Close-up view of the structure of one of the many glass sponges observed at Shostakovich Seamount. Image courtesy of the NOAA Office of Ocean Exploration and Research, Deep-Sea Symphony: Exploring the Musicians Seamounts. Download larger version (jpg, 789 KB).
The coral community at Shostakovich Seamount was different than the ones observed on other dives. Bamboo corals were the most abundant large coral species present, all of the colonies observed were roughly the same size. Our science team thinks that this could indicate that the colonies are all the same age and potentially from the same spawning event. Image courtesy of the NOAA Office of Ocean Exploration and Research, Deep-Sea Symphony: Exploring the Musicians Seamounts. Download larger version (jpg, 1.1 MB).
Rattail fish observed while exploring Shostakovich Seamount. Image courtesy of the NOAA Office of Ocean Exploration and Research, Deep-Sea Symphony: Exploring the Musicians Seamounts. Download larger version (jpg, 704 KB).

Dive 10: Shostakovich Seamount and Midwater Transects

September 16, 2017

Dive 10: Bamboozled

On September 16, while exploring Shostakovich Seamount at a depth of ~2,800 meters (9,190 feet), the team saw a dense community of huge bamboo coral, some of which were as wide and tall as the remotely operated vehicle. Based on the size of the corals, scientists estimate the corals could be hundreds of years old. This seamount is the oldest and most northern seamount to be surveyed during the expedition. Video courtesy of the NOAA Office of Ocean Exploration and Research, Deep-Sea Symphony: Exploring the Musicians Seamounts. Download (mp4, 37.7 MB)

Dive 10 at Shostakovich Seamount was northernmost point of our exploration of the Musicians Seamounts. While not as diverse as some of the other communities we have observed during this cruise, Dive 10 was still fascinating. As we scaled the slope of the seamount, remotely operated vehicle (ROV) Deep Discoverer encountered several large bamboo corals, all approximately the same size or taller than the ROV. The corals were sparely spaced out as we climbed the slope, but they were consistently present. Also observed were black corals, stoliniferous octocorals, and precious and bubblegum corals. At the summit of the feature was a high-density coral community composed primarily of the large bamboo corals and small chrysogorgids. This is our eleventh high-density community discovered during this cruise, a primary objective of this expedition. Several fish, including cusk eels, an arrow-tooth eel, a chaunax, rattails, and a codling, were also documented. At the end of the benthic portion of the dive, we completed a series of midwater transects at 100-meter intervals from 800 meters to 300 meters. During these transects, observations included a diversity of ctenophores, jellyfish, siphonophores, krill, doliolids, radiolarian, and several protists. The sweet spot for high biomass was between 700 and 600 meters, where we observed many arrow worms and an extreme abundance of bristlemouths (Cyclothone).