Phytoplankton Program Evaluation 



It has become increasingly apparent that power plant operation has 

 negligible impact on the phytoplankton community. Carpenter (1975) at 

 Millstone found that the higher discharge temperature depressed producti- 

 vity only during warmer periods which has been found in other studies 

 (Morgan and Stross 1969, Brook and Baker 1972, Tilly 1974, Briand 1975, 

 Kreh and Derwort 1976, Miller et al. 1976, Flemer and Sherk 1977, McKellar 

 1977) . Chlorination has the greatest impact on phytoplankton, but 

 during chlorination the predicted 5-10% decrease in productivity and 

 biomass in the effluent mixing zone at Millstone could not be detected 

 (Carpenter et al. 1974a). Phytoplankton studies at Cape Cod Canal and 

 Montaup Power Plants demonstrated that entrained phytoplankton populations, 

 similar to those at Millstone, recover with virtually no change in 

 species composition and density, once returned to the receiving waters 

 even with chlorination (Goldman and Quinby 1979). 



The phytoplankton community in the vicinity of Millstone is not 

 unique. The species composition and seasonality at Millstone are similar 

 to adjacent areas of Long Island Sound (Riley 1952, Nuzzi 1973, Smayda 

 1973, NUSCo 1976, Staker and Bruno 1978, LILCo 1981). Although differ- 

 ences in annual abundance have been detected (NUSCo 1981) , these are due 

 to natural population fluctuations and not associated with power plant 

 impact. These density differences appear to be regional and not localized 

 (LILCo 1982). 



We have adequately documented the phytoplankton community in the 

 vicinity of Millstone over an extended period of time. Studies at 

 Millstone and other sites have demonstrated that entrainment impact is 

 minimal on the local phytoplankton community. . At the consensus of NUSCo 



