Today’s dive further demonstrated the importance of collecting high-resolution mapping data prior to a remotely operated vehicle (ROV) dive, as the data collected last night revealed only flat seafloor in the original planned location for the dive. Because of this, the dive site was moved to an area in the Cape Fear Lophelia Banks Deepwater Marine Protected Area. This new site yielded a very exciting and very fishy dive.

This goneasterid sea star was imaged during Dive 10 of the Windows to the Deep 2018 expedition and might be a new species or a range extension, as it had not been documented in this region before. Image courtesy of the NOAA Office of Ocean Exploration and Research, Windows to the Deep 2018. Download larger version (jpg, 1.1 MB).

The ROV Deep Discoverer was on the seafloor from 13:11:13 - 20:13:56 UTC. The ROV dive began at 447 meters (about 1,467 feet) and ascended a low-slope ridge (5 - 10 degree slope) on the mound’s northwestern flank. The ROV then climbed a 15-degree slope to the peak at a depth of 370 meters (1,214 feet). The seascape traversed included a lot of standing, but dead, Lophelia pertusa, in what was once probably a live standing coral thicket. This suggested a potential shift in the conditions in the 'not-so-distant' past resulting in the death of much of this community, as evidenced by the still largely intact structure of dead corals in the area observed. Further investigation is needed over this feature as well as into the recent oceanographic conditions and any changes to better understand how this habitat has come to its current state of being.

Different from our last several dives, today the scientists observed a lower diversity and density of cnidarians. Observations were primarily of small colonies of Lophelia pertusa and some cup corals and a large number of anemones towards the end of the dive. However, the standout observation today was the high diversity of fish. Some of the species included several large wreckfish, redeye gapers, rat tails, conger eels, black belly rose fish, coral hakes, and two types of sharks including a chain dogfish and a cat shark. The chain dogfish had very effective disruptive camouflage in the dim natural light at this depth. This is one of the few species of sharks that can 'breathe' while sitting motionless, instead of needing to continuously swim. Additionally, a Chaunax anglerfish was seen during this dive. This anglerfish is a classic ambush predator. Its lure is chemical and is embedded in a pit on the forehead – not extended as a visual lure would be.

Other organisms imaged during the dive included squid, anemones, spider crab, brittle stars, and a goneasterid sea star not seen in this region before. The scientists collected a geological and biological sample of coral in the region for further analysis. The team was surprised to find low abundances of Lophelia at the top of the mound; instead, the area was densely populated with orange anemones, living on the dead coral skeletal framework. Stay tuned for the dive summary for more information on the samples collected and initial observations. Tune in tomorrow for the 11th dive of the expedition at Pamlico Canyon.