Study Site
General description (modified from Benstead et al. 2007): Fertilization of the Kuparuk River with P (added as H3PO4 via continuous dripper from mid-June to mid-August, fixed-rate with a target concentration of 0.3 μM at a nominal discharge of 2 m3/sec) started in the summer of 1983. The H3PO4 was added at an arbitrary point called 0.0 km, located 1.6 km upstream of the river crossing at the Dalton Highway (see Peterson et al., 1985 for early results of fertilization). In subsequent years, all points on the Kuparuk River were referenced relative to this datum. In 1985 the P dripper was moved 0.59 km downstream, forming the first Kuparuk recovery reach (enriched for the two previous summers, 1983-1984) between 0.0 km and 0.59 km. In 1996 the dripper was moved downstream a second time, to 1.4 km below the original dripper site. The reach between 0.59 km and 1.4 km became the second Kuparuk recovery reach (enriched for 13 consecutive summers, 1983-1995). See Slavik et al. (2004) for an summary of other relevant data the Kuparuk River long-term fertilization experiment.
The specific reaches represented in this data set come from the following general areas unless noted otherwise:
1992-1995
Fertilized from 0.59km to 18km
Reference from 0.5km to -9.5km
1996-2010
Fertilized from 1.6km to 6km
Recovery from 1km to 1.39km
Reference from -0.47 to 0.7km
2011-Present
Fertilized from 1.6km to 6km
Re-Fert 2 from 0.7km to 1.39km
Re-Fert 1 from 0km to 0.6km
Reference from -0.47 to -0.1km

Sampling Methods
Data were acquired using point transects (Bowden et al. 1994, Bowden et al. 2006). Typically five transects were established across the river at ever sampling station. The transect locations were not permanently monumented and so for sites that were revisited several times a year or over many years, the exact location of the transects vary somewhat. While useful information is contained in the individual transects, statistical comparisons should typically be based on the mean cover values for all transects done at a site as the fundamental reporting unit. At intervals of about 10 cm along each transect, we noted the nature of the plant cover on the cobbles. Three moss species (Schistidium [Grimmia] agassizii Sull. & Lesq. in Sull., a mixture of H. alpestre [Hedw.] Loeske and H. ochraceum [Turn.] Loeske, and Fontinalis neomexicana Sull. and Lesq.), one liverwort (Solenostoma sp.), and the macroalgae previously mentioned, could be identified easily by eye in the field and were recorded as being present or absent. In subsequent years, other easily recognizable cover categories were recorded (e.g. Lemanea spp., Phormidium spp.). Only one species was assigned to a point. For a typical river width of 15 m, each transect provided roughly 150 points or 750 points at each station. Species frequency was determined from the number of times each species was encountered, divided by the total number of points sampled in a transect. Only one species (or "bare") was recorded as present at any one point. “Bare” recordings in the field notes were assumed to consist of an epilithic biofilm of diatoms and other microalgae as reported by Miller et al. (1992) and are recorded in the database here as "Epilithic algae".
In different years slightly different river sites were sometimes measured. Any measured site is a representative sample of the reach from which it came. The dataset contains the "actual" station location information. However, to consolidate the data and facilitate comparisons among reaches and across years, the data from closely co-located actual stations has been aggregated

Arctic LTER Streams Protocol, http://arc.lternet.edu/streams/arctic-lter-streams-protocol

http://ecosystems.mbl.edu/ARC/streams/protocol2.html