TY - JOUR
T1 - Water response of ecosystem respiration regulates future projection of net ecosystem productivity in a semiarid grassland
AU - Lei, Lingjie
AU - Xia, Jianyang
AU - Li, Xiaona
AU - Huang, Kun
AU - Zhang, Ang
AU - Chen, Shiping
AU - Weng, Ensheng
AU - Luo, Yiqi
AU - Wan, Shiqiang
N1 - Funding Information:
We thank Hongyan Han, Yue Du, Qian Zhang, and Mingxing Zhong for providing experimental observations, and Dafeng Hui and Zheng Shi for the programming help. This work was financially supported by the National Key R&D Program of China (2017YFA0604600) and the National Natural Science Foundation (31430015, 41630528), Ministry of Science and Technology (2013CB956300), and the National 1000 Young Talents Program of China.
Funding Information:
We thank Hongyan Han, Yue Du, Qian Zhang, and Mingxing Zhong for providing experimental observations, and Dafeng Hui and Zheng Shi for the programming help. This work was financially supported by the National Key R&D Program of China ( 2017YFA0604600 ) and the National Natural Science Foundation ( 31430015 , 41630528 ), Ministry of Science and Technology ( 2013CB956300 ), and the National 1000 Young Talents Program of China .
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/4/15
Y1 - 2018/4/15
N2 - Recent evidences show that terrestrial biogeochemical models have large uncertainty in estimating climate-change effect on grassland net ecosystem productivity (NEP), which is defined as the difference between gross ecosystem photosynthesis (GEP) and respiration (ER). It remains unclear that whether GEP or ER limits the model capability to simulate NEP responses to climate change in semiarid grasslands. Given the surrogate CENTURY-type model is widely used for Earth system modeling, we investigated two of them (i.e., DAYCENT and TECO models) and examined which processes dominate their ability to capture the responses of NEP to experimental climate changes in a temperate steppe of northern China. During the simulation from 2006 to 2008, the two models captured the observed mean annual NEP in the control plots when they were validated by the observations from an adjacent eddy-flux tower. However, they failed to capture the treatment effects of experimental warming and increased precipitation on NEP because of the poor estimations of ER responses. DAYCENT model simulated a higher precipitation effect on ER (37.83%) and TECO model overestimated the warming effect on ER by 8.18%. The simulation of treatment effects on ER and therefore NEP can be improved by an optimized parameterization of the water-related decay functions for soil organic carbon (C). The simulated cumulative loss of total ecosystem C stock during 2010–2100 were decreased when the TECO model used experiment-fitted parameters (0.72 kg C m−2) instead of using the initial validation with eddy-flux data (0.96 kg C m−2). The ecosystem shifted from C sink to source at threshold of 435 mm of annual total precipitation. Our findings indicate that future projection of C cycle in semiarid grasslands could be improved by better understanding of water response of ecosystem respiratory processes.
AB - Recent evidences show that terrestrial biogeochemical models have large uncertainty in estimating climate-change effect on grassland net ecosystem productivity (NEP), which is defined as the difference between gross ecosystem photosynthesis (GEP) and respiration (ER). It remains unclear that whether GEP or ER limits the model capability to simulate NEP responses to climate change in semiarid grasslands. Given the surrogate CENTURY-type model is widely used for Earth system modeling, we investigated two of them (i.e., DAYCENT and TECO models) and examined which processes dominate their ability to capture the responses of NEP to experimental climate changes in a temperate steppe of northern China. During the simulation from 2006 to 2008, the two models captured the observed mean annual NEP in the control plots when they were validated by the observations from an adjacent eddy-flux tower. However, they failed to capture the treatment effects of experimental warming and increased precipitation on NEP because of the poor estimations of ER responses. DAYCENT model simulated a higher precipitation effect on ER (37.83%) and TECO model overestimated the warming effect on ER by 8.18%. The simulation of treatment effects on ER and therefore NEP can be improved by an optimized parameterization of the water-related decay functions for soil organic carbon (C). The simulated cumulative loss of total ecosystem C stock during 2010–2100 were decreased when the TECO model used experiment-fitted parameters (0.72 kg C m−2) instead of using the initial validation with eddy-flux data (0.96 kg C m−2). The ecosystem shifted from C sink to source at threshold of 435 mm of annual total precipitation. Our findings indicate that future projection of C cycle in semiarid grasslands could be improved by better understanding of water response of ecosystem respiratory processes.
KW - Carbon cycle
KW - Climate change
KW - Ecosystem respiration
KW - Manipulative experiment
KW - Terrestrial biogeochemical model
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U2 - 10.1016/j.agrformet.2018.01.020
DO - 10.1016/j.agrformet.2018.01.020
M3 - Article
AN - SCOPUS:85041479842
SN - 0168-1923
VL - 252
SP - 175
EP - 191
JO - Agricultural and Forest Meteorology
JF - Agricultural and Forest Meteorology
ER -