Sample Notes 



Sullivan Creek above Connor Creek. This sample was sparse and the entire sample 

 was oxidized to make the diatom slides. The Phormidium sp. in this sample occurred as an 

 epiphyte on Hydrurus foetidus . Hannaea arcus was visually the dominant diatom in this sample. 



Sullivan Creek below Quintonkon Creek. This sample was heavier than the one 

 collected upstream. Hannaea arcus was the visual dominant among the diatoms in this sample. 



Skyland Creek above Bear Creek. This sample was poorly preserved and in the 

 process of decomposing. It was black and smelled strongly of hydrogen sulfide. The visually 

 dominant diatoms in this sample were Encyonema silesiacum and Hannaea arcus. 



Non-Diatom Algae (Table 3) 



Hydrurus foetidus ranked first in biovolume in samples from all three sites (Table 3). 



Nicholls and Wujek (2003) reviewed the biology of this common alga of mountain streams: 



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 

 streams of North America. The gelatinous envelope in which the cells are embedded is 

 exceedingly tough and the plant frequently covers the entire surface of submerged rocks 

 and has caused more than one hiker to lose his or her footing when crossing a stream. It 

 normally begins to disappear when water temperatures rise much above lO^C. . .Other 

 requirements for this species apparently include low pH and bright sunlight. 



Hydrurus foetidus often dominates the winter and spring algal communities of glacier- fed 

 streams of the Swiss Alps, which exhibit unstable channels and wide seasonal fluctuations in 

 flow, temperature, and turbidity (Hieber et al. 2001). Elsewhere, Kawecka (1990) reported that 

 Hydrurus foetidus (along with Ulothrix zonata) dominated the algal communities of unregulated 

 streams in a study of paired regulated and unregulated streams. 



Sullivan Creek above Connor Creek. Diatoms, which were abundant, ranked second to 

 Hydrurus foetidus in terms of total biomass, followed by the filamentous cyanobacterium 



