title: Degradation potentials of dissolved organic carbon (DOC) from thawed permafrost peat.
abstract: Global warming can substantially affect the export of dissolved organic carbon (DOC) from peat-permafrost to aquatic systems. The direct degradability of such peat-derived DOC, however, is poorly constrained because previous permafrost thaw studies have mainly addressed mineral soil catchments or DOC pools that have already been processed in surface waters. We incubated peat cores from a palsa mire to compare an active layer and an experimentally thawed permafrost layer with regard to DOC composition and degradation potentials of pore water DOC. Our results show that DOC from the thawed permafrost layer had high initial degradation potentials compared with DOC from the active layer. In fact, the DOC that showed the highest bio- and photo-degradability, respectively, originated in the thawed permafrost layer. Our study sheds new light on the DOC composition of peat-permafrost directly upon thaw and suggests that past estimates of carbon-dioxide emissions from thawed peat permafrost may be biased as they have overlooked the initial mineralization potential of the exported DOC.
authors.affiliation: Department of Physical Geography and Ecosystem Science, Lund University, Sweden.
authors.forename: Balathandayuthabani
authors.initials: B
authors.lastname: Panneer Selvam
authors.affiliation: Département de sciences biologiques, Université de Montréal, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Lapierre
authors.affiliation: Research Center for Watershed ̶ Aquatic Ecosystem Interactions (RIVE), Department of Environmental Sciences, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada.
authors.forename: Francois
authors.initials: F
authors.lastname: Guillemette
authors.affiliation: Department of Environmental and Biological Sciences, University of Eastern Finland, Finland.
authors.forename: Carolina
authors.initials: C
authors.lastname: Voigt
authors.affiliation: Department of Environmental and Biological Sciences, University of Eastern Finland, Finland.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Lamprecht
authors.affiliation: Department of Environmental and Biological Sciences, University of Eastern Finland, Finland.
authors.forename: Christina
authors.initials: C
authors.lastname: Biasi
authors.affiliation: Department of Physical Geography and Ecosystem Science, Lund University, Sweden.|Arctic Research Centre, Aarhus University, Denmark.
authors.forename: Torben R
authors.initials: TR
authors.lastname: Christensen
authors.affiliation: Department of Environmental and Biological Sciences, University of Eastern Finland, Finland.
authors.forename: Pertti J
authors.initials: PJ
authors.lastname: Martikainen
authors.affiliation: Department of Physical Geography and Ecosystem Science, Lund University, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Berggren