near-surface, reduced sediment patches were evident in 76% of the 

 CS-1 images and 82% of the CS-2 images. 



Compared to the 1984 survey, the Norwalk mound showed 

 evidence of continued recovery in 1985. Boundary roughness values 

 were lower, indicating "smoothing" due to currents and 

 bioturbation. Both RPD depths and the abundance of Stage III seres 

 had increased throughout the mound, except for the southern 

 transect. The low-order successional status of this southern 

 region may be related to its proximity to adjacent disposal mounds. 



The NH-74 mound did not change markedly between 1984 and 

 1985. The mound remains a patchy mosaic of Stage I and Stage III 

 seres. Some stations showed obvious retrograde conditions which 

 appear to be due to local erosion, while 53% show biogenic patches 

 of reduced sediment near the interface. Similar to NH-74, the NH- 

 83 mound exhibited a mosaic of Stage I and Stage III infaunal 

 assemblages. Since 1984, RPD values have gotten shallower at this 

 mound . 



As in 1984, the MQR mound in August 1985 appeared held 

 in a late Stage I condition. The abnormally slow recolonization 

 rate of this mound coupled with the continued presence of highly- 

 reduced, low-reflectance sediment immediately below the apparent 

 RPD boundary (typical of either freshly deposited dredged material 

 or anoxic sediment with high organic content) indicates a potential 

 for high sediment contaminant levels which could have been 

 responsible for precluding Stage III recolonization. Near-surface 

 patches of reduced sediment, widespread at other CLIS mounds, were 

 evident in only 9% of the MQR images; this was not surprising, 

 given the lack of head-down deposit feeding infauna present in the 

 area. The large-scale (>10 cm) vertical redistribution of 

 sediments at the other mounds was likely due to large, mobile 

 predatory taxa, e.g., decapods or stomatopods, which were 

 excavating burrows or preying on deep-dwelling Stage III infauna. 

 In the absence of these infauna, this large-scale biogenic 

 reworking activity would not take place. 



This megafaunal foraging activity apparently overturns 

 patches of relatively deep sediment layers (i.e., greater than 10 

 cm) . On disposal mounds, such burrowing activities may result in 

 the reintroduction of highly reduced (and potentially contaminated) 

 sediments to the sediment-water interface. This reintroduction may 

 also lead to a retrograde succession of the infaunal community. 

 This sequence of events appears to have occurred at the FVP site 

 in June 1985. Until that time, the FVP site had exhibited 

 progressively deepening RPD depths and increasing abundances of 

 Stage III infauna. In June 1985, this pattern was reversed, and 

 patches of reduced sediment were evident near the interface 

 throughout the site. This retrograde condition may represent a new 

 phase in the recolonization of a disposal mound. The pattern of 

 events at the MQR site suggests that, in the absence of 



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