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Composition and concentration of root exudate analogues regulate greenhouse gas fluxes from tropical peat

Girkin, N.T.; Turner, B.L.; Ostle, N.; Sjögersten, S.


N.T. Girkin

B.L. Turner

N. Ostle


Tropical peatlands are a significant carbon store and source of carbon dioxide (CO2) and methane (CH4) to the atmosphere. Plants can contribute to these gas emissions through the release of root exudates, including sugars and organic acids amongst other biomolecules, but the roles of concentration and composition of exudates in regulating emissions remains poorly understood. We conducted a laboratory incubation to assess how the type and concentration of root exudate analogues regulate CO2 and CH4 production from tropical peats under anoxic conditions. For CO2 production, substrate concentration was the more important driver, with increased CO2 fluxes following higher addition rates of four out of the six exudate analogues. In contrast, exudate type was the more important driver of CH4 production, with acetate addition associated with the greatest production, and inverse correlations between exudate concentration and CH4 emission for the remaining five treatments. Root exudate analogues also altered pH and redox potential, dependent on the type of addition (organic acid or sugar) and the concentration. Overall, these findings demonstrate the contrasting roles of composition and concentration of root exudate inputs in regulating greenhouse gas emissions from tropical peatlands. In turn this highlights how changes in plant communities will influence emissions through species specific inputs, and the possible impacts of increased root exudation driven by rising atmospheric CO2 and warming.


Girkin, N., Turner, B., Ostle, N., & Sjögersten, S. (2018). Composition and concentration of root exudate analogues regulate greenhouse gas fluxes from tropical peat. Soil Biology and Biochemistry, 127, (280-285). doi:10.1016/j.soilbio.2018.09.033. ISSN 0038-0717

Journal Article Type Article
Acceptance Date Sep 29, 2018
Online Publication Date Oct 3, 2018
Publication Date 2018-12
Deposit Date Oct 9, 2018
Publicly Available Date Oct 11, 2018
Journal Soil Biology and Biochemistry
Print ISSN 0038-0717
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 127
Pages 280-285
Keywords Tropical peat; Carbon dioxide; Methane; Root exudates; Organic acids; Methanogenesis
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