indicates stable flows of cool water and little physical disturbance. Teratological cells were not 

 encountered during the diatom proportional count. 



Diatom metrics at the lower site on Eagle Creek indicate fair biological integrity and 

 partial support of aquatic life uses for a mountain stream and good biological integrity and full 

 support of uses for a prairie stream (Table 5). The limiting factors here were sedimentation 

 (moderate impairment for a mountain stream) and organic loading (minor impairment for a 

 mountain stream). Diatom species richness and diversity were excellent and no teratological 

 diatoms were encountered. 



The lower site shared a little less than half of its diatom flora with the upper site on Eagle 

 Creek. This indicates only a minor change in the diatom flora and a small difference in 

 ecological conditions between the sites. Again, the dominant species was Rhoicosphenia 

 abbreviata, a common epiphyte on Cladophora. The next most abundant species here were 

 Diatoma moniliformis, which indicates somewhat elevated salt content, and Nitzschia paleacea, 

 a motile diatom adapted to living on unstable and aggrading substrates. 



Several ecological attributes were selected from the diatom reports in the appendix and 

 modal categories of these attributes were extracted to characterize water quality tendencies at the 

 two sites (Table 6). Modal categories for the selected attributes were identical for the two sites. 

 The majority of diatoms at both sites were non-motile nitrogen autotrophs that exert a fairly high 

 demand for dissolved oxygen. Nitrogen autotrophs require inorganic nitrogen (nitrates and 

 ammonia) as nutrients. The majority of diatoms at both sites also indicate fresh, alkaline and 

 eutrophic waters with only a small amount of BOD loading. 



