This report would not have been possible without the assistance 

 of four Montana Department of Fish and Game employees who did most of 

 the field collecting: Dennis Schwehr, Missoula; Rod Berg, Livingston; 

 Larry Peterman, Miles City; and Bob Newell, Glendive. The Department 

 of Fish and Game also contributed some essential laboratory supplies. 

 Duane Klarich, Montana Department of Health and Environmental Sciences, 

 Billings, contributed a number of additional samples. Roger Knapton, 

 hydrologist for the Geological Survey, Helena, permitted examination 

 of the most recent National Stream Quality Accounting Network (NASQAN) 

 phytoplankton data. Thanks are also due Marian Higgins, secretary for 

 the Environmental Quality Council, who typed this report, and to my 

 wife, Peggy, who performed all statistical calculations. The writing 

 of this report was supported in part by the Environmental Quality 

 Council. The remaining time and effort involved were contributed by 

 the author and all errors, opinions, etc. are his alone. 



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