Non-Diatom Algae 



Only two genera of non-diatom algae were found in the sample from the upper site on 

 Eagle Creek and both of these were filamentous green algae (Table 4). An abundance of 

 Cladophora here indicates eutrophic conditions. Diatoms were dominant and ranked T" in 

 biovolume. 



Vaucheria or "water felt" was the most abundant alga in the sample from the lower site 

 on Eagle Creek (Table 4). Vaucheria requires a steady supply of cool, flowing water and is often 

 found in springs and spring brooks. Diatoms were abundant here and ranked 2"*^ in biovolume. 

 The filamentous green algae Cladophora and Spirogyra ranked 3"^ and 4"^, respectively. Both of 

 these indicate eutrophic waters. These were followed in abundance by the cold-water 

 chrysophyte Tribonema and the filamentous cyanophyte Phormidium, both of which were rare. 

 The sample from the lower site contained a total of 5 genera of non-diatom algae. 



Diatoms 



Four of the major diatom species in Eagle Creek are sensitive to organic pollution. Three 

 of these were abundant at both sites and one {Staurosira construens) was abundant only at the 

 upper site (Table 5). Six of the major species are somewhat tolerant of organic pollution and 

 these were present at both sites. Nitzschia paleacea, a somewhat tolerant species that is also 

 highly motile, was abundant only at the lower site. None of the major diatom species in the 2003 

 samples from Eagle Creek are most tolerant of organic pollution (pollution tolerance class 1). 



The upper site on Eagle Creek had good biological integrity for a mountain stream and 

 excellent biological integrity for a prairie stream (Table 5). The limiting factors here were minor 

 impairment from sedimentation and borderline minor impairment from organic loading. Diatom 

 species richness, diversity, and equitability were excellent. The major diatom species here were 

 either sensitive to or only somewhat tolerant of organic pollution. The most abundant species at 

 the upper site were Rhoicosphenia abbreviata and Staurosira construens. Both are non-motile 

 species. R. abbreviata is an epiphyte and S. construens is a free-living araphid diatom that 



