of certain algae to pollution due to gas liquor and 

 organic chemical wastes from tar distilling . The 

 effluent from this industry included tar acids, cy- 

 anides, and ammonium. The totals, shown under 

 the different algal species identified, represent 

 average growth in numbers of plants per square 

 millimeter of slide, surface on slides submerged in 

 the River Trent (England) . Noteworthy here is the 

 striking build-up in numbers of Nitzschia palea 

 and Stiqeoclonium tenue throughout the polluted 



(polysaprobic) portion from 2 to 8 miles below the 

 source of pollution, and the great abundance at the 

 lower end of this region. Also significant is the 

 striking elimination of Cocconeis placentula from 

 the flora with the accession of the chemical wastes, 

 and the reappearance only after many miles of the 

 stream's course had permitted sufficient reduction 

 and oxidation of the wastes, dilution, and mixing 

 adequate to return the water to a condition once 

 more suitable for growth of the Cocconeis. 



References 



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Blum, J. L. 1957. An ecological study of the algae of the Saline River, Michigan. Hydrobiologia 

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