Predicting the impact of climate change on the glacier-fed streams microbiome

Glacier shrinkage is among the most conspicuous impacts of climate change with numerous effects on downstream ecosystems. Lying at the glacier forefront, glacier-fed streams represent important headwaters in high-mountain regions across the world. Owing to climate change, the latter are predicted to undergo major physical and chemical modifications as the glaciers recede, potentially inducing important ecological shifts. In the glacier-fed streams ecosystem, bacteria play a key role, forming biofilms along with eukaryotic algae in the sediments, and driving biogeochemical fluxes of global relevance. However, little is known about the glacier-fed stream microbiome and how climate change will impact it. To unravel and understand the glacier-fed stream ecosystem, the Vanishing Glaciers Project aims at characterising its global microbiome by sequencing metagenomes, coupled with glaciological and biogeochemical parameters measurements. To predict the impact of climate change on the glacier-fed streams microbiome, we will characterise the geophysical parameters affecting the distribution of bacterial amplicon sequence variants using a species distribution modelling approach. Using climatic, glaciological and biogeochemical parameters, we will model the abundance of the most prevalent amplicon sequence variants at a global scale. We will then leverage glaciological and climatic future scenarios of climate change to model the evolution of biogeochemical parameters and how they will be impacted. Importantly, this approach will allow us to project the species distribution models onto these future scenarios to predict how key bacterial taxa and lineages will be affected by climate change.