Maciolek and Grassle Page 2 



Fewer faunal differences were evident at 2100 m, and these were not of 

 the same magnitude as those seen at shallower depths. The polychaete 

 Aurospio dibranchiata was the top dominant at both the canyon station 

 and two adjacent slope stations, where it accounted for 8 to 10% of the 

 total fauna. Of the next 19 dominant canyon species, 10 or 11 were 

 among the top dominants at the two slope stations, respectively. These 

 dominants often held similar ranks at the canyon and slope stations. 

 Unlike the situation at the shallower stations, diversity was higher at 

 the 2100-m canyon station than at either of the corresponding slope 

 stations. Sediment texture was similar at all three stations. 



Infaunal biomass was measured on up to 12 sampling dates at the 150-m 

 stations and on one sampling date at the 2100-m stations. At both 

 depths, the mean biomass, reported as ash-free dry weight (AFDW) , was 

 higher at the canyon station than at the slope station. Mean AFDW was 

 2.4 times higher at the 150-m canyon station and 2.0 times higher at 

 the 2100-m canyon station than at the corresponding slope stations. 



B-15 



