Plankton 1970 - 1982 



Studies have been conducted since the early 1970' s to evaluate the 

 effects entrainment may have on local phytoplankton, zooplankton, and 

 ich thy op lank ton populations. 



The entrainment of phytoplankton represents the potential loss of 

 primary producers which are at the base of the marine food web. Phyto- 

 plankton studies have been conducted at Millstone since 1970; and have 

 included species composition or abundance and assessment of entrainment 

 impact on the phytoplankton community. Results indicate that the species 

 composition and abundance of entrained phytoplankton are similar to 

 adjacent areas of Long Island Sound. Chlorination was identified as the 

 most detrimental entrainment effect on primary productivity. Phytoplank- 

 ton studies at Millstone and other plant sites have demonstrated that 

 entrainment has minimal impact on the phytoplankton community. Based on 

 this information, phytoplankton studies were terminated as of June 1982. 



Zooplankton are an important food source for young and adult fish. 

 Entrainment loss of zooplankton could potentially affect the stability 

 of the food web and benthic communities. 



Entrainment studies (begun in 1970) have determined entrained 

 zooplankton species composition, abundance, and the effects entrainment 

 has on adjacent zooplankton communities. Review indicated that a recurring 

 annual pattern in species composition exists at Millstone. Additional 

 Unit 3 cooling water demand would not cause detectable changes in the 

 holozooplankton (primarily copepods) community due to its reproductive 

 capabilities and the small amount of local waters affected. Meroplankton 

 (developmental stages of benthic invertebrates) and tychoplankton (primarily 



