A process map of the survey area shows the distribution 

 of features which are indicative of bottom disturbance (Figure 3- 

 8) . For example, many stations showed the presence of low 

 reflectance (black) sediment at, or near, the sediment surface. 

 This reduced sediment appears to have its origins from below the 

 high reflectance (ferric hydroxide) bioturbated zone as either a 

 layer or discrete mud clasts (Figures 3-7 and 3-9) . Oxidized mud 

 clasts were also present in many images. Surface patches of 

 reduced sediment (which were also observed in the August 1985 

 WLIS survey) were likely produced by predator excavation and/or 

 bottom scour. The depth of excavation or scour need not be great 

 to expose this reduced material to the interface because RPD 

 depths are shallow (< 2.0 cm) over much of the area. Methane gas 

 pockets were observed at depth in the sediment at station 3-D 

 (Figure 3-10) . The presence of methane is an indication of high 

 sediment oxygen demand (SOD) . Surface shell lag deposits, 

 produced by physical bottom scour, were observed in 5 images. In 

 general, evidence of small-scale physical and biogenic bottom 

 disturbance was widespread. This is similar to the pattern 

 observed during the post-"Gloria" REMOTS® survey in October 1985. 

 The relative frequency distributions of surface boundary 

 roughness values at the WLIS survey area and WLIS Reference are 

 shown in Figure 3-11. The major mode was 0.80 for both regions. 

 This represents an increase in small-scale surface roughness 

 since August 1985 when the major modal value was 0.4 cm. This 

 may reflect the impacts of Hurricane Gloria on the region. 



The mean apparent Redox Potential Discontinuity (RPD) 

 frequency distribution for the survey area (Figure 3-12) is 

 bimodal with modes centered at 1.0 cm and 3.0 cm. The mean RPD 

 depth was 2.16 cm. The WLIS Reference RPD distribution is skewed 

 right with the major mode at 1.0 cm, and a mean value of 0.59 cm. 

 RPD depths at WLIS Reference were significantly shallower than 

 RPD depths at the survey area (Mann-Whitney U-test, p < 0.001). 

 This pattern is noteworthy and suggests that the "disturbance" 

 factors affecting the WLIS Reference station were more severe 

 than the effects of the dredged material disposal operations 

 occurring within the WLIS survey area. At the WLIS survey area, 

 RPD depths have shallowed significantly since August 1985 (ANOVA, 

 p = 0.004); suggesting an increase in oxygen depletion in the 

 region. The mapped distribution of mean RPD depths is shown in 

 Figure 3-13. The hatched areas exhibited RPD values greater than 

 3 cm. In general, these areas were restricted to the edge of the 

 survey area. Most of the region was represented by RPD values 

 between 3 and 1 cm. Based on past experience, values less than 1 

 cm represent highly stressed habitats. The largest highly- 

 stressed area extended N-S through the area occupied by mounds 

 "A" and "C" ; this likely reflects the influence of recent 

 disposal operations. Another area of low values existed adjacent 

 to mound "B". 



