TY - JOUR
T1 - The surface-atmosphere exchange of carbon dioxide in tropical rainforests
T2 - Sensitivity to environmental drivers and flux measurement methodology
AU - Fu, Zheng
AU - Gerken, Tobias
AU - Bromley, Gabriel
AU - Araújo, Alessandro
AU - Bonal, Damien
AU - Burban, Benoît
AU - Ficklin, Darren
AU - Fuentes, Jose D.
AU - Goulden, Michael
AU - Hirano, Takashi
AU - Kosugi, Yoshiko
AU - Liddell, Michael
AU - Nicolini, Giacomo
AU - Niu, Shuli
AU - Roupsard, Olivier
AU - Stefani, Paolo
AU - Mi, Chunrong
AU - Tofte, Zaddy
AU - Xiao, Jingfeng
AU - Valentini, Riccardo
AU - Wolf, Sebastian
AU - Stoy, Paul C.
N1 - Funding Information:
PCS and JDF acknowledges funding support from the U.S. Department of Energy as part of the GoAmazon project (Grant SC0011097 ). PCS additionally acknowledges the U.S. National Science Foundation grants 1552976 and 1702029 , and The Graduate School at Montana State University . ZF is supported by the China Scholarship Council and National Natural Science Foundation of China ( 31625006 ). This work used eddy covariance data acquired and shared by the FLUXNET community, including the AmeriFlux, AfriFlux, AsiaFlux, CarboAfrica, LBA, and TERN- OzFlux networks. The FLUXNET eddy covariance data processing and harmonization was carried out by the ICOS Ecosystem Thematic Center, AmeriFlux Management Project and Fluxdata project of FLUXNET, with the support of CDIAC, and the OzFlux, ChinaFlux and AsiaFlux offices. The Guyaflux program belongs to the SOERE F-ORE-T which is supported annually by Ecofor, Allenvi and the French national research infrastructure ANAEE-F. The Guyaflux program also received support from the "Observatoire du Carbone en Guyane" and an "investissement d'avenir" grant from the Agence Nationale de la Recherche (CEBA, ref ANR-10-LABX-25-01). Funding for the site PA-SPn was provided by the North-South Centre of ETH Zurich. We acknowledge the World Climate Research Programme's Working Group on Coupled Modeling for the CMIP and thank the climate modeling groups for producing and making available their model output. For CMIP, the U.S. Department of Energy's Program for Climate Model Diagnosis and Intercomparison provides coordinating support and led development of software infrastructure in partnership with the Global Organization for Earth System Science Portals. Angela Tang and Taylor Rodenburg provided valuable comments to earlier drafts of this manuscript. We thank Dr. Tim Hill and two anonymous reviewers for their constructive comments on the manuscript.
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/12/15
Y1 - 2018/12/15
N2 - Tropical rainforests play a central role in the Earth system by regulating climate, maintaining biodiversity, and sequestering carbon. They are under threat by direct anthropogenic impacts like deforestation and the indirect anthropogenic impacts of climate change. A synthesis of the factors that determine the net ecosystem exchange of carbon dioxide (NEE) at the site scale across different forests in the tropical rainforest biome has not been undertaken to date. Here, we study NEE and its components, gross ecosystem productivity (GEP) and ecosystem respiration (RE), across thirteen natural and managed forests within the tropical rainforest biome with 63 total site-years of eddy covariance data. Our results reveal that the five ecosystems with the largest annual gross carbon uptake by photosynthesis (i.e. GEP > 3000 g C m−2 y-1) have the lowest net carbon uptake – or even carbon losses – versus other study ecosystems because RE is of a similar magnitude. Sites that provided subcanopy CO2 storage observations had higher average magnitudes of GEP and RE and lower average magnitudes of NEE, highlighting the importance of measurement methodology for understanding carbon dynamics in ecosystems with characteristically tall and dense vegetation. A path analysis revealed that vapor pressure deficit (VPD) played a greater role than soil moisture or air temperature in constraining GEP under light saturated conditions across most study sites, but to differing degrees from -0.31 to -0.87 μmol CO2 m−2 s-1 hPa-1. Climate projections from 13 general circulation models (CMIP5) under the representative concentration pathway that generates 8.5 W m−2 of radiative forcing suggest that many current tropical rainforest sites on the lower end of the current temperature range are likely to reach a climate space similar to present-day warmer sites by the year 2050, warmer sites will reach a climate not currently experienced, and all forests are likely to experience higher VPD. Results demonstrate the need to quantify if and how mature tropical trees acclimate to heat and water stress, and to further develop flux-partitioning and gap-filling algorithms for defensible estimates of carbon exchange in tropical rainforests.
AB - Tropical rainforests play a central role in the Earth system by regulating climate, maintaining biodiversity, and sequestering carbon. They are under threat by direct anthropogenic impacts like deforestation and the indirect anthropogenic impacts of climate change. A synthesis of the factors that determine the net ecosystem exchange of carbon dioxide (NEE) at the site scale across different forests in the tropical rainforest biome has not been undertaken to date. Here, we study NEE and its components, gross ecosystem productivity (GEP) and ecosystem respiration (RE), across thirteen natural and managed forests within the tropical rainforest biome with 63 total site-years of eddy covariance data. Our results reveal that the five ecosystems with the largest annual gross carbon uptake by photosynthesis (i.e. GEP > 3000 g C m−2 y-1) have the lowest net carbon uptake – or even carbon losses – versus other study ecosystems because RE is of a similar magnitude. Sites that provided subcanopy CO2 storage observations had higher average magnitudes of GEP and RE and lower average magnitudes of NEE, highlighting the importance of measurement methodology for understanding carbon dynamics in ecosystems with characteristically tall and dense vegetation. A path analysis revealed that vapor pressure deficit (VPD) played a greater role than soil moisture or air temperature in constraining GEP under light saturated conditions across most study sites, but to differing degrees from -0.31 to -0.87 μmol CO2 m−2 s-1 hPa-1. Climate projections from 13 general circulation models (CMIP5) under the representative concentration pathway that generates 8.5 W m−2 of radiative forcing suggest that many current tropical rainforest sites on the lower end of the current temperature range are likely to reach a climate space similar to present-day warmer sites by the year 2050, warmer sites will reach a climate not currently experienced, and all forests are likely to experience higher VPD. Results demonstrate the need to quantify if and how mature tropical trees acclimate to heat and water stress, and to further develop flux-partitioning and gap-filling algorithms for defensible estimates of carbon exchange in tropical rainforests.
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U2 - 10.1016/j.agrformet.2018.09.001
DO - 10.1016/j.agrformet.2018.09.001
M3 - Article
AN - SCOPUS:85053139172
VL - 263
SP - 292
EP - 307
JO - Agricultural and Forest Meteorology
JF - Agricultural and Forest Meteorology
SN - 0168-1923
ER -