Soil carbon loss with warming: New evidence from carbon‐degrading enzymes

• Published in: Global change biology Vol. 26; no. 4; pp. 1944 - 1952
• Main Authors: Chen, Ji, Elsgaard, Lars, Groenigen, Kees Jan, Olesen, Jørgen E., Liang, Zhi, Jiang, Yu, Lærke, Poul E., Zhang, Yuefang, Luo, Yiqi, Hungate, Bruce A., Sinsabaugh, Robert L., Jørgensen, Uffe
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.04.2020
• Subjects: Carbon; Carbon dioxide; Cellulase; Climate; Climate change; Climate prediction; climate‐carbon feedback; Enzymes; experimental warming; Extracellular; extracellular enzyme; Extracellular enzymes; Global warming; labile carbon pool; Ligninase; Microorganisms; Ratios; recalcitrant carbon pool; Soil; soil carbon storage; Soil dynamics; Soil erosion; soil microorganism; Soil microorganisms; Soils; Stocks; Storage; warming duration; experimental warming; labile carbon pool; recalcitrant carbon pool; warming duration; climate-carbon feedback; soil microorganism; extracellular enzyme; soil carbon storage
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/gcb.14986

Climate warming affects soil carbon (C) dynamics, with possible serious consequences for soil C stocks and atmospheric CO2 concentrations. However, the mechanisms underlying changes in soil C storage are not well understood, hampering long‐term predictions of climate C‐feedbacks. The activity of the extracellular enzymes ligninase and cellulase can be used to track changes in the predominant C sources of soil microbes and can thus provide mechanistic insights into soil C loss pathways. Here we show, using meta‐analysis, that reductions in soil C stocks with warming are associated with increased ratios of ligninase to cellulase activity. Furthermore, whereas long‐term (≥5 years) warming reduced the soil recalcitrant C pool by 14%, short‐term warming had no significant effect. Together, these results suggest that warming stimulates microbial utilization of recalcitrant C pools, possibly exacerbating long‐term climate‐C feedbacks. Our results, for the first time, identify progressive shifts from cellulase to ligninase as key drivers of soil C storage to long‐term experimental warming. These results provide new insights to reconcile the highly debated topic of the effects of climate warming on soil C storage, particularly for long‐term climate warming.