Carbon loss from northern circumpolar permafrost soils amplified by rhizosphere priming

• Published in: Nature Geoscience
• Main Authors: Keuper, Frida, Wild, Birgit, Kummu, Matti, Beer, Christian, Blume-Werry, Gesche, Fontaine, Sébastien, Gavazov, Konstantin, Gentsch, Norman, Guggenberger, Georg, Hugelius, Gustaf, Jalava, Mika, Koven, Charles, Krab, Eveline, Kuhry, Peter, Monteux, Sylvain, Richter, Andreas, Shahzad, Tanvir, Weedon, James, Dorrepaal, Ellen
• Other Authors: Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Transfrontalière BioEcoAgro - UMR 1158 (BioEcoAgro), Université d'Artois (UA)-Université de Liège-Université de Picardie Jules Verne (UPJV)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL), Climate Impacts Research Centre (CIRC), Umeå University, Stockholm University, Bolin Centre for Climate Research, Department of Earth Sciences Gothenburg, University of Gothenburg (GU), Aalto University School of Science and Technology Aalto, Finland, Universität Hamburg (UHH), Center for Earth System Research and Sustainability (CEN), Department of Mathematics Stockholm University, Swedish Academy, Universität Greifswald - University of Greifswald, Unité Mixte de Recherche sur l'Ecosystème Prairial - UMR (UREP), VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Leibniz Universität Hannover=Leibniz University Hannover, Lawrence Berkeley National Laboratory Berkeley (LBNL), Swedish University of Agricultural Sciences (SLU), University of Vienna Vienna, International Institute for Applied Systems Analysis Laxenburg (IIASA), Government College University of Faisalabad (GCUF), Vrije Universiteit Amsterdam Amsterdam (VU)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: Organic-matter; Arctic vegetation; Climate change; Root; Decomposition; Respiration; Temperature; Nitrogen; [SDE.MCG]Environmental Sciences/Global Changes; Arctic; Global warming; permafrost
• Online Access: https://hal.science/hal-03027874; https://doi.org/10.1038/s41561-020-0607-0

International audience As global temperatures continue to rise, a key uncertainty of climate projections is the microbial decomposition of vast organic carbon stocks in thawing permafrost soils. Decomposition rates can accelerate up to fourfold in the presence of plant roots, and this mechanism-termed the rhizosphere priming effect-may be especially relevant to thawing permafrost soils as rising temperatures also stimulate plant productivity in the Arctic. However, priming is currently not explicitly included in any model projections of future carbon losses from the permafrost area. Here, we combine high-resolution spatial and depth-resolved datasets of key plant and permafrost properties with empirical relationships of priming effects from living plants on microbial respiration. We show that rhizosphere priming amplifies overall soil respiration in permafrost-affected ecosystems by similar to 12%, which translates to a priming-induced absolute loss of similar to 40 Pg soil carbon from the northern permafrost area by 2100. Our findings highlight the need to include fine-scale ecological interactions in order to accurately predict large-scale greenhouse gas emissions, and suggest even tighter restrictions on the estimated 200 Pg anthropogenic carbon emission budget to keep global warming below 1.5 degrees C.