The Arctic is an area of growing strategic importance for European policy. As a consequence, there is an increasing need to estimate the impact that environmental change will have on the Arctic and our planet. Among the most critical, yet under-studied components of the Arctic cryosphere is seasonal snow. Next to the ocean, snow is the second largest interface between the atmosphere and the Earth’s surface during winter. Since snow on the land surface is thermodynamically unstable, it is in constant evolution due to metamorphism, whose rate is a function of temperature and the temperature gradient in the snow pack. As a result, snow, especially seasonal snow, is very sensitive to climate conditions and undergoes continuous modification in a changing environment. Despite the crucial role of snow for climatic, hydrological and biological processes, there are relatively few regular measurements of even the most basic snow parameters (e.g. snow thickness, snow density, temperature, snow hardness, the presence of ice layers) from the Arctic region in general and from Svalbard in particular. Even less is known about the biodiversity of the microbial communities inhabiting the snowpack and their biogeochemical processes in comparison with the rest of the terrestrial biosphere. In order determine the impact of climate change on terrestrial ecosystems, longer time series are needed that integrate different types of data (physical, chemical and biological). Many samples need to be collected, including precipitation sampling. The seasonal variability of snow also needs to be assessed in term of properties and length of the period between senescence and freezing (before/after the snow comes). With MicroLife2, we are proposing to provide such time series data through yearly sampling of snow in collaboration with NPI and onsite research staff. Using these samples, we will address a series of questions related to microbial ecology as well as adaptation to change. The knowledge of the relative importance of colonization processes, post-depositional selection, wintertime activity and microbial redistribution within snow packs is of crucial importance to understand biological activity in Arctic systems. Microorganisms in Arctic environments are still the unknown variable in the climate change equation.