Arctic LTER Streams Chemistry Toolik Field Station, Alaska 1978 to 2019.

Since 1983, the Streams Project at the Toolik Field Station has monitored physical, chemical, and biological parameters in a 5-km, fourth-order reach of the Kuparuk River near its intersection with the Dalton Highway and the Trans-Alaska Pipeline. In 1989, similar studies were begun on a 3.5-km, third-order reach of a second stream, Oksrukuyik Creek. In each river, physical conditions (such as discharge and temperature), nutrient levels, primary production, insects, and fishes are monitored throughout the summer. Also, we conduct experimental fertilization of the Kuparuk River and Oksrukuyik Creek to determine the effects of added phosphorus and nitrogen on primary productivity, insect communities, and fish growth in arctic rivers. The Oksrukuyik Creek has not been fertilized since 1996. The Kuparuk River received phosphorus additions from 1983 through 2016. Station sites are relative distance from the original nutrient drippers for both the Kuparuk and Oksrukuyik. Kuparuk stations include sites in a reference, recovery, and fertilized reach. Reaches were defined based on the location of nutrient addition (see methods).