GEOGRAPHICAL RESEARCH ›› 2013, Vol. 32 ›› Issue (6): 1025-1032.doi: 10.11821/yj2013060006

• Article • Previous Articles     Next Articles

Hydrological characteristics and the atmospheric carbon sink in the chemical weathering processes of the Sanchahe watershed

JIAO Shulin1, LIU Li1, SUN Ting1, TIAN Qingying1, DING Rong2, XIANG Shang1, YE Meng1   

  1. 1. School of Geography and Environmental Science, Guizhou Normal University;Guiyang 550001, China;
    2. Liupanshui Hydrographic and Water Resources Survey Bureau;Liupanshui 553000, Guiyang, China
  • Received:2012-08-15 Revised:2013-03-25 Online:2013-06-10 Published:2013-06-10

Abstract: In a karstic drainage basin,the fluxes of the riverine dissolved inorganic carbon (DIC)implied the atmospheric CO2 consumption in the chemical weathering processes because of carbonate karst dissolution for the carbonic acid water closely related to the hydrological processes.In order to calculate the atmospheric carbon sink(ACS)on the riverine chemical runoff of the weathering processes and to understand the effects of the hydrologic processes on the carbon biogeochemical behaviors in the land surface processes, by the correlation analysis on the hydrological characteristics and its ACS,an investigation was carried out with a case study of the three hydrological cross-sections of the Sanchahe Watershed source area in which the karst landforms were widely developed.The results revealed that:(1)the intensity of annual atmospheric carbon sinks in chemical weathering processes of the Sanchahe Watershed was far greater than those of the non-karst granite basins because of the hot-humid environment of the subtropical karst basin during the studied hydrological year,in which the greatest part of the flux of the ACS occurred from June to November of the high-temperature and rainy monsoon with striking seasonal variation;(2) The correlation analysis demonstrated that there were distinct positive correlations between the basin ACS strength and basin temperature,precipitation,and runoff,while there was striking negative correlation between the basin ACS strength and riverine total dissolved solids concentration(TDS);(3)The variation of the DIC concentration indicated a significant dilution effect because of the high flow in the humid runoff period.The watershed ACS strength,which was closely related to the hydrological characteristics of a watershed, depended mainly on the TDS and DIC output loads instead of their concentrations.

Key words: Sanchahe Watershed, hydrologic characteristics, chemical weathering, atmospheric carbon sink(ACS), Wujiang River source area