was influenced more by local upwelling and geology. 



Although diatom species composition and community structure 

 show that the Boulder River above Natural Bridge fully supports 

 its aquatic life uses, large standing crops of filamentous algae 

 in this reach may impair certain beneficial uses. The status of 

 the periphyton community in the lower reach of the river, from 

 Natural Bridge to Big Timber, is unknown at this time. 



LITERATURE CITED 



Bah.^s, L.L. 1979. Benthic diatom diversity as a measure of 

 water quality. Proc . Mont. Acad. Sci . 38:1-6. 



Bahls, L.L. 1993. Periphyton Bioassessment Methods for Montana 

 Streams (Revised) . Montana Department of Health and 

 Environmental Sciences, Helena. 



Bahls, L.L., Bob Bukantis, and Steve Tralles. 1992. Benchmark 



Biology of Montana Reference Streams . Montana Department of 

 Health and Environmental Sciences, Helena. 



Barbour, M.T., J. Gerritsen, B.D. Snyder, and J.B. Stribling. 



1999. Rapid Bioassessment Protocols for Use in Streams and 

 Wadeable Rivers: Periphyton, Benthic Macroinvertebrates and 

 Fish. Second Edition. EPA/841-B-99-002 . U.S. EPA, Office 

 of Water, Washington, D.C. 



Cox, E.J. 1996. Identification of Freshwater Diatoms from Live 

 Material. Chapman & Hall, New York. 



Karr, J.R., and D.R. Dudley. 1981. Ecological perspectives on 

 water quality goals. Environmental Management 5:55-69. 



Krammer, K., and Horst Lange-Bertalot . 1986. Bacillariophyceae, 

 Part 2, Volume 1: Naviculaceae . In Ettl, H., J. Gerloff, 

 H. Heynig, and D. Mollenhauer (eds.). Freshwater Flora of 

 Middle Europe. Gustav Fischer Publisher, New York. 



Lange-Bertalot, Horst. 1979. Pollution tolerance of diatoms as 

 a criterion for water quality estimation. Nova Hedwigia 

 64:285-304. 



Levine, C.L. 1996. Boulder River Nutrient and Algae Monitoring 

 Results. Water Quality Division, Montana Department of 

 Environmental Quality, Helena. 



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