Jared Baker


The objective of this study was to use a 5 day bioassay experiment to assess whether nitrogen or phosphorus limited the growth of algae in the Little Bear River watershed. Four sites were sampled along the river in September 2012. The locations of the sites were south of Avon (Station 2), near Paradise, UT (Station 6), downstream of Hyrum Reservoir (Station 7), and downstream of the Waste Water Treatment Facility in Wellsville (Station 10). Chlorophyll a analysis was conducted prior to, after 2.5 days, and at the conclusion of the 5 days. Varying combinations of nitrogen and phosphorus were added to water samples from each site and these were incubated in 125-ml flasks with 150 uM m-2 lighting and at 15°C. ANOVA was used to determine nutrient limitations within samples. Chlorophyll concentrations measured at the conclusion of the experiment indicated that both nitrogen and phosphorus limited algal growth at Stations 2 and 10 while phosphorus alone was limiting at Stations 6 and 7.