DOI: 10.1111/gcb.13300
论文题名: Limited effect of ozone reductions on the 20-year photosynthesis trend at Harvard forest
作者: Yue X. ; Keenan T.F. ; Munger W. ; Unger N.
刊名: Global Change Biology
出版年: 2016
卷: 22, 期: 11 起始页码: 3750
结束页码: 3759
语种: 英语
英文关键词: artificial neural networks
; decadal trend
; deciduous forest
; gross primary production
; ozone inhibition
; photosynthesis
; stomatal conductance
; terrestrial biosphere model
Scopus关键词: artificial neural network
; decadal variation
; deciduous forest
; ozone depletion
; photosynthesis
; primary production
; stomatal conductance
; Harvard Forest
; Massachusetts
; United States
; ozone
; artificial neural network
; forecasting
; forest
; photosynthesis
; plant leaf
; United States
; Forecasting
; Forests
; Neural Networks (Computer)
; Ozone
; Photosynthesis
; Plant Leaves
; United States
英文摘要: Ozone (O3) damage to leaves can reduce plant photosynthesis, which suggests that declines in ambient O3 concentrations ([O3]) in the United States may have helped increase gross primary production (GPP) in recent decades. Here, we assess the effect of long-term changes in ambient [O3] using 20 years of observations at Harvard forest. Using artificial neural networks, we found that the effect of the inclusion of [O3] as a predictor was slight, and independent of O3 concentrations, which suggests limited high-frequency O3 inhibition of GPP at this site. Simulations with a terrestrial biosphere model, however, suggest an average long-term O3 inhibition of 10.4% for 1992–2011. A decline of [O3] over the measurement period resulted in moderate predicted GPP trends of 0.02–0.04 μmol C m−2 s−1 yr−1, which is negligible relative to the total observed GPP trend of 0.41 μmol C m−2 s−1 yr−1. A similar conclusion is achieved with the widely used AOT40 metric. Combined, our results suggest that ozone reductions at Harvard forest are unlikely to have had a large impact on the photosynthesis trend over the past 20 years. Such limited effects are mainly related to the slow responses of photosynthesis to changes in [O3]. Furthermore, we estimate that 40% of photosynthesis happens in the shade, where stomatal conductance and thus [O3] deposition is lower than for sunlit leaves. This portion of GPP remains unaffected by [O3], thus helping to buffer the changes of total photosynthesis due to varied [O3]. Our analyses suggest that current ozone reductions, although significant, cannot substantially alleviate the damages to forest ecosystems. © 2016 John Wiley & Sons Ltd 资助项目: Yue, X.
; School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, United States
; 电子邮件: xu.yue@yale.edu
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/61265
Appears in Collections: 影响、适应和脆弱性
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作者单位: School of Forestry and Environmental Studies, Yale University, 195 Prospect Street, New Haven, CT, United States; Climate Change Research Center, Chinese Academy of Sciences, Beijing, China; Lawrence Berkeley National Lab, Berkeley, CA, United States; Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia; Department of Earth and Planetary Sciences, School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States
Recommended Citation:
Yue X.,Keenan T.F.,Munger W.,et al. Limited effect of ozone reductions on the 20-year photosynthesis trend at Harvard forest[J]. Global Change Biology,2016-01-01,22(11)