机构地区：[1]中国地质科学院岩溶地质研究所,广西桂林541004 [2]自然资源部、广西岩溶动力学重点实验室/联合国教科文组织国际岩溶研究中心,广西桂林541004 [3]斯洛文尼亚科学与艺术院岩溶研究所,斯洛文尼亚波斯托尼亚SI-6230 [4]塞尔维亚贝尔格莱德大学水文地质系岩溶水文地质中心,塞尔维亚贝尔格兰德Djusina 7
出 处：《地球学报》2025年第2期397-408,共12页Acta Geoscientica Sinica
基 金：国家重点研发计划项目(编号:2020YFE0204700);国家自然科学基金项目(编号:42261144672);中国地质调查局地质调查项目(编号:DD20230547,DD20240095)联合资助。
摘 要：土壤CO_(2)是岩溶作用的核心驱动因子,也是研究土壤呼吸及其与大气CO_(2)源汇关系的核心指标。快速的岩溶动力学和碳循环过程及其对生态系统的敏感性,暗示其在现今全球碳循环中仍在发挥积极作用。本文以斯洛文尼亚第纳尔岩溶区典型草地土壤生态系统为例,开展不同深度土壤温度、水分和土壤CO_(2)含量等指标高分辨率在线监测。监测工作在2021年6—9月草地生长季进行,每10 min记录一组数据。结果表明,土下20 cm、30 cm和50 cm土温均值分别为19.69℃、18.54℃和17.42℃,暗示土温随深度增加逐渐变小。土下20 cm、30 cm和50 cm水分含量均值分别为23.2%、21.7%和24.9%。土壤水分变化主要受降雨控制,降雨强度越大,水分上升幅度越大。土下20 cm、30 cm和50 cm土壤CO_(2)变化范围分别为(1884~6705)×10^(–6)、(2088~5516)×10^(–6)、(2771~3606)×10^(–6),均值分别为3578×10^(–6)、3468×10^(–6)、3174×10^(–6)。无雨期间土壤水分显示出白天下降,夜晚基本保持不变的阶梯状下降趋势,受土壤水分控制,土壤CO_(2)多日总体变化呈现锯齿状持续降低趋势。不同降雨条件下均出现土壤CO_(2)向下迁移现象,从强降雨过程初期产生的土壤CO_(2)含量快速下降看,表明雨水入渗产生的脉冲效应导致CO_(2)快速向下迁移,进一步进入下伏岩溶含水层,可为碳酸盐岩溶蚀提供CO_(2)驱动力,比较下降幅度与雨前CO_(2)含量,暗示降雨过程中12%~33%的土壤CO_(2)进入岩溶含水层并参与碳酸盐岩溶蚀。监测结果暗示岩溶作用是陆地生态系统碳循环的横向延伸,具有土壤CO_(2)汇效应,也就是说,岩溶作用过程具有缓解土壤CO_(2)向大气释放功能,即减源效应。因此,在研究岩溶区碳循环及其碳汇效应时,应把植被-土壤-碳酸盐岩溶蚀作为一个整体,从岩溶关键带角度,系统开展监测与研究,以期获得岩溶区碳循环过程的完整认识,揭示其碳�Soil CO_(2) is a critical driving factor for karst processes and the core index for studying soil respiration and its relationship with atmospheric CO_(2) source-sink.The rapid dissolution kinetics of karst carbon cycle and its sensitivity to ecosystem suggest that karst carbon cycle is still playing an active role in the global carbon cycle.Taking the typical grassland soil ecosystem in Dinar karst,Slovenia as an example,high-resolution online monitoring of soil temperature,water content and soil CO_(2) concentration at different depths was carried out during the growing season from June to September in year 2021,the data were recorded in 10-minute time interval.Results showed that mean soil temperatures at depths of 20 cm,30 cm and 50 cm are 19.69℃,18.54℃and 17.42℃respectively,implying soil temperature decreases gradually with increase of soil depth.Mean soil water contents at depths of 20 cm,30 cm and 50 cm were 23.2%,21.7%and 24.9%respectively.Soil moisture mainly was controlled by precipitation,i.e.the greater the rainfall intensity,the larger the moisture rises.The ranges of soil CO_(2) concentrations at depths of 20 cm,30 cm and 50 cm were(1884–6705)×10^(–6),(2088–5516)×10^(–6) and(2771–3606)×10^(–6) respectively,with mean value of 3578×10^(–6),3468×10^(–6) and 3174×10^(–6) respectively.During the no-rain days,soil moisture presented a tendency of stair-stepped down,with decrease in day time and basically remain unchanged at night,and controlled by soil moisture,the multi-day changes of soil CO_(2) showed a jagged falling constantly.The downward movement of soil CO_(2) was observed during different rainfall conditions.Specifically,the soil CO_(2) concentration decreased rapidly at the early stage of storm events,suggesting that the pulse effect caused by rainfall infiltration is the main controlling factor to push CO_(2) move downward into the underlying karst aquifer furtherly,thus providing a critical driving force for carbonate rock dissolution.The value difference of CO_(2
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