HR: 1330h
AN: NB33L-13    [Abstracts]
TI: Spatial and Temporal Nitrogen Dynamics in Streams of the H.J. Andrews Experimental Forest
AU: * Johnson, S
EM: sherrijohnson@fs.fed.us
AF: USDA Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, OR 97331 United States
AB: Nitrogen concentrations and fluxes have been studied for over 30 years in selected gaged streams at the Andrews Experimental Forest, Oregon. As we expand our scope of study to try to understand N dynamics throughout forested stream networks, we are examining how spatially representative these basins and measurements are within the 6400 ha Lookout Creek Basin. We are also intensively sampling nutrient concentrations during storm flows in several gaged basins across seasons. We have found that the existing monitored basins are not good representatives of headwater stream nitrate concentrations at baseflow within Lookout Creek Basin. NO3-N concentrations are generally low in the Cascades. During baseflow synoptic sampling of headwater streams, concentrations range up to 0.100 mg/L, while in the monitored basins, concentrations are an order of magnitude less (0.005 mg/L). Streams with higher NO3 cannot be explained by forest type. Storm sampling during both spring and fall storms shows similar flushing of DON and DOC on the rising limb of the hydrograph, but NO3 fluxes increase with the first fall storm only in specific basins.
DE: 0400 Biogeosciences
DE: 1806 Chemistry of fresh water
DE: 1871 Surface water quality
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly