ZHANG Qianzhu1, TAO Zhen1, MA Zanwen1, TANG Wenkui1, XU Peng1, GAO Quanzhou1,2, LIN Youwen3
(1.Geography and Planning School of Sun Yat-Sen University, Guangdong Provincial Key Laboratory for Urbanization and Geo-simulation, Guangzhou 510275, China;
2. Key Laboratory of Mineral Resource & Geological Processes of Guangdong Province, Guangzhou 510275, China;
3.Hydrology and Water Resources Survey Bureau of Hainan Province, Haikou 570203, China)
Abstract: On the basis of chemical compositions of the Changhuajiang River in Hainan Island investigated in January 2014, sources and controlling factors were studied, the output processes of HCO3- and DSi were evaluated, and the eco-environmental mass balance and its correlation were also analyzed. Results show that water from the Changhuajiang River presents gentle to middle alkalinities. The compositions of chemical runoff were dominated by HCO3- in anions and Ca2+ and Na+ in cations. In chemical runoff, 77.30% of ions originated from the silicate chemical weathering, and those from the carbonates chemical weathering accounted for 1.38%. The atmospheric precipitation contributed 5.45%. Additionally, 15.90% and 21.04% of chemical runoff components stemmed from human activities in trunk stream and tributaries, respectively, with a significantly difference (P<0.01). The chemical compositions of the Changhuajiang River are mainly controlled by the terrain, lithology and runoff depth. The Changhuajiang River had transported about 2.12×108 mol of HCO3- and 1.38×108 mol of DSi into the South China Sea during a dry season, which constituted one of the main material sources for primary productivity in marine ecosystems and could not be ignored on matter cycle budget.
Keywords: chemical weathering; dissolved silica; Hainan Island
EARTH AND ENVIRONMENT Vol. 43, No.6 Tot No.308, 2015, Page 589-599
