EFFECTS OF POWER-PLANT OPERATION 

 ON THE PHYTOPLANKTON COMMUNITY 

 OF BELEWS LAKE, NORTH CAROLINA 



PETER H. CAMPBELL 



Department of Environmental Sciences and Engineering, 



University of North Carolina, Chapel Hill, North Carolina 



ABSTRACT 



The phytoplankton community of Belews Lake, North Carolina, a 1500-ha 

 cooling reservoir, was studied over a 4-year period. Two preoperational years 

 served as a base line for 2 years of operation by the Belews Creek Steam Station, 

 a 2200-MW coal-fired power plant. Circulation of surface waters by the power 

 plant resulted in greater seasonal and spatial homogeneity of total standing-crop 

 values and of distribution of dominant phytoplankton classes and taxa. No 

 major changes in standing crop were found, but general successional changes in 

 the phytoplankton community appeared to be accelerated after power-plant 

 operation. Chlorophyceae dominance, measured by cell density, and Dino- 

 phyceae dominance, measured by biovolume, increased, but Bacillariophyceae 

 dominance greatly decreased. Density and biovolume levels of all three classes 

 exhibited no marked changes. No negative thermal influence on phytoplankton 

 populations was found. No selection was observed for blue-green algae by the 

 elevated temperatures of the thermal plume. Mean total cell densities and 

 enrichment indexes exhibited steady decreases through all 4 years, and mean 

 total biovolumes, numbers of taxa, and Shannon— Weaver diversity indexes 

 exhibited steady increases. The values of these parameters all remained within 

 ranges indicative of an oligomesotrophic lake. 



Belews Lake was constructed by Duke Power Company as a cooling 

 reservoir for their coal-fired Belews Creek Steam Station. Creation of 

 the lake provided an opportunity to measure physical, chemical, and 

 biological properties of a newly formed impoundment, to follow it 

 through several years of natural development to obtain a base-line 

 evaluation, and to determine the effects of heated-water effluent on 



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