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| Titel |
Soil CO2 efflux of a larch forest in northern Japan |
| VerfasserIn |
N. Liang, T. Hirano, Z.-M. Zheng, J. Tang, Y. Fujinuma |
| 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 ; 7, no. 11 ; Nr. 7, no. 11 (2010-11-05), S.3447-3457 |
| Datensatznummer |
250005050
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| Publikation (Nr.) |
 copernicus.org/bg-7-3447-2010.pdf |
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| Zusammenfassung |
| We had continuously measured soil CO2 efflux (Rs) in a larch forest
in northern Japan at hourly intervals for the snow-free period in 2003 with
an automated chamber system and partitioned Rs into heterotrophic
respiration (Rh) and autotrophic respiration (Rr) by using the
trench method. In addition, we applied the soil CO2 concentration
gradients method to continuously measure soil CO2 profiles under
snowpack in the snowy period and to partition Rs into topsoil (Oa
and A horizons) CO2 efflux (Ft) with a depth of 0.13 m and sub-soil
(C horizon) CO2 efflux (Fc). We found that soil CO2 effluxes
were strongly affected by the seasonal variation of soil temperature but
weakly correlated with soil moisture, probably because the volumetric soil
moisture (30–40% at 95% confidence interval) was within a plateau
region for root and microbial activities. The soil CO2 effluxes changed
seasonally in parallel with soil temperature in topsoil with the peak in
late summer. On the other hand, the contribution of Rr to Rs was the
largest at about 50% in early summer, when canopy photosynthesis and
plant growth were more active. The temperature sensitivity (Q10) of
Rr peaked in June. Under snowpack, Rs was stable until mid-March and
then gradually increased with snow melting. Rs summed up to
79 gC m−2 during the snowy season for 4 months. The annual Rs was
determined at 934 gC m−2 y−1 in 2003, which accounted for 63%
of ecosystem respiration. The annual contributions of Rh and Rs to
Rs were 57% and 43%, respectively. Based on the gradient approach,
Rs was partitioned vertically into litter (Oi and Oe horizons)
with a depth of 0.01–0.02 m, topsoil and sub-soil respirations with
proportions of 6, 72 and 22%, respectively, on an annual basis. The
vertical distribution of CO2 efflux was consistent with those of soil
carbon and root biomass. |
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