Sample Notes 



All of the samples in this sample set, except the one from near the mouth of Prairie Elk 

 Creek (3014-01), were septic, black in color, and smelled of rotten eggs (H2S). Decomposition 

 of soft algae was not complete, however, allowing for identification of most specimens. All of 

 the samples were silty to extremely silty. The samples from Garoutte's and Taylor's contained 

 macroph^les. 



i/r 



Non-Diatom Algae (Table 3) 



Filamentous green algae dominated the samples from all sites except Taylor's on 

 Prairie Elk Creek and Sand Creek near mouth. Spirogyra ('pond scum') was the dominant alga 

 at Garoutte's and Rhizoclonium was most abundant at the other 3 sites where filamentous greens 

 dominated. Diatoms ranked first in biovolume at Taylor's, where filamentous green algae 

 {Rhizoclonium and Oedogonium) were common. Diatoms were the only algae present in the 

 sample from Sand Creek. 



Rhizoclonium has been reported to cause problems in standing and slowly flowing waters 

 across the western United States (Wehr and Sheath 2003). Algae interfere with water uses — e.g., 

 fishing, swimming, boating, and irrigation — only when standing crops are excessive. Mat- 

 fomiing filamentous algae are nomial components of many aquatic ecosystems, including prairie 

 streams, and there is no evidence from this study that standing crops o{ Rhizoclonium or 

 Spirogyra in Prairie Elk Creek are excessive. Also, criteria have not been established for 

 determining when algal growth in prairie streams is excessive. 



Cyanobacteria (mainly Oscillatoria) were found only in samples collected from Prairie 

 Elk Creek at Garoutte's and near its mouth. The red alga Audouinella was also present in the 

 sample collected from Prairie Elk Creek near its mouth. 



