Dive 17: Rapano Ridge and Midwater Transects
September 23, 2017
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Dive 17: Yum Yum Yum

Today’s dive at Rapano Ridge revealed yet another high-density deep-sea coral community and a close up of a sea star dining on a Nurella and i's polyps. Video courtesy of the NOAA Office of Ocean Exploration and Research, Deep-Sea Symphony: Exploring the Musicians Seamounts. Download (mp4, 12.6 MB)

Today’s dive at Rapano Ridge revealed yet another high-density deep-sea coral community! Dive 17 began on a sedimented plain covered by a gravelly surface composed of uniform sized manganese-encrusted cobbles with a few sponge and small coral colonies. As remotely operated vehicle Deep Discoverer (D2) moved upslope, we encountered more corals, glass sponges, sea stars and brittle stars, crinoids, several fish including a cusk eel, and a very pink squat lobster that may belong to a new genus. Upslope, geological observations include large boulders, intact pillow flow outcrops with talus in between, and a blocky columnar basalt outcrop that persisted for quite some time along slope. As the slope flattened out, we observed larger corals and sponges, sea stars, and primnoid corals, along with intact flow units, talus, and sediment. As D2 reached the broad summit ridge, we observed mostly talus and smaller corals, although larger corals were observed to either side of the ridgeline. Sample collections included two pieces of angular talus rock, an unknown Euplectellidae “frilly vase” sponge, a piece from a large coral (Acanthogorgia sp.), and an unusual, wavy primnoid with large disorganized branches. After the benthic portion of the dive, the team conducted midwater transects at varying depths. Highlights included included multiple ctenophores, siphonophores, jellyfish, a fangtooth fish (Anoplogaster sp.), and a piglet squid (Helicocranchia sp.).