Effects of Light Component and Water Stress on Photosynthesis of Amazon Rainforests During the 2015/2016 El Niño Drought

Yan, H; Wang, SQ; Huete, A; Shugart, HH

Effects of Light Component and Water Stress on Photosynthesis of Amazon Rainforests During the 2015/2016 El Niño Drought

Yan, H Wang, SQ Huete, A

Shugart, HH

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Publication Type:: Journal Article
Citation:: Journal of Geophysical Research: Biogeosciences, 2019, 124 (6), pp. 1574 - 1590
Issue Date:: 2019-06-01

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Field	Value	Language
dc.contributor.author	Yan, H	en_US
dc.contributor.author	Wang, SQ	en_US
dc.contributor.author	Huete, A https://orcid.org/0000-0003-2809-2376	en_US
dc.contributor.author	Shugart, HH	en_US
dc.date.issued	2019-06-01	en_US
dc.identifier.citation	Journal of Geophysical Research: Biogeosciences, 2019, 124 (6), pp. 1574 - 1590	en_US
dc.identifier.issn	2169-8953	en_US
dc.identifier.uri	http://hdl.handle.net/10453/135804
dc.description.abstract	©2019. American Geophysical Union. All Rights Reserved. Whether enhanced sunshine increases photosynthesis in Amazon rainforests during drought is unclear. Here we used a light component-based two-leaf-photosynthesis model, driven with climate data and satellite vegetation data, to inspect the controlling mechanisms among climate factors on gross primary production (GPP) during the 2015/2016 El Niño drought event. We found that simulated GPP and Moderate Resolution Imaging Spectroradiometer enhanced vegetation index indicated an Amazonian “browning” and not a “green up” during the 2015/2016 El Niño year relative to the 2011–2014 interval. The result shows that, along with intensified sunlight, diffuse sunlight and diffuse fraction as well as canopy light use efficiency decreased, which further produced a decreased potential GPP* (determined by light components and leaf area index of shaded and sunlit leaves). The decreased GPP* and drought-induced water stress jointly reduced canopy photosynthesis of Amazon rainforests during the 2015/2016 drought. The light component variations caused a reduction in GPP but with a magnitude inferior to the GPP reduction from water stress. These findings suggest that intensified sunlight did not enhance photosynthesis of Amazon rainforests and highlight the important role of light components in interannual and seasonal variations of photosynthesis in Amazon rainforests.	en_US
dc.relation.ispartof	Journal of Geophysical Research: Biogeosciences	en_US
dc.relation.isbasedon	10.1029/2018JG004988	en_US
dc.title	Effects of Light Component and Water Stress on Photosynthesis of Amazon Rainforests During the 2015/2016 El Niño Drought	en_US
dc.type	Journal Article
utslib.citation.volume	6	en_US
utslib.citation.volume	124	en_US
utslib.for	0406 Physical Geography and Environmental Geoscience	en_US
utslib.for	0404 Geophysics	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
pubs.organisational-group	/University of Technology Sydney/Strength - CAMGIS - Centre for Advanced Modelling and Geospatial lnformation Systems
utslib.copyright.status	closed_access
pubs.issue	6	en_US
pubs.publication-status	Published	en_US
pubs.volume	124	en_US

Abstract:

©2019. American Geophysical Union. All Rights Reserved. Whether enhanced sunshine increases photosynthesis in Amazon rainforests during drought is unclear. Here we used a light component-based two-leaf-photosynthesis model, driven with climate data and satellite vegetation data, to inspect the controlling mechanisms among climate factors on gross primary production (GPP) during the 2015/2016 El Niño drought event. We found that simulated GPP and Moderate Resolution Imaging Spectroradiometer enhanced vegetation index indicated an Amazonian “browning” and not a “green up” during the 2015/2016 El Niño year relative to the 2011–2014 interval. The result shows that, along with intensified sunlight, diffuse sunlight and diffuse fraction as well as canopy light use efficiency decreased, which further produced a decreased potential GPP* (determined by light components and leaf area index of shaded and sunlit leaves). The decreased GPP* and drought-induced water stress jointly reduced canopy photosynthesis of Amazon rainforests during the 2015/2016 drought. The light component variations caused a reduction in GPP but with a magnitude inferior to the GPP reduction from water stress. These findings suggest that intensified sunlight did not enhance photosynthesis of Amazon rainforests and highlight the important role of light components in interannual and seasonal variations of photosynthesis in Amazon rainforests.

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http://hdl.handle.net/10453/135804