Close up image of a Hexactinellid or glass sponge, with commensal anemones growing throughout its tissues. Image courtesy of the NOAA Office of Ocean Exploration and Research, 2015 Hohonu Moana. Download larger version (jpg, 1.3 MB).
Dive 11 was conducted today on a modest ridge that extends north from the northern half of Bank 9 to explore for high-density communities of deep-sea corals and sponges along the ridge. The dive started at 2,147 meters, very close to the western drop-off of the ridge on a substrate of well defined, manganese-crusted pillows, which were covered with a low density of sponges and corals. As the ROV surveyed up the slope of the ridge, there were several patches that were dominated by sponges, others by stylasterid corals, and still others by bamboo corals. As we continued the survey, the ROV encountered an enormous, unidentified sponge that was over 3.5 meters long and 2.5 meters high. Towards the end of the dive, the ROV moved towards the east side of the ridge, where there was a marked increase in the density of corals and sponges close to the edge of the cliff. The ROV left the bottom at a depth of 2,100 meters after covering a linear distance of 650 meters.