Océano Profundo 2018: Exploring Deep-Sea Habitats off Puerto Rico and the U.S. Virgin Islands

Holothurian Hill

by Chris Mah, Smithsonian Institution, National Museum of Natural History
November 7, 2018

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Video courtesy of the NOAA Office of Ocean Exploration and Research, Exploring Deep-sea Habitats off Puerto Rico and the U.S. Virgin Islands. Download larger version (mp4, 79.2 MB).

The swimming sea cucumber, Enypniastes eximia, sometimes referred to as the “headless chicken monster,” is a widespread species present in the abyss. It is encountered widely around the world with records from the Gulf of Mexico, Tropical Atlantic, East Atlantic, New Zealand, and the Southern Ocean (Antarctica). The scientific name Enypniastes was assigned to this animal in 1882 and means “dreamer;” it was taken from Genesis 37:19 of the Septuagint: "... Behold, that dreamer comes.”

These sea cucumbers are different from their more worm-like, shallow-water relatives in that they have a wing-like flange as well as a much more gelatinous body which allows them to take off and swim for short periods of time.

Swimming sea cucumbers like Enypniastes eximia have a special 'flap' which they use to lift' themselves off the seafloor. The transparent body reveals the sediment filled intestine looping around from the mouth (top) to the anus (bottom).

Swimming sea cucumbers like Enypniastes eximia have a special 'flap' which they use to 'lift' themselves off the seafloor. The transparent body reveals the sediment-filled intestine looping around from the mouth (top) to the anus (bottom). Image courtesy of the NOAA Office of Ocean Exploration and Research, Exploring Deep-sea Habitats off Puerto Rico and the U.S. Virgin Islands. Download image (jpg, 1.1 MB).

If you observe this species when they have landed, you will notice their oral tentacles voraciously shoveling sediment into their mouths. Enypniastes will digest all of the recently fallen marine snow, organic material which has fallen from the upper water column. Once the animal has become satisfied, or the food source is exhausted, it then proceeds to take off.

But before they do take off, they will “vent” the processed sediment behind them, leaving a cleaned sediment casting similar to what you might see from an earthworm. This is an important ecological process, as it clears and aerates the sediment, thereby making it available for other animals to work through. The transparent bodies of these sea cucumbers clearly reveal their sediment-filled intestines before and after they swim into the deep.

The oral tentacles of Enypniastes eximia are shown here picking up sediment before shoveling this food into its mouth.

The oral tentacles of Enypniastes eximia are shown here picking up sediment before the sea cucumber shovels this food into its mouth. Image courtesy of the NOAA Office of Ocean Exploration and Research, Exploring Deep-sea Habitats off Puerto Rico and the U.S. Virgin Islands. Download image (jpg, 1.3 MB).