Vapor pressure deficit dominates the spatiotemporal variations in ecosystem photosynthetic quantum yield
Discuss this preprint
Start a discussion What are Sciety discussions?Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
-
The quantum yield ( α ) of photosynthesis represents the maximum efficiency of light use as indicated by the initial slope of photosynthetic light response curves. Understanding α is crucial for accurate modeling of photosynthesis and terrestrial carbon cycle. Despite its importance, the spatial and temporal variations in α at large scales remain largely elusive.
-
We leveraged long-term eddy-covariance observations from 90 sites globally and examined the spatiotemporal variations in α due to climatic drivers, using statistical and machine learning approaches.
-
We found significant spatial variability in α across and within biomes, primarily driven by atmospheric vapor pressure deficit and soil moisture variations. Meanwhile, the temporal changes in α are mainly driven by the negative effect of vapor pressure deficit, which weakens the positive effects of elevated CO 2 and leaf area index.
-
Our results highlight the dominant role of vapor pressure deficit in controlling the spatiotemporal variations of α as well as the unneglectable impacts of soil water content, CO 2 , and leaf area on α . Those new results provide insights for improving the representation of α in ecosystem photosynthesis models.
