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small numbers. Five taxa of green algae, including the pollution tolerant and ubiquitous • <br />species Scenedesmus quadri cauda, were also found. S n_y edra minuscula was the most abundant <br />of the 21 diatom taxa, accounting for 80.3 percent of the total periphyton at the upper <br />Sage Creek Station. The number of species was substantially lower in downstream samples, <br />which were dominated by various spe cies of Navicula. <br />Upper and lower Dry Creek locations (Sites D-1 and D-3) exhibited different periphyton <br />assemblages. In May, upper Dry Creek was dominated by 5 ny edra minuscula and lower Dry <br />Creek was dominated by Suri rella ap tells. Various species of Navicula accounted for 64.6 <br />percent of the total periphyton at lower Dry Creek in November. Navicula viridula and <br />S ny edra minuscula were important species common to both locations. <br />Hubberson Gulch (Site D-2) supported Suri rella ap tells (51.5 percent) and Fragilaria <br />vi re scens (32.1 percent) as the most ahunda nt species. The drainage immediately below <br />drill hole 220 as depicted rri thin the geology report of this permit to mine application <br />w•3s dominated by Me ri dion circulare (63.6 percent), a species which prefers flowing <br />w•3ter of less than 15°C. The dominance of this species on ly at this location was probably <br />due to the excellent temperature and f low conditions afforded by the constant cold water • <br />d~i scha rge of the well. <br />In summary, a great deal of variation was observed in the species composition of <br />poriphy ton assemblages. This was probably caused by the normal mosaic distribution of <br />po ri phyton species throughout the many microhabitats of the stream systems. Pollution <br />tolerant diatoms were the most important members of the periphyton at all locations. <br />Overall, Synedra minuscula, Navicula viridula, Navicula minima, Surirella atp ells, <br />Fragilaria vi re scens, and various other species of Navicula accounted for most of the <br />periphyton observed. <br />Although there were signficant differences in certain water quality parameters between <br />Sage Creek and Dry Creek, most of the important species occurred at some time in both <br />systems. <br />Benthos - Streams. A species list of benthic macroinvertebrates collected in the spring <br />and autumn from streams draining the Seneca II-W study area is presented as Table 11-29. <br />Tlris list represents a rather diverse assemblage of benthic fauna. • <br />26 <br />