特别是雪，与所有其他栖息地有显著差异。差异丰度分析表明，与应激反应（如伴侣蛋白）相关的基因在冰生境中富集，这支持了冰川对微生物来说是一个恶劣环境的事实。与碳氮循环有关的微生物代谢能力在冰雪栖息地之间存在差异。辅助活性相关基因在冰下沉积物中过度表达，表明对难降解碳（如木质素）的降解具有更高的遗传潜力。至于氮循环，与固氮相关的基因在贫瘠的冰川前缘土壤中更为丰富，可能是由于该栖息地存在蓝藻。我们的研究结果加深了我们对冰川生态系统中微生物过程的理解，这些过程容易受到正在发生的全球变暖的影响，对下游生态系统也有影响。
