abundance. First, at JC, and particularly at WP, 

 there was an mcrease in sediment grain size start- 

 ing in June 1985, and continuing through March 

 1987. Since no corresponding increase occurred 

 at GN, this change was not attributable to a re- 

 gional climatic event. Neither was it likely to be 

 power plant-related because the change was evi- 

 dent before operation of Unit 3. Increased grain 

 size at WP was accompanied by a reduction in 

 oligochaetes, although few other taxa seemed af- 

 fected. Lower oligochaete abundances in 1986 

 may have been a response to reduced food avail- 

 ability given the increased grain size. At .IC, al- 

 though sediment size increased, levels of silt/clay 

 content were witliin the historical range and no 

 changes in macrofaunal communities could be 

 attributed to the observed changes in sediment 

 characteristics. 



The second event that occurred during this 

 study was the passage of Hurricane Gloria (Sep- 

 tember 1985). This storm passed within 72 km 

 of the Millstone sampling area, producing winds 

 nearing 161 km/h. Following the storm, lower 

 abundances and species number were observed 

 (December 1985 and March 1986) at all monitor- 

 ing stations. This contrasts however, with other 

 studies reporting surprisingly minor effects on 

 interidal communities after hurricanes (Croker 

 1968; Saloman and Naughton 1977). Studies in 

 the Millstone area (Dobbs and Vozarik 1983) 

 identified only minor rearrangements in commu- 

 nity dominance patterns in the shallow subtidal 



area adjacent to our JC intertidal station associated 

 with the passage of Hurricane David. 



Conclusions 



Sampling of intertidal communities during 

 1986-87 revealed no immediate changes to these 

 communities which could be directly attributed 

 to Unit 3 start-up or to 3-unit operations at 

 MNPS. Spatial distribution and abundance pat- 

 terns of dominant species at the intertidal stations 

 were consistent with those observed during base- 

 line studies. Major temporal shifts observed over 

 1986-87 appeared to be mediated by natural shifts 

 in grain size and passage of Hurricane Gloria. 

 Given the limited 3-unit operational history, ad- 

 ditional data will be needed before subtle impacts 

 (like those due to plant-related temperature in- 

 creases) can be assessed. 



Benthic Infauna 



85 



