Zhao Rui-yi, Liang Zuo-bing, Wang Zun-bo, Yu Zheng-liang, Jiang Ze-li
Huan Jing Ke Xue. 2015 May;36(5):1598-604.
In order to identify the distinction of soil CO2 consumed by carbonate rock dissolution, Baishuwan spring, Lanhuagou spring and Hougou spring were selected as objects to monitor the hydrochemistry from November 2013 to May 2014. The results showed that the highest HCO3- concentration was observed in Baishuwan spring which is covered by pine forest, while the lowest HCO3- concentration was observed in Hougou spring which is mainly covered by cultivated land. In Baishuwan spring, HCO3- was mainly derived from carbonic acid dissolving carbonate rock and the molar ratio between Ca(2+) + Mg2+ and HCO3- was close to 0. 5; while the molar ratio between Ca(2+) + Mg2+ and HCO3- exceeded 0.5 because the carbonate rock in Lanhuagou spring and Hougou spring was mainly dissolved by nitric acid and sulfuric acid. Because of the input of litter and the fact that gas-permeability of soil was limited in Baishuwan spring catchment, most of soil CO2 was dissolved in infiltrated water and reacted with bedrock. However, in Lanhuagou spring catchment and Hougou spring catchment, porous soil made soil CO2 easier to return to the atmosphere in the form of soil respiration. Therefore, in order to accurately estimate karst carbon sink, it was required to clarify the distinction of CO2 consumption by carbonate rock dissolution under different land use and land cover areas.
为了确定碳酸盐岩溶解消耗的土壤二氧化碳的差异，选取了白水湾泉、兰花沟泉和后沟泉作为研究对象，于2013年11月至2014年5月对其水化学特征进行监测。结果表明，被松林覆盖的白水湾泉中HCO3-浓度最高，而主要被耕地覆盖的后沟泉中HCO3-浓度最低。在白水湾泉中，HCO3-主要来源于碳酸对碳酸盐岩的溶解，Ca(2+) + Mg2+与HCO3-的摩尔比接近0.5；而在兰花沟泉和后沟泉中，由于碳酸盐岩主要被硝酸和硫酸溶解，Ca(2+) + Mg2+与HCO3-的摩尔比超过了0.5。由于白水湾泉集水区有枯枝落叶输入且土壤透气性有限，大部分土壤二氧化碳溶解于渗入水中并与基岩发生反应。然而，在兰花沟泉集水区和后沟泉集水区，多孔土壤使土壤二氧化碳更易以土壤呼吸的形式返回大气。因此，为准确估算岩溶碳汇，需要明确不同土地利用和土地覆盖区域下碳酸盐岩溶解对二氧化碳消耗的差异。
