Microbial dynamics in rapidly transforming Arctic proglacial landscapes

Abstract

Arctic glacial environments are rapidly changing, as the Arctic warms at a rate three to four times faster than the global average (the phenomenon known as Arctic amplification). Microorganisms are uniquely adapted to extreme glacial environments and studying how ecological and climatic feedback loops affect the diversity of these communities is crucial to the characterisation of vulnerable Arctic habitats. Glacial landscapes span a wide range of habitats, from glacier ice to marine waters, and encompass terrestrial, aquatic, and interzonal systems. While glacier shrinkage has been the focus of scientific attention, auxiliary habitats are also impacted by rapid glacier retreat. Auxiliary habitats include terrestrial systems, such as outwash plains, vegetated periglacial environments, and aquatic systems, such as glacier-fed streams, lakes, and glacier-adjacent marine environments. Glacier recession drives high-impact changes in glacier-associated habitats: rising temperatures, increased light penetration of glacial streams, changes in nitrogen-to-phosphate ratios, and increases in availability of glacier-derived organic compounds. In turn, microbial systems in these habitats may experience changes in nutrient dynamics and shifts in community structures. The exposure of new lands by retreating glaciers may also result in increased dust and microbial dispersal into the atmosphere. Here, we discuss the effects of climate change on glacial microbiomes and the feedback loops between microbial community dynamics and the large-scale climatic processes in the Arctic. We characterise aspects of vulnerable microbial ecosystems and highlight the importance of preserving unseen microbial biodiversity. We then outline current capacities for microbial conservation, focusing on cryopreservation and biobanking. Lastly, we suggest future research directions and steps that academic and governmental institutions may take to foster research and collaboration with Indigenous communities.