Slowly sinking particles underlie dissolved iron transport across the Pacific Ocean

Observational data suggest that basin-scale transport of sedimentary sourced Fe accompanies the ventilation of the intermediate layer in the North Pacific. Here we use a marine biogeochemical model to explore the Fe transport mechanism with a focus on the role of sinking particles.

The lateral penetration of sedimentary sourced Fe was best simulated when we assumed a short desorption and disaggregation length scale of Fe from sinking particles. The simulation results indicated that Fe is laterally transported mainly through interactions with particles with sinking velocities of 180-460 m yr(-1); these velocities are two orders of magnitude slower than typical sinking rates of marine aggregates determined from mass flux measurements.