title: Warming increases isoprene emissions from an arctic fen.
abstract: Emissions of biogenic volatile organic compounds (BVOCs) from dry ecosystems at high latitudes respond strongly to small increases in temperature, and warm canopy surface temperatures drive emissions to higher levels than expected. However, it is not known whether emissions from wetlands, cooled by through-flowing water and higher evapotranspiration show similar response to warming as in drier ecosystems. Climate change will cause parts of the Arctic to experience increased snow fall, which delays the start of the growing season, insulates soil from low temperatures in winter, and increases soil moisture and possibly nutrient availability. Currently the effects of increasing snow depth on BVOC emissions are unknown. BVOC emissions were measured in situ across the growing season in a climate experiment, which used open top chambers to increase temperature and snow fences to increase winter snow depth. The treatments were arranged in a full factorial design. Measurements took place during two growing seasons in a fen ecosystem in west Greenland. BVOC samples collected by an enclosure technique in adsorbent cartridges were analysed using gas chromatography-mass spectrometry. Gross ecosystem production (GEP) was measured with a closed chamber technique, to reveal any immediate effect of treatments on photosynthesis, which could further influence BVOC emissions. Isoprene made up 84-92% of the emitted BVOCs. Isoprene emission increased 240 and 340% due to an increase in temperature of 1.3 and 1.6°C in 2014 and 2015, respectively. Isoprene emissions were 25 times higher in 2015 than in 2014 most likely due to a 2.4°C higher canopy air temperature during sampling in 2015. Snow addition had no significant effect on isoprene emissions even though GEP was increased by 24%. Arctic BVOC emissions respond strongly to rising temperatures in wet ecosystems, suggesting a large increase in arctic emissions in a future warmer climate.
authors.affiliation: Terrestrial Ecology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Center for Permafrost, Department of Geoscience and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Frida
authors.initials: F
authors.lastname: Lindwall
authors.affiliation: Terrestrial Ecology, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Sophie Sylvest
authors.initials: SS
authors.lastname: Svendsen
authors.affiliation: Center for Permafrost, Department of Geoscience and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Cecilie Skov
authors.initials: CS
authors.lastname: Nielsen
authors.affiliation: Terrestrial Ecology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Center for Permafrost, Department of Geoscience and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Michelsen
authors.affiliation: Terrestrial Ecology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; Center for Permafrost, Department of Geoscience and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark. Electronic address: riikkar@bio.ku.dk.
authors.forename: Riikka
authors.initials: R
authors.lastname: Rinnan
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001110:Arctic Regions; D002070:Butadienes / Q000032:analysis*; D057231:Climate Change; D004784:Environmental Monitoring; D057232:Global Warming; D006116:Greenland; D045782:Hemiterpenes / Q000032:analysis*; D010420:Pentanes / Q000032:analysis*; D055549:Volatile Organic Compounds / Q000032:analysis*; D053833:Wetlands
chemical_list: D000393:Air Pollutants; D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; D055549:Volatile Organic Compounds; C005059:isoprene
keywords: Biogenic volatile organic compounds; Climate change; Open top chamber; Snow addition; Temperature; Wetland