HR: 17:00h
AN: B22D-04    [PDF]
TI: Total Carbon Export from a Boreal Forested Catchment and the Relative Importance of Temperature and Flow
AU: * Bishop, K
EM: kevin.bishop@ma.slu.se
AF: Dept. of Env. Assessment, SLU, PO Box 7050, Uppsala, 750 07 Sweden
AU: Kohler, S
EM: Skohler@lmtg.ups-tlse.fr
AF: CNRS (UMR 5563), 38 rue des trente-six ponts, Toulouse, 31400 France
AU: Laudon, H
EM: hjalmar.laudon@sek.slu.se
AF: Dept of Forest Ecology, Swedish Univ. of Agricultural Sci., Ume†, 901 83 Sweden
AU: Seibert, J
EM: Jan.Seibert@ma.slu.se
AF: Dept. of Env. Assessment, SLU, PO Box 7050, Uppsala, 750 07 Sweden
AU: Grip, H
EM: Harald.Grip@sek.slu.se
AF: Dept of Forest Ecology, Swedish Univ. of Agricultural Sci., Ume†, 901 83 Sweden
AB: For over a decade, streamwater dissolved organic carbon (DOC) has been sampled weekly to daily on one mire and two forested subcatchments within the boreal, 50 ha Svartberget catchment in Sweden. During the last year, DIC measurements have been added. This high resolution record of outputs from different landscape elements was analyzed to examine the role of climate on DOC flux and concentration, as well as to set the DIC export from headwaters in relation to the carbon budget for this region. Over the entire study period, export of total organic carbon (OC) averaged 7 g m-2 year-1 from the forested subcatchments, and 11 g m-2 from the mire subcatchment. The snowmelt exported ca. 45 % of all TOC, but the concentration-flow pattern indicated depletion of a soil source with time. Variation in summer TOC flux was four times larger than for the winter/spring flux. This large interannual variation in summer TOC export was related to the variability in both summer temperatures and flows, especially the latter. High flows during summer mobilized much more carbon than comparable winter/spring high flows.. The importance of sampling high flows when doing flux estimates was illustrated by the fact that 5 % of the highest flow events accounted for 40 % of the exported water but more than 50 % of the total organic carbon exported. Intensive snow melting followed by warm and exceptionally wet summers released around four times more TOC than during dry years. The headwater DIC export appears to be of the same order of magnitude as DOC export, but much of the DIC has left the stream via degassing within a few hours of leaving the soil, meaning that this DIC is not seen if the DIC budget is based on measurements further downstream.
DE: 1806 Chemistry of fresh water
DE: 1860 Runoff and streamflow
DE: 1871 Surface water quality
SC: Biogeosciences [B]
MN: 2003 Fall Meeting