EXECUTIVE SUMMARY (continued) 



Historic dredged material disposal activity has led to a broad distribution of dredged 

 material over the western Long Island Sound seafloor. As a result, the detection of 

 dredged material within WLIS reference areas is possible, even though special care is 

 taken at their initial selection. In the past, reference areas EAST, WLIS-REF, and 2000S 

 in the vicinity of WLIS have been abandoned due to the presence of historic dredged 

 material. The results of the July 1996 REMOTS® survey over the current WLIS reference 

 areas suggest that the use of 2000W for comparison with WLIS disposal mounds should be 

 discontinued as well. The presence of dark, reduced sediments and methane gas bubbles 

 indicate the surface sediments are not representative of the ambient sediment, free from the 

 effects of anthropogenic activity. 



Seasonal hypoxia in the western Long Island Soimd region was identified as an 

 obstacle to benthic recolonization at WLIS as early as 1985. Hypoxia, a condition of low 

 dissolved oxygen (DO; <3.0 mg-l'^) in the water column, generally develops within the 

 bottom waters of western and central Long Island Sound in mid to late August. However, 

 the onset and severity of seasonal hypoxia are directly dependent on many other 

 enviroimiental factors (i.e., nutrient input, frequency of storms, rainfall, fresh water input, 

 water temperature, etc.). 



Upon review of the benthic community assessment data collected at WLIS since 

 1984, a trend of shallow RPD depths, indications of low DO, and poor benthic habitat can 

 be associated with mid-summer monitoring efforts. The results obtained during the July 

 1996 and other recent surveys (June 1991, July 1992) suggest the completion of benthic 

 community assessment operations in early summer, before the development of hypoxia and 

 the deterioration of conditions, yields a more realistic perspective into the year round 

 condition of the benthic environment. 



