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| Titel |
Carbon and oxygen isotope analysis of leaf biomass reveals contrasting photosynthetic responses to elevated CO2 near geologic vents in Yellowstone National Park |
| VerfasserIn |
S. Sharma, D. G. Williams |
| 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. 1 ; Nr. 6, no. 1 (2009-01-07), S.25-31 |
| Datensatznummer |
250003312
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| Publikation (Nr.) |
 copernicus.org/bg-6-25-2009.pdf |
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| Zusammenfassung |
| In this study we explore the use of natural CO2 emissions in
Yellowstone National Park (YNP) in Wyoming, USA to study responses of
natural vegetation to elevated CO2 levels. Radiocarbon (14C)
analysis of leaf biomass from a conifer (Pinus contortus; lodgepole pine) and an invasive,
non-native herb (Linaria dalmatica; Dalmation toadflax) was used to trace the inputs of vent
CO2 and quantify assimilation-weighted CO2 concentrations
experienced by individual plants near vents and in comparable locations with
no geologic CO2 exposure. The carbon and oxygen isotopic composition
and nitrogen percent of leaf biomass from the same plants was used to
investigate photosynthetic responses of these plants to naturally elevated
atmospheric CO2 concentrations. The coupled shifts in carbon and oxygen
isotope values suggest that dalmation toadflax responded to elevated
CO2 exposure by increasing stomatal conductance with no change in
photosynthetic capacity and lodgepole pine apparently responded by
decreasing stomatal conductance and photosynthetic capacity. Lodgepole pine
saplings exposed to elevated levels of CO2 likewise had reduced leaf
nitrogen concentrations compared to plants with no enhanced CO2
exposure, further suggesting widespread and dominant conifer
down-regulated photosynthetic capacity under elevated CO2 levels near
geologic vents. |
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