Triose phosphate limitation in photosynthesis models reduces leaf photosynthesis and global terrestrial carbon storage

Abstract

Triose phosphate utilization (TPU)-limited photosynthesis occurs when carbon export from the Calvin-Benson cycle cannot keep pace with carbon inputs and processing. This condition is poorly constrained by observations but may become an increasingly important driver of global carbon cycling under future climate scenarios. However, the consequences of including or omitting TPU limitation in models have seldom been quantified. Here, we assess the impact of changing the representation of TPU limitation on leaf- and global-scale processes. At the leaf scale, TPU limits photosynthesis at cold temperatures, high CO2 concentrations, and high light levels. Consistent with leaf-scale results, global simulations using the Community Land Model version 4.5 illustrate that the standard representation of TPU limits carbon gain under present day and future conditions, most consistently at high latitudes. If the assumed TPU limitation is doubled, further restricting photosynthesis, terrestrial ecosystem carbon pools are reduced by 9 Pg by 2100 under a business-as-usual scenario. The impact of TPU limitation on global terrestrial carbon gain suggests that CO2 concentrations may increase more than expected if models omit TPU limitation, and highlights the need to better understand when TPU limitation is important, including variation among different plant types and acclimation to temperature and CO2

Description

© 2018 The Author(s). cc-by

Rights

Availability

Keywords

Photosynthesis models, Terrestrial carbon storage, Triose phosphate utilization

Citation

Lombardozzi, D.L., Smith, N.G., Cheng, S.J., Dukes, J.S., Sharkey, T.D., Rogers, A., Fisher, R., & Bonan, G.B.. 2018. Triose phosphate limitation in photosynthesis models reduces leaf photosynthesis and global terrestrial carbon storage. Environmental Research Letters, 13(7). https://doi.org/10.1088/1748-9326/aacf68

Collections