Massive peatland carbon banks vulnerable to rising temperatures

A. M. Hopple, R. M. Wilson, M. Kolton, C. A. Zalman, J. P. Chanton, J. Kostka, P. J. Hanson, J. K. Keller, S. D. Bridgham

Research output: Contribution to journalArticlepeer-review

87 Scopus citations

Abstract

Peatlands contain one-third of the world’s soil carbon (C). If destabilized, decomposition of this vast C bank could accelerate climate warming; however, the likelihood of this outcome remains unknown. Here, we examine peatland C stability through five years of whole-ecosystem warming and two years of elevated atmospheric carbon dioxide concentrations (eCO2). Warming exponentially increased methane (CH4) emissions and enhanced CH4 production rates throughout the entire soil profile; although surface CH4 production rates remain much greater than those at depth. Additionally, older deeper C sources played a larger role in decomposition following prolonged warming. Most troubling, decreases in CO2:CH4 ratios in gas production, porewater concentrations, and emissions, indicate that the peatland is becoming more methanogenic with warming. We observed limited evidence of eCO2 effects. Our results suggest that ecosystem responses are largely driven by surface peat, but that the vast C bank at depth in peatlands is responsive to prolonged warming.

Original languageEnglish
Article number2373
JournalNature Communications
Volume11
Issue number1
DOIs
StatePublished - Dec 1 2020

Funding

This material is based upon work supported by the U. S. Department of Energy, Office of Science, Office of Biological and Environmental Research. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for the U. S. Department of Energy. Funding was provided by the U. S. Department of Energy under DE-SC0014416, DE-SC00008092, DE-AC05-00OR22725, DE-SC0007144 and DE-SC0012088. Radiocarbon samples were run at the National Ocean Sciences Accelerator Mass Spectrometry Facility (Falmouth, MA). We thank Samantha Bosman and Claire Wilson for preparing and running isotope samples, Laura McCullough and Jessica Rush for assisting in running anaerobic laboratory incubations and porewater chemistry analyses, and Laurel Pfeifer-Meister for her input on laboratory-based experimental design.

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