Performing a Nutrient Diffusion Substrata Test

A White Paper presented to Oglala Lakota College for use in pre-engineering class exercises. Available nutrients, primarily nitrogen (N) and phosphorus (P), control the growth of periphyton in lakes and streams. The nutrient diffusing substrata (NDS) is an economic and replicable way to determine whether an aquatic environment is limited by a particular nutrient (Capps et al., 2011). The NDS commonly uses clay pots, plastic cups, or periphytometers (Rugenski et al., 2008). The NDS in this paper uses plastic cups based on Methods in Stream Ecology (Hauer and Lamberti, 2007). The agar solution is mixed with 8 different types of nutrients in Table 1. Each nutrient type has 6 replicates. The control is an agar solution with no nutrient addition