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| Titel |
CO2 and CH4 emission patterns of alpine peatland on the eastern
Qinghai-Tibet Plateau and their controlling factors |
| VerfasserIn |
Haijun Peng, Bing Hong |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250121530
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| Publikation (Nr.) |
 EGU/EGU2016-292.pdf |
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| Zusammenfassung |
| Though covering only 3% of the Earth’s land surface, peatlands contain more than 600 Pg C,
which is equivalent to one third of the world’s soil organic carbon pool. Peatlands are
sensitive to climate change, and remain an important carbon sink and CH4 source. There
were 4.6×109 m2 peatlands developed in the eastern Qinghai-Tibet Plateau (average 3400 m
above sea level), while 69% of them are intact peatlands. These peatlands climatologically
located in the overlapping area of East Asian summer monsoon and Indian Ocean summer
monsoon, thus are more sensitive to the global change. However, little is known about the
carbon emission patterns of those peatlands and how they react to climate change. For
assessing the magnitude of diurnal, seasonal and inter-annual variations in CH4 flux, Net
Ecosystem CO2 Exchange (NEE) and Ecosystem Respiration (ER), and identifying the
dependence of these fluxes on environmental factors, from August 2012 to May 2015,
an eddy covariance tower with open-path CH4 and CO2 analyzer, and a LI-8100
automated soil flux system were established in Hongyuan Peatland, which is a
typical intact alpine peatland in the eastern Qinghai-Tibet Plateau region. During
growing season, there was a clear sinusoid-like diurnal pattern in ER with peaks
occurred at 14:00 and valleys occurred at 10:00, the NEE peak values occurred
between 12:00-15:00, and the diurnal peaks and valleys in CH4 fluxes appeared at
approximately 17:00 and 1:00, respectively. Daily mean NEE were negetive values
and daily mean ER were above 1 μmol CO2/m2/s, the lowest NEE is -4.65 μmol
CO2/m2/s, and the largest ER was 5.78 μmol CO2/m2/s, and they all appeared
in July; daily mean CH4 fluxes varied between 0.05-0.25 μmol CH4/m2/s with
peak value appeared in June and July. While during non-growing season, NEE,
ER and CH4 fluxes varied at a relatively low level and showed no clear diurnal
patterns, daily mean NEE and ER are between 0 to 1 μmol CO2/m2/s, and daily mean
CH4 fluxes are between 0 to 0.05 μmol CH4/m2/s. The annual NEE, ER, and CH4
emission of Hongyuan peatland were -286.2 g C/m2, 599.98 g C/m2 and 47.04
g CH4/m2, respectively. And the growing season NEE, ER, and CH4 emission
account for 121%, 78%, and 75% of the annual sum, indicating that emissions in
non-growing season were of great importance. Soil temperature at 10 cm depth and soil
moisture at 10 cm depth are key environmental factors controlling the variation of
NEE (R2=0.70) and ER (R2=0.98), while CH4 flux variations can be explained
by soil temperature at 25 cm depth and soil moisture at 10 cm depth (R2=0.87). |
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