粤东五华河流域的化学风化与CO_2吸收

Chemical weathering and CO_2 consumption in the Wuhua River basin,eastern Guangdong Province

基于对粤东五华河干流和支流水体的物理、化学组成测试数据,应用质量平衡法和相关分析法探讨湿热山地丘陵地区岩石化学风化过程对大气CO2的吸收.结果表明:五华河水体的总溶解性固体含量(77.11 mg/L)接近于世界河流的平均值(65 mg/L);离子组成以Ca2+、Na+和HCO3-为主,可溶性Si次之.五华河流域化学径流组成主要源自硅酸盐矿物化学风化过程的贡献,碳酸盐矿物的贡献较少;大气和土壤CO2是流域内岩石化学风化的主要侵蚀介质.与同一气候带其他河流相比较,五华河流域岩石化学风化过程对大气CO2的吸收通量(2.14×105mol/(km2.a))较低,这主要是由于流域内缺乏碳酸盐岩所导致.

Measurements of physicochemical components in the mainstream and tributaries of the Wuhua River system and applica- tion of methocls of mass-balance and Pearson correlation analysis were conducted to investigate the atmospheric CO2 consumption caused by rocks chemical weathering processes in the subtropical humid mountainous and hill region. Results show that the average concentration （77.11 mg/L） of the total dissolved solids within the Wuhua River was close to that （65 mg/L） in the world rivers, dominated by ions of Ca2 ＋ , Na ＋ and HCO3 and followed by dissolved Si ; ions of Ca2 ＋ , Na ＋ and HCO3- were characterized by the effect of runoff dilution. Chemical runoff in the Wuhua River was dominated by silicate mineral weathering, followed by carbon- ate mineral. Atmospheric and soil CO2 were major erosive mediums during rocks chemical weathering in the basin, with acids pre- cipitation as the secondary erosive mediums. Comparatively, the atmospheric CO2 consumption flux （2.14 × 105 tool/（ km2 · a） ） by the rock chemical weathering processes in the Wuhua River basin is lower than that of the world. This is in agreement with the distribution of extensively rocks composed of silicate minerals, sparselv rock eontaining carbonate minerals.