Dive 12: Kingman Deep
May 13, 2017
Access Dive Summary and ROV Data
Loading the player...

Dive 12: Poop, Prey, or Procreation?

During Dive 12, scientists observed several snails on crinoids. As this behavior had not been previously seen, it was unclear as to whether the snails were eating on waste from the crinoids, eating the crinoids themselves, or engaged in mating behavior. Video courtesy of the NOAA Office of Ocean Exploration and Research, Mountains in the Deep: Exploring the Central Pacific Basin. Download (mp4, 59.1 MB)

Today's dive at Kingman Deep took us to approximately 2,250 meters (7,380 feet). We enjoyed seeing some interesting animals in the water column on the descent, and highlights included some beautiful jellyfish, ctenophores, siphonophores, shrimp, and ray-finned fishes. When we arrived on bottom, the substrate composition was ferro-manganese (Fe-Mn) crusted volcanic rocks, with soft sediment in between. We observed chrysogorgiid corals with ophiuroids (brittle stars) wrapped in their branches. Different species of ophiuroids crawled along the seafloor, and we observed what may have been a Pteraster slime star, a sea pen, black coral, bamboo coral, brisingid sea star, and a carnivorous sponge.

As we headed upslope, we saw a stalked crinoid that – oddly, we thought – had a relatively large snail crawling on its underside. A close-up view showed the snail appeared to be feeding on the crinoid using a greatly extended proboscis. We encountered more sea pens, sponges, ophiuroids, brisingids, and bamboo coral and made first sightings of corallimorphs, holothurians (sea cucumbers), acorn worms, bryzoans, anemones, shrimp, squat lobsters, tunicates, urchins, a venus flytrap anemone, and cup corals. We came upon another stalked crinoid with a snail on its underside – then we found several more crinoids with snails. Some snails had their proboscis out and appeared to be feeding, others were laying eggs on the crinoids! We observed several bubblegum corals overgrown with yellow zoanthids and clung to by ophiuroids, and a pair of amphipods perched on a red stalked crinoid. Fish highlights included a rattail and a halosaur.

We conducted midwater transects on the way back to the surface at 1,500 meters (4,920 feet), 1,200 meters (3,935 feet), the oxygen minimum zone at 600 meters (1,970 feet), and the peak scattering layer at 300 meters (985 feet). We saw copepods, chaetognaths, jellyfish, shrimp, siphonophores, a dragonfish with a very long bioluminescent lure, and several hatchetfish. One unusual jellyfish had rigid protrusions that made it look like a carnival tent.