title: Interactions between elevated CO2 and warming could amplify DOC exports from peatland catchments.
abstract: Peatlands export more dissolved organic carbon (DOC) than any other biome, contributing 20% of all terrestrial DOC exported to the oceans. Both warming and elevated atmospheric CO2 (eCO2) can increase DOC exports, but their interaction is poorly understood. Peat monoliths were, therefore, exposed to eCO2, warming and eCO2 + warming (combined). The combined treatment produced a synergistic (i.e., significant interaction) rise in DOC concentrations available for export (119% higher than the control, interaction P < 0.05) and enriched this pool with phenolic compounds (284%). We attribute this to increased plant inputs, coupled with impaired microbial degradation induced by competition with the vegetation for nutrients and inhibitory phenolics. Root biomass showed a synergistic increase (407% relative to the control, P < 0.1 only), while exudate inputs increased additively. Phenol oxidase was suppressed synergistically (58%, interaction P < 0.1 only) and beta-glucosidase (27%) additively, while microbial nutritional stress increased (51%) additively. Such results suggest intensified carbon exports from peatlands, with potentially widespread ramifications for aquatic processes in the receiving waters.
authors.affiliation: School of Biological Sciences, Memorial Building, University of Wales, Bangor, Deiniol Road, Bangor, Gwynedd, LL57 2UW, UK. n.fenner@bangor.ac.uk
authors.forename: Nathalie
authors.initials: N
authors.lastname: Fenner
authors.forename: Christopher
authors.initials: C
authors.lastname: Freeman
authors.forename: Maurice A
authors.initials: MA
authors.lastname: Lock
authors.forename: Harry
authors.initials: H
authors.lastname: Harmens
authors.forename: Brian
authors.initials: B
authors.lastname: Reynolds
authors.forename: Tim
authors.initials: T
authors.lastname: Sparks
mesh_terms: D044002:Bryophyta / Q000254:growth & development; D002244:Carbon / Q000032:analysis*; D002245:Carbon Dioxide; D019684:Magnoliopsida / Q000254:growth & development; D014442:Monophenol Monooxygenase / Q000378:metabolism; D009584:Nitrogen / Q000032:analysis; D010636:Phenols / Q000032:analysis; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D012987:Soil; D013696:Temperature; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D010636:Phenols; D012987:Soil; D002245:Carbon Dioxide; D002244:Carbon; D014442:Monophenol Monooxygenase; D010744:Phosphoric Monoester Hydrolases; D001617:beta-Glucosidase; D009584:Nitrogen