significantly greater than those measured in the June 1985 survey (p 

 < 0.05, Mann-Whitney U-test) . 



Seasonal changes in the rates of biogenic reworking as well 

 as physically-induced surface erosional and depositional events can 

 result in changes in boundary roughness. At the FVP area, the 

 increase in boundary roughness values in October 1985 was physically- 

 induced, attributable to the influence of Hurricane Gloria. In the 

 present survey, the boundary roughness was attributed to increased 

 biological activity in the area; a higher rate of biogenic reworking 

 of surface sediments is normally expected during the warmer months of 

 the year. 



A layer of floccular material, interpreted to represent a 

 depositional layer of detritus associated with a decaying spring 

 plankton bloom was described in the March 1985 report. This layer 

 was not observed in any REMOTS® photographs from the present survey. 



Average RPD depths were 3.67 ± 0.90 cm at mound stations 

 and 4.06 ± 1.22 at the edge and ambient stations (Figures 3-21 and 

 3-22). The new CLIS reference station had a mean RPD depth of 3.39 

 ± 0.77 cm. The RPD depths at the edge and ambient stations were 

 significantly deeper than those at the mound stations and the new 

 CLIS reference station (p < 0.05, Mann-Whitney U-test). There was 

 no significant difference in RPD depths between the mound stations 

 and the new CLIS reference station (p = 0.0618, Mann-Whitney U-test). 



The trend toward shallower RPD depths, which began in March 

 1985 and was later exaggerated by the passage of Hurricane Gloria, 

 apparently has been reversed at the FVP mound. The average RPD depths 

 for the mound, edge and ambient and new CLIS reference stations were 

 significantly deeper than those recorded at these stations in both the 

 June and October 1985 REMOTS® surveys (p < 0.001, Mann-Whitney U- 

 test) . Following the hurricane, the October 1985 survey revealed that 

 stations near the center of the mound totally lacked oxidized surface 

 layers as a result of scouring; highly-reduced dredged material that 

 was formerly underlying aerated sediment was visible at the sediment- 

 water interface. Since that time, the average RPD depth has returned 

 to a level comparable to what it was before June 1985, when "stress" 

 or disturbance factors were first indicated (Figures 3-23a and b) . 



Relative to both the June and October 1985 surveys, the 

 number of stations from the FVP disposal area that showed Stage III 

 seres has increased dramatically (Figure 3-24) . For example, in 

 October 1985 only 28% of the photographs from the mound stations, 35% 

 of edge and ambient station photographs and 30% of the photographs 

 from the CLIS reference station exhibited Stage III assemblages. At 

 that time, these values represented a low point in a trend of 

 progressively decreasing presence of Stage III assemblages at these 

 stations during 1985. In the present survey, 66% of the mound station 

 replicates exhibited Stage III seres compared with 73% for the edge 

 and ambient stations and 90% for the new CLIS reference station. 



12 



