TY - JOUR
T1 - Temperature sensitivity of soil organic carbon decomposition increased with mean carbon residence time
T2 - Field incubation and data assimilation
AU - Zhou, Xuhui
AU - Xu, Xia
AU - Zhou, Guiyao
AU - Luo, Yiqi
N1 - Funding Information:
National Natural Science Foundation of China, Grant/Award Number: 31370489, 31770559; “Thousand Young Talents” Program in China; US National Science Foundation (NSF), Grant/Award Number: DEB 0743778, DEB 0840964, DBI 0850290, ESP 0919466; Terrestrial Carbon Program at the Office of Science; US Department of Energy, Grant/Award Number: DE-FG03-99ER62800, DE-FG02-006ER64317
Funding Information:
The authors thank Dr. Eric Davidson and three anonymous reviewers for their insightful comments and suggestions. This research has also been benefited from discussions with Yuanhe Yang, Shuli Niu, Rebecca Sherry, and Christina Schaedel in the early stage of manuscript. This research was financially supported by the National Natural Science Foundation of China (Grant No. 31370489, 31770559), the “Thousand Young Talents” Program in China, US National Science Foundation (NSF) under DEB 0743778, DEB 0840964, DBI 0850290, and ESP 0919466, and by the Terrestrial Carbon Program at the Office of Science, US Department of Energy, Grants No.: DE-FG03-99ER62800 and DE-FG02-006ER64317.
Publisher Copyright:
© 2017 John Wiley & Sons Ltd
PY - 2018/2/1
Y1 - 2018/2/1
N2 - Temperature sensitivity of soil organic carbon (SOC) decomposition is one of the major uncertainties in predicting climate-carbon (C) cycle feedback. Results from previous studies are highly contradictory with old soil C decomposition being more, similarly, or less sensitive to temperature than decomposition of young fractions. The contradictory results are partly from difficulties in distinguishing old from young SOC and their changes over time in the experiments with or without isotopic techniques. In this study, we have conducted a long-term field incubation experiment with deep soil collars (0–70 cm in depth, 10 cm in diameter of PVC tubes) for excluding root C input to examine apparent temperature sensitivity of SOC decomposition under ambient and warming treatments from 2002 to 2008. The data from the experiment were infused into a multi-pool soil C model to estimate intrinsic temperature sensitivity of SOC decomposition and C residence times of three SOC fractions (i.e., active, slow, and passive) using a data assimilation (DA) technique. As active SOC with the short C residence time was progressively depleted in the deep soil collars under both ambient and warming treatments, the residences times of the whole SOC became longer over time. Concomitantly, the estimated apparent and intrinsic temperature sensitivity of SOC decomposition also became gradually higher over time as more than 50% of active SOC was depleted. Thus, the temperature sensitivity of soil C decomposition in deep soil collars was positively correlated with the mean C residence times. However, the regression slope of the temperature sensitivity against the residence time was lower under the warming treatment than under ambient temperature, indicating that other processes also regulated temperature sensitivity of SOC decomposition. These results indicate that old SOC decomposition is more sensitive to temperature than young components, making the old C more vulnerable to future warmer climate.
AB - Temperature sensitivity of soil organic carbon (SOC) decomposition is one of the major uncertainties in predicting climate-carbon (C) cycle feedback. Results from previous studies are highly contradictory with old soil C decomposition being more, similarly, or less sensitive to temperature than decomposition of young fractions. The contradictory results are partly from difficulties in distinguishing old from young SOC and their changes over time in the experiments with or without isotopic techniques. In this study, we have conducted a long-term field incubation experiment with deep soil collars (0–70 cm in depth, 10 cm in diameter of PVC tubes) for excluding root C input to examine apparent temperature sensitivity of SOC decomposition under ambient and warming treatments from 2002 to 2008. The data from the experiment were infused into a multi-pool soil C model to estimate intrinsic temperature sensitivity of SOC decomposition and C residence times of three SOC fractions (i.e., active, slow, and passive) using a data assimilation (DA) technique. As active SOC with the short C residence time was progressively depleted in the deep soil collars under both ambient and warming treatments, the residences times of the whole SOC became longer over time. Concomitantly, the estimated apparent and intrinsic temperature sensitivity of SOC decomposition also became gradually higher over time as more than 50% of active SOC was depleted. Thus, the temperature sensitivity of soil C decomposition in deep soil collars was positively correlated with the mean C residence times. However, the regression slope of the temperature sensitivity against the residence time was lower under the warming treatment than under ambient temperature, indicating that other processes also regulated temperature sensitivity of SOC decomposition. These results indicate that old SOC decomposition is more sensitive to temperature than young components, making the old C more vulnerable to future warmer climate.
KW - C turnover time
KW - data assimilation
KW - field incubation
KW - soil organic carbon decomposition
KW - warming
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U2 - 10.1111/gcb.13994
DO - 10.1111/gcb.13994
M3 - Article
C2 - 29314486
AN - SCOPUS:85041366098
SN - 1354-1013
VL - 24
SP - 810
EP - 822
JO - Global change biology
JF - Global change biology
IS - 2
ER -