Products of 10S-DOX-like lipoxygenase and fatty acid cis-trans isomerase activity of bacteria attached to ice algae have been previously proposed as potential biomarkers of ice biota contribution to the seafloor in Arctic. To date, neither the bacteria at the origin of such enzymatic activities or the detection of these potential biomarkers at their supposed production-location have been elucidated. Herein, we determined and compared the diversity of bacterial communities attached to sea ice algae and under ice sinking particles during an early stage of ice melt in Baffin Bay (Canadian Arctic).