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| Titel |
Isoprene emission from wetland sedges |
| VerfasserIn |
A. Ekberg, A. Arneth, H. Hakola, S. Hayward, T. Holst |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 6, no. 4 ; Nr. 6, no. 4 (2009-04-16), S.601-613 |
| Datensatznummer |
250003641
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| Publikation (Nr.) |
 copernicus.org/bg-6-601-2009.pdf |
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| Zusammenfassung |
| 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°C of about 100 degree days. Maximum measured growing season
standardized (basal) emission rates (20°C, 1000 μmol m−2 s−1) were 1075 (2005) and 1118 (2006) μg C m−2 (leaf area) h−1 in E. angustifolium, and 489
(2005) and 396 (2006) μg C m−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. |
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