1 At the 150-meter depth in Lydonia Canyon, we had two canyon 



2 stations at 150 meters. One of them was sampled only four times because 



3 we realized we were actually on the wall of the canyon, and the 



4 sediments there were very highly variable. 



5 This photograph was taken in November, and this was the photograph 



6 taken in February. In general, though, the sediments at this station 



7 were very coarse and contained less than 1 percent silt-plus-clay. 



8 After the fourth sampling date the canyon station was relocated to 



9 an area of finer sediments, as seen in this slide, unfortunately we 



10 didn't pay much attention to the large crab in the picture, we were more 



11 interested in the animals you can't see under the sediment surface. 



12 This station had on the average about 30 percent silt-plus-clay. 



13 The station that was located on the slope outside the canyon had fine, 



14 sandy sediments with about 2 percent silt-plus-clay. 



15 The small objects on the sediment surface here are small onufid 

 15 [phonetic] polychaetes called Nothuria britanm'ca [phonetic] that were 



17 very common in photographs from this station on the slope during all the 



18 seasons that we took photographs. We didn't see this species in the 



19 canyon, 



20 We found that species composition at the three stations was 



21 somewhat different, especially so between the canyons, the coarse 



22 sediment canyon station and the fine sediment canyon station. 



23 At the coarse station, the dominant species was a polychaete 



24 called Lumbrineris latreilli, which accounted for 7 percent of the total 



25 fauna that we collected at that station. The rank of several of the 



26 subdominants at the station varied widely over the four seasons or the 



27 four sampling dates. 



28 Rather than this being a seasonal effect, we suspect it's because 



29 we really were sampling a different location and sediment type each time 



30 that we went back. 



31 At the station with finer sediments, which was sampled during 



32 eight seasons, the top dominant was the arthropod Ampelisca agassizi, 



33 which accounted for close to 12 percent of all the individuals at that 



119 



