Englacial Microbiota Emergence and Roles in Glacier Ecosystems

The project explores the dynamic life of microbes within glaciers, redefining them as living habitats rather than frozen repositories. Sequestering 70% of Earth's freshwater as ice, glaciers harbour vast, yet underexplored, microbial populations. Englacial microbial ecology remains poorly understood, relying on sparse ice-core samples. These snapshots lack spatial and temporal resolution, and are collected from the locations least likely to harbour active life, limiting insights. The project proposes a novel approach of shallow ice coring along glacier flowlines to study microbial dynamics across decadal to millennial timescales. Microbes within glaciers are not merely ancient and dormant but some show signs of activity in microhabitats such as brines or water films on ice-encased mineral surfaces. This challenges traditional assumptions of inactivity. With glaciers rapidly shrinking due to climate change, understanding their englacial ecosystems is urgent. The project aims to uncover the rules of microbial life in ice, offering transformative insights into the cryosphere’s ecological role. EMERGE will investigate englacial microbes (microorganisms embedded within glacier ice) to understand their ecological roles, biogeochemical processes, and biodiversity. We hypothesize that these microbes are active, influence glacier biogeochemistry, and contribute to the ecology of glacier surfaces. Our pilot studies revealed three critical insights which prompt this project. Firstly, we found englacial microbes significantly differ from snow and aeolian sources, with active microbial growth of emerging englacial microbes influencing glacier surface ecology. Secondly, there is evidence microbial communities change during englacial transit, suggesting post-depositional transformations. Thirdly, even in cold ice with no available liquid water, microbes exhibit signs of nitrate transformation indicating microbe-mediated processes are still active while buried in ice. Our approach involves sampling different isochrones (time-marked ice layers) within Svalbard's glaciers, using advanced molecular and isotopic methods, and linking microbial findings with glacial structure and dynamics. Our specific objectives are To access different stages of succession within englacial microbial communities by sampling different isochrones of ice To determine the activities and biogeochemical processes associated with englacial microbes by direct and isotopic methods To understand the variation in biodiversity, activities, and biogeochemical processes within glacial ice by linking spatial and structurally explicit sampling with mass balance and ice-flow models Fieldwork will span glaciers across Svalbard, capitalizing on the archipelago’s diverse glacial conditions and its accessibility. The project will employ cutting-edge lab techniques, including DNA and RNA sequencing, isotopic analysis and flow cytometry. By integrating microbial and environmental data with glacial flow models, the study aims to predict englacial microbial ecology and its response to rapid glacial loss due to climate change. Outputs will contribute to glaciology, microbiology, and conservation efforts. The study is particularly timely given the 2025 UN International Year of Glaciers' Preservation and the anticipated loss of glaciers due to climate change. Improving our understanding of englacial ecosystems is timely given their emerging roles in seeding other components of glacial ecosystems with vast numbers of microbes and as an unappreciated locus of slow but cumulative microbial processes. Our project offers a unique opportunity to study these ecosystems before they are lost.