Rights statement: This is the peer reviewed version of the following article: Ryan, E. M., Ogle, K., Peltier, D., Walker, A. P., De Kauwe, M. G., Medlyn, B. E., Williams, D. G., Parton, W., Asao, S., Guenet, B., Harper, A. B., Lu, X., Luus, K. A., Zaehle, S., Shu, S., Werner, C., Xia, J. and Pendall, E. (2017), Gross primary production responses to warming, elevated CO2, and irrigation: quantifying the drivers of ecosystem physiology in a semiarid grassland. Glob Change Biol, 23: 3092–3106. doi:10.1111/gcb.13602 which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/gcb.13602/abstract This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
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Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Gross primary production responses to warming, elevated CO2, and irrigation
T2 - quantifying the drivers of ecosystem physiology in a semiarid grassland
AU - Ryan, Edmund
AU - Ogle, Kiona
AU - Peltier, Drew
AU - Walker, Anthony
AU - De Kauwe, Martin
AU - Medlyn, Belinda
AU - Williams, David
AU - Parton, William
AU - Asao, Shinichi
AU - Guenet, Bertrand
AU - Harper, Anna
AU - Lu, Xingjie
AU - Luus, Kristina
AU - Shu, Shijie
AU - Werner, Christian
AU - Xia, Jianyang
AU - Zaehle, Sonke
AU - Pendall, Elise
N1 - This is the peer reviewed version of the following article: Ryan, E. M., Ogle, K., Peltier, D., Walker, A. P., De Kauwe, M. G., Medlyn, B. E., Williams, D. G., Parton, W., Asao, S., Guenet, B., Harper, A. B., Lu, X., Luus, K. A., Zaehle, S., Shu, S., Werner, C., Xia, J. and Pendall, E. (2017), Gross primary production responses to warming, elevated CO2, and irrigation: quantifying the drivers of ecosystem physiology in a semiarid grassland. Glob Change Biol, 23: 3092–3106. doi:10.1111/gcb.13602 which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/gcb.13602/abstract This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
PY - 2017/8
Y1 - 2017/8
N2 - Determining whether the terrestrial biosphere will be a source or sink of carbon (C) under a future climate of elevated CO2 (eCO2) and warming requires accurate quantification of gross primary production (GPP), the largest flux of C in the global C cycle. We evaluated six years (2007-2012) of flux-derived GPP data (~2500 values) from the Prairie Heating and CO2 Enrichment (PHACE) experiment, situated in a mixed prairie grassland in Wyoming, USA. The GPP data were used to calibrate a light response model whose basic formulation has been successfully used in a variety of ecosystems. The model, however, was extended to allow for variable maximum photosynthetic rate (Amax) and light-use efficiency (Q) by modeling these terms as functions of time varying driving variables (soil water content, air temperature, vapor pressure deficit, vegetation greenness, nitrogen) at current and antecedent (past) time scales. The model fit the observed GPP well (R2 = 0.79), which was confirmed by other model performance checks (deviance information criterion and posterior predictive loss) that compared different variants of the model (e.g., with and without antecedent effects). Stimulation of cumulative six-year GPP by warming (29%, P=0.02) and eCO2 (26%, P=0.07) was primarily driven by enhanced C uptake during spring (129%, P=0.001) and fall (124%, P=0.001), respectively. These enhancements were consistent across each year, suggesting mechanisms for extending the growing season. Antecedent air temperature (Tairant) and vapor pressure deficit (VPDant) effects on Amax were the most significant predictors of temporal variability in GPP among most treatments. The importance of VPDant suggests that atmospheric drought plays an important role for predicting GPP under current and future climate. Given the limited research supporting the role of VPDant in this context, we highlight the need for experimental studies to identify the mechanisms underlying such antecedent effects.
AB - Determining whether the terrestrial biosphere will be a source or sink of carbon (C) under a future climate of elevated CO2 (eCO2) and warming requires accurate quantification of gross primary production (GPP), the largest flux of C in the global C cycle. We evaluated six years (2007-2012) of flux-derived GPP data (~2500 values) from the Prairie Heating and CO2 Enrichment (PHACE) experiment, situated in a mixed prairie grassland in Wyoming, USA. The GPP data were used to calibrate a light response model whose basic formulation has been successfully used in a variety of ecosystems. The model, however, was extended to allow for variable maximum photosynthetic rate (Amax) and light-use efficiency (Q) by modeling these terms as functions of time varying driving variables (soil water content, air temperature, vapor pressure deficit, vegetation greenness, nitrogen) at current and antecedent (past) time scales. The model fit the observed GPP well (R2 = 0.79), which was confirmed by other model performance checks (deviance information criterion and posterior predictive loss) that compared different variants of the model (e.g., with and without antecedent effects). Stimulation of cumulative six-year GPP by warming (29%, P=0.02) and eCO2 (26%, P=0.07) was primarily driven by enhanced C uptake during spring (129%, P=0.001) and fall (124%, P=0.001), respectively. These enhancements were consistent across each year, suggesting mechanisms for extending the growing season. Antecedent air temperature (Tairant) and vapor pressure deficit (VPDant) effects on Amax were the most significant predictors of temporal variability in GPP among most treatments. The importance of VPDant suggests that atmospheric drought plays an important role for predicting GPP under current and future climate. Given the limited research supporting the role of VPDant in this context, we highlight the need for experimental studies to identify the mechanisms underlying such antecedent effects.
KW - gross primary production
KW - elevated CO2
KW - warming
KW - multi-factor global change experiment
KW - Bayesian modelling
KW - carbon cycle
KW - grasslands
U2 - 10.1111/gcb.13602
DO - 10.1111/gcb.13602
M3 - Journal article
VL - 23
SP - 3092
EP - 3106
JO - Global Change Biology
JF - Global Change Biology
SN - 1354-1013
IS - 8
ER -