Ezzat Leïla, Peter Hannes, Bourquin Massimo, Busi Susheel Bhanu, Michoud Grégoire, Fodelianakis Stilianos, Kohler Tyler J, Lamy Thomas, Geers Aileen, Pramateftaki Paraskevi, Baier Florian, Marasco Ramona, Daffonchio Daniele, Deluigi Nicola, Wilmes Paul, Styllas Michail, Schön Martina, Tolosano Matteo, De Staercke Vincent, Battin Tom J
River Ecosystems Laboratory, Alpine and Polar Environmental Research Center, Ecole Polytechnique Fédérale de Lausanne, Sion, Switzerland.
MARBEC, University of Montpellier, CNRS, IFREMER, IRD, Montpellier, France.
Nature. 2025 Jan;637(8046):622-630. doi: 10.1038/s41586-024-08313-z. Epub 2025 Jan 1.
The rapid melting of mountain glaciers and the vanishing of their streams is emblematic of climate change. Glacier-fed streams (GFSs) are cold, oligotrophic and unstable ecosystems in which life is dominated by microbial biofilms. However, current knowledge on the GFS microbiome is scarce, precluding an understanding of its response to glacier shrinkage. Here, by leveraging metabarcoding and metagenomics, we provide a comprehensive survey of bacteria in the benthic microbiome across 152 GFSs draining the Earth's major mountain ranges. We find that the GFS bacterial microbiome is taxonomically and functionally distinct from other cryospheric microbiomes. GFS bacteria are diverse, with more than half being specific to a given mountain range, some unique to single GFSs and a few cosmopolitan and abundant. We show how geographic isolation and environmental selection shape their biogeography, which is characterized by distinct compositional patterns between mountain ranges and hemispheres. Phylogenetic analyses furthermore uncovered microdiverse clades resulting from environmental selection, probably promoting functional resilience and contributing to GFS bacterial biodiversity and biogeography. Climate-induced glacier shrinkage puts this unique microbiome at risk. Our study provides a global reference for future climate-change microbiology studies on the vanishing GFS ecosystem.
山区冰川的快速融化及其溪流的消失是气候变化的象征。冰川补给溪流（GFSs）是寒冷、贫营养且不稳定的生态系统，其中微生物生物膜主导着生命活动。然而，目前关于GFS微生物群落的知识匮乏，这妨碍了我们对其对冰川萎缩反应的理解。在此，通过利用宏条形码和宏基因组学，我们对来自地球上主要山脉的152条GFSs的底栖微生物群落中的细菌进行了全面调查。我们发现，GFS细菌微生物群落在分类学和功能上与其他冰冻圈微生物群落不同。GFS细菌种类多样，超过一半的种类特定于某一山脉，有些仅存在于单个GFSs中，还有一些是世界性且数量丰富的。我们展示了地理隔离和环境选择如何塑造它们的生物地理学，其特征是山脉和半球之间存在明显的组成模式。系统发育分析进一步揭示了由环境选择导致的微观多样化进化枝，这可能促进了功能恢复力，并对GFS细菌的生物多样性和生物地理学有所贡献。气候导致的冰川萎缩使这个独特的微生物群落面临风险。我们的研究为未来关于正在消失的GFS生态系统的气候变化微生物学研究提供了全球参考。
