south. The overall grain size distribution generally corresponds 

 to that mapped at this site in a combined side-scan and REMOTS® 

 survey in 1981 (Germano et al. , 1989) . Further physical 

 oceanographic studies of sediment transport within the BBDS are 

 recommended to determine if off-site transport of disposed material 

 may be a problem. 



The topographic apex of the central mound was a small (60 

 m wide) feature with flank deposits located south of the mound. 

 Dredged material deposits extended to 200 m east and 100 m west of 

 the mound apex. 



The thin nature of the mean apparent RPD depths on the 

 mound apex and at stations 2, 3, and 16 probably were related to 

 natural disturbance in this area (sediment transport as manifested 

 by rippled sands) . Deep bioturbators (Stage III taxa) were not 

 observed in areas north and west of the grid center. Depth of the 

 RPD is controlled largely by the depth of bioturbation, and the 

 absence of Stage III seres in these areas supports this inference. 



The distribution of Stage I seres around the disposal 

 site center and to the northwest apparently was related to the 

 disturbance of the bottom by dredged material and/or bedload 

 transport of sand. The balance of stations showed within-station 

 patchiness, with some replicates showing the presence of Stage III 

 seres and others only Stage I seres. The photographs from all 3 

 reference areas contained evidence of Stage III infauna. These 

 results are similar to those found in the 1981 survey; the "Rubble 

 Field" was populated by Stage I organisms, and the "Wave Field", to 

 the south and east of the disposal site center, was populated by 

 Stage I, I-II, and III infauna (Figure 1-1; Germano et al. . 1989). 



The overall distribution of Organism-Sediment Indices 

 shows that all reference areas represented undisturbed benthic 

 habitats with mature successional assemblages. Areas where OSI 

 values were <+6 were concentrated on the mound apex with the 

 exception of stations 11 and 34. OSI values were not calculated 

 for stations in the 1981 survey, so a comparison cannot be made for 

 this parameter. 



This REMOTS® data set showed significant statistical 

 differences in the distributions of mean apparent RPD depths, 

 successional stages, and OSI values between the disposal site and 

 the three reference areas. This data set should allow for 

 detection of change in future surveys for both reference and 

 disposal site stations. 



4.3 Benthic Communities 



The species composition found in this study was similar 

 to that of benthic communities in Cape Cod Bay (Battelle, 1987) and 

 Boston Harbor/ Massachusetts Bay (Blake et al. , 1987, 1989). 



10 



