三岔河pCO2特征及水-气界面通量分析  

Partial pressure of CO_2 and CO_2 outgassing fluxes of Sancha River

作　　者：钱娟婷 吴起鑫[1] 安艳玲[1] 侯祎亮 韩贵琳[2] 涂成龙[3] WU Qi-xin;HAN Gui-lin;TU Cheng-long;QIAN Juan-ting;AN Yan-ling;HOU Yi-liang(Key Laboratory of Karst Environment and Geohazard Prevention,Guizhou University , Guiyang 550003, China;School of Scientific Research, China University Geosciences (Beijing),Beijing 100083, China;State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Science, Guiyang 550002, China)

机构地区：[1]贵州大学喀斯特环境与地质灾害防治重点实验室,贵州贵阳550003 [2]中国地质大学(北京),科学研究院,北京100083 [3]中国科学院地球化学研究所环境地球化学国家重点实验室,贵州贵阳550002

出　　处：《中国环境科学》2017年第6期2263-2269,共7页China Environmental Science

基　　金：国家自然科学基金资助项目(42603123);中国博士后科学基金资助项目(2014M562388);水利部公益性项目(201401050)

摘　　要：为了解喀斯特中小型河流p_(CO_2)的分布及其影响因素,于2014年2月和8月调查了三岔河的温度、EC、DO、pH值和溶解无机碳(DIC),并计算水体CO_2分压(p_(CO_2)).结果表明:EC、pH、TDS和DIC均表现为枯水期>丰水期,水体p_(CO_2)在300~10000μatm之间,年平均值3100μatm,枯水期<丰水期.过饱和CO_2与表观耗氧量的相关关系分析发现,枯水期p CO_2与HCO_3^-含量呈正相关,表明枯水期主要受碳酸盐岩溶解控制的碳酸体系的影响;而丰水期河流水体高p_(CO_2)则主要受有机好氧呼吸作用和高浓度土壤CO_2进入到水体的影响.三岔河水-气界面CO_2交换速率为10.8~20.3MgC/(hm^2·a),CO_2释放通量约为0.9~1.7×109molC/a.对比分析发现,喀斯特中小型河流三岔河CO_2释放速率高于亚马逊河、长江、西江等大型河流,却低于喀斯特地区以及北欧等小型溪流,可见不同级别河流具有不同的CO_2释放通量,长期以来可能低估了中小型河流对区域CO_2循环的贡献.In order to understand the distributions and influences of2pCO in medium and small karstic rivers,the SanchaRiver was investigated in February and August2014.The temperature,EC,DO,pH and dissolved inorganic carbon(DIC)of the river were measured and the partial pressure of CO2(2pCO)was calculated.The results showed that EC、pH、TDSand DIC in dry season were higher than that in wet season.The2pCO in the surface water ranged between300and10000μatm,with an average value of3100μatm.The2pCO values in the wet season were higher than that in dry season.The analyses of supersaturated CO2and apparent oxygen utilization demonstrated that2pCO was controlled by thecarbonate system in the dry season.The in-situ aerobic respiration was one of the significantin fluencing factors in the wetseason,and the supersaturated CO2may attribute to the flushing of carbon dioxide from soils.The CO2emission flux fromSancha River to atmosphere was estimated about0.9~1.7×109molC/a and10.8~20.3MgC/(hm2·a).The water-to-air CO2outgassing flux from Sanchahe River was higher than that from large rivers(i.e.Amazon River、Yangtze River)and lowerthan that from streams(i.e.Houzhai River、G鋎dtj鋜n River).The results indicated that the CO2emission fluxes fromsurface water systems are influenced by the scale of rivers,and the contribution to the regional carbon cycling brought bythe medium and small river may be underestimated for a long time.

关 键 词：三岔河 二氧化碳分压( 

分 类 号：X131.2[环境科学与工程—环境科学]