贵州典型岩溶流域水循环驱动的岩溶碳汇通量及其主控因素分析

利用高分辨率水文水化学自动记录仪,对地处湿润亚热带季风气候条件下的贵州省黔南峰丛洼地区的板寨和黄后,以及位于黔中高原面上丘原区的后寨3个岩溶流域进行了为期6年半(2007年5月至2013年10月)的连续监测。结合流域出口水中主要化学组分的野外滴定与室内分析实验,建立了水中碳酸氢根、钙和镁等主要离子与电导率之间的线性相关关系,进而获得了高时间分辨率的水中CO_2分压、方解石饱和指数和岩溶碳汇通量等指标。数据统计分析发现:(1)板寨、黄后和后寨岩溶流域的多年平均岩溶碳汇通量分别为29、33和39 t-CO_2km~(-2)·a~(-1);(2)岩溶流域出口水中碳酸氢根离子具有化学稳定性行为,流量是流域岩溶碳汇通量的主控因子。

Karst Related Carbon Sink Flux Driven by Water Cycle in Typical Karst Catchments of Guizhou Province and Its Main Controlling Factors

Hydrological and Hydrochemical variations of the three karst catchments, Banzhai, Huanghou(both in peak-cluster depression region) and Houzhai(in plateau hilly region) with similar subtropical monsoonal climate in South Guizhou Province were monitored with high-resolution hydrological and hydrochemical automatic data loggers during the period of May 2007-October 2013.Linear correlations between bicarbonate, calcium and magnesium concentrations with electrical conductivity were established with titration in field and chemical analysis in laboratory of major components of discharge waters. The continuous data of CO₂ partial pressure, calcite saturation index and karst related carbon sink were therefore calculated. Statistical analyses show that the annual average karst related carbon sink fluxes in Banzhai, Huanghou and Houzhai karst catchments were 29, 33 and 39 t-CO₂ km^-2a^-1, respectively. There is a chemostatic behavior of bicarbonate ion in the catchments. Runoff(karst river discharge) plays a key role in controlling the karst related carbon sink flux.