2021 North Atlantic Stepping Stones: New England and Corner Rise Seamounts

Dive 07: “Corner Rise 1” Seamount

Date: July 10, 2021
Location: Lat: 35.890163°, Lon: -51.523687°
Dive depth range: 2,422 - 2,594 meters (7,946 - 8,510 feet)

This tiny red jellyfish in the class Scyphozoa was seen just above the seafloor during exploration of “Corner Rise 1” Seamount on Dive 07 of the 2021 North Atlantic Stepping Stones expedition. Video courtesy of NOAA Ocean Exploration, 2021 North Atlantic Stepping Stones: New England and Corner Rise Seamounts. Download largest version (mp4, 48.1 MB).

This beautiful solitary hydroid in the family Corymorphidae was imaged at a depth of 2,563 meters (8,409 feet) during Dive 07 of the 2021 North Atlantic Stepping Stones expedition.

This beautiful solitary hydroid in the family Corymorphidae was imaged at a depth of 2,563 meters (8,409 feet) during Dive 07 of the 2021 North Atlantic Stepping Stones expedition. Watch a video of this hyrdoid. Image courtesy of NOAA Ocean Exploration, 2021 North Atlantic Stepping Stones: New England and Corner Rise Seamounts. Download largest version (jpg, 684 KB).

Overnight mapping of “Corner Rise 1” Seamount revealed a kidney bean-shaped guyot with steep flanks. During Dive 07, we had a fascinating dive from both the biological and geological perspectives as we explored the southeast end of this seamount.

Remotely operated vehicle Deep Discoverer landed on a smooth, sediment-free rock pavement interrupted in places by higher-relief outcrops of what appeared to be volcanic flow materials. Further upslope, we encountered an extremely steep rock wall that was approximately 100 meters (328 feet) tall. This wall was covered with abundant sponges and corals; fossilized cup corals (Desmophilum dianthus) covered many of the exposed surfaces. Other biological observations were sparse and spread out for most of the dive, with a low overall abundance. Sponges were relatively well represented and we also saw several urchins, a few fish, and our first octopod of the expedition (a dumbo!).

Black coral in the genus Bathypathes, shown in this image, was the most abundant coral seen during Dive 07 of the 2021 North Atlantic Stepping Stones expedition. It was observed almost from the beginning through to the end of the dive. Black corals have dark skeletons, hence their name, but when alive they appear white, pink, or other colors because of the living tissue that covers their skeletons.

Black coral in the genus Bathypathes, shown in this image, was the most abundant coral seen during Dive 07 of the 2021 North Atlantic Stepping Stones expedition. It was observed almost from the beginning through to the end of the dive. Black corals have dark skeletons, hence their name, but when alive they appear white, pink, or other colors because of the living tissue that covers their skeletons. Image courtesy of NOAA Ocean Exploration, 2021 North Atlantic Stepping Stones: New England and Corner Rise Seamounts. Download largest version (jpg, 1.3 MB).

A large outcrop of cup coral (Desmophyllum dianthus) fossils, covered in live sponges and bamboo corals, was seen during the seventh dive of the 2021 North Atlantic Stepping Stones expedition. A sample of the fossilized material was collected. Carbon-14 dating of the sample could be used to estimate the age of the coral skeletons.

A large outcrop of cup coral (Desmophyllum dianthus) fossils, covered in live sponges and bamboo corals, was seen during the seventh dive of the 2021 North Atlantic Stepping Stones expedition. A sample of the fossilized material was collected. Carbon-14 dating of the sample could be used to estimate the age of the coral skeletons. Image courtesy of NOAA Ocean Exploration, 2021 North Atlantic Stepping Stones: New England and Corner Rise Seamounts. Download largest version (jpg, 1.1 MB).

During Dive 07, we had our first octopod sighting of the 2021 North Atlantic Stepping Stones expedition. Scientists believe that this dumbo octopod is the rare species Cirrothauma magna. It was seen peacefully floating through the water column at a depth of 2,484 meters (8,150 feet).

During Dive 07, we had our first octopod sighting of the 2021 North Atlantic Stepping Stones expedition. Scientists believe that this dumbo octopod is the rare species Cirrothauma magna. It was seen peacefully floating through the water column at a depth of 2,484 meters (8,150 feet). Image courtesy of NOAA Ocean Exploration, 2021 North Atlantic Stepping Stones: New England and Corner Rise Seamounts. Download largest version (jpg, 735 KB).

Prior to reaching the steepest section of the seventh dive of the 2021 North Atlantic Stepping Stones expedition, remotely operated vehicle Deep Discoverer traversed a large, seemingly intact block of the flank of “Corner Rise 1” Seamount.

Prior to reaching the steepest section of the seventh dive of the 2021 North Atlantic Stepping Stones expedition, remotely operated vehicle Deep Discoverer traversed a large, seemingly intact block of the flank of “Corner Rise 1” Seamount. Image courtesy of NOAA Ocean Exploration, 2021 North Atlantic Stepping Stones: New England and Corner Rise Seamounts. Download largest version (jpg, 518 KB).

A brisingid sea star in the process of regrowing some of its arms and a white echinoid urchin seen at 2,586 meters (8,484 feet) depth during exploration of “Corner Rise 1” Seamount on the seventh dive of the 2021 North Atlantic Stepping Stones expedition. These urchins were observed throughout the dive, including one that was feeding on a bamboo coral.

A brisingid sea star in the process of regrowing some of its arms and a white echinoid urchin seen at 2,586 meters (8,484 feet) depth during exploration of “Corner Rise 1” Seamount on the seventh dive of the 2021 North Atlantic Stepping Stones expedition. These urchins were observed throughout the dive, including one that was feeding on a bamboo coral. Image courtesy of NOAA Ocean Exploration, 2021 North Atlantic Stepping Stones: New England and Corner Rise Seamounts. Download largest version (jpg, 1.2 MB).


Location of Dive 07 of the 2021 North Atlantic Stepping Stones expedition on July 10, 2021.

Location of Dive 07 of the 2021 North Atlantic Stepping Stones expedition on July 10, 2021. Map courtesy of NOAA Ocean Exploration, 2021 North Atlantic Stepping Stones: New England and Corner Rise Seamounts. Download largest version (jpg, 232 KB).

Image showing the dive track of Dive 07 of the 2021 North Atlantic Stepping Stones expedition. Scale is water depth in meters.

Image showing the dive track of Dive 07 of the 2021 North Atlantic Stepping Stones expedition. Scale is water depth in meters. Image courtesy of NOAA Ocean Exploration, 2021 North Atlantic Stepping Stones: New England and Corner Rise Seamounts. Download largest version (jpg, 1.6 MB).