Sinking fluxes of Pb-210 and Po-210 in the deep basin of the northern South China Sea

摘要

Vertical fluxes of total mass (F-mass), particulate organic carbon (F-POC), particulate inorganic carbon (F-PIC), Pb-210 (FPb-210), and Po-210 (FPo-210) were determined by sediment traps deployed at two depths, 2000 m and 3500 m, at SEATS (South East Asian Time-series Study, 116 degrees 00 degrees E, 18 degrees 00 degrees N) in the northern South China Sea during June 2008-June 2009. The F-mass ranges from 12.2 to 55.1 mg m(-2) d(-1) and from 89.3 to 250.8 mg m(-2) d(-1), at 2000 m and 3500 m, respectively, and shows seasonal and inter-annul variation. The temporal variation of F-POC, F-PIC, and FPb-210 were in phase with the F-mass, which was coupled with the seasonal cycles of primary production in the euphotic layer. The FPb-210 ranges from 5 to 48 dpm m(-2)d(-1) and from 38 to 105 dpm m(-2)d(-1), at 2000 m and 3500 m, respectively.Episodic events of the settling of biological particles from the surface layer and the regeneration processes the deep layer control the Po-210 removal in the water column of the South China Sea. Strong correlations of the flux and source ratio of Pb-210, (F/P)(Pb-210), and the particulate carbon fluxes were found, which give relationships of F-POC (mu g cm(-2)y(-1)) = 26.8 + 371.0 (F/P)(Pb-210) and F-PIC (mu g cm(-2)y(-1)) = -1.4 + 533.1 (F/P)(Pb-210). (C) 2016 Elsevier Ltd. All rights reserved.