Spatially consistent microbial biomass and future cellular carbon release from melting Northern Hemisphere glacier surfaces

Melting glacier ice surfaces host active microbial communities that enhance glacial melt, contribute to biogeochemical cycling, and nourish downstream ecosystems; but these communities remain poorly characterised. This study shows regionally consistent mean microbial abundance of 10⁴ cells mL⁻¹ in surface meltwaters from ten glaciers across Europe, North America, and Greenland. Microbial abundance is correlated with suspended sediment concentration. The study forecasts that under a medium carbon emission scenario (RCP 4.5), the release of these microbes will deliver 2.9 × 10²² cells yr⁻¹ (0.65 million tonnes yr⁻¹ of cellular carbon) to downstream ecosystems over the next ~80 years.

Ian T. Stevens, Tristram D. L. Irvine-Fynn, Arwyn Edwards, Andrew C. Mitchell, Joseph M. Cook, Philip R. Porter, Tom O. Holt, Matthias Huss, Xavier Fettweis, Brian J. Moorman, Birgit Sattler, Andy J. Hodson