Isoprene emissions from a tundra ecosystem

TitleIsoprene emissions from a tundra ecosystem
Publication TypeJournal Article
Year of Publication2013
AuthorsPotosnak M.J, Baker B.M, LeStourgeon L., Disher S.M, Griffin K.L, Bret-Harte MS, Starr G.
JournalBiogeosciencesBiogeosciencesBiogeosciences
Volume10
Pagination871-889
ISBN Number1726-4170
Accession NumberISI:000315093000014
KeywordsArctic tundra, biogenic hydrocarbons, boundary-layer, climate-change, compound emissions, eddy covariance, flux measurements, july august 1988, layer expedition able-3a, volatile organic-compounds
Abstract

Whole-system fluxes of isoprene from a moist acidic tundra ecosystem and leaf-level emission rates of isoprene from a common species (Salix pulchra) in that same ecosystem were measured during three separate field campaigns. The field campaigns were conducted during the summers of 2005, 2010 and 2011 and took place at the Toolik Field Station (68.6 degrees N, 149.6 degrees W) on the north slope of the Brooks Range in Alaska, USA. The maximum rate of whole-system isoprene flux measured was over 1.2 mg C m(-2) h(-1) with an air temperature of 22 degrees C and a PAR level over 1500 mu mol m(-2) s(-1). Leaf-level isoprene emission rates for S. pulchra averaged 12.4 nmol m(-2) s(-1) (27.4 mu g C gdw(-1) h(-1)) extrapolated to standard conditions (PAR = 1000 mu mol m(-2) s(-1) and leaf temperature = 30 degrees C). Leaf-level isoprene emission rates were well characterized by the Guenther algorithm for temperature with published coefficients, but less so for light. Chamber measurements from a nearby moist acidic tundra ecosystem with little S. pulchra emitted significant amounts of isoprene, but at lower rates (0.45 mg C m(-2) h(-1)) suggesting other significant isoprene emitters. Comparison of our results to predictions from a global model found broad agreement, but a detailed analysis revealed some significant discrepancies. An atmospheric chemistry box model predicts that the observed isoprene emissions have a significant impact on Arctic atmospheric chemistry, including a reduction of hydroxyl radical (OH) concentrations. Our results support the prediction that isoprene emissions from Arctic ecosystems will increase with global climate change.

Short TitleBiogeosciencesBiogeosciences
Alternate JournalBiogeosciences