27 



< 1 cm deep, the stations cluster together, aligning in a NE-SW orientation over CLIS-90 

 and north of CS-90-1 (Figure 3-13). Based on the original sixty-six-station grid over the 

 active mounds, and the reference areas, the RPD values were significantly different between 

 the disposal site and the reference areas (Figure 3-14; Mann- Whitney U-test, p< 0.001). 



3.2.4.2 Inactive Mounds and Reference Areas 



All three reference areas had mean apparent RPD depths greater than 1 cm. Nineteen 

 out of thirty-nine stations had RPD depths greater than 3 cm (Figure 3-15). Inactive mounds 

 FVP and NHAV-74 had RPD values similar to 2500W-REF and 4500E-REF. At MQR, 

 eight stations located near the center of the MQR mound apex (100E, 100N, 100S, 100W, 

 200E, 200N, 200W, and CTR) had mean apparent RPD depths that were anomalously 

 shallow relative to the three reference areas. Inactive mounds CS-1, CLIS-88, and CLIS-89 

 had one station with RPD depth less than or equal to 1 cm, eight stations greater than 3 cm, 

 and thirty stations between 1 and 3 cm. 



3.2.5 Successional Stages 



3.2.5.1 Active Mounds 



Within the survey area, the only apparent successional stage pattern involving several 

 stations was the NE-SW orientation over CS-90-1 and CLIS-90, and stations clustered on the 

 eastern side of the survey, with only Stage I taxa (Figure 3-16). Isolated areas of azoic 

 (station E5), Stage I, and Stage II organisms occurred where dredged material was deposited 

 within the last two years (Germano et al. 1993). 



3.2.5.2 Inactive Mounds and Reference Areas 



All stations within the three CLIS reference areas contained Stage III infauna except 

 for 100W at the 2500W-REF area (Figure 3-17). On the inactive mounds, Stage IE fauna 

 predominated. Only Stage I fauna was present at CS-1 300E, and MQR 200N, 200S, and 

 200E. 



3.2.6 Organism-Sediment Index 



The multiparameter REMOTS® Organism-Sediment Index (OSI) characterizes habitat 

 disturbance. The parameters used to calculate the OSI values are the mean apparent RPD 

 depth, the presence of methane or the inferred absence of dissolved oxygen in surface 

 sediment pore waters, and the successional stage (SAIC 1989). Based on the results of past 

 REMOTS® surveys, OSI values < +6 indicate a recently or chronically stressed benthic 

 habitat (e.g., erosion, dredged material disposal, hypoxia, demersal foraging, etc.; Rhoads 

 and Germano 1986). 



Monitoring Cruise at the Central Long Island Sound Disposal Site, June 1991 



