The Polychaete Dance
A polychaete worm 'dances' through the water column during a dive to explore an unnamed forearc ridge. Video courtesy of the NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas. Download (mp4, 65.4 MB)
Dive 11 was conducted along an unnamed forearc ridge. This feature was initially believed to be a potential mud volcano, but overnight multibeam mapping revealed it was not. Remotely operated vehicle Deep Discoverer (D2) transited up a steep wall of highly pale-brown to pale-gray rock. The slope was punctuated with a series of ridges 10 to 20 meters wide, with narrower channels between them. The face of the wall was cut by numerous thin white veins snaking across the exposed surface at a variety of angles. As D2 traversed, a patch of pale-gray rock of clay-like consistency draped with talus was observed, as well as outcropping sequences of finely to coarsely layered dark-brown material. There were also sheets of variable thicknesses of blue-gray and yellow-tan sequences containing rocks of varying sizes. The ridge was intermittently covered with talus and/or finer unconsolidated sediment, and the top of the ridge showed thin sediment. Among the few fauna observed on this dive were squat lobsters, stalked and unstalked crinoids, and hexactinellid and demosponge sponges.