AUTHOR=Liu Dan , Zhang Wenling , Xiong Chunmei , Nie Qingyu 

TITLE=Warming increases the relative change in the turnover rate of decadally cycling soil carbon in microbial biomass carbon and soil respiration

JOURNAL=Frontiers in Earth Science

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2022.1089544

DOI=10.3389/feart.2022.1089544

ISSN=2296-6463

ABSTRACT=<p>Decadally cycling soil carbon (dSOC) is the main component of the terrestrial soil carbon (C) pool. The response of dSOC to warming largely determines the feedback between climate warming and the C cycle. However, there is a lack of investigations about the effect of warming on the relative change in turnover rate (RCT) of dSOC and annually cycling SOC (aSOC) in dissolved organic carbon (DOC), microbial biomass carbon (MBC) and CO<sub>2</sub>. We clarified this issue by incubating two C<sub>3</sub>-C<sub>4</sub> vegetation switch soils (23 years switch, HA soil and 55 years switch, GG soil) at 20°C and 30°C in the recently improved continuous airflow CO<sub>2</sub> trapping system for 1 year. Warming increased the contribution of dSOC (C<sub>3</sub>-C) by 21℅ (soil HA) and 8℅ (soil GG) in MBC, and 38℅ (soil HA) and 15℅ (soil GG) in CO<sub>2</sub>, while only 2%–3℅ increase in DOC at the final stage of the incubation. Furthermore, warming increased the RCT in MBC and CO<sub>2</sub> by 5.3- and 4.1-fold, respectively, but had no significant influence on the RCT in DOC, indicating that soil microbes may be an important engine to accelerate dSOC-derived CO<sub>2</sub> emission in a warming world.</p>