Gene-informed decomposition model predicts lower soil carbon loss due to persistent microbial adaptation to warming

Xue Guo,Chang Gyo Jung,Feifei Liu,James R Cole,Lijun Chen,Liyou Wu,Zhili He,Lauren Hale,Qun Gao,Xingkai Xu ,James M Tiedje,Mengting Yuan,Shuli Niu,Joy D Van Nostrand,Konstantinos T Konstantinidis,C Ryan Penton,Daliang Ning,Yunfeng Yang,Yiqi Luo,Bo Wu,Arthur Escalas,Lifen Jiang,Renmao Tian,Zhou Shi,Xueduan Liu,Jiajie Feng,Edward A G Schuur ,Xuelong Zhou ,Dejun Li,Linwei Wu,Gangsheng Wang,Aifen Zhou,Jizhong Zhou

doi:10.1038/s41467-020-18706-z

Abstract

Soil microbial respiration is an important source of uncertainty in projecting future climate and carbon (C) cycle feedbacks. However, its feedbacks to climate warming and underlying microbial mechanisms are still poorly understood. Here we show that the temperature sensitivity of soil microbial respiration (Q10) in a temperate grassland ecosystem persistently decreases by 12.0 ± 3.7% across 7 years of warming. Also, the shifts of microbial communities play critical roles in regulating thermal adaptation of soil respiration. Incorporating microbial functional gene abundance data into a microbially-enabled ecosystem model significantly improves the modeling performance of soil microbial respiration by 5–19%, and reduces model parametric uncertainty by 55–71%. In addition, modeling analyses show that the microbial thermal adaptation can lead to considerably less heterotrophic respiration (11.6 ± 7.5%), and hence less soil C loss. If such microbially mediated dampening effects occur generally across different spatial and temporal scales, the potential positive feedback of soil microbial respiration in response to climate warming may be less than previously predicted.

Highlights

Soil microbial respiration is an important source of uncertainty in projecting future climate and carbon (C) cycle feedbacks
Our main objectives are to answer the following questions: (i) How does long-term experimental warming affect the temperature responses of soil microbial respiration over time? (ii) Whether or not thermal adaptation of microbial respiration occurs persistently across years under warming and by what underlying mechanisms? (iii) Can the microbial mechanisms underlying soil respiration be incorporated into ecosystem models to improve model performance and reduce model uncertainty? Our study reveals that thermal adaptation of microbial respiration exists persistently over the long-term and that the shifts of microbial communities play critical roles in regulating such thermal adaptation of microbial respiration
C3 plant biomass was significantly (p < 0.01) lower under warming than control, but no significant change was observed in C4 and total plant biomass (Supplementary Fig. 1a), which results in a plant community shift towards relatively more C4 plants

Summary

Results and discussion

C3 plant biomass was significantly (p < 0.01) lower under warming than control, but no significant change was observed in C4 and total plant biomass (Supplementary Fig. 1a), which results in a plant community shift towards relatively more C4 plants. No overall differences were detected in total organic C (TOC), total nitrogen (TN) and soil pH (Supplementary Fig. 1b, c), but the amount of NO3− was significantly (p < 0.05) higher under warming than control (Supplementary Fig. 1c). These alterations in ecosystem variables by warming are expected to lead to changes in soil respirations and microbial community functions.

50 Decomposition

Methods

Code availability