1 structure between the canyon and the slope stations. These differences 



2 become very minimal at 2,100 meters. 



3 Now, there can be some speculation as to what's causing these 



4 differences and in some cases, for instance, at the 150-meter stations 



5 we think that there are very subtle effects due to differences in 

 5 sediment texture. 



7 Apparently if you have a station with at least a small percent of 



8 silt-plus-clay, you get the Ampelisca coming in and perhaps being 



9 dominant. The underlying differences at those stations may be related 



10 to some differences in sediment texture. It's not quite clear at that 



11 depth. 



12 At 550 meters, the sediment texture was very similar between the 



13 canyon station and the slope station and yet we saw some yery major 



14 differences in terms of the percent that the dominant species accounted 



15 for at each of the two stations. There were very dominants shared in 



16 common. 



17 We think that obviously rather than sediment playing a major role 



18 here, it perhaps could be the current regime at that depth in the 



19 canyon. Also, Barbara Hecker's results indicate some major differences 



20 in the epifauna at that particular depth. There are more Geryon on the 



21 slope, so there could be differences in predation pressure as well. 



22 At 2,100 meters. Brad, correct me if I'm wrong, I guess we don't 



23 know that much about subtle differences in the current regime. There 



24 don't appear to be differences between the canyon and the slope at that 



25 depth. The sediments are very similar, the communities are wery 



26 similar. 



27 That concludes the information on the infaunal community 



28 structure. I'd like to just give you some results of the recolonization 



29 analysis and I can answer questions on either of the two topics later 



30 on. 



31 Fred Grassle was responsible for recolonization experiments that 



32 were conducted both in our North Atlantic study region and the mid- 

 33 Atlantic study region. He had asked me to be sure to make two points in 

 34 particular today for him. 



125 



