Oziel, L., Schourup-Kristensen, V., Wekerle, C., & Hauck, J. (2022). The Pan-Arctic Continental Slope as an Intensifying Conveyer Belt for Nutrients in the Central Arctic Ocean (1985–2015). Global Biogeochemical Cycles, 36(6), e2021GB007268. https://doi.org/10.1029/2021GB007268
Microscopic algae called phytoplankton are the base of the trophic chain, sustaining the entire Arctic Ocean (AO) ecosystem. In the central parts of the AO, multi-year sea-ice used to limit transmission of light in the surface ocean and therefore control phytoplankton growth and primary productivity. However, the massive loss in sea-ice during the last 3 decades allowed more and more light to penetrate the water column, making nutrient availability the main bottom-up control of the AO productivity. A major part of the bio-available nutrients reaching the surface in the central AO are transported with ocean currents from the adjacent North Atlantic and Pacific and from deeper water masses. Using a biogeochemical model resolving processes at high spatial resolution, we were able to quantify the different transport pathways of nutrients with ocean currents and revealed that despite increasing supply along the anticlockwise flowing boundary current, the central AO is still running into more severe nutrient limitation.
Policy relevant message:
The continental slope contributes to the transport of nutrients in the Arctic Ocean. Yet, despite an intensification of ocean dynamics, the Arctic Ocean is still shifting from a light-limited to a nutrient-limited system.