HR: 0800h
AN: H51D-1173    [Abstracts]
TI: Landscape regulation of nitrogen export during snowmelt in boreal watersheds of northern Sweden
AU: * Petrone, K C
EM: ftkcp@uaf.edu
AF: Dept. of Forest Ecology, Swedish University of Agricultural Sciences, Swedish University of Agricultural Sciences, Ume†, 901 83 Sweden
AU: Laudon, H
EM: hjalmar.laudon@sek.slu.se
AF: Dept. of Forest Ecology, Swedish University of Agricultural Sciences, Swedish University of Agricultural Sciences, Ume†, 901 83 Sweden
AU: Buffam, I
EM: ishi.buffam@sek.slu.se
AF: Dept. of Forest Ecology, Swedish University of Agricultural Sciences, Swedish University of Agricultural Sciences, Ume†, 901 83 Sweden
AB: In boreal watersheds of northern Sweden, the four week period of snowmelt provides nearly 50% of the annual runoff and a majority of the annual flux of carbon and nutrients to streams. Since the average snow cover is 170 days per year, changes in the depth of snow cover are likely to influence winter conditions such as soil moisture and soil frost which in turn affect microbial processes. Changes in the amount and timing of snow melt can also affect the thawing of seasonal frost and dominant water flow paths from hillslopes to streams. We examined dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and dissolved inorganic nitrogen (nitrate and ammonium) in three streams which differ in catchment characteristics. We found that the stream with the greatest proportion of wetland coverage had higher concentrations of DOC, DON, and ammonium, but undetectable amounts of nitrate during snow melt. Conversely, two streams with low wetland coverage had three-fold lower DOC and two-fold lower DON concentrations, but nearly equal amounts of ammonium and nitrate. Across all catchments, nitrate was inversely related to the ratio of DOC to DON, suggesting that soil organic matter quality and microbial processes influence nitrate flux during snow melt. Ongoing research will expand upon current knowledge of stream chemistry by incorporating snow pack, lysimeter, and groundwater chemistry to examine the mechanisms which regulate nitrogen flux during the snow melt period in northern Sweden.
DE: 1719 Hydrology
DE: 0400 Biogeosciences
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting