Nitrogen fluxes in a high elevation Colorado Rocky Mountain basin

Measured, calculated and simulated values were combined to develop an annual nitrogen budget for Loch Vale Watershed (LVWS) in the Colorado Front Range. Nine-year average wet nitrogen deposition values. were 1.6 (s = 0.36) kg NO₃-N ha^{- 1}, and 1.0 (s = 0.3) kg NH₄-N ha^-1. Assuming dry nitrogen deposition to be half that of measured wet deposition, this high elevation watershed receives 3.9 kg N ha^-1. Although deposition values fluctuated with precipitation, measured stream nitrogen outputs were less variable. Of the total N input to the watershed (3.9 kg N ha^-1 wet plus dry deposition), 49% of the total N input was immobilized. Stream losses were 2.0 kg N ha^-1 (1125 kg measured dissolved inorganic N in 1992, 1--2 kg calculated dissolved organic N, plus an average of 203 kg algal N from the entire 660 ha watershed). Tundra and aquatic algae were the largest reservoirs for incoming N, at approximately 18% and 15% of the total 2574 kg N deposition, respectively. Rocky areas and forest stored the remaining 11% and 5%, respectively. Fully 80% of N losses from the watershed came from the 68% of LVWS that is alpine. [ABSTRACT FROM AUTHOR]