title: Climatic warming increases isoprene emission from a subarctic heath.
abstract: Emissions of isoprene, a reactive hydrocarbon, from Subarctic vegetation are not well documented. However, the Arctic is likely to experience the most pronounced effects of climatic warming, which may increase temperature-dependent isoprene emission. Here, we assessed isoprene emission from a Subarctic heath subjected to a 3-4 degrees C increase in air temperature and mountain birch (Betula pubescens ssp. czerepanovii) litter addition for 7-8 yr, simulating climatic warming and the subsequent expansion of deciduous shrub species and migration of the treeline. The measurements were performed using the dynamic chamber method on a wet heath with a mixture of shrubs, herbs and graminoids. Isoprene emissions averaged across the treatments were 36 +/- 5 microg m(-2) h(-1) in 2006 and 58 +/- 7 microg m(-2) h(-1) in 2007. The experimental warming increased the emissions by 83% in 2007 (P = 0.021) and by 56% in 2006 (P = 0.056), while litter addition had no significant effects. The net ecosystem CO(2) exchange was significantly decreased by warming in 2007. These results show that isoprene emissions from Subarctic heaths are comparable to those from Subarctic peatlands. Climatic warming will increase the emissions, and the amount of carbon lost as isoprene, from Subarctic heath ecosystems.
authors.affiliation: Department of Environmental Science, University of Kuopio, PO Box 1627, FI-70211 Kuopio, Finland. paivi.tiiva@uku.fi
authors.forename: Päivi
authors.initials: P
authors.lastname: Tiiva
authors.forename: Patrick
authors.initials: P
authors.lastname: Faubert
authors.forename: Anders
authors.initials: A
authors.lastname: Michelsen
authors.forename: Toini
authors.initials: T
authors.lastname: Holopainen
authors.forename: Jarmo K
authors.initials: JK
authors.lastname: Holopainen
authors.forename: Riikka
authors.initials: R
authors.lastname: Rinnan
mesh_terms: D001110:Arctic Regions; D018533:Biomass; D002070:Butadienes / Q000737:chemistry*; D002245:Carbon Dioxide / Q000502:physiology*; D017753:Ecosystem; D004777:Environment; D017752:Greenhouse Effect; D045782:Hemiterpenes / Q000737:chemistry*; D008027:Light; D009822:Oils, Volatile / Q000737:chemistry*; D010420:Pentanes / Q000737:chemistry*; D010944:Plants / Q000737:chemistry*; D025341:Principal Component Analysis; D055549:Volatile Organic Compounds / Q000737:chemistry*
chemical_list: D002070:Butadienes; D045782:Hemiterpenes; D009822:Oils, Volatile; D010420:Pentanes; D055549:Volatile Organic Compounds; C005059:isoprene; D002245:Carbon Dioxide