Bio-SENTINEL – Using microBIOmes to help determine the impact of sea ice diSappearance on highEr North aTlaNtic climatE and biogeochemical cycLes

With Bio-SENTINEL, we propose to apply our cold environment metagenomic expertise developed over the last ten years to answering fundamental questions on the impact of sea ice disappearance on higher North Atlantic climate and biogeochemical cycles. We will focus on changes in the functional responses of microbial communities to organic pollutants and black carbon, as well as mercury contamination. We will also relate shifts in the abundance and diversity of microbial communities to marine ecosystem dynamics. This is the first time that metagenomics and microbial community analysis will be integrated into a research program that seeks to understand recent climate forcing and sea ice retreat in the Arctic. A key novelty will be the simultaneous analysis of mercury, bromine, stable isotopes, black carbon, organic pollutants and microbiology in ice cores drilled at Holtedahlfonna covering the satellite monitoring period (1970-present). Bio-SENTINEL will face several scientific and technological challenges related to data acquisition, including a field campaign to drill for ice cores and some methodological developments to extract sufficient microbial biomass for analysis. However, the success of this project will allow us to: develop a unique database on the microbiology of ice cores (eukaryotes and prokaryotes), in association to a detailed chemical characterization (mercury, black carbon and organic pollutants), link microbial community evolution to changes in climate and sea ice extent, obtain an over 70 year-long record of microbiomes in an Arctic ice core and develop and validate new biological markers of climate and biogeochemical processes.