LaMarche Creek. Except for several abnormal cells at site 02, both sites had excellent 

 biological integrity. Diatom species richness, diversity, and equitability were outstanding. Both 

 sites supported more than 80 species (90 species at site 02!) and produced Shannon diversity 

 values greater than 5. Among the major species in LaMarche Creek was Aulacoseira alpigena, a 

 planktonic species. The headwaters of LaMarche Creek drain several lakes and ponds in the 

 Anaconda Pintler Wilderness. These waters are the likely source of .4. alpigena in LaMarche 

 Creek and the main reason for the unusually high species richness and diversity here. The two 

 sites shared slightly more than half of their diatom floras. 



Delano Creek. Diatom metrics indicate excellent biological integrity and full support of 

 aquatic life uses at sites 01 and 02 on Delano Creek. None of the core metric values exceeded 

 their respective thresholds for minor impairment here. However, an abundance of Planothidium 

 species suggests sandy substrates at both sites. Other than Planothidium, the major species at 

 sites 01 and 02 were sensitive to pollution and indicate cold temperatures. Based on the larger 

 percentage of attached diatoms {Achnanthidium and Cocconeis), sites 01 and 02 appear to have 

 steeper gradients and faster currents than most of the other sites in the sample set. The diatom 

 assemblages at sites 01 and 02 were \'irtually identical. 



The pollution index indicated minor impairment from organic enrichment at site 03. The 

 composition of the diatom assemblage here was quite different from sites 01 and 02. Site 03 

 supported large numbers of unattached diatoms {Fragilaria and Synedra) and fewer attached 

 species, which indicates more gentle gradients and slower current velocities. Although an 

 abundance of Diatoma mesodon and Meridian circulare indicate a continuation of cool water 

 temperatures here, site 03 also supported major species that indicate human disturbance with 

 elevated sediment {Planothidium spp.) and inorganic nutrients {Synedra ulna). Fragilaria 

 nitzschioides was also a major species at site 03. This rather uncommon pollution sensitive 

 species seems to prefer slightly dystrophic waters of low mineral content. No abnormal diatom 

 cells were observed at site 03, which shared less than half of its diatom assemblage with site 02. 



Charcoal Gulch. Diatom metrics indicate minor impairment from sedimentation and 

 organic loading at this site. The dominant diatom species here {Planothidium) are adapted to 



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