1018 / 2024-09-20 06:30:31

Sources and trajectories of sinking particles in the Chukchi Sea, Arctic

Neodymium,Arctic,Biological carbon pump,Sediment Trap,radiocarbon

To investigate the ocean carbon cycle and understand its dynamics in the rapidly changing Arctic Ocean, we examined the seasonal and interannual fluxes and compositions of sinking particle samples collected by sediment traps on the Chukchi Sea slope in the Pacific Arctic Ocean between August 2017 and August 2021. The sinking particle flux exhibited a distinct seasonal pattern, with a peak during the summer when primary production increased. Sudden increases of sinking particle fluxes were also observed in the winter despite its complete sea ice coverage. The interannual variability of sinking particles appear to be influenced by not only the sea ice concentration, but hydrological factors such as surface currents, shelf break upwelling, and the Beaufort Gyre. Among these, the Beaufort Gyre, which is modulated by the Arctic Oscillation seems the most significant factor affecting summer sinking particle fluxes. In addition, high lithogenic material content (accounted for 46% of the sinking particle) indicate substantial resuspension and/or lateral transport from nearby regions. We analyzed organic (radiocarbon) and inorganic (detrital neodymium isotopic) tracers and will discuss the origins and trajectories of sinking particles in the Arctic Ocean.