ROV Deep Discoverer (D2) places a piece of an uknown Corallium species collected at 2,078 meters depth in one of the bio boxes on the ROV. Following collection, the boxes are sealed to keep specimens insulated for their return to the surface. Image courtesy of the NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana. Download larger version (jpg. 1.2 MB).
Dive 07 of the expedition was conducted on a sharp ridge extending to the south of Pioneer Bank to survey an unknown area below previous Pisces submersible dives on the ridge in order to determine the lower depth limit of known communities of corals and sponges. The dive started on a ridge crest at about 2,115 meters where the density of animals was immediately high from the start and included numerous bamboo corals, black corals, primnoid corals, and sponges. Unlike yesterday, the dominant bamboo corals were branched and there was an absence of Acanthogorgia, and the community somewhat differs from the community observed further upslope. Large fields of dead organic material that appeared to be barnacle plates were seen on several locations. As the ROV moved up the crest of the ridge, the density of animals increased and included numerous gorgonians, black corals, and sponges. The ROV left the bottom at a depth of 2,000 meters after the team determined that the dense community seen by the previous submersible dives further upslope extended at least six kilometers down the ridge to where today’s dive was conducted. This is clearly an important large, high-density community of corals and sponges.