• 



Non-Diatom Algae (Table 3) 



Meadow Creek. Diatoms were the only common algae in the sample from Meadow 

 Creek. Other algae included a few genera of green algae and cyanobacteria. 



Martin Creek. Diatoms ranked first in biovolume in both samples from Martin Creek. 

 In addition to diatoms, the desmid Closterium and the filamentous cyanophyte Tolypothrix were 

 common at the upper site. Tolpothrix prefers unpolluted fresh waters. At the lower site, the 

 most common non-diatom algae were Microspore! sp., a filamentous green, and Nostoc sp., a 

 colonial cyanophyte. Microspora prefers cool waters and some species are frequent in low pH 

 environments. Tolypothrix and Nostoc are both nitrogen fixers and indicate that nitrogen is 

 probably the limiting nutrient in Martin Creek. 



Reimel Creek. The sample from upper Reimel Creek contained only diatoms and an 

 occasional cell of Microspora. Diatoms dominated the sample from lower Reimel Creek, where 

 the cyanophyte Oscillatoria was frequent and ranked second and the chrysophyte Hydrurus 

 foetidus was common and ranked third in biovolume. Hydrurus foetidus is a cold-water 

 stenotherm that is common in mountain streams. It requires water temperatures below 10°C and 

 prefers bright sunlight and waters of relatively low pH. 



Ditch Creek. Cells of Tolypothrix were frequent and this nitrogen-fixing cyanophyte 

 ranked first in biovolume in the sample from Ditch Creek. Other filamentous cyanobacteria 

 were also found here, including the nitrogen-fixing genus Nodularia. Diatoms were sparse in the 

 sample from Ditch Creek. 



Deer Creek. The cyanophyte Oscillatoria was abundant and ranked first in biovolume in 

 Deer Creek. Oscillatoria is a large genus and species from this genus are found in a wide range 

 of habitats. Some species of Oscillatoria are tolerant of pollution and when abundant they may 

 indicate nutrient enrichment and eutrophic conditions. The nitrogen-fixing cyanophyte Nostoc 

 ranked second in the sample from Deer Creek. Nostoc par melioides, the species found in Deer 

 Creek, grows on stones in mountain streams. It normally produces spherical colonies, but 



