Isoprene emission from a subarctic peatland under enhanced UV‐B radiation

Abstract

Summary• Isoprene is a reactive hydrocarbon with an important role in atmospheric chemistry, and emissions from vegetation contribute to atmospheric carbon fluxes. The magnitude of isoprene emissions from arctic peatlands is not known, and it may be altered by increasing UV-B radiation.• Isoprene emission was measured with the dynamic chamber method from a subarctic peatland under long-term enhancement of UV-B radiation targeted to correspond to a 20% loss in the stratospheric ozone layer. The site type of the peatland was a flark fen dominated by the moss Warnstorfia exannulata and sedges Eriophorum russeolum and Carex limosa . The relationship between species densities and the emission was also assessed.• Isoprene emissions were significantly increased by enhanced UV-B radiation during the second (2004) and the fourth (2006) growing seasons under the UV-B exposure. Emissions were related to the density of E. russeolum . The dominant moss, W. exannulata , proved to emit small amounts of isoprene in a laboratory trial.• Subarctic fens, even without Sphagnum moss, are a significant source of isoprene to the atmosphere, especially under periods of warm weather. Warming of the Arctic together with enhanced UV-B radiation may substantially increase the emissions.

Non-methane biogenic volatile organic compound emissions from boreal peatland microcosms under warming and water table drawdown

“…350 million ha globally and act as important carbon sinks (Gorham 1991). These ecosystems release also significant amount of non-methane biogenic volatile organic compounds (BVOCs) in the atmosphere (Klinger et al 1994;Tiiva et al 2007a;Bäckstrand et al 2008;Faubert et al 2010b).…”

Isoprene emission from wetland sedges

“…High-latitude wetlands are important sinks for carbon dioxide (CO 2 ) (Frolking and Roulet, 2007) and sources of methane (CH 4 ) (Christensen et al, 2004;Pelletier et al, 2007;Svensson and Rosswall, 1984), but belong to the least studied ecosystems with respect to emissions of other gaseous reduced hydrocarbons that are generally summarized as biogenic volatile organic compounds (BVOC) (Hellén et al, 2006;Janson and De Serves, 1998;Janson et al, 1999;Tiiva et al, 2007). The unsaturated BVOCs exhibit high reactivity towards the hydroxyl radical, as well as to ozone and nitrate radicals and therefore play a critical role for local tropospheric chemistry (Atkinson, 2000) as well as, for instance, having effects on the atmospheric lifetime and concentrations of CH 4 (Poisson et al, 2000).…”

Isoprene emissions from a tundra ecosystem

“…Other studies have stretched from savannahs (e.g., Guenther et al, 1996;Otter et al, 2003) to boreal forests (e.g., Rinne et al, 2000;Spirig et al, 2004). However, Arctic (latitude above 66.6 • N) tundra ecosystems have been neglected, with most studies coming from the same field station near Abisko, Sweden Faubert et al, 2010;Rinnan et al, 2011;Tiiva et al, 2008;Ekberg et al, 2011;Holst et al, 2010;Faubert et al, 2012; note that no isoprene emissions were detected in the Faubert et al, 2012 study) and another study in northern Finland (Tiiva et al, 2007).…”