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Details for article 13 of 43 found articles
| Title: |
Continuous measurement of soil CO2 efflux in a larch forest by automated chamber and concentration gradient techniques |
| Author: |
N. Liang T. Hirano Z.-M. Zheng J. Tang Y. Fujinuma |
| Appeared in: |
Biogeosciences discussions |
| Paging: | Volume 7 (2010) nr. 1 pages 1345-1375 |
| Year: |
2010 |
| Contents: |
Winter measurements of soil CO2 effluxes are few because such measurements are difficult when the ground is snow-covered, limiting the ability of chamber systems to characterize soil CO2 effluxes accurately year-round. In this study, we used two systems for continuous measurements of soil CO2 effluxes in a larch forest in northern Japan: (1) a 16-channel automated soil chamber system with eight chambers for measuring soil CO2 efflux and eight chambers for measuring heterotrophic respiration during snow-free periods, and (2) a soil CO2 concentration gradient system used year-round, including when the ground was snow-covered. During the warm season, the gradient approach yielded systematically higher CO2 effluxes than the automated chamber technique, whereas it yielded lower CO2 effluxes during the cold season. As a result of this bias (p<0.001), the annual soil CO2 efflux estimated by the automated chamber was 959 g C m−2 (of which 57% was contributed by heterotrophic respiration), whereas the efflux estimated by the gradient approach was 1040 g C m−2. Because of the fast-response infrared gas analyzer adopted for the chamber technique, the soil CO2 efflux response to the onset of rain was detected immediately and the efflux returned to pre-rain values several hours after the rain had stopped. Rain events accounted for about 24 g C m−2 (about 2% of the annual soil CO2 efflux). The gradient system successfully measured the soil CO2 effluxes when the ground was snow-covered (9 December to 17 April), when they ranged from 0.40 to 0.70 μmol m−2 s−1. Total CO2 efflux from the snowpack estimated by the gradient technique approached 73 g C m−2, corresponding to about 7% of the annual soil CO2 efflux. The Q10 coefficient of the soil CO2 efflux showed large seasonal variation, mainly because of the large temperature sensitivity of root respiration. |
| Publisher: |
Copernicus Publications (provided by DOAJ) |
| Source file: |
Elektronische Wetenschappelijke Tijdschriften |
Details for article 13 of 43 found articles
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