NON- DIATOM ALGAE 



Box Elder Creek had a very diverse algal flora, even for a 

 prairie stream (Table 4) . [Prairie streams generally have more 

 genera of non-diatom algae and more species of diatoms than do 

 mountain streams (Bahls 1993) .] Reach 022 supported 21 genera of 

 non-diatom algae. The other sites supported fewer genera, but 

 still had good taxonomic richness. 



All sites supported green algae (Chlorophyta) , euglenoid 

 algae, chrysophytes (mostly diatoms), and cyanobacteria . 

 Dinof lagellates {Gonyaulax) and Cryptomonads {Rhodomonas) were 

 uncommon to common at some of the upper sites. Algae in these 

 latter groups are typically planktonic and found in open water. 



Filamentous green algae, mainly Cladophora, Rhizoclonium, 

 and Spirogyra, dominated at most of the sites (Table 4) . 

 Cyanobacteria, mainly AnaJbaena, Calothrix, and Lyngbya, were also 

 abundant, particularly at stations near the middle and lower end 

 of the study section. Diatoms were very common to abundant at 

 all sites (Table 4) . 



Certain genera of algae have rather specific environmental 

 requirements and serve as good indicators of water quality. 

 Chara, a green macroalga, requires soft but stable substrates and 

 clear water; it does not do well in turbid water. Chara was 

 found only in Reaches 004 and 003 (Table 4) . The samples from 

 these reaches were relatively free of silt (see Sample Notes, 

 above) . 



A species of Calothrix (Division Cyanophyta) with filaments 

 embedded in profuse gelatinous masses, was, like Chara, abundant 

 only in the lower reaches of the study section (Table 4) . This 

 taxon may also be sensitive to turbid waters. 



