Non-Diatom Algae (Table 4) 



Twenty-two genera representing five divisions of non-diatom algae were found in 

 samples that were collected from tributaries of Ninemile Creek (Table 4). Divisions represented 

 by the most genera were the Chlorophyta or green algae (13 genera) and the Cyanophyta or 

 cyanobacteria (6 genera). The Divisions Chrysophyta (yellow-green algae), Rhodophyta (red 

 algae), and Phaeophaeta (brown algae) were represented by one genus each. 



Cyanobacteria, mainly Nostoc and Oscillatoria, were found in all samples. Green algae 

 were found in all but 1 sample (Big Blue Creek). The yellow-green alga Tribonema was 

 common in 2 samples (lower McCormick and lower Josephine). The red alga Audouinella was 

 found only in lower Josephine Creek. Heribaudiclla fluviatilis, a rare freshwater brown alga 

 [most other species of brown algae are marine], was found only in upper McCormick Creek. 

 The number of genera of non-diatom algae ranged from 1 in Big Blue Creek to 1 3 in lower 

 Josephine Creek. 



Nitrogen-fixing Algae. Cyanobacteria that possess a certain type of specialized cell 

 (heterocyst) are capable of fixing molecular or atmospheric nitrogen under aerobic conditions. 

 These algae have a competitive advantage in waters where nitrogen is in short supply relative to 

 phosphorus and other nutrients. Among tributaries of Ninemile Creek, genera of blue-green 

 algae with heterocysts include Anabaena, Calothrix, Nostoc, and Tolypothrix. Collectively, 

 these algae were most abundant in McCormick Creek and Josephine Creek (Table 4). Nitrogen 

 is most likely the limiting nutrient in these streams. 



Mat-forming Filamentous Algae. Large standing crops of filamentous algae can 

 interfere with swimming, boating, fishing, and other water uses. Algal genera in tributaries of 

 Ninemile Creek that are known to produce nuisance growths in North American waters are 

 Oedogonium, Oscillatoria, Spirogyra, Ulothrix, and Zygnema (Wehr and Sheath 2003). One or 

 more of these genera were dominant or abundant only in lower Stony Creek, where the green 



