Global decadal variability of plant carbon isotope discrimination and its link to gross primary production
| Autor: | Rebecca J. Oliver, Deborah Hemming, Heather Graven, Rossella Guerrieri, Iain Colin Prentice, Aliénor Lavergne |
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| Přispěvatelé: | Lavergne A., Hemming D., Prentice I.C., Guerrieri R., Oliver R.J., Graven H., Commission of the European Communities |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: |
0106 biological sciences
ENVIRONMENT SIMULATOR JULES 010504 meteorology & atmospheric sciences Vapour Pressure Deficit Biodiversity & Conservation 05 Environmental Sciences Atmospheric sciences 01 natural sciences Photosynthesis General Environmental Science MODEL DESCRIPTION Global and Planetary Change Carbon Isotopes TREE GROWTH ATMOSPHERIC CO2 CONCENTRATION Ecology forest ecosystems Plants forest ecosystem C-13 DISCRIMINATION Isotopes of carbon Biodiversity Conservation Life Sciences & Biomedicine WATER-USE EFFICIENCY MESOPHYLL CONDUCTANCE JULES model Atmospheric carbon cycle chemistry.chemical_element Environmental Sciences & Ecology Ecology and Environment Carbon Cycle Forest ecology Environmental Chemistry Ecosystem TEMPERATURE RESPONSE FUNCTIONS 0105 earth and related environmental sciences EUROPEAN FORESTS Science & Technology land carbon uptake Primary production RADIAL GROWTH 06 Biological Sciences 15. Life on land Carbon Dioxide gross primary production carbon isotope discrimination Plant Leaves tree rings chemistry 13. Climate action Soil water Environmental science Carbon Environmental Sciences 010606 plant biology & botany |
| Zdroj: | Global Change Biology |
| Popis: | 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 Δ13C in those forests. Our results demonstrate that the combined analysis of Δ13C and GPP can help understand the drivers of photosynthesis changes in different climatic regions. |
| Databáze: | OpenAIRE |
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