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| Titel |
Integrating O3 influences on terrestrial processes: photosynthetic and stomatal response data available for regional and global modeling |
| VerfasserIn |
D. Lombardozzi, J. P. Sparks, G. Bonan |
| 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. 11 ; Nr. 10, no. 11 (2013-11-01), S.6815-6831 |
| Datensatznummer |
250085385
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| Publikation (Nr.) |
 copernicus.org/bg-10-6815-2013.pdf |
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| Zusammenfassung |
| Plants have a strong influence on climate by controlling the transfer of
carbon dioxide and water between the biosphere and atmosphere during the
processes of photosynthesis and transpiration. Chronic exposure to surface
ozone (O3) differentially affects photosynthesis and transpiration
because it damages stomatal conductance, the common link that controls both
processes, in addition to the leaf biochemistry that only affects
photosynthesis. Because of the integral role of O3 in altering plant
interactions with the atmosphere, there is a strong motivation to
incorporate the influence of O3 into regional and global models.
However, there are currently no analyses documenting both photosynthesis and
stomatal conductance responses to O3 exposure through time using a
standardized O3 parameter that can be easily incorporated into models.
Therefore, models often rely on photosynthesis data derived from the
responses of one or a few plant species that exhibit strong negative
correlations with O3 exposure to drive both rates of photosynthesis and
transpiration, neglecting potential divergence between the two fluxes. Using
data from the peer-reviewed literature, we have compiled photosynthetic and
stomatal responses to chronic O3 exposure for all plant types with data
available in the peer-reviewed literature as a standardized function of
cumulative uptake of O3 (CUO), which integrates O3 flux into leaves
through time. These data suggest that stomatal conductance decreases
~11% after chronic O3 exposure, while photosynthesis
independently decreases ~21%. Despite the overall decrease
in both variables, high variance masked any correlations between the decline
in photosynthesis or stomatal conductance with increases in CUO. Though
correlations with CUO are not easily generalized, existing correlations
demonstrate that photosynthesis tends to be weakly but negatively correlated
with CUO while stomatal conductance is more often positively correlated with
CUO. Results suggest that large-scale models using data with strong negative
correlations that only affect photosynthesis need to reconsider the
generality of their response. Data from this analysis are now available to
the scientific community and can be incorporated into global models to
improve estimates of photosynthesis, global land-carbon sinks, hydrology,
and indirect radiative forcing that are influenced by chronic O3
exposure. |
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