中文摘要：

以桂林毛村地下河为对象,研究了外源水对岩溶碳汇的影响。观测计算结果表明：外源水进入岩溶区后,由于内外源水相互混合,提高了岩溶水的溶蚀能力,以致DIC含量不断升高,其碳酸盐饱和指数也逐渐增加,SIc由不饱和达到饱和,增加了岩溶碳汇的通量。2010年9月至2011年3月仅以位于地下河上游的小龙背的外源水补给量和地下河出口的HCO3-浓度进行计算,岩溶碳汇通量由2.28×105 g增加至2.04×106 g,增加了近10倍。碳汇通量的增加固然与沿途大气降水、植被及土地利用等可能产生的CO2输入有关,但更与外源水加入形成的混合溶蚀作用有关。因此,在岩溶碳汇通量计算中外源水的影响作用不容忽视。

英文摘要：

Based on the field monitoring and theoretical calculation,this research studied the influence of allogenic water on karst carbon sink flux in the Maocun Subterranean Stream in Guilin.The results showed that（1） entered into karst area,allogenic water mixed with autogenic water,which enhanced karst water corrosion,increased DIC concentration and carbonate saturation index gradually,changed SIc from unsaturated into saturated and increased the karst carbon sink flux;（2）during September 7,2010 to March 26,2011,the carbon sink flux increased about 10 times（from 2.28×105 g to 2.04×106 g）,calculated only with the allogenic water recharge of Xiao Long Bei in the upstream and the HCO-3 concentration of outlet water of underground river;（3） the increase of carbon sink flux have some connection with potential CO2 input due to precipitation,vegetation and land-use types on the way,but have more to do with mixture corrosion of allogenic water.So,allogenic water takes an obvious contribution to karst carbon sink,and can’t be ignored in calculation of karst carbon sink.