喀斯特常绿落叶阔叶混交林旱季CO2通量特征及其影响因子  

CO Flux and Its Driving Factors in a Karst Evergreen Deciduous Broadleaf Mixed Forest in Dry Season

作　　者：李子涵 罗维均[1,3] 杜虎[4,5] 宋同清[4,5] 彭海军[1] 王彦伟 王世杰[1,3] LI Zihan;LUO W eijun;DU Hu;SONG Tongqing;PENG Haijun;WANG Yanwei;WANG Shijie(State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;University of Chinese Academy of Sciences,Beijing 100049,China;Puding Karst Ecosystem Research Station,Chinese Academy of Sciences,Puding Guizhou 562100,China;Key Laboratory of Agro-ecological Processes in Subtropical Region,Institute of Subtropical Agriculture,Chinese Academy of Sciences,Changsha 410125,China;Huanjiang Observation and Research Station for Karst Ecosystems,Chinese Academy of Sciences,Huanjiang Guangxi 547100,China)

机构地区：[1]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,贵阳550081 [2]中国科学院大学,北京100049 [3]中国科学院普定喀斯特生态系统观测研究站,贵州普定562100 [4]中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,长沙410125 [5]中国科学院环江喀斯特生态系统观测研究站,广西环江547100

出　　处：《地球与环境》2020年第5期525-536,共12页Earth and Environment

基　　金：国家重点研发计划项目(2016YFC0502300、2016YFC0502102);国家自然科学基金项目(41673121);中国科学院战略性先导科技专项(B类)(XDB40020100);贵州省高层次创新型人才培养计划“十”层次人才项目(黔科合平台人才[2016]5648);广西重点研发计划项目(桂科AB17129009、桂科AB16380255)。

摘　　要：对广西木论国家级自然保护区喀斯特常绿落叶阔叶混交林旱季生态系统CO2净交换(NEE)的变化特征及其与环境因子的关系进行初步分析,计算研究期间碳汇大小,与其他相似气候条件下的不同生态系统进行对比,以期为准确估算该生态系统的年碳汇量提供基础。利用涡度相关法对该地区旱季(2018年10月1日~2019年3月31日)CO2通量进行连续观测,同时开展降水量(P)、光合有效辐射(PAR)、空气温度(Tair)、土壤温度(Tsoil)以及土壤含水量(SWC)等环境因子监测。观测期内该生态系统CO2通量及浓度具有明显的"单谷"状日变化特征,白天表现为明显的碳汇,夜间则表现为明显的碳源,NEE在12:00最强,为-0.309±0.330 mg CO2/(m^2·s),18:30最弱,为0.074±0.061 mg CO2/(m^2·s);观测期内NEE、生态系统呼吸(Re)、生态系统总生产力(GEP)分别为-121.4、209.2、330.6 g C/m^2,该生态系统在2019年2月的碳吸收能力最强,Re、GEP在2018年10月达到最强;光合有效辐射是白天生态系统CO2净交换(NEEd)变化的主要控制因素(R^2=0.40,p<0.01),空气温度与夜间生态系统CO2净交换(NEEn)存在指数关系(R^2=0.1267,p<0.01);观测期内的降雨抑制了该生态系统的碳汇能力,即降水对NEE产生了抑制作用。旱季该生态系统整体表现出明显的碳汇,碳汇值为1.214 t C/ha,明显低于相似气候条件下的其他生态系统。The variation of net ecosystem CO2 exchange(NEE)and the environmental factors was analyzed preliminarily in a karst evergreen deciduous broad-leaf mixed forest ecosystem,Mulun National Nature Reserve in Guangxi,SW China,in dry season to estimate the carbon sinks of the ecosystem during the study period and try to provide a basis for accurately estimating the annual carbon sinks of this ecosystem,in addition,values obtained from other ecosystems under similar climatic conditions were compared.Open-path eddy covariance system was used to continuously measure the CO2 flux in a dry season from October 1 st,2018 to March 31 st,2019.Meanwhile,environmental factors such as precipitation(P),photosynthetic active radiation(PAR),air temperature(Tair),soil temperature(Tsoil),and soil water content(SWC)were also monitored.CO2 flux and concentration have obvious diurnal variation of singlevalley shape.NEE is highest at 12:00 with-0.309±0.330 mg CO2/(m^2·s),and is lowest at 18:30 with 0.074±0.061 mg CO2/(m^2·s).The accumulated NEE,Ecosystem Respiration(Re),and Gross Ecosystem Productivity(GEP)during the study period are-121.4,209.2 and 330.6 g C/m^2,respectively.The carbon sink capacity of this ecosystem is strongest in February 2019,while,Re and GEP reach the maximum in October 2018.PAR is the main controlling factor for the change of daytime NEE(R^2=0.40,p<0.01),and air temperature exponentially correlates with nighttime NEE(R^2=0.1267,p<0.01).Precipitation has an inhibitory effect on the carbon sink capacity of the ecosystem.Overall,this ecosystem in dry season performs as a carbon sink with 1.214 t C/ha,that significantly lower than other ecosystems under similar climate conditions.

关 键 词：涡度相关法 喀斯特山地 常绿落叶混交林 生态系统净交换 碳汇能力 

分 类 号：Q948[生物学—植物学]