3-77), with a mean value of 3.20 cm ± 0.89 cm. These were not 

 significantly different from the new CLIS reference station. The 

 mapped distribution shows that biogenic mixing apparently has been 

 successful in "ventilating" the sediment following disposal, 

 with the exception of stations 600W and 200SE (Figure 3-78) . The 

 latter station had a thin layer of low reflectance sediment 

 overlying high reflectance sediment (Figure 3-79) . 



Half of the stations had Stage III seres present (Figure 

 3-80) . Stations which were in a low-order stage of succession 

 included station Center to 600E, station 200N, 200NW, and 200SW. 

 This was roughly the area which showed the thinnest apparent RPD 

 (i.e., biogenic mixing) depths (Figure 3-78). These results 

 suggest that the CLIS 86 mound was being colonized successfully, 

 with infaunal irrigation of the sediment helping to depress the 

 mean apparent RPD to a depth of over 3 cm at most of the stations 

 having Stage III organisms present. The data must be interpreted 

 with care; however, as past experience has shown that the 

 successional status of disposed materials during initial post- 

 disposal monitoring surveys is typically highly variable within a 

 station. These results are based on analysis of only one station 

 replicate. 



The frequency distribution of OSI values showed a range 

 of values from +4 to +11 with a major mode at +5 (Figure 3-77) . 

 This was not unexpected, given the recent disposal, early stages 

 of colonization, and the fact that some of the stations were 

 located on the ambient seafloor (Figure 3-81) . Stations located 

 on dredged material at this mound had a mean OSI value of 7.29 ± 

 2.64. These values were significantly different from the new CLIS 

 reference station (p = 0.0272, Mann-Whitney U-test) . 



3.4 REMOTS® Sediment-Profile Surveys at Ghost sites 1 and 2 



3.4.1 Ghost Site-1 (GHOST-1) 



The major modal grain-size at all stations was silt-clay 

 (> 4 phi) . Sand-over-mud stratigraphy was present at 4 stations 

 (Figure 3-82) . Direct physical evidence of disposed material 

 (e.g., a buried oxidized sedimentary horizon, chaotic sedimentary 

 fabrics, methanogenic sediments) was not apparent in any of the 

 photographs from this survey. 



The frequency distribution of small-scale boundary 

 roughness showed a major mode at 0.8 cm, with a mean value of 0.89 

 cm ± 0.51 cm (Figure 3-83). This topography was imparted by a 

 smooth yet undulating bottom surface. Biogenic features such as 

 tube structures, burrows, and fecal pellet layers dominated this 

 surface. In general, high boundary roughness may reflect disposal 

 surfaces which have been progressively smoothed by currents and 

 bioturbation. However, these data alone are not sufficient to 



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