RESULTS AND DISCUSSION 



Results are presented in Tables 3 and 4, located near the 

 end of this report following the Literature Cited section. 

 Spreadsheets containing completed diatom proportional counts, 

 with species' pollution tolerance classes (PTC) and percent 

 abundances, are attached as Appendix A. 



SAMPLE NOTES 



Bear Creek at mouth. Hannaea arcus was present as an 

 epiphyte on Hydrurus foetidus and cells were erect and oriented 

 perpendicular to the surface of the host. A large stalked 

 Gomphoneis (Gomphoneis minuta) was also present. 



NON- DIATOM ALGAE 



The benthic flora of Bear Creek was dominated by diatoms, by 

 another chrysophyte- -Hydrurus foetidus- -and by an attached 

 filamentous green alga, Ulothrix (Table 3). However, only small 

 patches of filamentous green algae were present in Bear Creek and 

 the amount in the sample probably overestimates the amount in the 

 creek relative to the other algae that were present (Patrick 

 Newby, MDEQ, personal communication) . Hydrurus is a common alga 

 of cold mountain streams, and is particularly abundant in the 

 Spring. Ulothrix also prefers cold waters with moderate nutrient 

 enrichment . 



Cyanobacteria, formerly called blue-green algae, were of 

 secondary importance in Bear Creek. In Rocky Mountain streams, 

 cyanobacteria seem to prefer cold waters and low concentrations 

 of nutrients. In reference streams of the Middle Rockies 

 Ecoregion, green and blue-green algae were co-dominants, whereas 

 blue-green algae dominated the benthic floras of less productive 

 streams in the Northern Rockies Ecoregion (Bahls et al . 1992). 



