Forest soil carbon oxidation state and oxidative ratio responses to elevated CO2

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dc.citation.firstpage1797en_US
dc.citation.issueNumber9en_US
dc.citation.journalTitleJournal of Geophysical Research: Biogeosciencesen_US
dc.citation.lastpage1811en_US
dc.citation.volumeNumber120en_US
dc.contributor.authorHockaday, William C.en_US
dc.contributor.authorGallagher, Morgan E.en_US
dc.contributor.authorMasiello, Caroline A.en_US
dc.contributor.authorBaldock, Jeffrey A.en_US
dc.contributor.authorIversen, Colleen M.en_US
dc.contributor.authorNorby, Richard J.en_US
dc.date.accessioned2016-06-24T21:35:01Zen_US
dc.date.available2016-06-24T21:35:01Zen_US
dc.date.issued2015en_US
dc.description.abstractThe oxidative ratio (OR) of the biosphere is the stoichiometric ratio (O2/CO2) of gas exchange by photosynthesis and respiration—a key parameter in budgeting calculations of the land and ocean carbon sinks. Carbon cycle-climate feedbacks could alter the OR of the biosphere by affecting the quantity and quality of organic matter in plant biomass and soil carbon pools. This study considers the effect of elevated atmospheric carbon dioxide concentrations ([CO2]) on the OR of a hardwood forest after nine growing seasons of Free-Air CO2 Enrichment. We measured changes in the carbon oxidation state (Cox) of biomass and soil carbon pools as a proxy for the ecosystem OR. The OR of net primary production, 1.039, was not affected by elevated [CO2]. However, the Cox of the soil carbon pool was 40% higher at elevated [CO2], and the estimated OR values for soil respiration increased from 1.006 at ambient [CO2] to 1.054 at elevated [CO2]. A biochemical inventory of the soil organic matter ascribed the increases in Cox and OR to faster turnover of reduced substrates, lignin and lipids, at elevated [CO2]. This implicates the heterotrophic soil community response to elevated [CO2] as a driver of disequilibrium in the ecosystem OR. The oxidation of soil carbon pool constitutes an unexpected terrestrial O2 sink. Carbon budgets constructed under the assumption of OR equilibrium would equate such a terrestrial O2 sink to CO2 uptake by the ocean. The potential for climate-driven disequilibriua in the cycling of O2 and CO2 warrants further investigation.en_US
dc.identifier.citationHockaday, William C., Gallagher, Morgan E., Masiello, Caroline A., et al.. "Forest soil carbon oxidation state and oxidative ratio responses to elevated CO2." <i>Journal of Geophysical Research: Biogeosciences,</i> 120, no. 9 (2015) Wiley: 1797-1811. http://dx.doi.org/10.1002/2015JG003010.en_US
dc.identifier.doihttp://dx.doi.org/10.1002/2015JG003010en_US
dc.identifier.urihttps://hdl.handle.net/1911/90559en_US
dc.language.isoengen_US
dc.publisherWileyen_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.titleForest soil carbon oxidation state and oxidative ratio responses to elevated CO2en_US
dc.typeJournal articleen_US
dc.type.dcmiTexten_US
dc.type.publicationpublisher versionen_US
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