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| Titel |
Assessing the spatial variability in peak season CO2 exchange characteristics across the Arctic tundra using a light response curve parameterization |
| VerfasserIn |
H. N. Mbufong, M. Lund, M. Aurela, T. R. Christensen, W. Eugster, T. Friborg, B. U. Hansen, E. R. Humphreys, M. Jackowicz-Korczyñski, L. Kutzbach, P. M. Lafleur, W. C. Oechel, F. J. W. Parmentier, D. P. Rasse, A. V. Rocha, T. Sachs, M. K. van der Molen, M. P. Tamstorf |
| 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 ; 11, no. 17 ; Nr. 11, no. 17 (2014-09-15), S.4897-4912 |
| Datensatznummer |
250117592
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| Publikation (Nr.) |
 copernicus.org/bg-11-4897-2014.pdf |
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| Zusammenfassung |
This paper aims to assess the spatial variability in the response of
CO2 exchange to irradiance across the Arctic tundra during peak season
using light response curve (LRC) parameters. This investigation allows us to
better understand the future response of Arctic tundra under climatic
change. Peak season data were collected during different years (between 1998
and 2010) using the micrometeorological eddy covariance technique from 12
circumpolar Arctic tundra sites, in the range of 64–74° N.
The LRCs were generated for 14 days with peak net ecosystem exchange (NEE)
using an NEE–irradiance model. Parameters from LRCs represent site-specific
traits and characteristics describing the following: (a) NEE at light saturation
(Fcsat), (b) dark respiration (Rd), (c) light use efficiency
(α), (d) NEE when light is at 1000 μmol m−2 s−1
(Fc1000), (e) potential photosynthesis at light saturation
(Psat) and (f) the light compensation point (LCP).
Parameterization of LRCs was successful in predicting CO2 flux dynamics
across the Arctic tundra. We did not find any trends in LRC parameters
across the whole Arctic tundra but there were indications for temperature
and latitudinal differences within sub-regions like Russia and Greenland.
Together, leaf area index (LAI) and July temperature had a high explanatory power of the
variance in assimilation parameters (Fcsat, Fc1000 and Psat,
thus illustrating the potential for upscaling CO2 exchange for the
whole Arctic tundra. Dark respiration was more variable and less correlated
to environmental drivers than were assimilation parameters. This indicates
the inherent need to include other parameters such as nutrient availability,
substrate quantity and quality in flux monitoring activities. |
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