| 1. |
- Arneth, Almut, et al.
(author)
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CO2 inhibition of terrestrial isoprene production stabilises tropospheric oxidation capacity
- 2007
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In: Geophysical Research Letters. - 1944-8007. ; 34, L18813:18
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Journal article (peer-reviewed)abstract
- [1] Isoprene is the dominant volatile organic compound produced by the terrestrial biosphere and fundamental for atmospheric composition and climate. It constrains the concentration of tropospheric oxidants, affecting the lifetime of other reduced species such as methane and contributing to ozone production. Oxidation products of isoprene contribute to aerosol growth. Recent consensus holds that emissions were low during glacial periods ( helping to explain low methane concentrations), while high emissions ( contributing to high ozone concentrations) can be expected in a greenhouse world, due to positive relationships with temperature and terrestrial productivity. However, this response is offset when the recently demonstrated inhibition of leaf isoprene emissions by increasing atmospheric CO2 concentration is accounted for in a process-based model. Thus, isoprene may play a small role in determining pre-industrial tropospheric OH concentration and glacial-interglacial methane trends, while predictions of high future tropospheric O-3 concentrations partly driven by isoprene emissions may need to be revised.
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| 2. |
- Hickler, Thomas, et al.
(author)
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CO2 fertilisation in temperate forest FACE results not representative for global forests.
- 2008
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In: Global Change Biology. - : Wiley. - 1354-1013. ; 14:7, s. 1531-1542
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Journal article (peer-reviewed)abstract
- Abstract in UndeterminedResults from free-air CO(2) enrichment (FACE) experiments in temperate climates indicate that the response of forest net primary productivity (NPP) to elevated CO(2) might be highly conserved across a broad range of productivities. In this study, we show that the LPJ-GUESS dynamic vegetation model reproduces the magnitude of the NPP enhancement at temperate forest FACE experiments. A global application of the model suggests that the response found in the experiments might also be representative of the average response of forests globally. However, the predicted NPP enhancement in tropical forests is more than twice as high as in boreal forests, suggesting that currently available FACE results are not applicable to these ecosystems. The modeled geographic pattern is to a large extent driven by the temperature dependence of the relative affinities of the primary assimilation enzyme (Rubisco) for CO(2) and O(2).
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