Winter warming in Alaska accelerates lignin decomposition contributed by Proteobacteria
Posted on 2020-06-06 - 03:34
Abstract Background In a warmer world, microbial decomposition of previously frozen organic carbon (C) is one of the most likely positive climate feedbacks of permafrost regions to the atmosphere. However, mechanistic understanding of microbial mediation on chemically recalcitrant C instability is limited; thus, it is crucial to identify and evaluate active decomposers of chemically recalcitrant C, which is essential for predicting C-cycle feedbacks and their relative strength of influence on climate change. Using stable isotope probing of the active layer of Arctic tundra soils after depleting soil labile C through a 975-day laboratory incubation, the identity of microbial decomposers of lignin and, their responses to warming were revealed. Results The β-Proteobacteria genus Burkholderia accounted for 95.1% of total abundance of potential lignin decomposers. Consistently, Burkholderia isolated from our tundra soils could grow with lignin as the sole C source. A 2.2 °C increase of warming considerably increased total abundance and functional capacities of all potential lignin decomposers. In addition to Burkholderia, α-Proteobacteria capable of lignin decomposition (e.g. Bradyrhizobium and Methylobacterium genera) were stimulated by warming by 82-fold. Those community changes collectively doubled the priming effect, i.e., decomposition of existing C after fresh C input to soil. Consequently, warming aggravates soil C instability, as verified by microbially enabled climate-C modeling. Conclusions Our findings are alarming, which demonstrate that accelerated C decomposition under warming conditions will make tundra soils a larger biospheric C source than anticipated. Video Abstract
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Tao, Xuanyu; Feng, Jiajie; Yang, Yunfeng; Wang, Gangsheng; Tian, Renmao; Fan, Fenliang; et al. (2020). Winter warming in Alaska accelerates lignin decomposition contributed by Proteobacteria. figshare. Collection. https://doi.org/10.6084/m9.figshare.c.5010137.v1
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AUTHORS (23)
XT
Xuanyu Tao
JF
Jiajie Feng
YY
Yunfeng Yang
GW
Gangsheng Wang
RT
Renmao Tian
FF
Fenliang Fan
DN
Daliang Ning
CB
Colin T. Bates
LH
Lauren Hale
MY
Mengting M. Yuan
LW
Linwei Wu
QG
Qun Gao
JL
Jiesi Lei
ES
Edward A. G. Schuur
JY
Julian Yu
RB
Rosvel Bracho
YL
Yiqi Luo
KK
Konstantinos T. Konstantinidis
EJ
Eric R. Johnston
JC
James R. Cole