Summary
Snow covers about 35% of the Earth's surface during the year and represents one of the most important climatic and ecological systems. It is a transitory and climatically very sensitive ecosystem, which relates the atmosphere compartment with the soil or the underlying ice. Snow also represents an environment that allows the development of unique microbial communities, which actively participate in biogeochemical cycles and environmental dynamics. Mercury (Hg) can be emitted both by anthropogenic processes and from land surfaces through natural processes. Once emitted, due to its long atmospheric residence time, Hg can undergo long-range transport and arrive in remote regions such as the Arctic, where it is subsequently deposited. Atmospheric Hg is deposited onto the cryosphere (snow and ice-covered surfaces) as onto other surfaces. Many approaches to Hg remediation have been researched and tested. But all these techniques have serious side effects. Therefore, bioremediation is currently the most cost-effective and remarkably environmentally friendly technique for mercury pollution remediation. This technique is based on Hg-resistant bacteria that consists of a broad spectrum of gram-positive and gram-negative bacteria possessing a peculiar mechanism of countering and eventually converting Hg from highly toxic form to non-toxic form, and their population is proportional to the scale of Hg pollution at the site

Objectives
SNOW-BALL research proposal aims at evaluating Hg presence in the Arctic snow surface and the relative difference in Hg forms abundance. Related to this, the bacterial community composition and activity will be evaluated, using microscopy, DNA probe, and metagenomics analyses. Specific mer gene abundance will also be investigated. The final goal will be the isolation of promising bacterial strains and their genetic and metabolic characterization, which will be useful for future bioremediation action.
Sampling will be carried out in winter 2022 around the area of Kuujjuarapik (Québec, Canada) with the logistic support of the CEN WHAPMAGOOSTUI-KUUJJUARAPIK RESEARCH STATION.

Project Partners
• University of Lyon, Lyon, France