喀斯特山区筑坝河流水-气界面CO_(2)通量变化特征及影响因素分析  

Variation and Influencing Factors of CO_(2) Flux at the Water-Air Interface of Dammed Rivers in Karst Mountainous Areas

作　　者：张富强 周忠发[1,2] 孔杰 丁圣君 王翠 谢江婷 温朝程 邹艳 ZHANG Fuqiang;ZHOU Zhongfa;KONG Jie;DING Shengjun;WANG Cui;XIE Jiangting;WEN Chaocheng;ZOU Yan(College of Geography And Environmental Sciences/Karst Research Institute,Guizhou Normal University,Guiyang 550001,China;The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province,Guiyang 550001,China)

机构地区：[1]贵州师范大学地理与环境科学学院/喀斯特研究院,贵阳550001 [2]贵州喀斯特山地生态环境国家重点实验室培育基地,贵阳550001

出　　处：《地球与环境》2024年第1期11-20,共10页Earth and Environment

基　　金：国家自然科学地区基金项目(42161048);贵州省科技计划(黔科合基础[2020]1Y154)。

摘　　要：水库是内陆水域生态系统的重要组成部分,在调节区域和全球碳循环中发挥着重要作用,为了解喀斯特山区筑坝河流水-气界面CO_(2)扩散通量的变化特征及影响因素,本研究以贵州省黔中水利枢纽工程区平寨水库为对象,于2020年1月、5月、7月和11月对其水体理化指标进行系统监测,运用TBL模型法计算水-气界面CO_(2)扩散通量。结果表明,平寨水库水化学类型为HCO_(3)+SO_(4)-Ca型,水化学特征主要受碳酸盐岩风化控制;表层水体pCO_(2)与CO_(2)扩散通量变化范围分别在124.64~558.76μatm和-18.85~15.90 mg/(m^(2)·d)之间,1月表现为大气CO_(2)的源,5月、7月、11月均表现为大气CO_(2)的汇;垂向上水体pCO_(2)变化范围为124.64~5409μatm,表现为表层低、底层高的差异特征。分析认为,影响平寨水库水-气界面CO_(2)扩散通量的因素主要是:碳酸盐岩平衡体系改变了水中碳化物的存在形态使其水体pCO_(2)发生变化、浮游植物光合作用对水体碳化合物的吸收从而抑制CO_(2)向大气扩散,以及水库热分层期时对底层水体CO_(2)暂封存和混合期时底层水体发生上覆脱气的影响。Reservoirs are an important component of inland water ecosystems and play an important role in regulating regional and global carbon cycles.In order to understand the variation and influencing factors of CO_(2) diffusion fluxes at the water-air interface of dammed rivers in karst mountainous areas,we systematically monitored the physicochemical parameters of the water column in Pingzhai Reservoir within Guizhou Province Qianzhong Water Conservancy Shuniu Project in January,May,July and November 2020,and calculated the CO_(2) diffusion fluxes at the water-air interface using the TBL model.The results reveal that the water chemistry of Pingzhai reservoir is of HCO_(3)+SO_(4)-Ca type and is mainly controlled by carbonate weathering.The variation in pCO_(2) and CO_(2) diffusion fluxes in surface water ranged from 124.64 to 558.76μatm and from-18.85 to 15.90 mg/(m^(2)·d).The surface water served as a source of atmospheric CO_(2) in January and as a sink of atmospheric CO_(2) in May,July and November.The value of pCO_(2) along the water column was low in the surface layer and high in the bottom,ranging from 124.64 to 5409μatm.The factors affecting the CO_(2)diffusion flux at the water-air interface in Pingzhai Reservoir are mainly(1)the changes of pCO_(2) along the water column caused by the carbonate equilibrium shift,altering subsequently the carbon speciation in water,(2)suppression of CO_(2) diffusion into the atmosphere via the uptake of carbon compounds by phytoplankton for photosynthesis and(3)the temporary CO_(2) sequestration during the thermal stratification period and the overlying degassing during the mixing period in the bottom waters.

关 键 词：CO_(2)扩散通量 变化特征 影响因素 喀斯特水库 

分 类 号：P592[天文地球—地球化学]