Joint control of terrestrial gross primary productivity by plant phenology and physiology
Joint control of terrestrial gross primary productivity by plant phenology and physiology
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DOI：
10.1073/pnas.1413090112
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发表时间：
2015-02
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影响因子：
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通讯作者：
J. Xia;S. Niu;P. Ciais;I. Janssens;Jiquan Chen;C. Ammann;A. Arain;P. Blanken;A. Cescatti;
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文献类型：
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作者：
J. Xia;S. Niu;P. Ciais;I. Janssens;Jiquan Chen;C. Ammann;A. Arain;P. Blanken;A. Cescatti;
陆地总初级生产力（GPP），即生态系统水平上的总光合CO2固定，为陆地上的所有生命提供燃料。然而，它的时空变异性知之甚少，因为GPP是由许多相关的植物物候和生理活动的过程。在这项研究中，我们发现，植物的物候和生理特性可以集成在一个强大的指数的产品的CO2吸收期的长度和季节性最大光合作用解释GPP的变化在空间和时间上的极端气候和干扰后的恢复。陆地总初级生产力在时间和空间上变化很大。更好地了解这种变异性对于更准确地预测未来气候碳循环反馈是必要的。最近的研究表明，全球初级生产力的变化是由一系列生物和非生物因素驱动的，这些因素主要通过植被物候和生理过程的变化发挥作用。然而，目前还不清楚如何植物物候学和生理学可以整合来解释陆地GPP的时空变异。基于涡度相关分析和卫星遥感数据，将陆地年GPP分解为CO2吸收期长度（CUP）和季节最大CO2吸收能力（GPPmax）。CUP和GPPmax的乘积解释了2000-2010年期间北美大部分地区GPP时间变化的90%以上，以及全球分布的涡动通量塔站点之间的GPP空间变化。它还解释了GPP对2003年欧洲热浪的响应（r2 = 0.90）和南达科他州火灾扰动后GPP的恢复（r2 = 0.88）。对涡度协方差通量数据的进一步分析表明，年GPP中的生物群落间变化比CUP中的GPP max更好地解释。这些发现表明，陆地GPP由生态系统水平的植物物候和光合能力共同控制，因此，更好地了解GPPmax和CUP对环境和生物变化的响应将改善GPP随时间和空间的预测。
Significance Terrestrial gross primary productivity (GPP), the total photosynthetic CO2 fixation at ecosystem level, fuels all life on land. However, its spatiotemporal variability is poorly understood, because GPP is determined by many processes related to plant phenology and physiological activities. In this study, we find that plant phenological and physiological properties can be integrated in a robust index—the product of the length of CO2 uptake period and the seasonal maximal photosynthesis—to explain the GPP variability over space and time in response to climate extremes and during recovery after disturbance. Terrestrial gross primary productivity (GPP) varies greatly over time and space. A better understanding of this variability is necessary for more accurate predictions of the future climate–carbon cycle feedback. Recent studies have suggested that variability in GPP is driven by a broad range of biotic and abiotic factors operating mainly through changes in vegetation phenology and physiological processes. However, it is still unclear how plant phenology and physiology can be integrated to explain the spatiotemporal variability of terrestrial GPP. Based on analyses of eddy–covariance and satellite-derived data, we decomposed annual terrestrial GPP into the length of the CO2 uptake period (CUP) and the seasonal maximal capacity of CO2 uptake (GPPmax). The product of CUP and GPPmax explained >90% of the temporal GPP variability in most areas of North America during 2000–2010 and the spatial GPP variation among globally distributed eddy flux tower sites. It also explained GPP response to the European heatwave in 2003 (r2 = 0.90) and GPP recovery after a fire disturbance in South Dakota (r2 = 0.88). Additional analysis of the eddy–covariance flux data shows that the interbiome variation in annual GPP is better explained by that in GPPmax than CUP. These findings indicate that terrestrial GPP is jointly controlled by ecosystem-level plant phenology and photosynthetic capacity, and greater understanding of GPPmax and CUP responses to environmental and biological variations will, thus, improve predictions of GPP over time and space.