stations were clustered between +4 to +7. This bimodality was also 

 present in the August 1985 survey, and the OSI values were not 

 significantly different between these two surveys. Direct station 

 comparisons show, however, that station Center in 1985 had an OSI of 

 +11. This dropped to -1 in this survey (Figure 3-70) due to surface 

 erosion at the mound apex (Figure 3-65) . Surface erosion at NH74 

 station Center was estimated to have been approximately 3.55 cm from 

 1985 and 1986 by comparison of mean RPD's at the apex of the mound. 



3.3.8 New Haven 83 (NH-83) Mound 



The major modal grain-size of the New Haven 83 mound fell 

 within the silt-clay fraction (> 4 phi) . Several stations showed the 

 presence of a subordinate sand mode in the upper surface layers (very 

 fine sand, fine sand and medium sand; Figure 3-71) . Disposed material 

 was found at all stations except 60 ON, 40 OS, and 600E; at most 

 stations, it exceeded the camera prism penetration depth. 



In the August 1985 survey, 60% of the station replicates 

 showed the presence of reduced sediment at the surface. This was 

 attributed to the intensive foraging activity of large epifaunal 

 organisms. Five stations in the present survey showed the presence 

 of reduced sediment at or near the sediment-water interface (Figure 

 3-71) . However, this reduced sediment occured on a much smaller scale 

 compared with the August 1985 results and was probably related to 

 infaunal bioturbation activity rather than epifaunal foraging. 



The major mode of small-scale boundary roughness fell within 

 the 0.8 cm class interval (Figure 3-72; sample mean = 1.09 ± 0.78 

 cm.). These values were significantly greater than those measured in 

 August 1985 (p < 0.05, Mann-Whitney U-test) . The increase in small- 

 scale boundary roughness was potentially related to the physical 

 disturbance of the area as a result of Hurricane Gloria. 



The mean apparent RPD depth frequency distribution (Figure 

 3-72) showed that most values fell within the 2 to 3 cm class 

 intervals, with an overall mean value of 2.63 ± 0.98 cm. These did 

 not differ significantly from RPD measurements in August 1985 (p = 

 0.5512) , but they were significantly lower than values at the new CLIS 

 reference station (p < 0.01, Mann-Whitney U-test). Given the 

 normally-expected sequence of infaunal colonization and increased 

 bioturbation, it would seem likely that the RPD depth (which is 

 comparatively shallow) should increase in this area. The lack of a 

 significant increase in RPD depth at the NH-83 mound between August 

 1985 and July 1986 may indicate that infaunal colonization is not 

 proceeding at a normal rate. However, it should be noted that erosion 

 of surface layers (approximately the top 2-3 cm) associated with 

 Hurricane Gloria probably caused the RPD to become more shallow 

 between the two surveys (SAIC, 1989a) . This would also explain the 

 observed results. The areal distribution of RPD values showed no 

 clear spatial trends (Figure 3-73) . Station Center had a 



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