58 



3.4 CLIS Reference Areas 



As part of the DAMOS tiered monitoring protocols, reference area data are 

 collected to provide a baseline against which results from the dredged material mounds are 

 compared. CLIS-REF has been a reference area for CLIS since the beginning of the 

 DAMOS Program. The two newer reference areas, 2500W and 4500E, have been 

 monitored since approximately 1987. A total of thirteen stations were occupied over the 

 three reference areas. Complete REMOTS® results for the CLIS reference areas (CLIS- 

 REF, 2500W, 4500E) are available in Appendix B: Table 4. 



3.4.1 Sediment Grain Size and Stratigraphy 



Physical indicators of the benthic environment include the grain size and boundary 

 roughness of the sediment surface. The major modal grain size was > 4 phi in all 

 reference station replicates. Replicate-averaged camera penetration ranged from 8.93 cm 

 to 13.68 cm (Appendix A: Table 3-5). Boundary roughness values ranged from 0.42 cm 

 to 1.23 cm and were determined to be caused by biogenic or unidentifiable processes. 

 Biological disturbance tends to be associated with a mature sediment deposit, whereas 

 physical disturbance is often associated with recent benthic impact. 



Dredged material was not identified in any photograph, and no redox rebound 

 intervals were identified. No station exhibited indications of methane or low dissolved 

 oxygen. 



3.4.2 Benthic Community Assessment 



Replicate-averaged RPD depths at all three reference areas ranged from 0.62 cm to 

 1 .60 cm (Appendix A: Table 3-5). This is a relatively low range of RPDs for CLIS 

 reference stations and was lower than the averaged values for all three dredged material 

 mounds sampled in 1995. In the past, reference area RPDs ranged from 0.55 cm to 

 2.7 cm during the July 1994 survey; 5.68 cm to 1.49 cm in June 1991; and 3.4 cm to 6.6 

 cm in July 1990 (Morris and Tufts 1997; Wiley and Charles 1995; Germano et al. 1995). 



The successional stage status at all reference stations was most commonly Stage I on 

 Stage III, indicating a mature benthic assemblage. Only one station exhibited no Stage III 

 community in any replicates (Station 3 at CLIS-REF). Stage II was identified in one 

 replicate at 4500E. Median OSIs at the reference areas generally ranged from 6 to 7, 

 except for a minimum OSI of 3 at CLIS-REF Station 3 (lack of Stage III) and a maximum 

 of 8 at 4500E Station 3. OSIs of 6 or less were present at four of five CLIS-REF stations, 



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



