The Little Bear River is a tributary to the Bear River that drains the south end of the Cache Valley in Northern Utah. The upper elevations are more pristine and are made up of mostly forested mountainous terrain with some grazing activity. The lower elevations are comprised of low gradient agricultural and urban parcels. Anthropogenically influenced landscapes can result in higher nitrogen inputs to streams, and these increases are often marked by an increase in the heavy-nitrogen isotope, δ15N. This study looked at the concentration of δ15N in periphyton on the river bed. These concentrations were then compared to anthropogenic land use in the surrounding watershed. δ15N values in the periphyton were significantly correlated with increasing percentages of anthropogenically affected land use in the Little Bear River watershed. It is likely that anthropogenic land uses (manure fertilization and wastewater treatment) caused the enrichment in δ15N concentrations.
"Anthropogenically Altered Land and its Effect on δ15N Values in Periphyton on a Fourth Order Stream in Utah’s Cache Valley,"
Natural Resources and Environmental Issues:
Vol. 18, Article 8.
Available at: http://digitalcommons.usu.edu/nrei/vol18/iss1/8