Some algae, such as the filamentous greens, are conspicuous 

 and their excessive growth may be aesthetically displeasing, 

 deplete dissolved oxygen, interfere with fishing and fish 

 spawning, clog water filters and irrigation intakes, create 

 tastes and odors in drinking water, and cause other problems. 



PROJECT AREA AND SAMPLING SITES 



The project area is in Carbon County in southcentral 

 Montana. East Rosebud Creek heads on the Beartooth Plateau in 

 the Absaroka-Beartooth Wilderness and its watershed includes 

 Granite Peak (el. 12,799 feet), Montana's highest peak. East 

 Rosebud Creek is a third-order tributary of Rosebud Creek, which 

 is a tributary of the Stillwater River. 



East Rosebud Creek begins in the Middle Rockies Ecoregion 

 and enters the Montana Valley and Foothill Prairies Ecoregion at 

 the upper end of the study reach (Woods et al . 1999) . The 

 surface geology of the upper watershed consists of Precambrian 

 metamorphic rocks (Renfro and Feray 1972) . Vegetation is alpine 

 tundra at the highest elevations, conifer forest at middle 

 elevations, and grassland along the study reach (USDA 1976) . 



Periphyton samples were collected at two sites on East 

 Rosebud Creek on August 18, 2000 (Map 1, Table 1) . The upper 

 site at the National Forest boundary is located at an elevation 

 of about 5,400 feet. Elevation of the lower site above Roscoe is 

 about 5,200 feet. East Rosebud Creek is classified B-1 in the 

 Montana Surface Water Quality Standards. 



METHODS 



Periphyton samples were collected by Patrick Newby of the 



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