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| Titel |
Isoprene emissions from a tundra ecosystem |
| VerfasserIn |
M. J. Potosnak, B. M. Baker, L. LeStourgeon, S. M. Disher, K. L. Griffin, M. S. Bret-Harte, G. Starr |
| 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 ; 10, no. 2 ; Nr. 10, no. 2 (2013-02-07), S.871-889 |
| Datensatznummer |
250017506
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| Publikation (Nr.) |
 copernicus.org/bg-10-871-2013.pdf |
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| Zusammenfassung |
| 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° N,
149.6° 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 °C and a
PAR level over 1500 μmol m−2 s−1. Leaf-level isoprene
emission rates for S. pulchra averaged
12.4 nmol m−2 s−1 (27.4 μg C gdw−1 h−1)
extrapolated to standard conditions
(PAR = 1000 μmol m−2 s−1 and leaf
temperature = 30 °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. |
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