| Volumes and Issues Contents of Issue 3 Special Issue |
www.biogeosciences-discuss.net/6/5705/2009/
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
Annual carbon gas budget for a subarctic peatland, northern Sweden
1Department of Geology and Geochemistry, Stockholm University, 106 91 Stockholm, Sweden
2GeoBiosphere Science Centre, Physical Geography and Ecosystem Analysis, Lund University, Sölvegatan 12, 223 62 Lund, Sweden
Abstract. Temperatures in the Arctic regions are rising, thawing permafrost and exposing previously stabile soil organic carbon (OC) to decomposition. This can result in that northern latitude soils which have accumulated large amounts of OC potentially shift from atmospheric C sinks to C sources with positive feedback on climate warming. In this paper, we estimate the annual net C gas balance (NCB) of the subarctic mire Stordalen, based on automatic chamber measurements of CO2 and total hydrocarbon (THC; CH4 and NMVOCs) exchange. We studied the dominant vegetation communities with different moisture and permafrost characteristics; a dry Palsa underlain by permafrost, an intermediate thaw site with Sphagnum spp. and a wet site with Eriophorum spp. where the soil thaws completely. Whole year accumulated fluxes of 2 were estimated to 30, −35 and −35 g C m−2, respectively for the Palsa, Sphagnum and Eriophorum sites (positive flux indicates an addition of C to the atmospheric pool). The corresponding annual THC emissions were 0.52, 6.2 and 32 g C m−2 for the same sites. Therefore, the NCB for each of the sites were 30, −29 and −3.1 g C m−2, respectively for the Palsa, Sphagnum and Eriophorum site. On average, the whole mire was a sink of CO2 (−2.6 g C m−2) and a source of THC (6.4 g C m−2) over a year. Consequently, the mire was a net source of C to the atmosphere (3.9 g C m−2). Snow season efflux of CO2 and THC emphasize the importance of winter measurements for complete annual C budgets. Decadal vegetation changes at Stordalen indicate that both the productivity and the THC emissions increased between 1970 and 2000. Considering the GWP100 of CH4, the net radiative forcing on climate increased 21% over the same time. Conclusively, reduced C compounds in these environments have high importance for both the annual C balance and climate.
Discussion Paper (PDF, 1059 KB) Interactive Discussion (Closed, 4 Comments) Final Revised Paper (BG)
Citation: Bäckstrand, K., Crill, P. M., Jackowicz-Korczyñski, M., Mastepanov, M., Christensen, T. R., and Bastviken, D.: Annual carbon gas budget for a subarctic peatland, northern Sweden, Biogeosciences Discuss., 6, 5705-5740, 2009. Bibtex EndNote Reference Manager
