euglenoid algae, and cyanobacteria (Table 4). After the diatoms, 

 Rhizoclonium and Stigeoclonium were the most common algae, 

 indicating moderate nutrient enrichment and some (internal?) 

 organic loading. 



DIATOMS 



Little Dry Creek 



Little Dry Creek proved to be a suitable reference site; 

 diatom metrics indicated full support of aquatic life uses. 

 Other than minor impairment from a low pollution index (Table 5) , 

 all metrics were normal for prairie streams. All of the sites in 

 this study exhibited at least minor impairment due to a slightly 

 depressed pollution index, leading one to suspect that this is 

 the nominal condition for streams in this part of the state. 



Redwater River 



The upper Redwater River site at Gackle (RWl-3) supported a 

 large percentage (58%) of pollution tolerant species. Amphora 

 delicatissima and Cymhella pusilla were the two most abundant 

 pollution tolerant species (Table 5) . These are mesohalobous 

 (brackish water) diatoms (Krammer and Lange-Bertalot 1986) . 

 Amphora delicatissima is closely related to Amphora coffeiformis, 

 which tolerates moderate organic loading (Lowe 1974) . Also 

 abundant here were two species of Synedra-. Synedra famelica and 

 Synedra pulchella. Both of these species prefer waters with 

 moderately high conductivity (Krammer and Lange-Bertalot 1991a) . 



The depressed pollution index and small number of species 

 indicate moderate impairment and partial support of beneficial 

 uses at the Gackle site. The probable causes of impairment here 

 are elevated salinity and loading by organic nutrients. 



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