seafloor affected by the disposal operation was overlain by 
relatively thin dredged material layers (ranging from 0 to 10 cm 
in thickness; Figure 3-32). 
Most of the site consisted of silt-clay and very fine 
sand mixtures (>4-3 phi, Figure 3-31); in large part, this 
reflected the texture of the disposed materials. Beyond the 
disposal mound to the north and west, more coarse-grained sediment 
was evident (fine to medium sands). Cobbles were also present at 
several of these sandy stations. The boundary roughness values had 
not changed significantly since the November survey (compare Figure 
3-33 with Figure 3-27; Mann-Whitney U-test, p = 0.482). The 
disposal operations apparently did not alter small-scale 
topographic relief in the area. 
As expected, the RPD depths significantly decreased since 
the pre-disposal survey (Mann-Whitney U-test, p = 0.006, Figure 3- 
33) 0 Fifty-four percent of the RPD depths were less than 1 cm 
(Figures 3-34 and 3-35); the spatial distribution of these 
extremely shallow RPD's corresponded to the distribution of dredged 
material. Beyond the disposal mound, RPD depths were similar to 
those observed in November. Also, there was no evidence of the 
apparent bottom hypoxia or high sediment oxygen demand which was 
observed in the southern portion of the region in November. 
In contrast to the November results, Stage III seres were 
not evident in the central portion of the region (hatched area in 
Figure 3-36). This was a direct result of the disposal operations. 
Stage III infauna were evident on the flanks of the mound. The 
rapid re-establishment of high-order successional taxa on the 
flanks of the mound indicates that recolonization occurred through 
lateral or vertical migration of these infaunal organisms. Beyond 
the apparent influence of the disposal operation, both Stage II and 
Stage III seres were evident. This represents the pre-disposal 
successional status of the site. 
The central portion of the disposal mound exhibited low 
OSI values (Figure 3-37) due to the extremely shallow RPD depths 
and the low-order successional status. The least disturbed region 
occurred north of station 200N. In contrast to the November 
results (see Figures 3-27 and 3-30), there were no negative OSI 
values (Figures 3-33 and 3-37); this was because hypoxic conditions 
may no longer have been apparent at the site. The polymodal OSI 
frequency distribution (Figure 3-33) illustrates the three habitats 
present at the site. The modal value at +2 represents the central 
disposal region which exhibited extremely shallow RPD depths and 
lacked Stage III infauna; the mode at +6 reflects stations on the 
disposal mound flanks which exhibited shallow RPD's, but had been 
recolonized at depth by high-order successional infauna; and the 
mode at 10 represents the surrounding seafloor which was unaffected 
by the disposal operations. 
23 
