HR: 1340h
AN: B23A-0953    [Abstracts]
TI: Growth Season Dynamics Of CO$_{2}$ Exchange In A Subarctic Mire: A Comparison Of Automated Chamber Measurements During Three Years
AU: * Mastepanov, M
EM: Mikhail.mastepanov@nateko.lu.se
AF: GeoBiosphere Science Centre. Physical Geography and Ecosystems Analysis, Solvegatan 12, Lund, 22362 Sweden
AU: Backstrand, K
EM: kristina.backstrand.892@student.lu.se
AF: Department of Geology and Geochemistry, Stockholm University , Stockholm, 106 91 Sweden
AU: Crill, P
EM: patrick.crill@geo.su.se
AF: Department of Geology and Geochemistry, Stockholm University , Stockholm, 106 91 Sweden
AU: Christensen, T R
EM: torben.christensen@nateko.lu.se
AF: GeoBiosphere Science Centre. Physical Geography and Ecosystems Analysis, Solvegatan 12, Lund, 22362 Sweden
AU: Strom, L
EM: lena.strom@nateko.lu.se
AF: GeoBiosphere Science Centre. Physical Geography and Ecosystems Analysis, Solvegatan 12, Lund, 22362 Sweden
AU: Johansson, T
EM: torbjorn.johansson@nateko.lu.se
AF: GeoBiosphere Science Centre. Physical Geography and Ecosystems Analysis, Solvegatan 12, Lund, 22362 Sweden
AU: Friborg, T
EM: tfj@geogr.ku.dk
AF: Geographical Institute, Copenhagen University, Oster Voldgade 10, Copenhagen, 1350 Denmark
AB: Peatlands are well-known to be a long-term sink for atmospheric carbon dioxide (CO$_{2}$). However the carbon balance and, hence, CO$_{2}$ flux can be significantly changed and peatlands may even become a significant atmospheric carbon source in a changing climate. Here we present results of CO2 flux measurements obtained by an automatic chamber method in a subarctic mire (Stordalen, $68\deg$22'N, $19\deg$03'E) during 3 seasons, 2002 to 2004. The study years had quite different climate (temperature, precipitation), causing different seasonal CO$_{2}$ flux patterns. In this presentation a detailed analysis of the causes for interannual differences in the carbon balance will be presented. Three different ecotypes (dry ombrotrophic, mesotrophic and wet minerotrophic) are studied and significant differences between their functional responses to different climate conditions were found. All three were atmospheric sinks in terms of accumulated CO$_{2}$ fluxes during the growing season (90 days). The dry ombrotrophic system accumulated 20-30 g C/m$\^{2}$, the mesotrophic between 37 and 43 g C/m$\^{2}$ and the wet minerotrophic system between 70 and 115 g C/m$\^{2}$. The interannual variability was mainly controlled by variations in snow-melt and precipitation patterns and the subsequent effects these have on the soil moisture regime. The CO$_{2}$ flux measurements presented provide a useful compliment to landscape scale micrometeorological (eddy correlation) measurements of CO$_{2}$ exchange over the mire conducted at the same site. Extrapolating the automated chamber fluxes to the mire as a whole gives mean growing season uptake rates that compare well with the corresponding numbers obtained with the eddy correlation method.
DE: 1890 Wetlands
DE: 1615 Biogeochemical processes (4805)
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting