title: Influence of a Decaying Cyclonic Eddy on Biogenic Silica and Particulate Organic Carbon in the Tropical South China Sea Based on 234Th-238U Disequilibrium.
abstract: Eddies play a critical role in regulating the biological pump by pumping new nutrients to the euphotic zone. However, the effects of cyclonic eddies on particle export are not well understood. Here, biogenic silica (BSi) and particulate organic carbon (POC) exports were examined inside and outside a decaying cyclonic eddy using 234Th-238U disequilibria in the tropical South China Sea. For the eddy and outside stations, the average concentrations of BSi in the euphotic zone were 0.17±0.09 μmol L-1 (mean±sd, n = 20) and 0.21±0.06 μmol L-1 (n = 34). The POC concentrations were 1.42±0.56 μmol L-1 (n = 34) and 1.30±0.46 μmol L-1 (n = 51). Both BSi and POC abundances did not show change at the 95% confidence level. Based on the 234Th-238U model, BSi export fluxes in the eddy averaged 0.18±0.15 mmol Si m-2 d-1, which was comparable with the 0.40±0.20 mmol Si m-2 d-1 outside the eddy. Similarly, the average POC export fluxes were 1.5±1.4 mmol C m-2 d-1 and 1.9±1.3 mmol C m-2 d-1 for the eddy and outside stations. From these results we concluded that cyclonic eddies in their decaying phase have little effect on the abundance and export of biogenic particles.
authors: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors: Weifeng
authors: W
authors: Yang
authors: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors: Min
authors: M
authors: Chen
authors: College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors: Minfang
authors: M
authors: Zheng
authors: College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors: Zhigang
authors: Z
authors: He
authors: College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors: Xinxing
authors: X
authors: Zhang
authors: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors: Yusheng
authors: Y
authors: Qiu
authors: College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors: Wangbin
authors: W
authors: Xu
authors: College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors: Lili
authors: L
authors: Ma
authors: College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors: Zhiyu
authors: Z
authors: Lin
authors: College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors: Wangjiang
authors: W
authors: Hu
authors: College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors: Jian
authors: J
authors: Zeng
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002681:China; D009930:Organic Chemicals / Q000737:chemistry; D012623:Seawater / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013910:Thorium / Q000032:analysis*; D014501:Uranium / Q000032:analysis*
chemical_list: D009930:Organic Chemicals; D014501:Uranium; D013910:Thorium; D002244:Carbon; D012822:Silicon Dioxide