Microbial Cell Retention in a Melting High Arctic Snowpack, Svalbard

While elution processes of ions and solutes from alpine and arctic snowpacks are well known, the scientific knowledge of the effects on microbial cells and their link to glacial surface ecology during this period is very limited. Here we show that dissolved substances are eluted from a High Arctic snowpack according to previous reports, while the microbial cells are retained and most likely also proliferate. Their retention enhances the interaction between the snowpack-derived microorganisms and microbial communities living on the surface of glaciers, a habitat known for its cell retention, especially those associated with debris known as cryoconite. Microbial biomass is retained during all stages of the summer ablation upon these Arctic glaciers, emphasizing the need to explore the feedback between microbial growth and meltwater biogeochemistry. Furthermore, the snowpack stratigraphy at Midtre Lovénbreen, Svalbard, shows a frequently low abundance of cells, typically corresponding to those of cloud water. However, a few layers show higher bacterial numbers (up to 104 cells mL-1) that occur with an increase of dust particles and most likely originate from local sources.