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Anna Ekberg. Photo.

Anna Ekberg

Project coordinator

Anna Ekberg. Photo.

Isoprene emission from wetland sedges

Author

  • Anna Ekberg
  • Almut Arneth
  • H. Hakola
  • Sean Hayward
  • Thomas Holst

Summary, in English

High latitude wetlands play an important role for the surface-atmosphere exchange of carbon dioxide (CO2) and methane (CH4), but fluxes of biogenic volatile organic compounds (BVOC) in these ecosystems have to date not been extensively studied. This is despite BVOC representing a measurable proportion of the total gaseous C fluxes at northern locations and in the face of the high temperature sensitivity of these systems that requires a much improved process understanding to interpret and project possible changes in response to climate warming. We measured emission of isoprene and photosynthetic gas exchange over two growing seasons (2005-2006) in a subarctic wetland in northern Sweden with the objective to identify the physiological and environmental controls of these fluxes on the leaf scale. The sedge species Eriophorum angustifolium and Carex rostrata were both emitters of isoprene. Springtime emissions were first detected after an accumulated diurnal mean temperature above 0 degrees C of about 100 degree days. Maximum measured growing season standardized (basal) emission rates (20 degrees C, 1000 mu mol m(-2) s(-1)) were 1075 (2005) and 1118 (2006) mu g Cm-2 (leaf area) h(-1) in E. angustifolium, and 489 (2005) and 396 (2006) mu g Cm(-2)h(-1) in C. rostrata. Over the growing season, basal isoprene emission varied in response to the temperature history of the last 48 h. Seasonal basal isoprene emission rates decreased with leaf nitrogen (N), which may be explained by the typical growth and resource allocation pattern of clonal sedges as the leaves age. The observations were used to model emissions over the growing season, accounting for effects of temperature history, links to leaf assimilation rate and the light and temperature dependencies of the cold-adapted sedges.

Department/s

  • Dept of Physical Geography and Ecosystem Science

Publishing year

2009

Language

English

Pages

601-613

Publication/Series

Biogeosciences

Volume

6

Issue

4

Document type

Journal article

Publisher

Copernicus Publications

Topic

  • Physical Geography

Status

Published

ISBN/ISSN/Other

  • ISSN: 1726-4189