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| Titel |
Interactive effects of elevated CO2 and warming on soil respiration in a mountain grassland |
| VerfasserIn |
David Reinthaler, Claudia Gstir, Markus Herndl, Erich Pötsch, Michael Bahn |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250138371
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| Publikation (Nr.) |
 EGU/EGU2017-1358.pdf |
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| Zusammenfassung |
| Soil respiration is the largest source of CO2 emitted from terrestrial ecosystems to the atmosphere. In grasslands, which cover over 30% of the global land area and around 70% of the world’s agricultural acreage, the contribution of soil respiration to total ecosystem respiration is particularly high. The ClimGrass experiment aims to understand individual and combined effects of multi-level changes in temperature and atmospheric CO2 concentrations and of extreme drought on the biogeochemical cycles of a managed C3 grassland typical for European mountain regions. The ClimGrass experiment, based at AREC Raumberg Gumpenstein in Central Austria, comprises a total of 54 plots subjected to different combinations of experimental warming (ambient, +1.5°C, +3°C) and elevated CO2 (ambient, +150°C, +300 ppm), as well as extreme drought and heatwave. Here, we present first results concerning the interactive effects of warming and elevated CO2 on soil respiration. For this study we combined measurements of an automated system (LiCor 8100) with manual measurements of soil respiration (PP-Systems EGM4), in plots exposed to ambient and elevated CO2, both under ambient temperature conditions and +3°C warming. Our results from the first year of treatment indicate a significant increase of soil CO2 efflux caused by warming and a decrease under elevated CO2, with a strong interactive effect leading to a dampened warming effect under elevated CO2. Interestingly, elevated CO2 had stronger indirect than direct effects on soil respiration, mediated by altered soil moisture under elevated CO2. In the second and third year, however, all treatments increased soil CO2 efflux, with higher flux rates under elevated CO2 than under warming. Overall, elevated CO2 and warming had additive effects on soil moisture, but non-additive effects on soil respiration. Analyses of isotopic signatures of soil respired CO2, of the contribution of the heterotrophic component to total soil respiration and of soil CO2 concentration profiles will help to disentangle the observed responses of soil respiration to climate change. |
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