Sample Notes 



Hughes Creek below first FS gate. Clean sample, little sediment is present. 



Hughes Creek above Thunder Mountain Road. Sediment (-10 micron diameter fine 

 sand) is extremely heavy. 



Non-Diatom Algae (Table 3) 



The two sites on Hughes Creek supported very similar algal floras consisting of green 

 algae, cyanobacteria, diatoms, and a chrysophyte. The lower site supported three more genera of 

 non-diatom algae than the upper site. A downstream increase in the number of non-diatom algal 

 genera and diatom species is the normal pattern in mountain streams. 



The sample collected at the upper site on Hughes Creek (below first gate on FS parcel) 

 was dominated by a filamentous green alga (Ulothrix) and a branched cyanobacterium with 

 heterocysts {Tolypothn.x)(Ta.b\e 3). These cold-water algae are common in mountain streams. 

 Tolypothrix is capable of fixing atmospheric (molecular) nitrogen, which is an advantage in 

 waters that are poor in nitrogen. Diatoms were abundant at this site and ranked 3^'' in biovolume. 

 The chrysophyte Hydrurus foetidus ranked 4"^ and was rare. 



The sample collected at the lower site on Hughes Creek was also dominated by 

 Ulothrix. The cyanobacterium Nostoc ranked 2"*^ in biovolume here and was a co-dominant with 

 Ulothrix. Like Tolypothrix, Nostoc has heterocysts, is a nitrogen fixer, and prefers cold waters. 

 Diatoms were abundant and ranked 3"^ in biovolume at the lower site. Cells of the chrysophyte 

 Hydrurus foetidus, which forms slimy mucilaginous masses, were frequent and this genus ranked 

 4' in biovolume at this site. Wehr and Sheath (2003) describe Hydrurus foetidus as follows: 



One of the most dramatic examples of a cold-water stenotherm is the mountain-stream 

 dwelling chrysophyte Hydrurus foetidus. This macroscopic, brown, gelatinous, 

 unpleasant-smelling alga is relatively abundant in both the eastern and western mountain 



