HR: 0830h
AN: B31C-0316    [PDF]
TI: Landscape controls on streamwater carbon export during spring flood in northern Sweden
AU: * Buffam, I
EM: ishi.buffam@sek.slu.se
AF: Department of Forest Ecology, Swedish University of Agricultural Sciences, SLU, Ume†, SE-901 83 Sweden
AU: Laudon, H
EM: hjalmar.laudon@sek.slu.se
AF: Department of Forest Ecology, Swedish University of Agricultural Sciences, SLU, Ume†, SE-901 83 Sweden
AU: Bishop, K
EM: kevin.bishop@ma.slu.se
AF: Department of Environmental Assessment, Swedish University of Agricultural Sciences, Box 7050, Uppsala, SE-750 07 Sweden
AB: Fifteen boreal catchments in northern Sweden were monitored during the spring flood season of 2003 to examine spatial and temporal variations in streamwater acidity, inorganic carbon (DIC) and dissolved organic carbon (DOC), and their relationship with catchment characteristics. The sites were sampled in a nested design resulting in catchments varying in size from 0.1 to 67 km$^{2}$, and varying widely in relative areal coverage of forest, mire and lake, three major features of the Swedish boreal landscape. Although wetland-dominated catchments had higher overall mean DOC concentration than did forested catchments, the spring flood had a moderating impact on this difference: DOC concentrations increased by two to four-fold in forested catchments, while decreasing by nearly 50% in the wetland-dominated catchments. Catchment characteristics, in particular catchment size and the areal extent of wetlands and humic lakes, appear to play a large role in regulating streamwater acidity and DOC concentrations during spring flood. Patterns in pH largely follow patterns in DOC concentration for these streams, which contain high levels of humic acids. During spring snowmelt, pH remained at a consistently low level in headwater mire sites, but dropped substantially in all other catchments. The pH decline was less pronounced in the larger, more well-buffered streams. DIC export was small relative to DOC, but DIC concentrations were substantial in headwater streams prior to the spring snowmelt, when many of the streams were oversaturated with respect to CO$_{2}$.
DE: 1806 Chemistry of fresh water
DE: 1860 Runoff and streamflow
DE: 1871 Surface water quality
DE: 1890 Wetlands
SC: Biogeosciences [B]
MN: 2003 Fall Meeting