between control and effected stations with five chlorophyll a and three 

 productivity replicates at a station. Based on the variability of the 

 chlorophyll a. samples it was determined that an average of 88 samples 

 per station would be necessary to detect a 5% change (Carpenter et al. 

 1974a). Field variability made it impractical to detect the small 

 differences expected due to entrainment. 



The remaining phytoplankton studies at Millstone were conducted to 

 determine the species composition and abundance of phytoplankton entrained 

 over an extended period of time. Normandeau Associates, Inc. collected 

 biweekly whole water samples for cell counts at Unit 1 Discharge from 

 July 1975 through December 1976 (NUSCo 1976, 1978). Phytoplankton cells 

 were identified and enumerated using Palmer -Maloney and Sedgwick-Raf ter 

 cells. NUSCo staff conducted the studies from January 1977 until its 

 termination in June 1982. Weekly whole water samples were collected at 

 Unit 1 and Unit 2 discharges on alternate weeks. Samples were processed 

 for chlorophyll a and cell counts (NUSCo 1978, 1979a, 1980, 1981). 

 Cells were enumerated with the Utermohl technique, similar to the earlier 

 Woods Hole Oceanographic Institution cell counts. The continuous series 

 of cell count data has well documented the species composition and 

 seasonality of the phytoplankton community in the Millstone area. 

 Microf lagellates and diatoms, are the dominant groups entrained (Table 

 1) , as was found in the early 1970' s (Carpenter 1975). Spring and 

 summer blooms have been apparent (Figure 2) , with diatoms (primarily 

 Skeletonema costatum ) and Phaeocystis spp. abundant in the spring bloom 

 and microf lagellates followed by diatoms abundant in the summer bloom. 

 Seasonality of chlorophyll a concentrations is closely related to total 

 phytoplankton abundance (Figure 2). 



