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| Titel |
Carbonyl sulfide exchange in a temperate loblolly pine forest grown under ambient and elevated CO2 |
| VerfasserIn |
M. L. White, Y. Zhou, R. S. Russo, H. Mao, R. Talbot, R. K. Varner, B. C. Sive |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 2 ; Nr. 10, no. 2 (2010-01-21), S.547-561 |
| Datensatznummer |
250007960
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| Publikation (Nr.) |
 copernicus.org/acp-10-547-2010.pdf |
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| Zusammenfassung |
| Vegetation, soil and ecosystem level carbonyl sulfide (COS) exchange was
observed at Duke Forest, a temperate loblolly pine forest, grown under
ambient (Ring 1, R1) and elevated (Ring 2, R2) CO2. During calm
meteorological conditions, ambient COS mixing ratios at the top of the
forest canopy followed a distinct diurnal pattern in both CO2 growth
regimes, with maximum COS mixing ratios during the day (R1=380±4 pptv
and R2=373±3 pptv, daytime mean ± standard error) and
minimums at night (R1=340±6 pptv and R2=346±5 pptv,
nighttime mean ± standard error) reflecting a significant nighttime
sink. Nocturnal vegetative uptake (−11 to −21 pmol m−2s−1,
negative values indicate uptake from the atmosphere) dominated nighttime net
ecosystem COS flux estimates (−10 to −30 pmol m−2s−1) in both
CO2 regimes. In comparison, soil uptake (−0.8 to
−1.7 pmol m−2 s−1)
was a minor component of net ecosystem COS flux. In both CO2
regimes, loblolly pine trees exhibited substantial COS consumption overnight
(50% of daytime rates) that was independent of CO2 assimilation.
This suggests current estimates of the global vegetative COS sink, which
assume that COS and CO2 are consumed simultaneously, may need to be
reevaluated. Ambient COS mixing ratios, species specific diurnal patterns of
stomatal conductance, temperature and canopy position were the major factors
influencing the vegetative COS flux at the branch level. While variability
in branch level vegetative COS consumption measurements in ambient and
enhanced CO2 environments could not be attributed to CO2
enrichment effects, estimates of net ecosystem COS flux based on ambient
canopy mixing ratio measurements suggest less nighttime uptake of COS in R2,
the CO2 enriched environment. |
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