| 岩溶关键带土壤—洞穴系统CO2运移的时空变化——以河南鸡冠洞为例 |
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| 引用本文： | 施晓,杨琰,李一冬,田宁,叶枝茂,李建仓,段军伟.岩溶关键带土壤—洞穴系统CO2运移的时空变化——以河南鸡冠洞为例[J].中国岩溶,2021,40(4):580-591. |
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| 作者姓名： | 施晓 杨琰 李一冬 田宁 叶枝茂 李建仓 段军伟 |
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| 作者单位： | 1.岩溶环境重庆市重点实验室,西南大学地理科学学院/重庆金佛山喀斯特生态系统国家野外科学观测研究站 |
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| 基金项目： | 国家自然科学基金项目（41877450；41672160） |
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| 摘 要： | 为了了解豫西鸡冠洞岩溶区不同尺度下水-土-气的中CO2的变化特征，探究CO2在岩溶关键带系统的运移关系，2019年5月至2020年10月，利用固态传感器对河南鸡冠洞上覆土壤取样点进行高时间分辨率监测，每隔15 min采集一次数据。结合每月采集洞内空气CO2浓度数据、每月测定洞穴水水化学指标数据及每月监测的降水、气温数据进行全面系统地分析。结果表明:①土壤CO2浓度、洞内空气CO2浓度和洞穴水水化学指标具有明显的季节性变化特征，均表现为夏秋高冬春低；②土壤CO2浓度在昼夜尺度下，白天高于夜晚，夏季的昼夜差值最大，冬季的昼夜差值最小，且昼夜变化滞后气温、土温变化约6 h；③洞内CO2浓度变化、洞穴水离子浓度和水化学指标在昼夜变化上具有同步性；④强降雨条件下（单场降雨量为42.2mm），土壤水分和土壤温度能及时响应降雨变化，而土壤CO2浓度对降雨的响应滞后2 h。洞穴水、洞穴CO2浓度对降雨的响应与土壤CO2具有相似性；⑤基于月均值的土壤CO2浓度与土壤温度、土壤湿度的相关系数分别为0.67、0.031。垂直方向上，CO2浓度变化依次为土壤>洞穴>空气。昼夜尺度上，土壤CO2浓度变化滞后于气温、土壤温度变化，其原因是受上覆植被光合作用强度影响。CO2在洞穴水运移中以脱气沉积为主，补给洞内空气CO2浓度。在强降雨过程中，土壤CO2浓度变化受控土壤的温度和湿度；而在更长时间尺度上，土壤CO2浓度变化更多地受土壤温度影响，土壤湿度对其影响较小。
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| 关 键 词： | 岩溶关键带 强降雨 土壤CO2浓度 土壤温度 鸡冠洞 |
Analysis of temporal and spatial variations of CO2 migration in the soil cave system in karst critical zone:A case study of Jiguan cave,western Henan |
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| SHI Xiao,YANG Yan,LI Yidong,TIAN Ning,Ye Zhimao,LI Jiancang,DUAN Junwei.Analysis of temporal and spatial variations of CO2 migration in the soil cave system in karst critical zone:A case study of Jiguan cave,western Henan[J].Carsologica Sinica,2021,40(4):580-591. |
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| Authors: | SHI Xiao YANG Yan LI Yidong TIAN Ning Ye Zhimao LI Jiancang DUAN Junwei |
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| Institution: | 1.Chongqing Key Laboratory of Karst Environment ， School of Geographical Sciences，Southwest University/Chongqing Jinfo Mountain Karst Ecosystem National Observation and Research Station2.Henan Jiguan Cave Tourism Development Co. ，Ltd |
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| Abstract: | In order to understand the characteristics of CO2 water-soil-gas at different scales in the karst area of Jiguan cave，western Henan，and to explore the relationship of CO2 migration in the karst critical zone system， we used the solid-state sensor method to monitor the change of overlying soil CO2 with high time resolution and collected the data every 15 minutes in Jiguan cave，Henan， from May 2019 to October 2020. Combined with monthly air CO2 data collected in the cave， the chemistry index of cave water， and monitoring data of rainfall and temperature for a systematic and comprehensive analysis，the result showed that，（1）The soil CO2 concentration，the air CO2 collected in the cave，and the chemistry index of cave water had obvious seasonal changes，all of which are high in summer and autumn and low in winter and spring.（2）On the day and night scale，the soil CO2 concentration during the day was higher than that at night.The difference between day and night was the largest in summer and the smallest in winter. The day and night change lagged behind air temperature and soil temperature by about 6 hours.The changes of air CO2 collected in the cave，the concentration of water ions in the cave ，and the chemistry index of cave water were synchronized in the day and night changes.（3）Under the scale of heavy rainfall（single rainfall was 42.2 mm），soil moisture and soil temperature can respond to rainfall changes in time，while the response of soil CO2 changes to rainfall lagged about 2 hours.Changes in cave water and cave CO2 were similar to changes in soil CO2.（4）The correlation coefficients of soil CO2，soil temperature and soil moisture based on monthly average values were 0.67and 0.031，respectively. In the vertical direction，the order of seasonal change of CO2 concentration was soil> cave> atmosphere. The lag of soil CO2 on air temperature and soil temperature day and night was affected by the photosynthesis intensity of the overlying vegetation. CO2 is mainly degassed and deposited in the cave water transportation，replenishing the air CO2 in the cave. During heavy rainfall，soil CO2 is controlled by soil temperature and humidity changes，but is more dominated by soil temperature on a long-term scale，with less soil moisture influences.In order to understand the characteristics of CO2 water-soil-gas at different scales in the karst area of Jiguan cave，western Henan，and to explore the relationship of CO2 migration in the karst critical zone system， we used the solid-state sensor method to monitor the change of overlying soil CO2 with high time resolution and collected the data every 15 minutes in Jiguan cave，Henan， from May 2019 to October 2020. Combined with monthly air CO2 data collected in the cave， the chemistry index of cave water， and monitoring data of rainfall and temperature for a systematic and comprehensive analysis，the result showed that，（1）The soil CO2 concentration，the air CO2 collected in the cave，and the chemistry index of cave water had obvious seasonal changes，all of which are high in summer and autumn and low in winter and spring.（2）On the day and night scale，the soil CO2 concentration during the day was higher than that at night.The difference between day and night was the largest in summer and the smallest in winter. The day and night change lagged behind air temperature and soil temperature by about 6 hours.The changes of air CO2 collected in the cave，the concentration of water ions in the cave ，and the chemistry index of cave water were synchronized in the day and night changes.（3）Under the scale of heavy rainfall（single rainfall was 42.2 mm），soil moisture and soil temperature can respond to rainfall changes in time，while the response of soil CO2 changes to rainfall lagged about 2 hours.Changes in cave water and cave CO2 were similar to changes in soil CO2.（4）The correlation coefficients of soil CO2，soil temperature and soil moisture based on monthly average values were 0.67and 0.031，respectively. In the vertical direction，the order of seasonal change of CO2 concentration was soil> cave> atmosphere. The lag of soil CO2 on air temperature and soil temperature day and night was affected by the photosynthesis intensity of the overlying vegetation. CO2 is mainly degassed and deposited in the cave water transportation，replenishing the air CO2 in the cave. During heavy rainfall，soil CO2 is controlled by soil temperature and humidity changes，but is more dominated by soil temperature on a long-term scale，with less soil moisture influences. |
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