Project Area and Sampling Sites 



The project area is located within the Northern Rockies Ecoregion (USEPA 2000). The 

 streams in this study are all tributaries of Ninemile Creek. Ninemile Creek is a large north side 

 tributary of the Clark Fork River, which it joins about 25 miles west of Missoula. The surface 

 geology of the watershed is complex, consisting mostly of Precambrian Belt Series Rocks in the 

 uplands and Tertiary basin fill in the Ninemile Valley (Renfro and Feray 1972). Climax 

 vegetation consists of alpine tundra at the highest elevations, mixed conifer forest at intermediate 

 elevations, and mixed grassland/sagebrush steppe in the Ninemile Valley. The main land uses 

 are recreation, logging, and ranching. 



Periphyton samples were collected at 8 sites on 5 tributaries of Ninemile Creek (Table 1). 

 All sites are in USGS HUC 17010204 (Middle Clark Fork) and are classified B-1 in the Montana 

 Surface Water Quality Standards. 



Methods 



Periphyton samples were collected following standard operating procedures of the 

 MDEQ Planning, Prevention, and Assistance Division. Using appropriate tools, microalgae 

 were scraped, brushed, or sucked from natural substrates in proportion to the importance of those 

 substrates at each study site. Macroalgae were picked by hand in proportion to their abundance 

 at the site. All collections of microalgae and macroalgae were pooled into a common container 

 and preserved with Lugol's (IKI) solution. 



The samples were examined to estimate the relative abundance of cells and rank by 

 biovolume of diatoms and genera of soft (non-diatom) algae according to the method described 

 in Bahls (1993). Soft algae were identified using Smith (1950), Prescott (1962, 1978), John et al. 

 (2002), and Wehr and Sheath (2003). These books also served as references on the ecology of 

 the soft algae, along with Palmer (1969, 1977). 



