Journal of Geographical Sciences ›› 2008, Vol. 18 ›› Issue (3): 363-372.doi: 10.1007/s11442-008-0363-3

• Climate and Environmental Change • Previous Articles     Next Articles

Stable isotopic composition of riverine dissolved inorganic carbon of the Xijiang River Inner Estuary

JIAO Shulin1,2, TAO Zhen1, GAO Quanzhou1, LIU Kun1, SHE Jianwei1, DING Jian1, LIU Zufa1   

  1. 1. School of Geography and Planning, Sun Yat-sen University, Guangzhou 510275, China|
    2. School of Geography and Biology, Guizhou Normal University, Guiyang 550001, China
  • Received:2008-03-06 Revised:2008-06-10 Online:2008-09-25 Published:2010-09-18
  • Supported by:

    National Natural Science Foundation of China, No.40671027; No.40471120; Guangdong Provincial Natural Science Foundation, No.7003669; Specialized Research Fund for the Doctoral Program of Higher Education, No.20040558025; The Program for New Century Excellent Talents in University

Abstract:

For researching the spatio-temporal variation of the stable isotopic composition of the riverine dissolved inorganic carbon (DIC), we had carried out a survey throughout the hydrologic year during which the δ13CDIC of the surface water and its physicochemical pa-rameter were examined along the Xijiang River Inner Estuarine waterway from September 2006 to June 2007. There was a striking seasonal variation on the average δ13CDIC, as the average δ13CDIC in summer (?13.91‰) or autumn (?13.09‰) was much less than those in spring (?11.71‰) or winter (?12.26‰). The riverine δ13CDIC was controlled by decomposed condition of the riverine organic matter linking the seasonal variation of the physicochemical parameter in the surface water according to the correlation analysis which indicated notable relations between δ13CDIC and water temperature (p = 0.000; r = ?0.569) or between δ13CDIC and oxide-reduction potential (p = 0.000; r = 0.646). The striking positive correlation between δ13CDIC and the sampling distance happened in the summer rainy season, while striking negative correlation happened in the spring dry season, indicating that river-sea interaction influenced water physicochemical parameters and controlled the riverine DIC property in the survey waterway. In view of the riverine δ13CDIC decreasing for the decomposition of the ter-restrial organic matter in the rainy season in summer and increasing for the briny invaded zone extending in the spring dry season along the waterway from the Makou gauging station to the Modaomen outlet, the δ13CDIC spatio-temporal variation was closely related to the geographical environment of the Xijiang drainage basin.

Key words: Xijiang River Inner Estuary, dissolved inorganic carbon, stable isotopic carbon, spatio-temporal variation