Several large deepwater corals grow in a high-density community. Image courtesy of the NOAA Office of Ocean Exploration and Research, Deepwater Wonders of Wake. Download larger version (jpg, 1.7 MB).
We conducted Dive 10 on guyot rift zone ridge about 50 nautical miles south of Wake Atoll. The dive start and end points were a bit shallower than most of our previous guyot dives, being 1,500 meters and 1,400 meters, respectively, to specifically investigate this depth range on an otherwise similar feature to one we had already visited. Similar to previous dives in deeper waters, this dive featured mainly volcanic rocks, thickly coated in manganese (Mn), on the seafloor. The dive track led up the side of the ridge obliquely and along this track, the seafloor consisted mainly of massive deposits of Mn crust, likely well over an inch thick, blanketing what looked like pillow lavas. On rare locations, some of the underlying material was exposed under the Mn crust, through small broken down sections. The truly exciting thing about this dive was the discovery of an old, high-density, moderate-diversity community dominated by large Hemicorallium and primnoid colonies with smaller-sized colonies of Acanthogorgia. Amongst these corals were occasional colonies of bamboo and black corals. Finally, only a few species of fishes were observed that included halosaurs and rat tails.