July, relatively large areas along the margins of the entire New 
London Disposal Site were apparently hypoxic. Although the 
sediment was apparently reduced close to the sediment surface, the 
overlying water column in November could have contained high 
concentrations of dissolved oxygen. One may expect a time lag 
between re-aeration of the bottom waters and irrigation and 
aeration of the sediment column. North of this area, RPD depths 
were relatively well-developed. The frequency distribution of RPD 
values (Figure 3-27) illustrates this dichotomy in bottom oxygen 
levels. The bimodal distribution reflects the presence of both 
aerobic and hypoxic areas. 
Surface tube mats of Stage II fauna (the amphipod 
Ampelisca sp.) were evident across most of the survey grid (Figure 
3=28) 2 Along the southern, apparently hypoxic, region, the 
amphipod mats appeared to be in various stages of decomposition and 
erosion (Figure 3-29). Evidence of Stage III seres (head-down 
deposit feeders) was also widespread across the survey grid. Only 
three stations, two of which occurred along the southern transect, 
lacked evidence of high-order successional infauna (hatched region 
in Figure 3-28). Overall, the infaunal successional status of this 
area coincided with the pattern observed in July. Excluding the 
area which was apparently subject to severe oxygen stress, 
animal-sediment interactions at the site were generally 
well-developed. 
Negative OSI values were calculated for stations along 
the southern edge of the mapped area and reflected the apparent 
hypoxic conditions (Figure 3-30). The remainder of the site 
consisted of a wide range of index values indicative of a 
heterogeneous benthic environment. The OSI frequency distribution 
(Figure 3-27) further illustrates this diversity; OSI values ranged 
from -3 to +11. Overall, the OSI values observed at this small 
survey site in November reflected the OSI values observed across 
the entire New London Disposal Site in July. 
January 1986 Survey 
An immediate post-disposal REMOTS® survey of the NLON-85 
area characterized in November was performed on 24 January 1986. 
The main objective of this survey was to delimit the distribution 
of newly disposed dredged material (scow log estimate = 377,500 
m°’). The new disposal mound was designated "NL-85". 
The distribution and thickness of dredged material layers 
evident in the REMOTS® photographs (Figure 3-31) indicated that the 
disposal mound was offset to the southeast relative to the center 
of the disposal point. Dredged material extended to stations 500E, 
500S, 300N, and 300W. As observed in the post-disposal survey at 
the Field Verification Program (FVP) disposal mound at the Central 
Long Island Sound Disposal Site (CLIS), much of the area of 
22 
