differences in sediment texture may account for faunal differences at 150 and 

 2,100 m, at 550 m the current regime may be more important than sediment 

 texture. 



At 550 m, the sediment texture was similar at both the canyon and slope 

 station, but there is evidence that currents may cause much sediment 

 resuspension (presentation by Butman). 



There appear to be differences in epifauna on the slope and in the canyon 

 at 550 m (presentation by Hecker). The red crab {Geryon quinquidens) is 

 common on the slope and may cause greater predation pressure on the infaunal 

 communities there. 



RECOLONIZATION 



Rates of recolonization were investigated using two designs of a free- 

 vehicle sediment tray, which were used to expose defaunated sediments at 

 2,100 m. The sediment was frozen and thawed to kill all living organisms 

 before being used in the trays. Based on field data, results from both 

 designs were found to be comparable. 



Sediment trays were placed at three stations at 2,100 m on the slope. 

 Two were on the slope near Lydonia Canyon and one was several kilometers to 

 the west. Trays near the Lydonia Canyon stations were exposed for 7 months, 

 and those at the third station for 14 months. Average density at the 7-month 

 stations was 35 individuals/m^. At the 14-month station, after twice as long 

 an exposure, density was about 12 times as great: 416 individuals/m^. 

 However, this still was far lower than the normal density of about 4,000 

 individuals/m^. From these results, it is likely that deep-sea benthic 

 communities would take years to recover from a catastrophic impact. 



72 - 



