Acta Geographica Sinica ›› 2006, Vol. 61 ›› Issue (7): 741-751.doi: 10.11821/xb200607008

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Phosphorus and Silicate Fluxes in the Yangtze River

SHEN Zhiliang   

  1. Key Laboratory of Marine Ecology and Environmental Science, Institute of Oceanology, CAS, Qingdao 266071, China
  • Received:2005-11-08 Revised:2006-03-29 Online:2006-07-25 Published:2010-09-06
  • Supported by:

    National Natural Science Foundation of China, No.50339040; Project of the Chinese Academy of Sciences, No.KZ952-S1-421; KZCX3-SW-232; Project of The State Council Three Gorges Project Construction Committee, No.SX2004-010

Abstract:

Systematic investigations in various forms of P and SiO3-Si in the Yangtze mainstream and major tributaries and lakes from the Jinshajiang River (a section in the upper Yangtze River) to the mouth were carried out from November to December, 1997 (dry season), and in August and October, 1998 (flood season). In the dry and flood seasons in the Yangtze mainstream, the variations in particulate P and total P concentrations were almost synchronous, which increased speedily in the upper reaches and then decreased with less variations in the middle and lower reaches, and the variations in dissolved P and SiO3-Si concentrations were little. The fluxes of various forms of P and SiO3-Si gradually increased from the river's upper reaches to the lower reaches. The fluxes of various forms of P and SiO3-Si in the dry season came mainly from the middle and lower reaches and over half of them were contributed by tributaries and lakes. Various forms of P and SiO3-Si in the flood season were mainly contributed by the mainstream except for tributaries in the upper reaches which contributed over half of the particulate P. The ratios of TPP in TP in the mainstream and tributaries were higher in the upper reaches than in the middle and lower, higher in the flood season than in the dry season and higher in the mainstream than in the tributaries, which were clearly relative with suspended matter content. The particulate P was the main contributor of P in the Yangtze River. In transport fluxes of dissolved P, DOP was slightly in dominance in the mainstream in the dry season, while organic P and inorganic P was 50% each in the tributaries. The transport fluxes of various forms of P and SiO3-Si and export fluxes of TP and PO4-P were mainly controlled by runoff, especially, it was more obvious than P that SiO3-Si flux increased with runoff. The transport equations of various forms of P and SiO3-Si and export fluxes equations of TP and PO4-P are suggested in this paper.

Key words: phosphorus, silicate, runoff amount, transport flux, Yangtze River