Biogeochemical Influences on the Determination of Water Chemistry in a Temperate Forest Basin: Factors Determining the pH value
Biogeochemical Influences on the Determination of Water Chemistry in a Temperate Forest Basin: Factors Determining the pH value
复制标题
生物地球化学对温带森林盆地水化学测定的影响：决定 pH 值的因素
DOI：
10.1029/95wr02041
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发表时间：
1995
影响因子：
5.4
通讯作者：
Masakazu Suzuki
中科院分区：
文献类型：
--
作者：
N. Ohte;N. Tokuchi;Masakazu Suzuki
为了阐明日本温带森林流域的 pH 测定机制，1991 年和 1992 年进行了包括原位测量溶解 pCO2 在内的密集水化学观测。根据观测到的 pCO2 和 pH 的变化以及与水文过程相关的估计碱度，描述了决定 pH 的因素。有两种水文过程具有不同的决定性水化学过程：（1）降雨和径流到土层下渗到稳定地下水；（2）稳定地下水到泉水到溪流水。在第一个过程中，pH值受到从低pCO2层向高CO2层的渗透以及碱度增加的影响，这主要是由交换反应和化学风化引起的。在浅土层中，用于产生碱度的质子由降雨和渗透产生的酸沉积物、微生物产酸和二氧化碳溶解反应提供。在更深的层中，随着深度的增加，由Na + 的生成引起的碱度的增加变得显着。这个过程受到化学风化的强烈控制。在第二个过程中，pH 值随着泉点周围二氧化碳脱气而增加。碱度保持在与稳定地下水相同的水平。这些结果表明，土壤中生化提供的CO2不仅直接控制pH值的测定，而且作为pH值的另一个决定因素也影响碱度的产生。
In order to clarify the mechanism of pH determination in a temperate forest watershed in Japan, intensive hydrochemical observations that included in situ measurement of dissolved pCO2 were carried out in 1991 and 1992. From the variations of observed pCO2 and pH and estimated alkalinity associated with the hydrological process, the factors determining pH were described. There were two hydrological processes which have different determining hydrochemical processes: (1) rainfall and throughfall to infiltration in the soil layer to stable groundwater and (2) stable groundwater to spring water to stream water. In the first process, pH is influenced by infiltration from the low pCO2 layer to the high CO2 layer and by an increase of alkalinity, which is mainly caused by an exchange reaction and chemical weathering. In the shallow soil layer the protons for alkalinity generation are supplied by acid deposits from rainfall and throughfall, microbial acid production, and CO2 dissolution reaction. In the deeper layer an increase of alkalinity caused by Na+ generation becomes remarkable as depth increases. This process is strongly controlled by chemical weathering. In the second process, pH increases with CO2 degassing around the spring point. The alkalinity is kept at the same level as that of the stable groundwater. These results suggests that the biochemically supplied CO2 in soil not only directly controls the pH determination, but also has influences on the alkalinity generation as another determining factor of pH.