古里雅冰芯中生物有机酸的初步分析

Preliminary Analyses of Biogenic Organic Acids in Guliya Ice Core

甲酸、乙酸是全球对流层中普遍存在的化学成分，它们对偏远地区降水中的酸度有很大影响，降水中存在的甲酸、乙酸必然会在冰川和冰盖中保存下来．然而，目前很少有文章报道山地冰川中甲酸、乙酸的测定结果及环境意义．我们用离子色谱法测定了古里雅上部５ｍ冰芯中甲酸、乙酸的浓度，结果显示，甲酸、乙酸具有明显的季节变化，峰值一般对应于夏季层位，说明甲酸、乙酸的来源不同于阳离子，粉尘不是其主要来源．将甲酸、乙酸的记录与冰芯中δ１８Ｏ和阳离子的记录对比，得出甲酸具有较敏感的气候指示意义．

Formic and acetic acids are recognized as ubiquitous constituents of the global troposphere. They play an important role on the free acidity in remote regions precipitation. Therefore, ice core may record their changes. So far, some papers reported their changes in polar ice cores, however, few paper reports their concentrations in mountain glaciers. The concentration of formate and acetate in the upper 5 m Guliya ice core was measured using ion chromatography. The mean concentrations for formate and acetate are 20 μg/L, ranging from 0 to 130 μg/L, and 15 μg/L, ranging from 0 to 210 μg/L, respectively. Formate and acetate have distinct variations with peaks most in the summer layer. This indicates that their sources are different from that of Ca 2+ and Mg 2+ , and dust is not their major source. The formate record seems to be negatively correlated with the records of δ 18 O, Mg 2+ and Ca 2+ , but it does not hold for acetate. These results indicate that the formate record is more sensitive to temperature change. The difference between formate and acetate may result from the fact that formic acid is stronger than acetic acid.