5.0 CONCLUSIONS 



The results of both the bathymetric and REMOTS surveys 

 at New London indicate an accumulation of dredged material well 

 within the disposal site boundaries in the immediate vicinity of 

 the buoy. The bathymetric results show that the mound formed as a 

 result of the past year's disposal activities was approximately 

 300 m in diameter centered about 60 m southeast of the buoy. The 

 REMOTS images show dredged material layers exceeding the prism 

 penetration depth both on the mound and extending approximately 

 200 m farther west, south, and southeast than indicated by the 

 bathymetric data. While some of this material was deposited in 

 the past year, it is likely that much of it was the result of 

 disposal prior to the July 1986 REMOTS survey. 



There was no depth change observed 530 m northwest of 

 the buoy on the southern flanks of the NL-RELIC mound, where some 

 dredged material was disposed due to miscommunications about the 

 precise disposal point. The apparently allocthonous sediments 

 seen in some REMOTS images from this location can not be 

 identified uneguivocally as dredged material due to the 

 heterogeneity in sediments at the site. It is hypothesized that 

 the amount of material indicated in scow logs to have been 

 disposed northwest of the buoy occurred in discontinuous, thin 

 layers which were difficult to detect by either bathymetry or 

 REMOTS . 



The widespread occurrence of Stage III taxa at New 

 London indicates that despite on-going disposal activities, 

 significant infaunal recolonization has occurred since the 1986 

 REMOTS survey. As in 1986, tubicolous amphipods continued to be a 

 major faunal component of the region. The high order successional 

 status and relatively deep RPD values present across the site 

 result in OSI values which were significantly greater than those 

 observed in July 1986. 



The relatively high OSI values in 1987 further suggest a 

 lack of stress which might otherwise be attributed to near-bottom 

 hypoxia in this region of the Sound. The absence of hypoxia was 

 confirmed by the results of the CTD/DO sampling, which show that 

 while the potential for transient hypoxic conditions exists, most 

 near-bottom waters at the site were aerobic (i.e., > 4 mg/1 DO) 

 and had higher DO concentrations than the reference stations at 

 the time of the survey. It is hypothesized that the observed 

 small-scale spatial and temporal variability in both DO 

 concentrations and the vertical distribution of salinity, 

 temperature, and density was due to the complex interplay of 

 tidal, riverine, and wind- induced water column mixing, which is 

 characteristic of an estuary such as Long Island Sound. 



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