however there is evidence that in quantity this alga may be functionally 

 significant, both in providing substrate and habitat for epiphytes and 

 micro-organisms, and as an energy source via the decomposer y 

 consumer pathway. For these reasons, any water management proposal 

 for the Yellowstone River should take into account the biology and 

 ecological requirements of this green alga. The information that 

 follows was extracted from an extensive review of the genus Cladophora 

 conducted by Whitton (15). 



Cladophora gl omerata appears to be the most abundant alga in 

 streams throughout the world. In temperate waters at this latitude it 

 has two annual growth peaks, the larger in summer (August) and the 

 smaller in soring (May). The temperature range for optimum growth 

 appears to be from 10°-24°C. C. glomerata is favored by high light 

 intensities. It is absent from quiet waters; the flow of water past 

 Cladophora appears to be required for efficient use of nutrients. Floods 

 may periodically remove the standing crop of Cladophora but they are 

 important in removing other algae from rocks to provide a bare substrate 

 for attachment by Cladophora zoospores. Cladophora is usually abundant 

 only in shallow, rapid water with a rocky substrate or exposed bedrock. 

 It is favored by hard or very hard water with a high pH. Growth responds 

 directly to nitrogen and phosphorous levels and is favored by high P/N 

 ratios. Cladophora supports a characteristic epiphytic flora most 

 frequently consisting of Chamaesiphon , Oedogonium , Diatoma , Cocconeis 

 and Rhoicoshpenia , all of which have been observed in the Yellowstone. 



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