An improved understanding of the relationship between nutrient spiraling and concentration has been noted as important to improve nutrient export models (Mulholland et al. 2008), but is also useful to assess stream proximity to saturation (e.g., Earl et al. 2006) and to increase basic understanding of stream solute transport. Because TASCC provides for spiraling curve characterization from ambient to saturation, we were able to quantify relationships between Vf-tot, Utot, and concentration.
Because Vf is indicative of nutrient use efficiency, these curves represent the impact increased nutrient load has on use (i.e., uptake) relative to concentration. In our study, Vftot-dyn decreased far less over a larger concentration range at Middle Fork and suggests this reach may have greater resiliency to increased nutrient load relative to the Beehive reach (Fig. 2C,D).