Export flux of POC in the main stream of the Kuroshio

Abstract

Particulate organic carbon (POC) export fluxes were measured using both a drifting sediment trap and a 234Th approach (ratio of POC/234Th multiple 234Th flux) in the main steam of the Kuroshio in August, 2006. The POC fluxes measured by sediment traps and the 234Th approach at 65, 90, 120 and 140 m ranged from 20 to 54 mg m−2 d−1, and 26 to 67 mg m−2 d−1, respectively. The results show that using POC/234Th ratios in intermediate particles (10–53 μm) and sinking particles is more comparable to the POC flux measured by sediment traps. Therefore, the POC export fluxes within the euphotic zone estimated by sediment trap and 234Th approaches are complementary methods for measuring POC flux in the Kuroshio.