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| Titel |
Seasonal and diurnal methane emissions from a wetland meadow on the Eastern
Qinghai-Tibetan Plateau: effects of soil temperature, water table level and
gross primary productivity (GPP) |
| VerfasserIn |
Haijun Peng, Qian Guo, Bing Hong, Hanwei Ding, Chao Xu, Hu Yao |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250144205
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| Publikation (Nr.) |
 EGU/EGU2017-8004.pdf |
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| Zusammenfassung |
| Peatlands covered about 4.6×109 m2 land surface of the eastern Qinghai-Tibet Plateau, and
accumulated about 7.14×108 t C since the beginning of Holocene. Over the last decades,
more than 30% of these peatlands have degradated due to climate change, land management
and disturbance. For assessing the magnitude of diurnal and seasonal variations in CH4
fluxes, and identifying the depence of CH4 fluxes on environmental factors, we measured
CH4 fluxes in a typical alpine peatland in this region using eddy covariance technique, and
tested the depence of CH4 fluxes on soil temperature, water table level and gross primary
productivity (GPP). The annual CH4 emission of Hongyuan peatland is 47.04 g
CH4/m2, while growing season emissions account for 75 of the annual sum. During
growing season, there was a clear diurnal pattern in CH4 fluxes with peaks and valleys
appeared at16:30 and 1:00, respectively. While during non-growing season, CH4
fluxes varied at a relatively low level and showed no clear diurnal patterns. The CH4
fluxes were significantly correlated with the variations of soil temperature, and
soil temperature at 25 cm depth can explain 83% of the variations in CH4 fluxes.
The CH4 emissions during the growing season were barely correlated with the
water table level (R2=-0.0001), and the water table mostly varied from 0 cm to -20
cm, which indicate that the anaerobic environment below -20 cm was relatively
stable for methanogenesis and CH4 transportation. In addition, considering the fact
that CH4 fluxes were more significantly correlated with soil temperature at 25 cm
depth, it might be concluded that the CH4 were mostly produced in the peat deposits
below -20 cm. The daily mean CH4 emissions were significantly correlated with
GPP (R2=0.82), which suggest that CH4 emissions were also regulated by plant
growth activities, and the CH4 fluxes might be decreased due to peatland degradation. |
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