54 



FVP mound during the September 1995 survey at CLIS. However, a full thirteen-station 

 REMOTS® sampling grid was occupied over the mound. Complete REMOTS® results for 

 the FVP disposal mound are available in Appendix B: Table 3. 



3.3.1 Sediment Grain Size and Stratigraphy 



Grain size and surface roughness data indicated no distinct pattern at the FVP 

 disposal mound. The major modal grain size at every station was >4 phi, except for one 

 replicate at 200W where the major mode was 4 to 3 phi. The replicate-averaged mean 

 camera penetration ranged from 12.73 to 15.69 cm (Appendix A: Table 3-4). Boundary 

 roughness values ranged from 0.52 cm to 1.33 cm. The primary cause of surface 

 disturbance was biogenic except at individual replicates at CTR and 200E where boundary 

 roughness was classified as physical in nature. 



Dredged material was present in all stations, except for the replicates at stations 

 300 m from the center. At stations where dredged material was present, replicate-averaged 

 thicknesses ranged from approximately 5 cm at 100W and 200N to full penetration (20 cm) 

 at several stations (Appendix A: Table 3-4). The apparent absence of dredged material 

 300 m from the center may be attributed to complete reworking of historical dredged 

 material, to the extent that there are no recognizable indicators commonly attributed to 

 dredged material. Redox rebound intervals were noted in one replicate at several stations 

 (100N, 100E, 200W). 



3.3.2 Benthic Community Assessment 



Replicate-averaged RPDs ranged from 0.77 cm at 100N to 2.84 cm at 200E (Figure 

 3-27; Appendix A: Table 3-4). This range is slightly higher than the average RPD depths 

 measured in the three reference areas. Methane was detected in two replicates at Station 

 100E, but indications of low dissolved oxygen within the bottom waters were not noted in 

 any photograph. 



The majority of the REMOTS® stations occupied over the FVP mound displayed 

 Stage III activity within the surface sediments. Only one station showed no evidence of 

 Stage III organisms (100N; Figure 3-28). Replicate median OSIs ranged from 2 at 100E 

 and 100N (low RPD, no Stage III, methane) to 8 at 300W (Figures 3-29A and 3-29B). 

 Several stations at FVP indicated, as at the CLIS reference areas, a decrease in benthic 

 habitat quality relative to prior monitoring surveys. 



Monitoring Cruise at the Central Long Island Sound Disposal Site, September 1995 



