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Research article - Peer-reviewed, 2022

Soil carbon loss in warmed subarctic grasslands is rapid and restricted to topsoil

Verbrigghe, Niel; Leblans, Niki I. W.; Sigurdsson, Bjarni D.; Vicca, Sara; Fang, Chao; Fuchslueger, Lucia; Soong, Jennifer L.; Weedon, James T.; Poeplau, Christopher; Ariza-Carricondo, Cristina; Bahn, Michael; Guenet, Bertrand; Gundersen, Per; Gunnarsdottir, Gunnhildur E.; Kaetterer, Thomas; Liu, Zhanfeng; Maljanen, Marja; Maranon-Jimenez, Sara; Meeran, Kathiravan; Oddsdottir, Edda S.;
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Abstract

Global warming may lead to carbon transfers from soils to the atmosphere, yet this positive feedback to the climate system remains highly uncertain, especially in subsoils (Ilyina and Friedlingstein, 2016; Shi et al., 2018). Using natural geothermal soil warming gradients of up to +6.4 degrees C in subarctic grasslands (Sigurdsson et al., 2016), we show that soil organic carbon (SOC) stocks decline strongly and linearly with warming (-2.8 t ha(-1) degrees C-1). Comparison of SOC stock changes following medium-term (5 and 10 years) and long-term (> 50 years) warming revealed that all SOC stock reduction occurred within the first 5 years of warming, after which continued warming no longer reduced SOC stocks. This rapid equilibration of SOC observed in Andosol suggests a critical role for ecosystem adaptations to warming and could imply short-lived soil carbon-climate feedbacks. Our data further revealed that the soil C loss occurred in all aggregate size fractions and that SOC stock reduction was only visible in topsoil (0-10 cm). SOC stocks in subsoil (10-30 cm), where plant roots were absent, showed apparent conservation after > 50 years of warming. The observed depth-dependent warming responses indicate that explicit vertical resolution is a prerequisite for global models to accurately project future SOC stocks for this soil type and should be investigated for soils with other mineralogies.

Published in

Biogeosciences
2022, volume: 19, number: 14, pages: 3381-3393
Publisher: COPERNICUS GESELLSCHAFT MBH

Authors' information

Verbrigghe, Niel
University of Antwerp
Leblans, Niki I. W.
University of Antwerp
Leblans, Niki I. W.
Umea University
Sigurdsson, Bjarni D.
Agricultural University of Iceland (LBHI)
Vicca, Sara
University of Antwerp
Fang, Chao
University of Antwerp
Fang, Chao
Nanjing University of Information Science and Technology
Fang, Chao
Lanzhou University
Fuchslueger, Lucia
University of Antwerp
Fuchslueger, Lucia
University of Vienna
Soong, Jennifer L.
University of Antwerp
Soong, Jennifer L.
Colorado State University
Weedon, James T.
Vrije Universiteit Amsterdam
Poeplau, Christopher
Johann Heinrich von Thunen Institute
Ariza-Carricondo, Cristina
University of Antwerp
Bahn, Michael
University of Innsbruck
Guenet, Bertrand
Ecole Normale Superieure (ENS)
Gundersen, Per
University of Copenhagen
Gunnarsdóttir, Gunnhildur
Soil Conservation Service of Iceland
Swedish University of Agricultural Sciences, Department of Ecology
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Sustainable Development Goals

SDG13 Climate action

UKÄ Subject classification

Climate Research
Environmental Sciences
Soil Science

Publication Identifiers

DOI: https://doi.org/10.5194/bg-19-3381-2022

URI (permanent link to this page)

https://res.slu.se/id/publ/118442