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| Titel |
Leaf level emissions of volatile organic compounds (VOC) from some Amazonian and Mediterranean plants |
| VerfasserIn |
A. Bracho-Nunez, N. M. Knothe, S. Welter, M. Staudt, W. R. Costa, M. A. R. Liberato, M. T. F. Piedade, J. Kesselmeier |
| 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. 9 ; Nr. 10, no. 9 (2013-09-06), S.5855-5873 |
| Datensatznummer |
250085323
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| Publikation (Nr.) |
 copernicus.org/bg-10-5855-2013.pdf |
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| Zusammenfassung |
| Emission inventories defining regional and global biogenic volatile organic
compounds (VOC) emission strengths are needed to determine the impact of VOC
on atmospheric chemistry (oxidative capacity) and physics (secondary organic
aerosol formation and effects). The aim of this work was to contribute with
measurements of tree species from the poorly described tropical vegetation in
direct comparison with the quite well-investigated, highly heterogeneous
emissions from Mediterranean vegetation. VOC emission from sixteen plant
species from the Mediterranean area were compared with twelve plant species
from different environments of the Amazon basin by an emission screening at
leaf level using branch enclosures. Analysis of the volatile organics was
performed online by a proton-transfer-reaction mass spectrometer (PTR-MS) and
offline by collection on adsorbent tubes and subsequent gas chromatographic
analysis. Isoprene was the most dominant compound emitted followed by
monoterpenes, methanol and acetone. The average loss rates of VOC carbon in
relation to the net CO2 assimilation were found below 4% and
indicating normal unstressed plant behavior. Most of the Mediterranean
species emitted a large variety of monoterpenes, whereas only five tropical
species were identified as monoterpene emitters exhibiting a quite
conservative emission pattern (α-pinene < limonene < sabinene < ß-pinene). Mediterranean
plants showed additional emissions of sesquiterpenes. In the case of
Amazonian plants no sesquiterpenes were detected. However, missing of
sesquiterpenes may also be due to a lack of sensitivity of the measuring
systems. Furthermore, our screening activities cover only 1% of tree
species of such tropical areas as estimated based on recent biodiversity
reports. Methanol emissions, an indicator of growth, were found to be common
in most of the tropical and Mediterranean species. A few species from both
ecosystems showed acetone emissions. The observed heterogeneous emissions,
including reactive VOC species which are not easily detected by flux
measurements, give reason to perform more screening at leaf level and,
whenever possible, within the forests under ambient conditions. |
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