喀斯特地下河涌出后CO_(2)逸散通量的时空格局——基于广西巴马盘阳河  

Spatiotemporal patterns of CO_(2) efflux fluxes from the outflow of karst underground river:A case study of the Panyang river in Bama,Guangxi

作　　者：冼金梅 宋贤威 张乐 林沛新 韦岳春 杨取宝 甘文静 杨露 XIAN Jinmei;SONG Xianwei;ZHANG Le;LIN Peixin;WEI Yuechun;YANG Qubao;GAN Wenjing;YANG Lu(School of Forestry,Guangxi University,Nanning,Guangxi 530000,China;Guangxi Bama Hetai Changshou Industry Co.,Ltd.,Bama Yao Autonomous County,Hechi City,Guangxi 547503,China;Meteorological Bureau of Bama Yao Autonomous County,Hechi,Guangxi 547503,China)

机构地区：[1]广西大学林学院,广西南宁530000 [2]广西巴马和泰长寿产业有限公司,广西河池市巴马瑶族自治县547503 [3]广西河池市巴马瑶族自治县气象局,广西河池547503

出　　处：《中国岩溶》2024年第4期753-765,共13页Carsologica Sinica

基　　金：广西科技基地和人才专项(桂科AD22035032,桂科AD23026312);巴马县人才科技计划项目(巴人科20220032)。

摘　　要：喀斯特流域是岩石风化碳汇的关键区域,同时也是CO_(2)逸散研究的热点区域。为探究喀斯特地下河涌出后CO_(2)分压(pCO_(2))及其逸散通量的时空变化格局,选择喀斯特流域巴马盘阳河为对象,分析水体的pH、碱度、总溶解性固体(TDS)、溶解无机碳(DIC)、溶解有机碳(DOC)、pCO_(2)的时空变化特征,探讨pCO_(2)的调控因素并估算了CO_(2)逸散通量。结果表明,流域内地下水碱度、TDS、DIC和pCO_(2)显著高于地表水,表明喀斯特碳酸盐风化释放大量DIC进入地下水,地下水涌出后产生CO_(2)逸散降低了地表水DIC含量和pCO_(2)。在时间尺度上,旱季常规地表、地下水的碱度、TDS、DIC、pCO_(2)、CO_(2)逸散通量均显著高于雨季,主要归结于雨季雨水的稀释效应。然而次降雨事件下地表、地下水的pH、碱度、TDS、DIC、DOC、pCO_(2)无显著性差异,可能由于降雨量不足或降雨持续时间短。研究期间,巴马盘阳河流域地表水、地下水CO_(2)逸散通量范围分别为-0.10~9.20 kg C m^(-2)year^(-1),-0.12~17.28kg C m^(-2)year^(-1),平均CO_(2)逸散通量分别为1.06±1.46 kg C m^(-2)year^(-1)和2.40±3.14 kg C m^(-2)year^(-1),远高于全球主要大型流域的平均CO_(2)逸散通量(0.64 kg Cm^(-2)year^(-1))。阐明喀斯特流域的CO_(2)逸散通量及其时空变化特征对准确评估河流碳收支状况与评估岩石风化碳汇具有重要意义。Karst basins are key regions for rock weathering and carbon sinks.Because water bodies in karst basins contain high concentrations of dissolved inorganic carbon(DIC),and can affect carbon cycle through both lateral migration of DIC and vertical efflux of CO_(2),they become research hotspots for CO_(2) efflux.Although there have been many studies on CO_(2) efflux fluxes in karst rivers,our understanding is still limited in terms of the spatiotemporal variations in CO_(2) efflux fluxes of water bodies from the outflow of karst underground rivers.In order to explore the spatiotemporal patterns of partial pressure of carbon dioxide(pCO_(2))and CO_(2) efflux flux from the outflow of karst underground rivers,this study focused on the Panyang river in Bama in the karst area of Southwest China.Monthly routine sampling of surface water and groundwater as well as sampling based on rainfall events was conducted from July 2022 to April 2023.The spatiotemporal variations of pH,alkalinity,total dissolved solids(TDS),DIC,dissolved organic carbon(DOC)and pCO_(2) in both the surface water and underground water were explored.The relationships between DIC,DOC and pCO_(2),as well as the relationships between TDS,alkalinity,and DIC,were also analyzed.The controlling factors of pCO_(2) were discussed,and the CO_(2) efflux flux was estimated.The results showed that alkalinity,TDS,DIC and pCO_(2) of groundwater in the basin were significantly higher than those of surface water,indicating that karst carbonate weathering released a large amount of DIC into groundwater,and the outflow of groundwater resulted in the CO_(2) efflux,reducing the DIC content and pCO_(2) of surface water.There was no significant difference in DIC concentrations and pCO_(2) of surface water from upstream to downstream,indicating that groundwater could release CO_(2) into the atmosphere in a short time and quickly reached equilibrium.During the rainy season,DIC and pCO_(2) of groundwater showed an increasing trend from upstream to downstream,while during the dry s

关 键 词：喀斯特岩溶泉 溶解无机碳 河流CO_(2)分压 CO_(2)逸散通量 

分 类 号：X143[环境科学与工程—环境科学] P641.134[天文地球—地质矿产勘探]