sand component was detected at some stations, but it appeared to be 

 highly diluted with the silt-clay fraction in most instances. Station 

 Center had a very thin surface sand layer and showed indications of 

 recent erosion (Figure 3-65) . This mound was capped with sand in 

 1973, before routine monitoring which might have provided an estimate 

 of the original cap thickness. It is possible that the sand cap may 

 have been largely homogenized within the mound apex. This may be the 

 long-term result of sedimentation of fines and mixing of the sand with 

 underlying ambient sediment and dredged material as a result of 

 bioturbation. It is also guite possible that a portion of the sand 

 cap could have been removed by short-term sediment transport, 

 particularly as a result of Hurricane Gloria. It should be noted that 

 it at the time of the July 1986 survey, 13 years had elapsed since the 

 original disposal and capping event. It might be expected that the 

 "optical signature" of the cap as seen in the REMOTS® photographs 

 would be lost over this time period due to the processes mentioned 

 above . 



Apparent dredged material was observed at all stations 

 except 600S (Figure 3-66) . Disposed material may have been present 

 at this station at one time, but it could no longer be distinguished. 



The freguency distribution of small-scale boundary roughness 

 had a major mode at the 0.8 cm class interval (Figure 3-67; sample 

 mean = 0.72 ± 0.42). This compares with a major mode of 0.4 cm 

 measured in the August 1985 survey, although statistically the two 

 sets of values were not significantly different (p = 0.60). The 

 slightly higher boundary roughness values found during the present 

 survey were apparently produced by local physical or biogenic 

 disturbance of the sediment surface. 



The major modal apparent RPD depth fell within the 4 cm 

 class interval (Figure 3-67), with a sample mean of 3.41 cm ± 0.95 

 cm. Station Center had an anomalously thin RPD (0.79 cm) apparently 

 due to surface erosion at the mound apex as a result of Hurricane 

 Gloria (Figure 3-68) . In the August 1985 survey, station Center had 

 a deep RPD (4.34 cm), but measurements from the adjacent station 

 (200W) were very shallow (0.88 cm). RPD depths at NH-74 were not 

 significantly different from those measured in August 1985. 



Half of the stations surveyed appeared to be in a Stage I 

 sere and half in a Stage III sere (Figure 3-69) . More stations 

 appeared to be in a low-order successional stage than measured in 

 August 1985. Results from the 1985 survey (based on an analysis of 

 three replicates per station) showed four stations in a Stage I sere: 

 200E, 200W, 400W, and 200SE. The present results were based on the 

 analysis of only one replicate per station, so within-station 

 variability could not be evaluated. 



The distribution of OSI values was distinctly bimodal 

 (Figure 3-67) . Eight stations were in a high successional status 

 with relatively deep RPD values (0SI= 10 to 11) . The remaining 



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