论文部分内容阅读
对乌江上游支流花溪河水进行了一年的监测,测定了DIC含量和δ13 CDIC。结果显示DIC含量在1.73～4.53mmol/L之间,δ13 CDIC的变化范围-9.6‰～-3.6‰,反映了碳酸盐岩的主要控制作用,δ13 CDIC和DIC含量之间存在负相关关系,表明有机质分解作用、生物作用对河水DIC也有着重要影响。冬季河水主要来自花溪水库,水体与大气CO2同位素平衡时间较长,加之少量地下水直接的补给使河水具有一年中较高δ13 CDIC和DIC含量。春季光合作用增强,δ13 CDIC达到一年中最高,DIC含量下降。夏季水体DIC库受有机质分解作用控制,δ13 CDIC达到一年中的最低值,由于雨水的稀释作用使得DIC含量处于一年中较低水平。在夏季晚期光合作用和CO2的逃逸使得δ13 CDIC升高变化但DIC含量下降。秋季有机质的降解导致δ13 CDIC的负向变化,同时伴随DIC含量的升高。
A year-long monitoring of the Huaxi River, an upstream tributary of the Wujiang River, measured DIC content and δ13 CDIC. The results showed that the content of DIC was between 1.73 and 4.53 mmol / L and the δ13 CDIC ranged between -9.6 ‰ and -3.6 ‰, reflecting the main controlling role of carbonate rock. There was a negative correlation between δ13 CDIC and DIC content, It shows that the decomposition of organic matter and biological action have an important influence on DIC of river water. The winter river water comes mainly from Huaxi Reservoir. The CO2 isotope balance between water and atmosphere is longer, and a small amount of groundwater directly replenishes the river water with higher δ13 CDIC and DIC content in one year. Spring photosynthesis increased, δ13 CDIC reached the highest in one year, DIC decreased. In summer, the DIC pool was controlled by the decomposition of organic matter, and the δ13 CDIC reached the lowest value of the year. Due to the dilution effect of rainwater, the DIC content was at a lower level in one year. In the late summer, photosynthesis and CO2 escape led to elevated δ13 CDIC but decreased DIC content. The degradation of organic matter in autumn led to the negative change of δ13 CDIC accompanied by the increase of DIC content.