Date: September 4, 2019
Location: Lat: 40.39768°, Lon: -68.13232°
Dive Depth Range: 538 - 600 meters (1,766 - 1,970 feet)
Today’s dive explored Oceanographer Canyon, the largest submarine canyon within the Northeast Canyons and Seamounts Marine National Monument and one of the largest off the Northeast U.S. coast. Previous dives within Oceanographer Canyon have documented dense deep-sea coral and sponge communities. This dive explored an area inside the canyon which had not been previously surveyed, and which was predicted to contain highly suitable habitat for deep-sea corals.
The substrate explored during the dive consisted mostly of hemipelagic drape, sand, cobbles and boulders. The current was relatively strong throughout the entire dive, which hindered remotely operated vehicle (ROV) positioning and made for poor visibility. Striped shrimp, monkfish, and shortfin squid were all observed. The area was notable for an abundance of hard substrate, but a scarcity of live deep-sea coral colonies. Dead or dying coral colonies were observed in the canyon axis and the lower walls of the canyon. Intact primnoid corals and encrusting demosponges were observed approximately 50 meters (164 feet) off the floor of the canyon. One sample was collected during the dive, a consolidated clay from a distinctively pyramid-shaped structure. These structures appear to have been formed from a partially dewatered clay layer eroded by canyon currents and debris flows.