Doubled volatile organic compound emissions from subarctic tundra under simulated climate warming

Abstract

Summary• Biogenic volatile organic compound (BVOC) emissions from arctic ecosystems are important in view of their role in global atmospheric chemistry and unknown feedbacks to global warming. These cold ecosystems are hotspots of climate warming, which will be more severe here than averaged over the globe. We assess the effects of climatic warming on non-methane BVOC emissions from a subarctic heath.• We performed ecosystem-based chamber measurements and gas chromatographymass spectrometry (GC-MS) analyses of the BVOCs collected on adsorbent over two growing seasons at a wet subarctic tundra heath hosting a long-term warming and mountain birch (Betula pubescens ssp. czerepanovii) litter addition experiment.• The relatively low emissions of monoterpenes and sesquiterpenes were doubled in response to an air temperature increment of only 1.9-2.5°C, while litter addition had a minor influence. BVOC emissions were seasonal, and warming combined with litter addition triggered emissions of specific compounds.• The unexpectedly high rate of release of BVOCs measured in this conservative warming scenario is far above the estimates produced by the current models, which underlines the importance of a focus on BVOC emissions during climate change. The observed changes have implications for ecological interactions and feedback effects on climate change via impacts on aerosol formation and indirect greenhouse effects.

Off-season biogenic volatile organic compound emissions from heath mesocosms: responses to vegetation cutting

“…This finding is in line with the results of Faubert et al (2012) who found that E. hermaphroditum was an important sesquiterpene source for the mountain birch forest floor emissions measured during the growing season. The total BVOC emission rate of the mixed heath mesocosms, 10.33 μg m −2 h −1 , was in the same range as the emission rates during the growing season from in situ measurements in Abisko: 10.9–14.61 μg m −2 h −1 for a mixed wet heath (Tiiva et al, 2008; Faubert et al, 2010) and 3.5–45 μg m −2 h −1 for an E. hermaphroditum -dominated forest floor (Faubert et al, 2012), depending on the year. The emission rates of the present experiment may be somewhat understated due to the light intensity in the growth chambers being lower than for open ecosystems under field conditions in full sunlight.…”

“…VOCs were sampled by a push-pull system described by Faubert et al (2010, 2012) for 30 min. A transparent polycarbonate chamber (23 × 23 cm, height 25 cm), equipped with a fan to mix the headspace air, was placed on top of a water-filled groove in the aluminum frame holding each mesocosm.…”

Two Decades of Experimental Manipulations of Heaths and Forest Understory in the Subarctic

“…It seems that the subarctic BVOC emissions increase more per unit temperature increase than the emissions from vegetation at lower latitudes (Holst et al 2010;Faubert et al 2010). Warming of the wet heath (Fig.…”

“…Warming of the wet heath (Fig. 1b) has been shown to double the emissions of monoterpenes and sesquiterpenes (Faubert et al 2010) and to increase the isoprene emissions by 50-80 % (Tiiva et al 2008;Fig. 5).…”

Evident elevation of atmospheric monoterpenes due to degradation-induced species changes in a semi-arid grassland

“…This might be caused by high isoprene emission that can increase isoprene concentration from 0 to 100 μg m −3 within 20 s based on the emission rate. Recently, growing evidence showed that isoprene emission from sedge in high-latitude wetlands was unexpectedly high (Ekberg et al, 2009;Faubert et al, 2010;Holst et al, 2010;Patrick et al, 2011;Tiiva et al, 2007aTiiva et al, , 2007b and that nitrogen deposition significantly and quickly increased sedge coverage in grassland (Bassin et al, 2007;Bowman et al, 2008) because sedge grows well in acidic soil. Moreover, our diurnal observation showed that sedge (C. korshinskyi Kom) in semi-arid grassland emitted isoprene at a high rate (N 9 mg m −2 h −1 ) compared to boreal wetlands, possibly due to drought and high temperature (N 25°C).…”