This resource contains the results of an experiment to test the effects of nutrients on stream biofilms at montane and urban sites in the Logan River, Red Butte Creek, and Middle Provo River watersheds located in northern Utah. We tested the effects of individual nitrogen and phosphorus additions and combined nitrogen and phosphorus additions at a series of concentrations on biofilm biomass using nutrient diffusing substrates (NDS). The Word document "methods_NDS" describes the methods used to construct the NDS and treatments included in our experiment.

At the end of the deployment period, biofilms grown on NDS were frozen. We measured chlorophyll a on half of the replicates and measured ash-free dry mass on the other half. The CSV file “biomass_nutrients_NDS” contains summary statistics (mean, standard deviation, count) of chlorophyll a concentrations and ash-free dry mass of biofilms on each nutrient treatment at our study sites. The Word document “methods_NDS” describes the analytical methods used to measure chlorophyll and ash-free dry mass.

We collected water column samples at each site for total and dissolved nutrient analyses. The CSV file “biomass_nutrients_NDS” contains total nitrogen, total phosphorus, ammonium, nitrate, and soluble reactive phosphorus concentrations at each site. The Word document “methods_NDS” describes the analytical methods used to measure nutrient concentrations.