Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought

Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought

Blog Article

Amazon forests play an important role in the global carbon cycle and Earth’s climate.The vulnerability of Amazon forests to drought remains highly controversial.Here we examine the impacts of the 2015 drought on the photosynthesis of Amazon forests to understand how solar radiation and precipitation jointly control forest photosynthesis during the severe drought.We use a variety of gridded vegetation and climate datasets, including solar-induced chlorophyll fluorescence (SIF), photosynthetic active wall basket radiation (PAR), the fraction of absorbed PAR (APAR), leaf area index (LAI), precipitation, soil moisture, cloud cover, and vapor pressure deficit (VPD) in our analysis.

Satellite-derived SIF observations provide a direct diagnosis of plant photosynthesis from space.The decomposition of SIF to SIF yield (SIF _yield ) and APAR (the product of PAR and fPAR) reveals the relative effects of precipitation and solar radiation on photosynthesis.We found that the drought significantly reduced SIF _yield , the emitted SIF per photon absorbed.The higher APAR resulting from lower cloud cover and higher LAI partly offset the negative effects of water stress on the photosynthesis of Amazon forests, leading to a smaller reduction in SIF than in SIF _yield and precipitation.

We further found that SIF _yield anomalies were more sensitive to precipitation and VPD anomalies in the southern regions of the Amazon than in the central and northern regions.Our findings shed light on the relative and combined effects of precipitation and solar radiation on photosynthesis, Butter Dishes and can improve our understanding of the responses of Amazon forests to drought.