祁连山南麓高寒草甸2002~2016年生长季CO_(2)通量对气温日较差的响应  

The response of CO_(2) fluxes to the amplitude of diurnal temperature in alpine meadow during growing season from 2002 to 2016 at the southern foot of Qilian Mountains

作　　者：祝景彬 张法伟[2,4] 李红琴 杨永胜[2,4] 王春雨 张光茹 罗方林 贺慧丹 李英年[2,4] Jingbin Zhu;Fawei Zhang;Hongqin Li;Yongsheng Yang;Chunyu Wang;Guangru Zhang;Fanglin Luo;Huidan He;Yingnian Li(College of Tourism,Resources and Environment,Zaozhuang University,Zaozhuang 277160,China;Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810001,China;College of Life Sciences,Luoyang Normal University,Luoyang 471934,China;Key Laboratory of Adaptation and Evolution of Plateau Biota,Chinese Academy of Sciences,Xining 810001,China)

机构地区：[1]枣庄学院旅游与资源环境学院,枣庄277160 [2]中国科学院西北高原生物研究所,西宁810001 [3]洛阳师范学院生命科学学院,洛阳471934 [4]中国科学院高原生物适应与进化重点实验室,西宁810001

出　　处：《科学通报》2021年第1期85-95,共11页Chinese Science Bulletin

基　　金：国家重点研发计划(2017YFA0604801);青海省科技基础条件平台项目(2018-ZJ-T09);国家自然科学基金(41877547)资助。

摘　　要：全球气候变化背景下气温日较差(amplitude of diurnal temperature,ADT)的减小将会对高寒生态系统的碳收支产生重要影响.基于涡度相关系统观测资料,研究祁连山南麓高寒草甸2002~2016年生长季(6~9月)ADT在日、月、年尺度上对CO2通量影响,为预测高寒草甸生态系统碳平衡对未来气候变化的响应具有重要参考价值.结果表明,2002~2016年的生长季中,最高气温(maximal air temperature,MaxTa)和最低气温(minimal air temperature,MinTa)呈先升高后降低的单峰变化趋势,ADT没有呈现明显的变化趋势.总初级生产力(gross primary production,GPP)和生态系统呼吸(ecosystem respiration,Re)呈先增加后降低的单峰趋势,净生态系统CO_(2)交换(net ecosystem exchange,NEE)呈先下降后上升的“V”型变化趋势.高寒草甸整个生长季总NEE、GPP和Re平均值分别为–230.4±17.3、668.8±25.5、438.3±27.5 g C m^(-2),表现为较强的碳汇.在月尺度和年尺度上,高寒草甸生长季ADT对NEE没有显著影响(P>0.05).在日尺度上,整个生长季的逐日NEE与ADT呈显著的二次曲线关系(P<0.001),阈值为19.8℃;但是,线性回归分析表明,在6~9月的日NEE与日ADT呈极显著负相关(P<0.001).整体上,仍能说明高寒草甸ADT的增大有利于生态系统的碳固持,暗示在未来气候变化背景下ADT的减小将会削弱高寒草甸生态系统的碳汇能力.Known as the“Third Pole”and“Early-warning region”of the world,the Qinghai-Tibetan Plateau(QTP)had an intense increase in surface temperature and marked change in the amplitude of diurnal temperature(ADT),which could have significant influences on the ecosystem carbon cycle.The increasing rate of the mean daily minimum temperature(MinTa)was about two times higher than that of maximum temperature(MaxTa)in the last five decades,and this asymmetric pattern has resulted in a smaller ADT,which substantially affected the plant phenology and vegetation productivity.The reduction in the ADT caused by global climate change would have a profound impact on the carbon balance of alpine ecosystems.However,the response of carbon budgets to the ADT over the QTP remained unclear.Here,we analyzed the 15-a growing seasonal(June−September)carbon fluxes(measured by the eddy covariance[EC]technique)in alpine meadow at the southern foot of Qilian Mountains,which is one of the most extensive vegetation types on the QTP.This study aimed to clarify how carbon fluxes respond to ADT at different temporal(daily,monthly and annual)scales in alpine meadow and to understand their potential response to future climate change.The results indicated that both the MaxTa and MinTa showed bell-shaped seasonal patterns,whereas the ADT failed to show an obvious trend during the growing season from 2002 to 2016.Besides,there was a non-significant increase in annual MaxTa,MinTa and ADT(P>0.05).Meanwhile,daily gross primary productivity(GPP)and ecosystem respiration(Re)exhibited a single-peaked trend that increased and then decreased,whereas daily net ecosystem CO_(2)exchange(NEE)showed a v-shaped trend.The alpine meadow ecosystem is a carbon sink during the growing season,and the annual NEE,GPP,and Re were−230.4±17.3,668.8±25.5,438.3±27.5 g C m^(-2),respectively.Moreover,the annual GPP and Re of alpine meadow in the growing season showed a significant increase trend(P<0.05),but the annual NEE showed no significant inter-annual change trend(P

关 键 词：青藏高原 高寒草甸 日较差 CO_(2)通量 

分 类 号：S812.1[农业科学—草业科学]