26 



apparent RPD, evidence of mature macrofaunal assemblage, and no apparent methane). 

 OSI values are useful in mapping disturbances and quantifying ecosystem recovery 

 (Rhoads and Germano 1982). 



The replicate-averaged mean RPD depths ranged from 0.39 cm at SOW to 2.91 cm 

 at 150N (Figure 3-8). Conditions indicative of a low dissolved oxygen (DO) environment, 

 no discernible RPD, were displayed by one replicate from Station 50W (Figure 3-9 A). No 

 traces of methane gas were observed in any replicate over the H mound. 



As anticipated with a recent dredged material deposit, the successional stage 

 recolonization stams of the H mound was limited to Stage I pioneering polychaetes with 

 occasional evidence of Stage III individuals (Figure 3-10; Germano et al. 1994). Stage III 

 activity was noted in the subsurface sediments at Stations CTR, 50S, lOON, lOOE, lOOW, 

 and 150W (Figure 3-9B). Due to the presence of Stage III individuals, median OSI values 

 were elevated to 8.0 at lOOW, 7.0 at CTR and 50S, and 4.0 at lOON, lOOE, and 150W 

 (Figure 3-8). With the exception of 50W, deep RPD depths (>2.5 cm) in conjunction 

 with mature Stage I populations contributed to higher OSI values (5.0 to 6.5) at the 

 remaining REMOTS® camera stations. 



The shallower RPD depths and lower OSI values associated with Station 50W are 

 due to the presence of low DO conditions in one replicate and indeterminate RPD data in a 

 second replicate. One photograph of the three collected over 50W displayed a moderate 

 RPD depth of 0.78 cm, Stage I recolonization stams, and an OSI value of 3.0. The 

 environmental conditions displayed in this single replicate are acceptable for a two-month- 

 old dredged material deposit. 



3.2 WLIS G Mound 



3.2.1 Bathymetry 



The G mound was the product of moderate disposal activity at WLIS during the 

 1994-95 season. An estimated barge volume of 52,500 m^ of material was deposited in 

 close proximity to the WD A 94 buoy. The resulting mound of sediment is approximately 

 220 m wide, with a minimum depth of 32.0 m, and simated 180 m west of the F mound 

 center (Figure 3-11). The G mound appears to be slightly elongated along its north-south 

 axis. This irregular shape is likely due to the disposal pattern, as well as the effects of the 

 east-west trending trough and a subtle ridge projecting south from the base of the D 

 mound. 



Monitoring Cruise at the Western Long Island Sound Disposal Site, July 1996 



