EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

The temperature effect on the Intrinsic quantum yield at the ecosystem level

David Sandoval1, Victor Flo1,2, Catherine Morfopoulos1,3, and Iain Colin Prentice1,4,5
David Sandoval et al.
  • 1Georgina Mace Centre for the Living Planet, Department of Life Sciences, Imperial College London, Ascot, UK (
  • 2Univ Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
  • 3Department of Geoscience, Environment & Society-BGEOSYS, Université Libre de Bruxelles, Brussels, Belgium
  • 4Department of Biological Sciences, Macquarie University, North Ryde, Australia
  • 5Department of Earth System Science, Tsinghua University, Beijing, China

The intrinsic quantum yield (φ0) is a measure of the efficiency of photosynthesis at low light levels and it is a crucial parameter for modelling gross primary productivity using “light use efficiency” (LUE) models. These models often assume that φ0 is constant, but there is evidence retrieved at leaf level in the lab, that it may depend on temperature in a bell-shaped curve, with a peak around 30°C. This temperature dependence of φ0(T) is still not fully understood, thus, it is still unknown if the shape of φ0(T) is universal or if the responses at the leaf and ecosystem levels widely differ. Here we derived φ0(T) at the ecosystem level for different sites during their growing season. We used sub-daily above and below-canopy measurements of photosynthetic flux density, long-wave radiation measurements to derive surface canopy temperature, and eddy covariance measurements of CO2 exchange. We then compared our estimations with empirical models found in the literature and propose a new empirical equation. We found that φ0(T) at the ecosystem level also follows a bell-shaped curve, with a rapid increase after 5 °C to peak around 20 °C to 25 °C, and a slight decrease with further increasing temperature. Overall, our estimations show lower values than previous leaf-level observations reported in the literature.  The results suggest that this new formulation for φ0(T) may improve the predictions of current LUE models, but further testing is needed.

How to cite: Sandoval, D., Flo, V., Morfopoulos, C., and Prentice, I. C.: The temperature effect on the Intrinsic quantum yield at the ecosystem level, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6949,, 2023.

Supplementary materials

Supplementary material file