Sample Notes 



Some of the samples in this sample set (RX)WEC04, 02, and 01) were septic, black in 

 color, and smelled of rotten eggs (H2S). Decomposition of soft algae in these samples was not 

 complete, however, allowing for identification of most specimens. Diatoms and blue-green 

 algae (cyanobacteria) were more resistant to decay than green algae, which were the most 

 problematic to identify. The samples from HRSECOl, RDWEC02, and RDWEC04 were silty to 

 extremely silty. Fine particulate organic matter (FPOM) was abundant in the sample collected 

 from RDWEC04. The samples from HRSEC02, RDWECOl, 03, and 04, and both sites on 

 Pasture Creek contained bits and pieces of aquatic macrophytes and/or terrestrial plants. 



Non-Diatom Algae (Table 3) 



These streams supported 13 genera of non-diatom algae in 3 algal divisions (Table 3). 

 Green algae and cyanobacteria were the most diverse and most abundant groups of non-diatom 

 algae. A filamentous chrysophyte (Tribonema) was present at upstream sites. Each site 

 supported from 1 to 8 genera of non-diatom algae. 



Diatoms accounted for most of the biovolume in samples from upper Horse Creek and 

 upper Pasture Creek (Table 3). The filamentous green alga Rhizoclonium was the most abundant 

 alga in all of the other samples. 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-forming filamentous algae are normal components of many aquatic 

 ecosystems, including prairie streams, and there is no evidence from this study that standing 

 crops oi Rhizoclonium are excessive in these streams. Also, criteria have not been established 

 for determining when algal growth in prairie streams is excessive. 



Cyanobacteria, some species of which can fix atmospheric nitrogen, were common in the 

 upper reaches of the East Rcdwater River and in Horse Creek and Pasture Creek. Nitrogen may 



