ena-STUDY-Stazione Zoologica Anton Dohrn-26-08-2021-16:35:41:678-1392
Bacteria and Archaea from Arctic sea ice collected during the N-ICE2015 expedition
The Arctic is warming 2-3 times faster than the global average, leading to a decrease in Arctic sea ice extent, thickness, and associated changes in sea ice structure. These physical changes impact sea ice habitat properties and the ice-associated ecosystems, including the timing, magnitude, and composition of the sea ice algae blooms. These blooms provide a plethora of algal derived carbon sources and thereby fuel the bacterial and archaeal communities within the sea ice. Here we detail the transition of these communities in Arctic sea ice from winter through spring to early summer during the Norwegian young sea ICE (N-ICE2015) expedition in the Arctic sea ice pack north of Svalbard, Norway. The winter community was dominated by amplicon sequence variants of the Candidatus Nitrosopumilus and Gammaproteobacteria (Colvellia, Kangiellaceae, Nitrinocolaceae), indicating that sulfur- and nitrogen based metabolisms are more prevalent. Particularly ammonia oxidation to nitrate by Cand. Nitrosopumilus and subsequent nitrification replenishing the nitrate pool for sea-ice algal spring blooms. At the onset of the vernal sea-ice algae bloom the community shifted to a dominance of Gammaproteobacteria (Kangiellaceae, Nitrinocolaceae ) and Bacteroidia (Polaribacter), as is commonly observed at lower latitudes during phytoplankton spring blooms, while Cand. Nitrosopumilus vanished. The PiCRUST predicted carbohydrate-active enzymes increased during spring and summer, as compared to winter, indicating that sea-ice algae derived carbon sources are a strong driver of bacterial and archaeal community succession in Arctic sea ice during the change of season. This implies an annual succession from a metabolically diverse winter community to a algal derived carbon sources based spring/ summer community.
The Arctic is warming 2-3 times faster than the global average, leading to a decrease in Arctic sea ice extent, thickness, and associated changes in sea ice structure. These physical changes impact sea ice habitat properties and the ice-associated ecosystems, including the timing, magnitude, and composition of the sea ice algae blooms. These blooms provide a plethora of algal derived carbon sources and thereby fuel the bacterial and archaeal communities within the sea ice. Here we detail the transition of these communities in Arctic sea ice from winter through spring to early summer during the Norwegian young sea ICE (N-ICE2015) expedition in the Arctic sea ice pack north of Svalbard, Norway. The winter community was dominated by amplicon sequence variants of the Candidatus Nitrosopumilus and Gammaproteobacteria (Colvellia, Kangiellaceae, Nitrinocolaceae), indicating that sulfur- and nitrogen based metabolisms are more prevalent. Particularly ammonia oxidation to nitrate by Cand. Nitrosopumilus and subsequent nitrification replenishing the nitrate pool for sea-ice algal spring blooms. At the onset of the vernal sea-ice algae bloom the community shifted to a dominance of Gammaproteobacteria (Kangiellaceae, Nitrinocolaceae ) and Bacteroidia (Polaribacter), as is commonly observed at lower latitudes during phytoplankton spring blooms, while Cand. Nitrosopumilus vanished. The PiCRUST predicted carbohydrate-active enzymes increased during spring and summer, as compared to winter, indicating that sea-ice algae derived carbon sources are a strong driver of bacterial and archaeal community succession in Arctic sea ice during the change of season. This implies an annual succession from a metabolically diverse winter community to a algal derived carbon sources based spring/ summer community.