Particulate organic carban fluxes from euphotic zone estimated with <sup>234</sup>Th deficiency in winters in the northwestern North Pacific Ocean

YANG Yong-liang; HAN Xu; KUSAKABE Masashi

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YANG Yong-liang, HAN Xu, KUSAKABE Masashi. Particulate organic carban fluxes from euphotic zone estimated with 234Th deficiency in winters in the northwestern North Pacific Ocean[J]. Haiyang Xuebao, 2005, 27(1): 84-92.

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YANG Yong-liang, HAN Xu, KUSAKABE Masashi. Particulate organic carban fluxes from euphotic zone estimated with ²³⁴Th deficiency in winters in the northwestern North Pacific Ocean[J]. Haiyang Xuebao, 2005, 27(1): 84-92.

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Particulate organic carban fluxes from euphotic zone estimated with ²³⁴Th deficiency in winters in the northwestern North Pacific Ocean

1.
National Research Center for Geoanalysis, Beijing 100037, China
2.
Department of Environmental Science, Ocean University of China, Qingdao 266071, China
3.
Nakaminato Laboratory, National Institute of Radiological Sciences, 3609 Isozakicho, Hitachinaka 311-1202, Japan;Japan Marine Science and Technology Center, 2-15 Natsushima-cho, Yokosuka 237-0061, Japan

Received Date: 2002-08-02
Rev Recd Date: 2003-11-06

Abstract

Abstract

Dissolved and particulate ²³⁴Th,particulate organic carbon (POC),particulate organic nitrogen (POC),and chlorophyll a concentrations in the upper 200 m of water columns from seven stations in the northw estern North Pacific Ocean were determined in the winter of 1997.The dissolved,particulate,and total ²³⁴Th activities (dissolved plus particulate) show a pronounced deficiency with respect to its parent ²³⁸U in the euphotic zone whereas the total ²³⁴Th shows near-equilibrium at the depth greater than 100 m.The ²³⁴Th data were used to derive the fluxes of particulate organic carbon and nitrogen output of the euphotic zone.The POC and PON fluxes range from 3.8 to 8.2 and 0.50 to 0.98 mmol/(m2·d),respectively,and are higher in the west region than in the east,and higher in the south than in the north.The co-influence of Kuroshio-Oyashio Currents with supply of substances from the coast area to the study area and the light condition are two factors determining the horizontal distribution of POC fluxes in winter.The depth distribution of the chlorophylla as well as the consistence of the ratio of POC to PON with the Redfield ratio suggest that phytoplankton is themain contributor to the export of POC in this area in winter.The POC fluxes in the northw estern North Pacific Ocean in winter are comparable to some areas in the world oceas in spring and summer seasons.
- ²³⁴Th,
- particulate organic carbon,
- particulate organicn itrogen,
- export production,
- northw estern North Pacific

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References(33)

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