Interannual and seasonal variability in carbon dioxide and methane fluxes of a pine peat bog in the Eastern Alps, Austria

Author(s)
Simon Drollinger, Andreas Maier, Stephan Glatzel
Abstract

Intact peat bogs are carbon dioxide (CO

2

)sinks and methane (CH

4

)sources. Facing drought and drainage, they may turn into CO

2

sources and decreased CH

4

sources. Information on the CO

2

and CH

4

exchange of alpine peat bogs in Central Europe has been missing so far. Here, we present data from two years of CO

2

and CH

4

exchange between an alpine low-shrub pine bog in the Eastern Alps and the atmosphere using the eddy covariance method. The annual net CO

2

ecosystem exchange of the peatland differs substantially between the two measurement years, with -24 ± 13 g C m

−2

yr

−1

for the drought affected first year and -84 ± 13 g C m

−2

yr

−1

for the more humid second year. We found ecosystem respiration (R

eco

)to depend on variations in soil temperature and soil moisture, and gross primary production (GPP)to be strongly linked to net radiation and daylength. The summer drought in 2015 shifted the peatland from a C sink to a C source, as increases in R

eco

clearly exceeded enhanced GPP. Annual CH

4

emission was 4.40 ± 2.40 g C m

−2

yr

−1

during the drought-affected year and 5.24 ± 2.57 g C m

−2

yr

−1

during the wetter year. Summer CH

4

fluxes contribute 44% to the annual balance, followed by autumn (27%), spring (20%)and winter season fluxes (9%). CH

4

fluxes most strongly depend on soil temperatures, soil moisture effects increase at smaller time-scales. Annual CH

4

emissions are low compared to other temperate bogs, which most likely is the result of the ongoing degradation, indicated by a shift in vegetation composition. Net flux of both greenhouse gases was positive in the first year (+75 g CO

2

-eq m

−2

)and negative in the second year (−110 g CO

2

-eq m

−2

). Our results indicate that drought events and seasonal and interannual variations in temperature and precipitation strongly affect the C cycle of alpine peat bogs.

Organisation(s)
Department of Geography and Regional Research, Faculty of Mathematics
Journal
Agricultural and Forest Meteorology
Volume
275
Pages
69-78
No. of pages
10
ISSN
0168-1923
DOI
https://doi.org/10.1016/j.agrformet.2019.05.015
Publication date
09-2019
Publication status
Published
Peer reviewed
Yes
Austrian Fields of Science 2012
106026 Ecosystem research, 105206 Meteorology, 105405 Geoecology, 105408 Physical geography
Keywords
Alpine peatland, Carbon dioxide, Carbon exchange, Eddy covariance, Methane, Ombrotrophic pine bog
ASJC Scopus subject areas
Forestry, Global and Planetary Change, Agronomy and Crop Science, Atmospheric Science
Portal url
https://ucris.univie.ac.at/portal/en/publications/interannual-and-seasonal-variability-in-carbon-dioxide-and-methane-fluxes-of-a-pine-peat-bog-in-the-eastern-alps-austria(3f2dbafc-950e-4322-8a30-2b146c79125b).html