Tribonema was also recorded at the lower South Fork station. There were 5 genera of blue-green 

 algae and 13 genera of green algae represented in samples collected from the study area. 

 Diatoms and the cyanobacterium Oscillatoria were recorded in all 6 of the samples. 



Dearborn River near Bean Lake. Diatoms and the filamentous green alga Mougeolia 

 were co-dominants in tliis sample, followed by Zygnema, another filamentous green (Table 4). 

 Mougeotia is a widely distributed genus and very common in lakes, ponds, and rivers. It 

 occasionally forms blooms in the littoral zones of lakes undergoing acidification (Wehr and 

 Sheath 2003). Zygnema is also widespread and usually occurs in neutral to slightly acid waters 

 intertwined with other filamentous green algae, such as Spirogyra and Mougeotia. Together in 

 abundance, as they occur here, Mougeotia and Zygnema probably indicate waters of lower pH 

 (circumneutral). The cyanophyte Oscillatoria was common and ranked 4' in biovolume at this 

 site. This site supported at least 10 genera of non-diatom algae. 



Dearborn River below Highway 200. The filamentous blue-green alga Oscillatoria 

 dominated the sample fi-om the lower site on the Dearborn River (Table 4). Oscillatoria includes 

 almost 70 species and typically grows in mats on different substrata (mud, plants, stones, sand) 

 in shallow water. Taking all species into account. Palmer (1969) ranks Oscillatoria second, next 

 only to Euglena, in terms of tolerance to organic loading. Diatoms were abundant and ranked 2" 

 in biovolume here, followed by the filamentous green alga Zygnema and the desmid Cosmarium, 

 which were frequent and common, respectively. This site supported at least 7 genera of non- 

 diatom algae. 



Middle Fork Dearborn River near Rogers Pass. Diatoms contributed the most 

 biovolume to this rather sparse sample. Oscillatoria was common and ranked second. An 

 occasional cell of the cyanophyte Amphithrix and the desmids Closterium and Cosmarium 

 completed the algal assemblage at this site (Table 4). 



Middle Fork Dearborn River below FAS 434. The filamentous green alga 

 Oedogonium dominated the sample from this site (Table 4). Oedogonium is fi-ee-living and 

 sometimes epiphytic on submerged plants in aquatic habitats (Wehr and Sheath 2003). Of over 



