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

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 precipitati...

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Main Authors: Xing Li, Jingfeng Xiao, Binbin He
Format: Article
Language:English
Published: IOP Publishing 2018-01-01
Series:Environmental Research Letters
Subjects:
Online Access:https://doi.org/10.1088/1748-9326/aab0b1
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author Xing Li
Jingfeng Xiao
Binbin He
author_facet Xing Li
Jingfeng Xiao
Binbin He
author_sort Xing Li
collection DOAJ
description 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 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, and can improve our understanding of the responses of Amazon forests to drought.
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spelling doaj.art-05e34ea2e1d54849950d0e68fb03e1ba2023-08-09T14:31:44ZengIOP PublishingEnvironmental Research Letters1748-93262018-01-0113404400510.1088/1748-9326/aab0b1Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 droughtXing Li0Jingfeng Xiao1https://orcid.org/0000-0002-0622-6903Binbin He2School of Resources and Environment , University of Electronic Science and Technology of China, No. 2006, Xiyuan Ave, West Hi-Tech Zone, Chengdu, 611731, People’s Republic of China; Earth Systems Research Center , Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, United States of AmericaEarth Systems Research Center , Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, United States of America; Author to whom any correspondence should be addressed.School of Resources and Environment , University of Electronic Science and Technology of China, No. 2006, Xiyuan Ave, West Hi-Tech Zone, Chengdu, 611731, People’s Republic of China; Center for Information Geoscience , University of Electronic Science and Technology of China, No. 2006, Xiyuan Ave, West Hi-Tech Zone, Chengdu, 611731, People’s Republic of China; Author to whom any correspondence should be addressed.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 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, and can improve our understanding of the responses of Amazon forests to drought.https://doi.org/10.1088/1748-9326/aab0b1solar-induced chlorophyll fluorescencedroughtAmazon rainforestssolar radiationwater stressphotosynthesis
spellingShingle Xing Li
Jingfeng Xiao
Binbin He
Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought
Environmental Research Letters
solar-induced chlorophyll fluorescence
drought
Amazon rainforests
solar radiation
water stress
photosynthesis
title Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought
title_full Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought
title_fullStr Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought
title_full_unstemmed Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought
title_short Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought
title_sort higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of amazon forests during the 2015 drought
topic solar-induced chlorophyll fluorescence
drought
Amazon rainforests
solar radiation
water stress
photosynthesis
url https://doi.org/10.1088/1748-9326/aab0b1
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AT jingfengxiao higherabsorbedsolarradiationpartlyoffsetthenegativeeffectsofwaterstressonthephotosynthesisofamazonforestsduringthe2015drought
AT binbinhe higherabsorbedsolarradiationpartlyoffsetthenegativeeffectsofwaterstressonthephotosynthesisofamazonforestsduringthe2015drought