Diversity and biogeography of the bacterial microbiome in glacier-fed streams

Leïla Ezzat; Hannes Peter; Massimo Bourquin; Susheel Bhanu Busi; Grégoire Michoud; Stilianos Fodelianakis; Tyler J Kohler; Thomas Lamy; Aileen Geers; Paraskevi Pramateftaki; Florian Baier; Ramona Marasco; Daniele Daffonchio; Nicola Deluigi; Paul Wilmes; Michail Styllas; Martina Schön; Matteo Tolosano; Vincent De Staercke; Tom J Battin

doi:10.1038/s41586-024-08313-z

Diversity and biogeography of the bacterial microbiome in glacier-fed streams

Nature. 2025 Jan 1. doi: 10.1038/s41586-024-08313-z. Online ahead of print.

Authors

Leïla Ezzat^{1

2}, Hannes Peter³, Massimo Bourquin³, Susheel Bhanu Busi^{4

5}, Grégoire Michoud³, Stilianos Fodelianakis³, Tyler J Kohler^{3

6}, Thomas Lamy⁷, Aileen Geers³, Paraskevi Pramateftaki³, Florian Baier³, Ramona Marasco⁸, Daniele Daffonchio⁸, Nicola Deluigi³, Paul Wilmes⁵, Michail Styllas^{3

9}, Martina Schön³, Matteo Tolosano³, Vincent De Staercke³, Tom J Battin¹⁰

Affiliations

¹ River Ecosystems Laboratory, Alpine and Polar Environmental Research Center, Ecole Polytechnique Fédérale de Lausanne, Sion, Switzerland. [email protected].
² MARBEC, University of Montpellier, CNRS, IFREMER, IRD, Montpellier, France. [email protected].
³ River Ecosystems Laboratory, Alpine and Polar Environmental Research Center, Ecole Polytechnique Fédérale de Lausanne, Sion, Switzerland.
⁴ UK Centre for Ecology and Hydrology, Wallingford, UK.
⁵ Systems Ecology Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg.
⁶ Department of Ecology, Faculty of Science, Charles University, Prague, Czechia.
⁷ MARBEC, University of Montpellier, CNRS, IFREMER, IRD, Montpellier, France.
⁸ Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia.
⁹ Institut de Physique du Globe de Paris, Paris, France.
¹⁰ River Ecosystems Laboratory, Alpine and Polar Environmental Research Center, Ecole Polytechnique Fédérale de Lausanne, Sion, Switzerland. [email protected].

PMID: 39743584
DOI: 10.1038/s41586-024-08313-z

Abstract

The rapid melting of mountain glaciers and the vanishing of their streams is emblematic of climate change^1,2. Glacier-fed streams (GFSs) are cold, oligotrophic and unstable ecosystems in which life is dominated by microbial biofilms^2,3. However, current knowledge on the GFS microbiome is scarce^4,5, 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.