Carbon loss from northern circumpolar permafrost soils amplified by rhizosphere priming

authored by

Frida Keuper, Birgit Wild, Matti Kummu, Christian Beer, Gesche Blume-Werry, Sébastien Fontaine, Konstantin Gavazov, Norman Gentsch, Georg Guggenberger, Gustaf Hugelius, Mika Jalava, Charles Koven, Eveline J. Krab, Peter Kuhry, Sylvain Monteux, Andreas Richter, Tanvir Shahzad, James T. Weedon, Ellen Dorrepaal

Abstract

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 ~12%, which translates to a priming-induced absolute loss of ~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 °C.

Organisation(s)

Institute of Soil Science

External Organisation(s)

Umea University
Stockholm University
University of Gothenburg
Aalto University
Universität Hamburg
University of Greifswald
Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)
Lawrence Berkeley National Laboratory
Swedish University of Agricultural Sciences
University of Vienna
International Institute for Applied Systems Analysis, Laxenburg
Government College University Faisalabad
Vrije Universiteit
Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE)
Russian Academy of Sciences (RAS)

Type

Article

Journal

Nature geoscience

Volume

13

Pages

560-565

No. of pages

6

ISSN

1752-0894

Publication date

08.2020

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General Earth and Planetary Sciences

Sustainable Development Goals

SDG 13 - Climate Action

Electronic version(s)

https://aaltodoc.aalto.fi/handle/123456789/45714 (Access: Open)
https://doi.org/10.1038/s41561-020-0607-0 (Access: Closed)