Total Dissolved Nitrogen data from the Kuparuk River near Toolik Field Station, 1994-2012.

Samples from designated stations from the Kuparuk River were collected during each summer from 1994 to current time. Three sampling dates occurred each summer; once in June prior to the start of fertilization and once each in July and August. Phosphorus addition has occurred since 1983; station sites are relative distance from the original 1983 phosphorus dripper. Stations include sites in a reference, recovery, and fertilized reach. Reaches were defined based on the location of phosphorous addition (see methods). Phosphoric acid is added to the stream to increase the soluble reactive phosphorus by 0.32 uM. Samples have been analyzed for total dissolved nitrogen on the Kuparuk since 1994.