I 



operating procedures of the MDEQ Planning, Prevention, and 

 Assistance Division. A duplicate sample was collected at station 

 #1 (mouth) for quality assurance purposes. 



Using appropriate tools, microalgae were scraped, brushed, 

 or sucked from natural substrates in proportion to the rank of 

 those substrates at the 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 solution. 



Samples were examined to estimate the relative abundance 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 Dillard (1999) , Prescott (1978) , 

 Smith (1950) , and Whitford and Schumacher (1984) . These books 

 also served as references on the ecology of the soft algae, along 

 with Palmer (1977) . 



After the identification of soft algae, raw periphyton 

 samples were cleaned of organic matter using sulfuric acid, and 

 permanent diatom slides were prepared using Naphrax, a high 

 refractive index mounting medium, following Standard Methods for 

 the Examination of Water and Wastewater (APHA 1998) . For each 

 slide, between 402 and 443 diatom cells (804 to 886 valves) were 

 counted at random and identified to species. The following were 

 used as the main taxonomic and autecological references for the 

 diatoms: Krammer and Lange-Bertalot 1986, 1988, 1991a, 1991b; 

 Patrick and Reimer 1966, 1975., 



Lowe (1974) was also used as an ecological reference for the 

 diatoms. Bahls et al . (1984) provide autecological information 

 on important diatom species that live in the Southern Fort Union 

 Coal Region of Montana, including many of the diatom species in 

 Squirrel Creek. 



