894 / 2024-09-19 18:33:35

Biogeochemical-Argo floats reveal seasonality of the biological carbon pump influenced by the Lofoten Basin Eddy

Biogeochemical Argo Floats,Biological carbon pump,particulate organic carbon

The Lofoten Basin Eddy (LBE) is a persistent topographically constrained anticyclonic eddy in the Norwegian Sea. Considering its local, dynamically distinct state, we test the hypothesis that the LBE has distinct biogeochemical signatures. Using satellite observations and a 12-year Biogeochemical-Argo float record, we constructed a climatological view of the annual biogeochemical cycle within and surrounding the LBE. The biological carbon pump influenced by the LBE was less effective than surrounding waters, particularly during late spring. Particulate organic carbon export out of the productive zone was generally hindered year-round and likely associated with enhanced respiration and slower particle sinking speeds. Enhanced export into the twilight zone was observed and consistent with shoaling deep mixed layers in early spring, production of large particles in late summer, and subduction in late autumn; however, these mechanisms appear accompanied by enhanced remineralization within the LBE influence zone, highlighting the biogeochemical complexity of eddies. The persistent nature of the LBE, coupled with its influence on heterotrophic activity and particle sinking rates, suggests it plays an important role in the ocean-atmosphere carbon balance modulating regional ocean carbon sequestration dynamics in this Arctic marginal sea.