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| Titel |
Seasonal variations in CO2 and CH4 fluxes of four different plant compositions of a Sphagnum-dominated Alpine peat bog |
| VerfasserIn |
Simon Drollinger, Andreas Maier, Jasmin Karer, Stephan Glatzel |
| 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 |
250151405
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| Publikation (Nr.) |
 EGU/EGU2017-15984.pdf |
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| Zusammenfassung |
| Peatlands are the only type of ecosystems which have the ability to accumulate significant
amounts of carbon (C) under undisturbed conditions. The amount of C sequestered in
peatlands depends on the balance between gross primary production, ecosystem respiration
and decomposition of plant material. Sphagnum-dominated bogs possess the greatest peat
accumulation potential of all peatlands, thus in turn, feature highest C release potentials.
Many studies report about the C balances of undisturbed northern peat bogs, however, little is
known about the effects of peatland degradation on the C balance between different plant
compositions within peat bog ecosystems. Particularly in the Alpine region, where
temperature increase during the last century has been almost twice as high as the global
mean.
The investigated peat bog is located in the inner Alpine Enns valley in the Eastern Alps,
Austria (N 47˚ 34.873’ E 14˚ 20.810’). It is a pine peat bog covered by Sphagnum mosses
and a present extent of about 62 ha. Due to increasing differences in surface height of the
peatland compared to the surrounding areas and related lowered water retention capacity
attributed to the subsidence of the adjacent intensively managed meadows on deeply drained
peat soils, the function of the peatland as a carbon sink is strongly endangered.
Hence, the current mean water table depth of the central peat bog area is about -12
cm.
To reveal differences in peatland-atmosphere C exchanges within the peatland ecosystem,
we investigated CO2 and CH4 fluxes of four different vegetation compositions (PM1-PM4) at
the treeless central peat bog area. PM1 is dominated by the graminoids Rhynchospora alba
and Eriophorum vaginatum. PM2 is inhabited by small individuals (< 35 cm) of the
conifer Pinus mugo, whereas PM3 is dominated by the ericaceous plant Calluna
vulgaris. PM4 again is populated by Pinus mugo, but higher growing (35 - 60 cm)
and with corresponding higher amount of biomass. Fluxes were measured for at
least 120 seconds with the closed dynamic chamber method using infrared gas
analysers (UGGA, Los Gatos Research and LI-802, LI-COR Biosciences) at four
study sites with three replicates each. Net ecosystem exchange was measured using
transparent chambers, whereas soil respiration was revealed using opaque chambers.
Measurements were conducted seasonally during the last two years with eight sampling
periods.
Here, we demonstrate the seasonal variations in CO2 and CH4 fluxes, evaluate the
underlying factors being responsible for these variations, examine the differences in diurnal
pattern during the seasons and compute the global warming potentials of the released
greenhouse gases. Moreover, we estimate the annual C balance per site and revise the
seasonal C fluxes by comparing the results with fluxes derived by eddy covariance method. |
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