2012-2013年重庆雪玉洞洞穴系统碳循环特征  

Carbon Cycle Characteristics in Karst Cave System of Xueyu Cave from 2012 to 2013

作　　者：任坤[1,2,3] 沈立成[3] 袁道先[1,2,3] 王晓晓[4] 徐尚全[3] 

机构地区：[1]中国地质科学院岩溶地质研究所,国土资源部广西岩溶动力学重点实验室,广西桂林541004 [2]联合国教科文组织国际岩溶研究中心,广西桂林541004 [3]西南大学地理科学学院,重庆400715 [4]中国科学院水利部成都山地灾害与环境研究所,四川成都610041

出　　处：《地球科学（中国地质大学学报）》2016年第8期1424-1434,共11页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金项目(No.41103068);中国地质科学院基本科研业务费专项项目(No.2016005);中国地质调查局项目(No.DD20160285);中央高校基本科研业务费专项项目(No.XDJK2015D003);重庆市院士专项项目(No.CSTC2013jcyjys20001)

摘　　要：重庆雪玉洞洞内CO_2浓度之高,在国内外皆罕见,但此洞穴系统碳循环特征及控制因素仍不清楚.利用土壤二氧化碳分压(P_(CO_2-soil))、洞内大气二氧化碳分压(P_(CO_2-cave))、地下河水二氧化碳分压(P_(CO_2-eq))、方解石饱和指数(SIc)、地下河水溶解无机碳同位素(δ^(13) CDIC)等指标来研究雪玉洞洞内CO_2浓度变化、控制因素以及地下河对洞内碳循环的影响.结果表明:雪玉洞上覆P_(CO_2-soil)雨季高,旱季低;降雨量是控制上覆P_(CO_2-soil)的重要因子.雪玉洞P_(CO_2-cave)变化规律明显,暖季高,冷季低;温度变化导致洞内外气流频繁交换是P_(CO_2-cave)突变的重要原因,地下河水CO_2脱气能够在短时间内让P_(CO_2-cave)上升到较高值.雨季由于土壤CO_2效应,地下河水具有低SIc、高P_(CO_2-eq)特性,矿化度较高,并且部分月份地下河水具有溶蚀性;旱季由于土壤CO_2效应及降雨较少,地下河水呈现高SIc、低P_(CO_2-eq)特性,矿化度较低,以沉积为主.The high CO_2 concentration in Xueyue cave,Chongqing,is rare at home and abroad.However,the circulation characteristics of carbon and its controlling factors in this cave system remain unknown.P_（CO_2-soil）,P_（CO_2-cave）,P_（CO_2-eq）,SIc,andδ^（13） CDIC of subterranean stream were analyzed to investigate the laws of CO_2 concentration variations in Xueyu cave and its contolling factors,as well as the impact on carbon cycle in this cave by subterranean stream.It is found that soil PCO_2 mainly controlled by precipitation in subtropical areas was higher in rainy season than that of dry season.Cave air PCO_2 exhibited seasonal variations,high cave air PCO_2 typically occurred during warm periods,and low cave air PCO_2 were typical of cold periods.It was ventilation driven by the temperature difference between cave and outside air that resulted in a sharp transition of cave air PCO_2.Meanwhile,cave air PCO_2 could rise to high level in a short period of time because of CO_2 degassing from subterranean stream.Due to soil CO_2 effect,groundwater became more mineralized water with low SIc and high water P_（CO_2-eq）,and dissolution in some months in rainy season.With the reduction of soil CO_2 and precipitation,groundwater had low degree of mineralization with high SIc and low water P_（CO_2-eq）in dry season.

关 键 词：岩溶洞穴系统 碳循环 二氧化碳分压 方解石饱和指数 雪玉洞 气候变化 

分 类 号：P592[天文地球—地球化学]