part of any moni torinj^ program, and with time, will result in sufficient 

 data to distinguish natural from man-induced changes in the community. 

 This discussion will examine the spatial relationships among stations and 

 the temporal variations at all stations observed in 1983 that could be 

 related to power plant operation. 



TNTERTIDAL 



Spatial differences among potentially impacted and non-impacted stations 



The 1983 sampling program clearly identified the presence of two 

 different intertidal communities inhabiting beaches in the Millstone Point 

 area. The community at JC included higher numbers of species and 

 individuals than either WP or GN and was primarily dominated by 

 ollgochaetes. Other analyses, based on species composition and abundance, 

 i.e. species diversity, cumulative species curves, cluster analysis, 

 supported the distinction between these communities. 



Although the JC station is located in an area potentially influenced 

 by power plant operation, differences between this and other communities is 

 most likely reflective of the station-specific differences in the degree to 

 which the JC community is subjected to natural, wave-induced beach scour. 

 The influence of scour in dictating sedimentary characteristics and in 

 structuring intertidal communities has been well documented (Maurer and 

 Aprill 1979; Oliver et al. 1980; Knott et al. 1983). Sheltered intertidal 

 communities, like that of JC , would be expected to include higher numbers 

 of species and individuals, and would include smaller, less mobile forms. 

 In contrast, communities inhabiting exposed beaches would include few 

 species in lower numbers with the organisms well suited to burrowing within 

 and through a constantly shifting habitat (Croker 1977; Withers and Thorpe 

 1978; Dexter 1979). 



Since the JC station is a southeasterly facing beach, wave scour 

 generally occurs only in winter; during the remainder of the year, finer 

 sand and large amounts of eelgrass and algae accumulate on the beach. This 

 habitat provides ideal conditions for small deposit-feeding organisms such 

 as ollgochaetes (Caspers 1980; Soulsby et al. 1982), In contrast, the GN 

 and WP beaches are subject to more constant wave scour from the dominant 



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