Abstract
Plant autotrophic respiration is responsible for the atmospheric release of about half of all photosynthetically fixed carbon and responds to climate change in a manner different from photosynthesis. The plant mass-specific respiration rate (rA), a key parameter of the carbon cycle, has not been sufficiently constrained by observations at ecosystem or broader scales. In this study, a meta-analysis revealed a global relationship with vegetation biomass that explains 67–77% of the variance of rA across plant ages and biomes. rA decreased with increasing vegetation biomass such that annual rA was two orders of magnitude larger in fens and deserts than in mature forests. This relationship can be closely approximated by a power-law equation with a universal exponent and yields an estimated global autotrophic respiration rate of 64 ± 12 Pg C yr−1. This finding, which is phenomenologically and theoretically consistent with metabolic scaling and plant demography, provides a way to constrain the carbon-cycle components of Earth system models.
Highlights
Plant autotrophic respiration is responsible for the atmospheric release of about half of all photosynthetically fixed carbon and responds to climate change in a manner different from photosynthesis
The present study provides an effective basis for reducing uncertainties in RA values simulated in carbon cycle and Earth system models
As reported by previous global carbon cycle syntheses[22,31], current evaluations of the global carbon cycle are still subject to considerable uncertainty
Summary
Plant autotrophic respiration is responsible for the atmospheric release of about half of all photosynthetically fixed carbon and responds to climate change in a manner different from photosynthesis. RA decreased with increasing vegetation biomass such that annual rA was two orders of magnitude larger in fens and deserts than in mature forests This relationship can be closely approximated by a power-law equation with a universal exponent and yields an estimated global autotrophic respiration rate of 64 ± 12 Pg C yr−1. This finding, which is phenomenologically and theoretically consistent with metabolic scaling and plant demography, provides a way to constrain the carbon-cycle components of Earth system models. Despite the increasing availability of global vegetation data (e.g., forest density15) thanks to satellite observations and dataset compilation, predicting large-scale
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