R ESULTS AND DISCUSSION 



Taxonomic Composition of the Zooplankton Community 



More than 80 taxa of zooplankton were identified at MNPS in 1983, 

 and more than 130 taxa have been identified since the zooplankton 

 program was initiated at MNPS in November 1970 (Appendix 1) . The 

 taxonomic composition of zooplankton collected at MNPS (Tables 1 and 2) 

 was consistent with other studies in Long Island and Block Island Sounds 

 (BIS) (Deevey 1952, 1956; LILCO 1983) and other North Atlantic coastal 

 areas (Jeffries and Johnson 1973; Hulsizer 1976; Turner 1982). 



Six major taxonomic groups contributed more than 99% to the 

 zooplankton collected in 1983, copepods (88.7%), cirripedians (5.4%), 

 gastropods (3.2%), decapods (1.2%), cladocerans (0.7%) and araphipods 

 (0.5%). These six groups have comprised more than 96% of the 

 zooplankton collected since 1976 (Table 3) . 



Two distinct zooplankton communities were identified at Millstone 

 Point, and were identical to the winter-spring/summer-fall communities 

 described by Deevey (1952, 1956) for LIS and BIS. The copepods Acartia 

 hudsonica , Pseudocalanus minutus , Temora longicornis and planktonic 

 larval stages of snails (Gastropoda) and barnacles (Cirripedia) 

 dominated the winter-spring community. The summer-fall community was 

 dominated by the copepods Acartia tonsa and Pseudodlaptomus coronatus, 

 crab larvae and other decapods (NUSCo 1983). Because of the wide annual 

 range of water temperature found in the MNPS area, approximately 0-21°C, 

 few species of zooplankton occur throughout the year. 



Copepoda 



Copepods form the dominant zooplankton group in all the world's 

 oceans and are the Largest single group of protein producers (Thorson 

 1971). Copepods have constituted more than 79% of the zooplankton in 

 the MNPS area since 1976 and more than 88% in 1983 (Table 3). The 

 dominant calanoid copepods Included Acartia hudsonica , A. tonsa > 

 Centropages hamatus , Pseudocalanus minutus and Temora longicornis 



