Imperial College London
Alternate

DrHeatherGraven

Faculty of Natural Sciences, Department of Physics

Reader in Climate Physics
 
 
 
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Contact

 

+44 (0)20 7594 5226h.graven Website

 
 
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Location

 

707Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Lavergne:2022:10.1111/gcb.15924,
author = {Lavergne, A and Hemming, D and Prentice, IC and Guerrieri, R and Oliver, R and Graven, H},
doi = {10.1111/gcb.15924},
journal = {Global Change Biology},
pages = {524--541},
title = {Global decadal variability of plant carbon isotope discrimination and its link to gross primary production.},
url = {http://dx.doi.org/10.1111/gcb.15924},
volume = {28},
year = {2022}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Carbon isotope discrimination (Δ13C) in C3 woody plants is a key variable for the study of photosynthesis. Yet how Δ13C varies at decadal scales, and across regions, and how it is related to gross primary production (GPP), are still incompletely understood. Here we address these questions by implementing a new Δ13C modelling capability in the land-surface model JULES incorporating both photorespiratory and mesophyll-conductance fractionations. We test the ability of four leaf-internal CO2 concentration models embedded in JULES to reproduce leaf and tree-ring (TR) carbon isotopic data. We show that all the tested models tend to overestimate average Δ13C values, and to underestimate interannual variability in Δ13C. This is likely because they ignore the effects of soil water stress on stomatal behavior. Variations in post-photosynthetic isotopic fractionations across species, sites and years, may also partly explain the discrepancies between predicted and TR-derived Δ13C values. Nonetheless, the “least-cost” (Prentice) model shows the lowest biases with the isotopic measurements, and lead to improved predictions of canopy-level carbon and water fluxes. Overall, modelled Δ13C trends vary strongly between regions during the recent (1979–2016) historical period but stay nearly constant when averaged over the globe. Photorespiratory and mesophyll effects modulate the simulated global Δ13C trend by 0.0015 ± 0.005‰ and –0.0006 ± 0.001‰ ppm−1, respectively. These predictions contrast with previous findings based on atmospheric carbon isotope measurements. Predicted Δ13C and GPP tend to be negatively correlated in wet-humid and cold regions, and in tropical African forests, but positively related elsewhere. The negative correlation between Δ13C and GPP is partly due to the strong dominant influences of temperature on GPP and vapor pressure deficit on Δ13
AU  - Lavergne,A
AU  - Hemming,D
AU  - Prentice,IC
AU  - Guerrieri,R
AU  - Oliver,R
AU  - Graven,H
DO  - 10.1111/gcb.15924
EP  - 541
PY  - 2022///
SN  - 1354-1013
SP  - 524
TI  - Global decadal variability of plant carbon isotope discrimination and its link to gross primary production.
T2  - Global Change Biology
UR  - http://dx.doi.org/10.1111/gcb.15924
UR  - https://onlinelibrary.wiley.com/doi/10.1111/gcb.15924
UR  - http://hdl.handle.net/10044/1/92553
VL  - 28
ER  -
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