Carbon enters deep Arctic Ocean mainly from continent edges
Scientists predict that the consequences of human-induced climate change will be greatly amplified in the Arctic, both on the surrounding continents and in the ocean. Changes in nutrient supply and diminishing sea ice extent have the potential to alter primary production, ecological structure, and carbon cycling in the Arctic Ocean. Currently, little information exists on carbon export and associated biogeochemical processes in the central Arctic Ocean, hindering predictions of how this system will respond to change. To address this knowledge gap, Hwang et al. analyze organic matter on particles settling out from the waters within the Arctic Ocean above the Canada Abyssal Plain. They find strikingly old radiocarbon ages (averaging about 1900 years) for the organic carbon. This, along with a spike in abundances of sediment from continental sources rather than deep-sea sources, suggests that the majority of the particulate organic carbon entering the deep Canada Basin is supplied from surrounding continental margins.