Several ecological attributes were selected from the diatom reports in the appendix and 

 modal categories of these attributes were extracted to characterize water quality tendencies at the 

 three sites (Table 5). The majority of diatoms at all three sites were freshwater nitrogen 

 autotrophs that tolerate only a small amount of BOD loading. Nitrogen autotrophs require 

 inorganic nitrogen (nitrates and ammonia) as nutrients. 



Most of the diatoms at the middle site were non motile, suggesting that this site had the 

 least amount of sedimentation. On the other hand, the largest motility category at the upper site 

 was "highly motile" and the largest category at the lower site was "moderately motile". The 

 sedimentation index indicated moderate impairment at both of these sites. 



The largest trophic state category at the upper site was "variable". Diatoms in this 

 category tolerate a wide range of concentrations of inorganic nutrients. At the middle and lower 

 sites, most diatoms were in the "eutraphentic" category, which suggests that concentrations of 

 inorganic nutrients (carbon, nitrogen, and phosphorus) were elevated at these sites. 



Most diatoms at the middle site belong to the "circumneutral" pH category. These 

 diatoms prefer pH levels around 7. At the upper and lower sites, the largest pH category was 

 "alkaliphilous", which suggests higher pH values and perhaps more photosynthesis (primary 

 production) at these sites. The modal category for dissolved oxygen demand was "continuously 

 high" at the upper and middle sites. The largest category for dissolved oxygen demand at the 

 lower site was "not classified". 



