Sinking fluxes of210Pb and210Po in the deep basin of the northern South China Sea.
Vertical fluxes of total mass (Fmass), particulate organic carbon (FPOC), particulate inorganic carbon (FPIC),210Pb (FPb-210), and210Po (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°00°E, 18°00°N) in the northern South China Sea during June 2008-June 2009. The Fmassranges from 12.2 to 55.1 mg m-2d-1and from 89.3 to 250.8 mg m-2d-1, at 2000 m and 3500 m, respectively, and shows seasonal and inter-annul variation. The temporal variation of FPOC, FPIC, and FPb-210were in phase with the Fmass, which was coupled with the seasonal cycles of primary production in the euphotic layer. The FPb-210ranges from 5 to 48 dpm m-2d-1and from 38 to 105 dpm m-2d-1, at 2000 m and 3500 m, respectively. Contrasting with210Pb, the FPo-210shows poor correlation with Fmass. The FPo-210ranges from 3 to 146 dpm m-2d-1and from 50 to 309 dpm m-2d-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 the210Po removal in the water column of the South China Sea. Strong correlations of the flux and source ratio of210Pb, (F/P)Pb-210, and the particulate carbon fluxes were found, which give relationships of FPOC(μg cm-2y-1) = 26.8 + 371.0 (F/P)Pb-210and FPIC(μg cm-2y-1) = -1.4 + 533.1 (F/P)Pb-210.
Institute of Oceanography, National Taiwan University, PO Box 23-13, Taipei 106, Taiwan. Electronic address: weic@ntu.edu.tw.
Ching-Ling
CL
Wei
Institute of Oceanography, National Taiwan University, PO Box 23-13, Taipei 106, Taiwan.
Chao-Yuan
CY
Chia
Institute of Marine Environmental Chemistry and Ecology, National Taiwan Ocean University, Keelung, Taiwan.
Wen-Chen
WC
Chou
Institute of Oceanography, National Taiwan University, PO Box 23-13, Taipei 106, Taiwan.
Wen-Huei
WH
Lee
D002681:China; D007856:Lead Radioisotopes / Q000032:analysis*; D011059:Polonium / Q000032:analysis*; D011834:Radiation Monitoring; D012623:Seawater / Q000737:chemistry*; D014875:Water Pollutants, Radioactive / Q000032:analysis*
D007856:Lead Radioisotopes; D014875:Water Pollutants, Radioactive; D011059:Polonium
(210)Pb; (210)Po; PIC flux; POC flux; Sediment trap; South China Sea